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Cyclic vomiting syndrome: Contribution to dysphagic infant death
Medical Hypotheses 73 (2009) 473–478
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Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy
Cyclic vomiting syndrome: Contribution to dysphagic infant death D.G. Talbert * Institute of Reproductive and Developmental Biology, Imperial College School of Medicine, Du Cane Road, London W12 ONN, UK
a r t i c l e
i n f o
Article history: Received 31 May 2009 Accepted 4 June 2009
s u m m a r y Vomiting involves the simultaneous violent contraction of abdominal and diaphragm muscles to produce a high pressure on the stomach. The heart right atrium forms a through path from IVC to SVC, so the high intra-abdominal pressure will drive blood from abdominal contents into the head. Normally internal viscous drags in organs will limit the volume leaving them during a single vomiting event. However, repetitive vomiting such as occurs in cyclic vomiting syndrome (CVS) may drive sufficient blood into head veins to produce extreme venous hypertension. Dysphagic infant death is essentially a head vein hypertension malady, some features of which match those that are postulated for Shaken Baby Syndrome. CVS was described by Gee in 1882 but is still poorly understood. Recently a consensus statement has been released by the North American Society for Pediatric Gastroenterology Hepatology and Nutrition setting out key issues to be addressed. Understanding CVS may therefore have important implications beyond its gastroenterological aspects. A case demonstrating a sequence of features suggesting CVS and the effects of increasing abdominal muscle strength with age is presented. It showed (1) swallowing dysfunction, (2) grunting and apnoea (surfactant poisoning), (3) reflux, (4) diarrhoea, (5) apparently unprovoked prolonged screaming fits (migraine?), (6) petechiae (local capillary rupture), (7) skull growth abnormalities (hydrocephalus) and (8) unconscious ‘‘blank staring spells ” (from which the infant would auto-resuscitate). Repetitive vomiting may also sensitise the epiglottis thus increasing the risk of laryngospasm, and making attempts at intubation hazardous, possibly leading to hypoxic brain death. Ó 2009 Elsevier Ltd. All rights reserved.
Introduction Cyclic vomiting syndrome (CVS) was described by Gee in 1882 [1] but is still poorly understood [2]. Li et al. [3] describe it as noted for its unique intensity of vomiting, and repeated emergency department visits and hospitalisations. The frequency of vomiting often appears to fluctuate cyclically and may present hazards to health, or even life at its peaks. Vomiting involves the simultaneous violent contraction of abdominal and diaphragm muscles to produce a high pressure on the stomach to squeeze its contents up the oesophagus. The same pressure is applied to all organs below the diaphragm. The liver and spleen hold significant proportions of the total blood volume and during a vomit some will get squeezed out and up the inferior vena cava (IVC) into the sinus vasorum of the right heart atrium. The sinus vasorum also normally accepts blood returning from the head and arms and upper thorax via the superior vena cava (SVC). This constitutes a through venous path from liver etc. to head and arms during vomiting. So when the abdominal organs are squeezed by the abdominal pressure some of their blood is forced up into veins in the head, raising head venous pressure. Blood viscous drag within organs normally * Tel.: +44 020 7594 2142. E-mail address: [email protected] 0306-9877/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.mehy.2009.06.011
limits the proportion that can be lost to the head etc. during each vomit, but if ejection efforts are continuously repeated or are extended, blood will accumulate in head veins producing pressures high enough to damage them. This is well illustrated by a case reported by Kravitz of an otherwise healthy 20-year old female who experienced an evening of repetitive vomiting [4]. Coloured photographs show her face marked by petechiae (small blood blebs under the skin) where small veins or capillaries had burst under the excessive venous pressure. The petechiae then rapidly disappeared within a day or so. There are valves in the jugular veins draining the head but they are not considered very strong, and certainly in this young person provided no protection. Petechiae signify excessive venous pressure, resulting from blood being forced through the sinus vasorum [5] up the SVC. In the literature they are described as occurring on the forehead, eyelids, face, [6] neck and upper thorax [7], i.e. anywhere drained by the inner or outer jugular veins when central venous pressure becomes excessive. Bleeding in the eyes is known to result from excessive venous pressure occurring for a wide range of causes [8–11]. In infants, before the sutures between skull bone plates have hardened, this may be accompanied by subdural bleeding [12]. Recently a consensus statement has been released by the North American Society for Pediatric Gastroenterology Hepatology and Nutrition setting out key issues to be addressed, in the study of
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CVS [3]. This present article concentrates on hazards external to gastroenterology, but relating to the excessive intracranial venous pressures produced during repetitive or extended vomiting, which make this consensus statement highly relevant in the field of suspected Shaken Baby Syndrome. Hypothesis During the repetitive and violent vomiting that occurs in CVS, the excessive intra-cranial venous pressures resulting from sustained high intra-abdominal pressure may reproduce many of the symptoms of abusive head injury in infants, previously considered diagnostic of ‘Shaken Baby Syndrome’. In addition, repetitive vomiting may produce inflammation of the epiglottal and laryngeal surfaces. The resulting increased sensitivity may then be sufficient to trigger laryngeal constriction. If Emergency Services, unaware of this condition, attempt intubation [13,14], a hazard of severe hypoxia or anoxia exists.
quent significant episodes are shown below in the order of their appearance and timings, Fig. 1. Swallowing dysfunction The first indication of abnormality occurred while still in maternity hospital, when baby A. was given an injection of Hep. B vaccine, and a vitamin K supplement by mouth. She screamed abnormally for an hour, and when removed from the nursery because she was disturbing other neonates, and given to the mother, continued for a further twenty minutes. In view of later events it seems likely that the vitamin K solution had leaked through her epiglottis into the larynx, which is intensely sensitive to ‘‘foreign” materials. Thereafter she would vomit independently of type of feed, suggesting a mechanical cause rather than an allergy or undue sensitivity. The hazard here, in young infants, is reactive upper airway closure [13] which can be fatal. Grunting and apnoea
An illustrative case history The mother of infant A. kept a fairly continuous written and photographic record of the infant’s developmental progress. Apgar score [15] was good at birth and lung function was normal. Subse-
Around 2 weeks it was noticed that A. was grunting and having periods of apnoea. The mother sought medical advice and was told that this was normal and that A. would grow out of it. She accepted that explanation, but A did not grow out of it. ‘‘Grunting”
Fig. 1. The sequence of significant events in an infant suffering from frequent vomiting. The vertical axis on the left shows postnatal age in weeks. Numbers in circles identify the first occurrence of each event recognised by the parents.
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is technically referred to as ‘‘expiratory braking” [16]. It is associated with a lack of, or malfunctioning of, ‘‘surfactant” (surface active molecules) that opposes surface tension in the water lining the lungs [17]. Surface tension is the force that draws the fibres of a wet tissue together and makes it impossible to untangle it. Without surfactant in the film of water lining the minute gas exchange surfaces (alveoli) of lungs they would collapse like the wet tissue and become useless [18–20]. Sometimes there is a lack of sufficient surfactant in the lungs of newborn infants (Respiratory Distress Syndrome). To hold these alveoli open various designs of ventilators keep the air they breathe at a positive pressure. Infants learn to achieve a similar support by constricting their larynx (upper airway) during expiration so that a positive pressure is required to drive gas out, causing the grunting noise. The surfactant molecule has an oily end (two 16-carbon paraffin chains) and is highly polar at the other (choline) end. Thus it cannot sink into the water film because of the hydrophobic paraffin chains, or leave the film without dragging a ballast of water molecules bound to the polar end. These effects keep surfactant molecules locked in the water surface opposing the water’s own surface tension. Leakage of feed, reflux, etc. through the glottis into the lungs can loosen the bonding of water ballast to the polar end and undermine the efficiency of surfactant [17,21]. In a normal infant part of the swallowing action includes closing the epiglottis to make leakage impossible. Thus from the beginning A. showed some form of swallowing defect, ‘‘dysphagia” (dys meaning malfunction and phagia meaning feeding). Such infants may learn to avoid epiglottal leakage problems by only partially opening their throat (oesophagus) while swallowing, to allow liquids to travel down ‘‘gutters” which form on both sides of the throat [22]. Liquid feeds then avoid the epiglottis altogether. Later, when semisolids are introduced (weaning), the food has to pass over the epiglottis and choking reactions to leakage, and apnoea etc., may re-appear. The hazard here is bronchial disorders unresponsive to normal treatment, or widespread atelectasis (lung alveolar collapse) leading to hypoxic damage or death. Reflux In week 4 reflux was diagnosed. Leakage of highly acidic digestive juices could then occur at any time, i.e. not limited to feeding times. Reflux in infants is not normally considered a serious hazard [23] but repetitive vomiting forms a continual challenge to the glottal sealing mechanism. Normal reflux is basically leakage through the oesophageal sphincters, possibly driven by stomach peristalsis, but is not driven by contraction of powerful abdominal muscles. Curci and Dibbins [24] described gastroesophageal reflux in children as an ‘‘underrated disease” In a group of 41 patients presenting for operative correction of gastroesophageal reflux, 49% had pulmonary problems, 6 had recurrent pneumonia unresponsive to antibiotic, 8 suffered from apnea or ‘‘dying spells”, varying from choking with mild cyanotic changes to respiratory arrest requiring cardiopulmonary resuscitation. Six had a wheezing chronic cough, and ‘‘wet-congested breathing” attributed to asthma and bronchitis but unresponsive to common treatment regimens. They say that maturation of reflux control normally occurs about 5–7 weeks postnatally but is abnormal after 3 months. They concluded that ‘‘The pernicious aspects of this disease include a potentially significant mortality in children with severe apnoea episodes. . .” Also, around 4 weeks, a ‘‘rash” or ‘‘acne” and redness of face which disappeared within a day or so were observed for the first time. This was diagnosed as acne, but the rapid disappearance suggests petechiae produced by the excessive head vein pressure. Similarly redness could result from dilated blood vessels stretched during raised venous pressure episodes.
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Diarrhoea 8 weeks In week 8 she developed fever and diarrhoea. Thereafter diarrhoea became a feature of her metabolism continuing after she had recovered from the fever. Screaming fits 9 weeks In week 9 she developed screaming fits lasting over an hour for no apparent reason. Observers thought she seemed to appear in abdominal pain but could find no cause. One such fit occurred suddenly for no apparent stimulus, about 10 min after the photo in the figure was taken, where she was happy and laughing. Petechiae and swollen eye 12 weeks In week 12 a ‘‘rash” (petechiae) appeared again, and one eye was swollen, following vomiting. Again this cleared rapidly in about 24 h, similarly to the 25-yr old case [4]. At the time they were ascribed to acne or fungal infection, but the position and rapidity of disappearance are more consistent with petechiae formed by brief leakage of blood from over-pressurised skin surface veins and capillaries. The swollen eye also suggests an episode of venous hypertension. The lens of the eye is free to change shape (focus) because it has aqueous humor in front and behind. This is a watery medium secreted from the inner surface of the ciliary body, a ring structure behind the lens and iris [28]. The aqueous humor then flows forward between the lens and the iris, through the pupil and out through loose connective tissue along the scleral venous sinus (SVS) which surrounds the junction of the cornea and scleral parts of the eyeball. This sinus then drains into the vorticose veins and on through the ophthalmic veins into the skull. There are no valves along this path. The pressure within the eyeball being about 20 mmHg the ciliary bodies have to secrete at a higher pressure, to produce a gradient that normally ensures that the SVS contains aqueous humor but no blood. However, if venous pressure exceeds ocular pressure, the gradient is reversed and water is forced into the eyeball. Thus the swollen eye also suggests that excessive venous pressures have occurred. The hazard here is from failure of intra-cranial vessels under the excessive venous pressure, even if it is brief [25]. Visit to pediatrician 14 weeks At this visit the parents voiced concerns about the unexplained screaming fits, eating irregularities, and diarrhoea etc. Blank staring spells (Transient Oedema) 18 weeks This picture was taken while she was experiencing what the parents described as a” blank staring spell”. During these ‘‘spells” she was limp and completely unreactive, but as the photograph shows she was not cyanotic but of normal colour. She would stay in this condition for sometime, then ‘‘wake up” and return to normal activity. A form of cerebral oedema is known that results when excessive rise in brain venous pressure drives water through cerebral capillary and venule walls. It resolves after the venous pressure returns to normal; a ‘‘Transient Edema” [26]. It differs from classic oedema in that the solutes producing osmotic pressure do not cross the capillary wall blood-brain-barrier. Their concentrations, and hence the osmotic pressures they exert in the brain interstitial space, change with the resulting local dilution. This may result in the failure of neuron action potential production and/or conduction, and hence unconsciousness. During violent vomiting or coughing intra-abdominal pressures can reach 80– 100 mmHg, resulting in cerebral capillary and venous pressures
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of 50 mmHg or so [27]. Since the blood-brain-barrier is permeable to water, water will be selectively driven out of the vessels into the cerebral interstitium. When venous pressure returns to normal, water can return from the interstitium. However, since the pressure restoring water balance (interstitial to capillary lumen) is roughly one tenth of those during abdominal contractions, recovery will take roughly ten times as long. Normally vomiting contractions are brief and water movements are too small to affect neurological function, but if muscle contractions are extended or rapidly repeated, significant dilution of interstitial fluid may occur. The brain stem, in which the respiratory control centres are located, is not drained by the jugular veins but by the vertebral veins, whose complex paths will delay their venous hypertension. Moreover, the diaphragm descends as part of the vomiting action, assisting in increasing abdominal pressure, but reducing intrathoracic pressure in the process. Some of the excess blood will spill down into the spinal vertebral system, further delaying build up of venous pressure in the brain stem. This would make the respiratory centres less vulnerable than the cortex, and explain the continued respiration observed in this infant while unconscious. The hazard here arises from neurological damage if the ‘‘transient oedema” becomes excessive or lasts too long. Blood can be seen in the conjunctivae of both eyes. It was dismissed by a pediatrician as due to crying, but may have a more significant explanation. Moore and Dalley [28], describing subconjunctival haemorrhages, comment ‘‘The haemorrhages may result from injury or inflammation.....excessively hard blowing of the nose, and paroxysms of coughing or violent sneezing can cause haemorrhages resulting from rupture of small subconjunctival capillaries.” These are all conditions that, like violent vomiting, produce excessive intra-cranial venous pressure and suggest that A. recently had an episode of vomiting. Skull growth abnormalities; a form of hydrocephalus 19 weeks About 2 weeks before the final event onlookers commented on her enlarging head. This also could have resulted from the transient edema and/or excess cerebrospinal fluid (CSF) volume. CSF is produced principally by chorionic plexuses in the walls of the ventricles, particularly the lateral ventricles [29]. It passes back through the ventricles and back into the venous circulation via arachnoid villi into the dural sinuses. Increased venous pressure will both increase production of CSF and impede its out flow [29]. Excessive CSF volume induces external-hydrocephalus-like skull growth [30]. The infant head grows rapidly, under two different control systems. The face, jaw, rotating bearing on top of the spine (atlas) and the floor of the braincase on which the brain rests,
are all genetically pre-programmed. The cranium genetic program includes a mechanism that adjusts skull size to match brain size. In the early fetus the skull starts as a half ‘‘balloon” of membranous tissue attached around its lower edge to this structure. As the brain grows and the ‘‘balloon ‘‘gets tight, the stretch in this membrane stimulates it to grow until it fits again. Later, but still before birth, bone gets laid down on this membrane, spreading from regions known as ossification centres. Membrane overlaid by bone can no longer stretch, and so skull growth depends on growth of the membrane between the edges of new bony plates (sutures) [31]. It is important at this stage that the bone plates do not join up, if they do, local growth becomes impossible and the skull grows distorted. So, the rate and geometry of suture growth are regulated by ‘‘messages” from the membrane underlying the sutures (dura mater) sensing the stretch and its direction [32,31,33]. Thus the dura acts to maintain a gentle stretch in itself. If the adjacent skull grows too fast, so that local stretch disappears, the dura produces less incentive for local growth. If growth is too slow (the skull is too tight on the brain) the dura signals the suture membrane to increase growth rate. So the rate at which the skull grows normally matches brain growth [32], but if an accumulation of cerebrospinal fluid (CSF) occurs, or the brain swells due to transient edema, this dural mechanism increases skull volume to accommodate it (macrocephally) [30]. In this infant the frequent vomiting appears to have started to increase brain + CSF volume sufficiently to cause a form of hydrocephalus. From this infants developmental health records, at 17.6 weeks she was 24 inches long, her head circumference was 40.5 cm, and her weight was 13.8 pounds. At autopsy (19 weeks) she was 25 in. long, head circumference was 44.5 cm and she weighed 17 pounds Fig. 2. Her length at both assessments thus remained within normal growth limits for her age, but during the interval her head circumference had risen above the 98% centile. So, while her head circumference had increased by almost 10%, her length had only increased by 4%, of which some would have been contributed by the head growth. Making the approximation that the body and head remain substantially the same shape, their volumes would have increased as the cube of their linear dimensions, i.e. body volume would have increased by a ratio of 1.04 1.04 1.04 = 1.12 or by 12%, but head volume would have increased by 1.1 1.1 1.1 = 1.33, = 33%. This remarkable skull growth rate is confirmed by the increase in total body weight of 23%. The parents noticed, and onlookers commented on this, but it was attributed to a ‘‘growth spurt”. In the 19 weeks photo as shown in Fig. 1 there is also a suggestion of developing skull asymmetry, the right side bulging slightly. This is likely to result from differing rates of growth across sutures at this unusually rapid rate of skull growth.
Fig. 2. Indication of developing hydrocephalus. Measurements made at a routine visit at 4.4 months appear to indicate that head growth had been normal. Measurements at 4.75 months were made at autopsy and indicate a rapid and disproportionate head growth. In the interval skull circumference (left) increased by 10%, but overall length by only 4%. If skull growth was 10% in all directions, skull volume, and hence head weight would have increased by 33%. This correlates well with a 25% increase in infant total weight (centre).
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This was confirmed 2 weeks later, in the CT scan on hospital admission and at autopsy, where it was found that she had a deformed occipital plate. This would have made the infant increasingly top heavy. Her carer accidently dropped her while holding her around the waist. This subtle change of balance may have been a factor in his losing his grip. The terminal event and trauma management 21 weeks After a semiquiescent period intense vomiting had returned. A. had had three vomiting events in the morning. Later in the day, when the father accidentaly dropped her, he made an emergency 911 call. The responding ambulance crew noted that she was then unresponsive and limp, though pink in colour. They were completely unaware that for the previous 4 weeks this infant had had ‘‘spells” of such unconsciousness from which she would make spontaneous recovery, because the father was being interviewed by police on suspicion of SBS and the mother was travelling from work. They attempted to establish a reliable airway, but were unsuccessful, probably because they had triggered reactive laryngeal closure. Textbooks on anaesthesia [34,35] warn of the danger of attempting intubation where there is a possibility that the epiglottis is inflamed for any reason. Beverage et al. [35] warn ‘‘Because any stimulus may worsen the airway occlusion, avoid examining the patient’s mouth. Initiate emergency measures and prepare for intubation. If edema is severe enough to prohibit intubation prepare for an emergency tracheotomy”. This case illustrates the danger of assuming SBS to the exclusion of obtaining any other relevant data. Whereas on ambulance arrival at the house the child had been found limp but pink, on arrival at the receiving hospital she was noted to be ashen and cold (34.5), with a heart rate of 160. Vital signs could not be obtained. Pupils were
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8 mm and fixed. The ED physician completed intubation of the patient within 1 min of arrival. However on X-ray visualisation the endotracheal tube was seen to have entered the right bronchus, RB Fig. 3. The left lung was collapsed and the right lung was over expanded forcing the mediastinum left. Since an over-expanded lung has very low stretch it resists further expansion and cannot ‘‘breathe”. As the air flow to the left lung (LL) was blocked off by the endotracheal tube, it was impossible for the infant to be adequately ventilated from the time endotracheal intubation was attempted until the tube was drawn back to its correct position. The blocking of airflow to the left lung would not simply halve the gas exchange area. Venous (used) blood would continue to flow through it, and mix with any oxygenated blood returning from the right lung (known as a right-left shunt). This would significantly reduce the partial pressure of oxygen in the arterial blood, leaving the heart. The partial pressure of oxygen in the capillary blood is what drives oxygen into the surrounding tissues. Low oxygen partial pressure in the blood means that oxygen does not reach tissues remote from capillaries, producing rapid and widespread oxygen starvation. Conclusions Dysphagic infant death [22] is fundamentally a venous hypertensive disorder. Like paroxysmal cough injury (PCI) [25] it develops when a normal action, in this case vomiting, is repeated sufficiently frequently for the small reverse displacements of blood into the head occurring with individual vomits, to accumulate and cause serious dilation of intracranial capillaries and venules. The various effects produced (petechiae, extended screaming fits, ‘‘dying spells”, reflux etc.) were viewed and ‘‘treated” individually by various medical personnel unaware of a possible common cause as hypothesised here. Some maladies actually resolve spontaneously, e.g. petechiae, and some fail to respond to any treatment, e.g. recurrent bronchiolitis, reflux and vomiting itself. This unusually well-documented case presented a chain of events of increasing severity which corresponded to the increasing power of the abdominal wall and diaphragmatic muscles. New research based on the consensus statement on cyclic vomiting syndrome released by the North American Society for Pediatric Gastroenterology Hepatology and Nutrition [36] would thus appear to have important implications beyond gastroenterology into the fields of abusive head injury in infants. The American Academy of Pediatrics recently issued a policy statement [37] recommending adoption of the term ‘‘abusive head trauma” (AHT) to replace ‘‘Shaken Baby Syndrome” in medical situations. SBS is to be regarded as a subset of AHT. AHT is intended to be less mechanistic and place more reliance on the judgment of local experts. SBS has been used here because although there may be increasing doubts about the causative agent of the syndrome (shaking) it undoubtedly defines a clinically observed set of associated features. Under the heading ‘‘The role of the pediatrician” the new policy statement places a ‘‘responsibility to consider alternative hypotheses when presented with a patient with findings suggestive of AHT. A diagnosis of AHT is made only after consideration of all the clinical data.” This present hypothesis is offered as such an alternative to be considered where the findings appear to suggest the SBS subset of AHT. Conflict of interest statement
Fig. 3. Endotracheal tube mis-placement. Where the primary bronchus forks the right bronchus (RB) is nearer in-line with the primary bronchus than the left (LB). If too much of the tube is fed into the airway it tends to enter the right bronchus, cutting off the left. The left lung (LL) then collapses, and the right (RL) balloons out causing the mediastimum (MED) to bow out to the left, further compressing the collapsed left lung.
There is no conflict of interest statement. References [1] Li BU, Balint JP. Cyclic vomiting syndrome: evolution in our understanding of a brain-gut disorder. Adv Pediatr 2000;47:117–60.
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[2] Bullard J, Page N. Cyclic vomiting syndrome: a disease in disguise. Pediatr Nurs 2005;31:27–9. [3] Li BU, Lefevre F, Chelimsky G, et al. North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition consensus statement on the diagnosis and management of cyclic vomiting syndrome. J Pediatr Gastroenterol Nutr 2008;47:379–93. [4] Kravitz P. The clinical picture of ‘‘Cough Purpura”. Virginia Med 1979;106:373–4. [5] Last RJ. The thorax. In: Last RJ, editor. Anatomy, regional and applied. Edinburgh: Churchill Livingstone; 1984. p. 211–55. [6] Morse SI. Whooping cough (Pertussis). In: Beeson PB, McDermott W, Wyngaarden JB, editors. Textbook of medicine. Philadelphia: Saunders; 1979. p. 341–3. [7] McKendrick GDW. Bordetella infections Whooping cough. In: Scott RB, editor. Price’s textbook of the practice of medicine. Oxford: Oxford University Press; 1978. p. 49–51. [8] Jones WL. Valsalva maneuver induced vitreous hemorrhage. J Am Optom Assoc 1995;66:301–4. [9] Chandra P, Azad R, Sharma Y, Chhabra MS. Valsalva and Purtscher’s retinopathy with optic neuropathy in compressive thoracic injury. Eye 2005;19:914–33. [10] Chapman-Davies A, Lazarevic A. Valsalva maculopathy. Clin Exp Optomet 2002;85:42–5. [11] Goetting MG, Sowa B. Retinal hemorrhage after cardiopulmonary resuscitation in children: an etiologic reevaluation. Pediatrics 1990;85:585–8. [12] Talbert DG. The ’Sutured Skull’ and intracranial bleeding in infants. Med Hypotheses 2006;66:691–4. [13] Widdicombe JG. Reflexes from the upper respiratory tract. In: Fishman AP, Cherniak NS, Widdicombe JG, editors. The repiratory system Section3. Control of breathing part 1, vol. 2. Bethesda: American Physiological Society; 1986. p. 363–94. [14] Boggs DF, Bartlett D. Chemical specificity of a laryngeal apneic reflex in puppies. J Appl Physiol 1982;53:455–62. [15] Henderson-Smart DJ, Read DJC. Fetal cardio-respiratory physiology. In: Shearman, editor. Human reproductive physiology. Oxford: Blackwell Scientific Publications; 1972. [16] Bryan AC, WohL ME. Respiratory mechanics in children. In: Fishman AP, editor. Handbook of physiology, Section3: the respiratory system. Bethesda: American Physiological Society; 1986. p. 179–91. [17] Pattle RE. Properties, function and origin of the alveolar lining layer. Proc R Soc Lond 1958;B148:217–40. [18] Bachofen H, Gehr P, Weibel ER. Alterations of mechanical properties and morphology in excised rabbit lungs rinsed with a detergent. J Appl Physiol 1979;47:1002–10. [19] Talbert DG, Southall DP. A bimodal form of alveolar behaviour induced by a defect in lung surfactant – a possible mechanism for sudden infant death syndrome. Lancet 1985:727–8.
[20] Nieman GF, Brendenburg CE, Clark WR, et al. Alveolar function following surfactant deactivation. J Appl Physiol 1981;51:895–904. [21] Goerke J, Gonzales J. Temperature dependence of dipalmitoylphosphatidylcholine monolayer stability. J Appl Physiol: Resp Environ Exercise Physiol 1981;51:1108–14. [22] Talbert DG. Dysphagia as a risk factor for sudden unexplained death in infancy. Med Hypotheses 2006;67:786–91. [23] Thach BT. Sudden infant death syndrome: can gastroesophageal reflux cause sudden infant death? Am J Med 2000;108(4A):144S–8S. [24] Curci M, Dibbins A. Gastroesophageal reflux in children: an underrated disease. Am J Surgery 1982;143:413–6. [25] Geddes JF, Talbert DG. Paroxysmal coughing, subdural and retinal bleeding: a computer modelling approach. Neuropathol Appl Neurobiol 2006. [26] Hinchey JCC, Appignani B. A reversible posterior leukoencephalopathy sysndrome. N Engl J Med 1996;334:494–500. [27] Man WD, Kyroussis D, Flemming TA, et al. Cough gastric pressure and maximum expiratory mouth pressure in humans. Am J Respir Crit Care Med 2003;168:714–7. [28] Moore KL, Dalley AF. Head. In: Moore KL, Dalley AF, editors. Clinically oriented anatomy. Philadelphia: Lippincott Williams and Wilkins; 2006. p. 885–1043. [29] Keele CA, Neil E. Oedema. In: Keele CA, Neil E, editors. Samson Wright’s applied physiology. London:: Oxford University Press; 1965. p. 44–50. [30] Kumar R. External hydrocephalus in small children. Childs Nerve Syst 2006;22:1237–41. [31] Yu JC, McClintock JS, Gannon F, Gao XX, Mobasser J, Sharawy M. Regional differences of dura osteo induction; squamous dura induces osteogenesis, sutural dura induces chondrogenesis and osteogenesis. Plast Reconstr Surg 1997;100:23–31. [32] Opperman LA. Cranial sutures as intramembranous bone growth. Dev Dynam 2000;219:472–85. [33] Ogle RC, Tholpady SS, McGlynn KA, Ogle RA. Regulation of cranial suture morphogenesis. Cells Tissues Organs 2004;176:54–66. [34] Mather SJ. Acute airway problems. In: Mather SJ, Hughes DG, editors. A handbook of paediatric anaesthesia. Oxford: Oxford University Press; 1996. p. 233–41. [35] Beverage D, Bruck L, Labus D, Munden J, Schaeffer L, Thompson G. Adventitious sounds: wheezes. In: Moreau D, editor. Breath sounds made incredibly easy! Ambler, PA: Lippincott Williams and Wilkins; 2005. p. 119–32. [36] Li B, Lefevre F, Chelimsky G, et al. North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition concensus statement on the diagnosis and management of cyclic vomiting syndrome. J Pediatr Gastroenterol Nutr 2008;47:379–93. [37] Christian CW, Block R. Abusive head trauma in infants and children. Pediatrics 2009;123:1409–11.
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Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy
Cyclic vomiting syndrome: Contribution to dysphagic infant death D.G. Talbert * Institute of Reproductive and Developmental Biology, Imperial College School of Medicine, Du Cane Road, London W12 ONN, UK
a r t i c l e
i n f o
Article history: Received 31 May 2009 Accepted 4 June 2009
s u m m a r y Vomiting involves the simultaneous violent contraction of abdominal and diaphragm muscles to produce a high pressure on the stomach. The heart right atrium forms a through path from IVC to SVC, so the high intra-abdominal pressure will drive blood from abdominal contents into the head. Normally internal viscous drags in organs will limit the volume leaving them during a single vomiting event. However, repetitive vomiting such as occurs in cyclic vomiting syndrome (CVS) may drive sufficient blood into head veins to produce extreme venous hypertension. Dysphagic infant death is essentially a head vein hypertension malady, some features of which match those that are postulated for Shaken Baby Syndrome. CVS was described by Gee in 1882 but is still poorly understood. Recently a consensus statement has been released by the North American Society for Pediatric Gastroenterology Hepatology and Nutrition setting out key issues to be addressed. Understanding CVS may therefore have important implications beyond its gastroenterological aspects. A case demonstrating a sequence of features suggesting CVS and the effects of increasing abdominal muscle strength with age is presented. It showed (1) swallowing dysfunction, (2) grunting and apnoea (surfactant poisoning), (3) reflux, (4) diarrhoea, (5) apparently unprovoked prolonged screaming fits (migraine?), (6) petechiae (local capillary rupture), (7) skull growth abnormalities (hydrocephalus) and (8) unconscious ‘‘blank staring spells ” (from which the infant would auto-resuscitate). Repetitive vomiting may also sensitise the epiglottis thus increasing the risk of laryngospasm, and making attempts at intubation hazardous, possibly leading to hypoxic brain death. Ó 2009 Elsevier Ltd. All rights reserved.
Introduction Cyclic vomiting syndrome (CVS) was described by Gee in 1882 [1] but is still poorly understood [2]. Li et al. [3] describe it as noted for its unique intensity of vomiting, and repeated emergency department visits and hospitalisations. The frequency of vomiting often appears to fluctuate cyclically and may present hazards to health, or even life at its peaks. Vomiting involves the simultaneous violent contraction of abdominal and diaphragm muscles to produce a high pressure on the stomach to squeeze its contents up the oesophagus. The same pressure is applied to all organs below the diaphragm. The liver and spleen hold significant proportions of the total blood volume and during a vomit some will get squeezed out and up the inferior vena cava (IVC) into the sinus vasorum of the right heart atrium. The sinus vasorum also normally accepts blood returning from the head and arms and upper thorax via the superior vena cava (SVC). This constitutes a through venous path from liver etc. to head and arms during vomiting. So when the abdominal organs are squeezed by the abdominal pressure some of their blood is forced up into veins in the head, raising head venous pressure. Blood viscous drag within organs normally * Tel.: +44 020 7594 2142. E-mail address: [email protected] 0306-9877/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.mehy.2009.06.011
limits the proportion that can be lost to the head etc. during each vomit, but if ejection efforts are continuously repeated or are extended, blood will accumulate in head veins producing pressures high enough to damage them. This is well illustrated by a case reported by Kravitz of an otherwise healthy 20-year old female who experienced an evening of repetitive vomiting [4]. Coloured photographs show her face marked by petechiae (small blood blebs under the skin) where small veins or capillaries had burst under the excessive venous pressure. The petechiae then rapidly disappeared within a day or so. There are valves in the jugular veins draining the head but they are not considered very strong, and certainly in this young person provided no protection. Petechiae signify excessive venous pressure, resulting from blood being forced through the sinus vasorum [5] up the SVC. In the literature they are described as occurring on the forehead, eyelids, face, [6] neck and upper thorax [7], i.e. anywhere drained by the inner or outer jugular veins when central venous pressure becomes excessive. Bleeding in the eyes is known to result from excessive venous pressure occurring for a wide range of causes [8–11]. In infants, before the sutures between skull bone plates have hardened, this may be accompanied by subdural bleeding [12]. Recently a consensus statement has been released by the North American Society for Pediatric Gastroenterology Hepatology and Nutrition setting out key issues to be addressed, in the study of
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CVS [3]. This present article concentrates on hazards external to gastroenterology, but relating to the excessive intracranial venous pressures produced during repetitive or extended vomiting, which make this consensus statement highly relevant in the field of suspected Shaken Baby Syndrome. Hypothesis During the repetitive and violent vomiting that occurs in CVS, the excessive intra-cranial venous pressures resulting from sustained high intra-abdominal pressure may reproduce many of the symptoms of abusive head injury in infants, previously considered diagnostic of ‘Shaken Baby Syndrome’. In addition, repetitive vomiting may produce inflammation of the epiglottal and laryngeal surfaces. The resulting increased sensitivity may then be sufficient to trigger laryngeal constriction. If Emergency Services, unaware of this condition, attempt intubation [13,14], a hazard of severe hypoxia or anoxia exists.
quent significant episodes are shown below in the order of their appearance and timings, Fig. 1. Swallowing dysfunction The first indication of abnormality occurred while still in maternity hospital, when baby A. was given an injection of Hep. B vaccine, and a vitamin K supplement by mouth. She screamed abnormally for an hour, and when removed from the nursery because she was disturbing other neonates, and given to the mother, continued for a further twenty minutes. In view of later events it seems likely that the vitamin K solution had leaked through her epiglottis into the larynx, which is intensely sensitive to ‘‘foreign” materials. Thereafter she would vomit independently of type of feed, suggesting a mechanical cause rather than an allergy or undue sensitivity. The hazard here, in young infants, is reactive upper airway closure [13] which can be fatal. Grunting and apnoea
An illustrative case history The mother of infant A. kept a fairly continuous written and photographic record of the infant’s developmental progress. Apgar score [15] was good at birth and lung function was normal. Subse-
Around 2 weeks it was noticed that A. was grunting and having periods of apnoea. The mother sought medical advice and was told that this was normal and that A. would grow out of it. She accepted that explanation, but A did not grow out of it. ‘‘Grunting”
Fig. 1. The sequence of significant events in an infant suffering from frequent vomiting. The vertical axis on the left shows postnatal age in weeks. Numbers in circles identify the first occurrence of each event recognised by the parents.
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is technically referred to as ‘‘expiratory braking” [16]. It is associated with a lack of, or malfunctioning of, ‘‘surfactant” (surface active molecules) that opposes surface tension in the water lining the lungs [17]. Surface tension is the force that draws the fibres of a wet tissue together and makes it impossible to untangle it. Without surfactant in the film of water lining the minute gas exchange surfaces (alveoli) of lungs they would collapse like the wet tissue and become useless [18–20]. Sometimes there is a lack of sufficient surfactant in the lungs of newborn infants (Respiratory Distress Syndrome). To hold these alveoli open various designs of ventilators keep the air they breathe at a positive pressure. Infants learn to achieve a similar support by constricting their larynx (upper airway) during expiration so that a positive pressure is required to drive gas out, causing the grunting noise. The surfactant molecule has an oily end (two 16-carbon paraffin chains) and is highly polar at the other (choline) end. Thus it cannot sink into the water film because of the hydrophobic paraffin chains, or leave the film without dragging a ballast of water molecules bound to the polar end. These effects keep surfactant molecules locked in the water surface opposing the water’s own surface tension. Leakage of feed, reflux, etc. through the glottis into the lungs can loosen the bonding of water ballast to the polar end and undermine the efficiency of surfactant [17,21]. In a normal infant part of the swallowing action includes closing the epiglottis to make leakage impossible. Thus from the beginning A. showed some form of swallowing defect, ‘‘dysphagia” (dys meaning malfunction and phagia meaning feeding). Such infants may learn to avoid epiglottal leakage problems by only partially opening their throat (oesophagus) while swallowing, to allow liquids to travel down ‘‘gutters” which form on both sides of the throat [22]. Liquid feeds then avoid the epiglottis altogether. Later, when semisolids are introduced (weaning), the food has to pass over the epiglottis and choking reactions to leakage, and apnoea etc., may re-appear. The hazard here is bronchial disorders unresponsive to normal treatment, or widespread atelectasis (lung alveolar collapse) leading to hypoxic damage or death. Reflux In week 4 reflux was diagnosed. Leakage of highly acidic digestive juices could then occur at any time, i.e. not limited to feeding times. Reflux in infants is not normally considered a serious hazard [23] but repetitive vomiting forms a continual challenge to the glottal sealing mechanism. Normal reflux is basically leakage through the oesophageal sphincters, possibly driven by stomach peristalsis, but is not driven by contraction of powerful abdominal muscles. Curci and Dibbins [24] described gastroesophageal reflux in children as an ‘‘underrated disease” In a group of 41 patients presenting for operative correction of gastroesophageal reflux, 49% had pulmonary problems, 6 had recurrent pneumonia unresponsive to antibiotic, 8 suffered from apnea or ‘‘dying spells”, varying from choking with mild cyanotic changes to respiratory arrest requiring cardiopulmonary resuscitation. Six had a wheezing chronic cough, and ‘‘wet-congested breathing” attributed to asthma and bronchitis but unresponsive to common treatment regimens. They say that maturation of reflux control normally occurs about 5–7 weeks postnatally but is abnormal after 3 months. They concluded that ‘‘The pernicious aspects of this disease include a potentially significant mortality in children with severe apnoea episodes. . .” Also, around 4 weeks, a ‘‘rash” or ‘‘acne” and redness of face which disappeared within a day or so were observed for the first time. This was diagnosed as acne, but the rapid disappearance suggests petechiae produced by the excessive head vein pressure. Similarly redness could result from dilated blood vessels stretched during raised venous pressure episodes.
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Diarrhoea 8 weeks In week 8 she developed fever and diarrhoea. Thereafter diarrhoea became a feature of her metabolism continuing after she had recovered from the fever. Screaming fits 9 weeks In week 9 she developed screaming fits lasting over an hour for no apparent reason. Observers thought she seemed to appear in abdominal pain but could find no cause. One such fit occurred suddenly for no apparent stimulus, about 10 min after the photo in the figure was taken, where she was happy and laughing. Petechiae and swollen eye 12 weeks In week 12 a ‘‘rash” (petechiae) appeared again, and one eye was swollen, following vomiting. Again this cleared rapidly in about 24 h, similarly to the 25-yr old case [4]. At the time they were ascribed to acne or fungal infection, but the position and rapidity of disappearance are more consistent with petechiae formed by brief leakage of blood from over-pressurised skin surface veins and capillaries. The swollen eye also suggests an episode of venous hypertension. The lens of the eye is free to change shape (focus) because it has aqueous humor in front and behind. This is a watery medium secreted from the inner surface of the ciliary body, a ring structure behind the lens and iris [28]. The aqueous humor then flows forward between the lens and the iris, through the pupil and out through loose connective tissue along the scleral venous sinus (SVS) which surrounds the junction of the cornea and scleral parts of the eyeball. This sinus then drains into the vorticose veins and on through the ophthalmic veins into the skull. There are no valves along this path. The pressure within the eyeball being about 20 mmHg the ciliary bodies have to secrete at a higher pressure, to produce a gradient that normally ensures that the SVS contains aqueous humor but no blood. However, if venous pressure exceeds ocular pressure, the gradient is reversed and water is forced into the eyeball. Thus the swollen eye also suggests that excessive venous pressures have occurred. The hazard here is from failure of intra-cranial vessels under the excessive venous pressure, even if it is brief [25]. Visit to pediatrician 14 weeks At this visit the parents voiced concerns about the unexplained screaming fits, eating irregularities, and diarrhoea etc. Blank staring spells (Transient Oedema) 18 weeks This picture was taken while she was experiencing what the parents described as a” blank staring spell”. During these ‘‘spells” she was limp and completely unreactive, but as the photograph shows she was not cyanotic but of normal colour. She would stay in this condition for sometime, then ‘‘wake up” and return to normal activity. A form of cerebral oedema is known that results when excessive rise in brain venous pressure drives water through cerebral capillary and venule walls. It resolves after the venous pressure returns to normal; a ‘‘Transient Edema” [26]. It differs from classic oedema in that the solutes producing osmotic pressure do not cross the capillary wall blood-brain-barrier. Their concentrations, and hence the osmotic pressures they exert in the brain interstitial space, change with the resulting local dilution. This may result in the failure of neuron action potential production and/or conduction, and hence unconsciousness. During violent vomiting or coughing intra-abdominal pressures can reach 80– 100 mmHg, resulting in cerebral capillary and venous pressures
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of 50 mmHg or so [27]. Since the blood-brain-barrier is permeable to water, water will be selectively driven out of the vessels into the cerebral interstitium. When venous pressure returns to normal, water can return from the interstitium. However, since the pressure restoring water balance (interstitial to capillary lumen) is roughly one tenth of those during abdominal contractions, recovery will take roughly ten times as long. Normally vomiting contractions are brief and water movements are too small to affect neurological function, but if muscle contractions are extended or rapidly repeated, significant dilution of interstitial fluid may occur. The brain stem, in which the respiratory control centres are located, is not drained by the jugular veins but by the vertebral veins, whose complex paths will delay their venous hypertension. Moreover, the diaphragm descends as part of the vomiting action, assisting in increasing abdominal pressure, but reducing intrathoracic pressure in the process. Some of the excess blood will spill down into the spinal vertebral system, further delaying build up of venous pressure in the brain stem. This would make the respiratory centres less vulnerable than the cortex, and explain the continued respiration observed in this infant while unconscious. The hazard here arises from neurological damage if the ‘‘transient oedema” becomes excessive or lasts too long. Blood can be seen in the conjunctivae of both eyes. It was dismissed by a pediatrician as due to crying, but may have a more significant explanation. Moore and Dalley [28], describing subconjunctival haemorrhages, comment ‘‘The haemorrhages may result from injury or inflammation.....excessively hard blowing of the nose, and paroxysms of coughing or violent sneezing can cause haemorrhages resulting from rupture of small subconjunctival capillaries.” These are all conditions that, like violent vomiting, produce excessive intra-cranial venous pressure and suggest that A. recently had an episode of vomiting. Skull growth abnormalities; a form of hydrocephalus 19 weeks About 2 weeks before the final event onlookers commented on her enlarging head. This also could have resulted from the transient edema and/or excess cerebrospinal fluid (CSF) volume. CSF is produced principally by chorionic plexuses in the walls of the ventricles, particularly the lateral ventricles [29]. It passes back through the ventricles and back into the venous circulation via arachnoid villi into the dural sinuses. Increased venous pressure will both increase production of CSF and impede its out flow [29]. Excessive CSF volume induces external-hydrocephalus-like skull growth [30]. The infant head grows rapidly, under two different control systems. The face, jaw, rotating bearing on top of the spine (atlas) and the floor of the braincase on which the brain rests,
are all genetically pre-programmed. The cranium genetic program includes a mechanism that adjusts skull size to match brain size. In the early fetus the skull starts as a half ‘‘balloon” of membranous tissue attached around its lower edge to this structure. As the brain grows and the ‘‘balloon ‘‘gets tight, the stretch in this membrane stimulates it to grow until it fits again. Later, but still before birth, bone gets laid down on this membrane, spreading from regions known as ossification centres. Membrane overlaid by bone can no longer stretch, and so skull growth depends on growth of the membrane between the edges of new bony plates (sutures) [31]. It is important at this stage that the bone plates do not join up, if they do, local growth becomes impossible and the skull grows distorted. So, the rate and geometry of suture growth are regulated by ‘‘messages” from the membrane underlying the sutures (dura mater) sensing the stretch and its direction [32,31,33]. Thus the dura acts to maintain a gentle stretch in itself. If the adjacent skull grows too fast, so that local stretch disappears, the dura produces less incentive for local growth. If growth is too slow (the skull is too tight on the brain) the dura signals the suture membrane to increase growth rate. So the rate at which the skull grows normally matches brain growth [32], but if an accumulation of cerebrospinal fluid (CSF) occurs, or the brain swells due to transient edema, this dural mechanism increases skull volume to accommodate it (macrocephally) [30]. In this infant the frequent vomiting appears to have started to increase brain + CSF volume sufficiently to cause a form of hydrocephalus. From this infants developmental health records, at 17.6 weeks she was 24 inches long, her head circumference was 40.5 cm, and her weight was 13.8 pounds. At autopsy (19 weeks) she was 25 in. long, head circumference was 44.5 cm and she weighed 17 pounds Fig. 2. Her length at both assessments thus remained within normal growth limits for her age, but during the interval her head circumference had risen above the 98% centile. So, while her head circumference had increased by almost 10%, her length had only increased by 4%, of which some would have been contributed by the head growth. Making the approximation that the body and head remain substantially the same shape, their volumes would have increased as the cube of their linear dimensions, i.e. body volume would have increased by a ratio of 1.04 1.04 1.04 = 1.12 or by 12%, but head volume would have increased by 1.1 1.1 1.1 = 1.33, = 33%. This remarkable skull growth rate is confirmed by the increase in total body weight of 23%. The parents noticed, and onlookers commented on this, but it was attributed to a ‘‘growth spurt”. In the 19 weeks photo as shown in Fig. 1 there is also a suggestion of developing skull asymmetry, the right side bulging slightly. This is likely to result from differing rates of growth across sutures at this unusually rapid rate of skull growth.
Fig. 2. Indication of developing hydrocephalus. Measurements made at a routine visit at 4.4 months appear to indicate that head growth had been normal. Measurements at 4.75 months were made at autopsy and indicate a rapid and disproportionate head growth. In the interval skull circumference (left) increased by 10%, but overall length by only 4%. If skull growth was 10% in all directions, skull volume, and hence head weight would have increased by 33%. This correlates well with a 25% increase in infant total weight (centre).
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This was confirmed 2 weeks later, in the CT scan on hospital admission and at autopsy, where it was found that she had a deformed occipital plate. This would have made the infant increasingly top heavy. Her carer accidently dropped her while holding her around the waist. This subtle change of balance may have been a factor in his losing his grip. The terminal event and trauma management 21 weeks After a semiquiescent period intense vomiting had returned. A. had had three vomiting events in the morning. Later in the day, when the father accidentaly dropped her, he made an emergency 911 call. The responding ambulance crew noted that she was then unresponsive and limp, though pink in colour. They were completely unaware that for the previous 4 weeks this infant had had ‘‘spells” of such unconsciousness from which she would make spontaneous recovery, because the father was being interviewed by police on suspicion of SBS and the mother was travelling from work. They attempted to establish a reliable airway, but were unsuccessful, probably because they had triggered reactive laryngeal closure. Textbooks on anaesthesia [34,35] warn of the danger of attempting intubation where there is a possibility that the epiglottis is inflamed for any reason. Beverage et al. [35] warn ‘‘Because any stimulus may worsen the airway occlusion, avoid examining the patient’s mouth. Initiate emergency measures and prepare for intubation. If edema is severe enough to prohibit intubation prepare for an emergency tracheotomy”. This case illustrates the danger of assuming SBS to the exclusion of obtaining any other relevant data. Whereas on ambulance arrival at the house the child had been found limp but pink, on arrival at the receiving hospital she was noted to be ashen and cold (34.5), with a heart rate of 160. Vital signs could not be obtained. Pupils were
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8 mm and fixed. The ED physician completed intubation of the patient within 1 min of arrival. However on X-ray visualisation the endotracheal tube was seen to have entered the right bronchus, RB Fig. 3. The left lung was collapsed and the right lung was over expanded forcing the mediastinum left. Since an over-expanded lung has very low stretch it resists further expansion and cannot ‘‘breathe”. As the air flow to the left lung (LL) was blocked off by the endotracheal tube, it was impossible for the infant to be adequately ventilated from the time endotracheal intubation was attempted until the tube was drawn back to its correct position. The blocking of airflow to the left lung would not simply halve the gas exchange area. Venous (used) blood would continue to flow through it, and mix with any oxygenated blood returning from the right lung (known as a right-left shunt). This would significantly reduce the partial pressure of oxygen in the arterial blood, leaving the heart. The partial pressure of oxygen in the capillary blood is what drives oxygen into the surrounding tissues. Low oxygen partial pressure in the blood means that oxygen does not reach tissues remote from capillaries, producing rapid and widespread oxygen starvation. Conclusions Dysphagic infant death [22] is fundamentally a venous hypertensive disorder. Like paroxysmal cough injury (PCI) [25] it develops when a normal action, in this case vomiting, is repeated sufficiently frequently for the small reverse displacements of blood into the head occurring with individual vomits, to accumulate and cause serious dilation of intracranial capillaries and venules. The various effects produced (petechiae, extended screaming fits, ‘‘dying spells”, reflux etc.) were viewed and ‘‘treated” individually by various medical personnel unaware of a possible common cause as hypothesised here. Some maladies actually resolve spontaneously, e.g. petechiae, and some fail to respond to any treatment, e.g. recurrent bronchiolitis, reflux and vomiting itself. This unusually well-documented case presented a chain of events of increasing severity which corresponded to the increasing power of the abdominal wall and diaphragmatic muscles. New research based on the consensus statement on cyclic vomiting syndrome released by the North American Society for Pediatric Gastroenterology Hepatology and Nutrition [36] would thus appear to have important implications beyond gastroenterology into the fields of abusive head injury in infants. The American Academy of Pediatrics recently issued a policy statement [37] recommending adoption of the term ‘‘abusive head trauma” (AHT) to replace ‘‘Shaken Baby Syndrome” in medical situations. SBS is to be regarded as a subset of AHT. AHT is intended to be less mechanistic and place more reliance on the judgment of local experts. SBS has been used here because although there may be increasing doubts about the causative agent of the syndrome (shaking) it undoubtedly defines a clinically observed set of associated features. Under the heading ‘‘The role of the pediatrician” the new policy statement places a ‘‘responsibility to consider alternative hypotheses when presented with a patient with findings suggestive of AHT. A diagnosis of AHT is made only after consideration of all the clinical data.” This present hypothesis is offered as such an alternative to be considered where the findings appear to suggest the SBS subset of AHT. Conflict of interest statement
Fig. 3. Endotracheal tube mis-placement. Where the primary bronchus forks the right bronchus (RB) is nearer in-line with the primary bronchus than the left (LB). If too much of the tube is fed into the airway it tends to enter the right bronchus, cutting off the left. The left lung (LL) then collapses, and the right (RL) balloons out causing the mediastimum (MED) to bow out to the left, further compressing the collapsed left lung.
There is no conflict of interest statement. References [1] Li BU, Balint JP. Cyclic vomiting syndrome: evolution in our understanding of a brain-gut disorder. Adv Pediatr 2000;47:117–60.
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