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PORTAL-VEIN THROMBOSIS IN INFANTS
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usually employed. They will receive six weeks of orientation similar to that provided by the Commonwealth schools, under the supervision of the local clinical tutor or area director of postgraduate medical education. At the end of their six weeks’ training it should be easy to provide them with house-officer appointments in the hospitals or groups to which they have been attached. In the Birmingham region 50% of junior hospital staff are overseas graduates. In some regions the proportion is even higher. The Birmingham experience will interest everyone facing the same situation.
PORTAL-VEIN THROMBOSIS IN INFANTS
THE type of portal
hypertension which offers the greattherapeutic challenge in its treatment arises from portal-vein thrombosis, which is not uncommon in the neonatal period. In the absence of liver-disease these children withstand the recurrent bleeding from varices remarkably well. The natural history of neonatal portal-vein thrombosis has been outlined by Clatworthy and Boles.l The child passes through a phase of ascites at about six months, which may be followed by a remission of several years, during which splenomegaly and portasystemic collaterals appear, before bleeding from oesophageal varices supervenes. Portacaval anastomosis is made difficult by the small size of vessels, and the surgeon often has to transect varices to control haemorrhage. This is seldom more than a temporary solution, and by cutting off the main outlet of the portal flow, and so elevating venous pressure further, transection may precipitate ascites or accentuate the growth of rectal varices, which in turn bleed. These problems have stimulated reflection upon the aetiology and prophylaxis of portal thrombosis in the newborn. Although adult patients with portal hypertension usually have liver-disease, this is not so in early childhood when extrahepatic causes predominated2 Careful pathological studies indicate that the cavernomatous transformation of the portal vein, often found in children with extra-hepatic portal obstruction, is a consequence of portalvein thrombosis rather than of a hamartoma or developmental abnormality. 34 At necropsy the thrombosed portal vein can often be identified in, or adjacent to, the cavernoma. The umbilical vein joins the left branch of the portal vein, and umbilical and intra-abdominal sepsis are generally believed to be important causes of neonatal portal-vein thrombosis. Of the 21 infants and children with extrahepatic portal obstruction reported by Hsia and Gellis,5 4 had had omphalitis or peritonitis in the neonatal period, and 5 others sepsis elsewhere, which by causing dehydration may have predisposed to thrombosis. Shaldon and Sherlock6 obtained a definite history of neonatal umbilical sepsis in 9 of 16 children with obstruction of the extrahepatic portal system in childhood, and sepsis had occurred in the neonatal period in 12 of the 23 patients under twenty years of age with portal-vein thrombosis described by Thompson and Sherlock.’ Staphyloest
1. 2. 3. 4. 5. 6. 7.
Clatworthy, H. W., Boles, E. T. Ann. Surg. 1959, 150, 371. Walker, R. M. The Pathology and Management of Portal Hypertension. London, 1959. Gibson, J. B., Richards, R. C. J. Path. Bact. 1955, 70. 81. Parker, R. A., Seal, R. M. E. ibid. p. 97. Hsia, D. Y. Y., Gellis, S. S. Am. J. Dis. Child. 1955, 90, 390. Shaldon, S., Sherlock, S. Lancet, 1962, i, 63. Thompson, E. N., Sherlock, S. Q. Jl Med. 1964, 33, 465.
frequently colonise the normal umbilical stump, but seldom give rise to infection,But catheterisation of the umbilical vein may introduce them into the portal vein, and Lipsitz and Cornet9 found that 45% of cultures of umbilical venous blood gave a growth of staphylococci, Escherichia coli, or Aerobacter aerogenes in 13 healthy infants. In recent years reports of extrahepatic portal-vein obstruction following exchange transfusion have appeared. Tizard 10 described 3 cases, and Oski et al.ll described 4 following this procedure, usually with antibiotic cover, and not always with obvious umbilical sepsis. Thus, trauma, rather than infection, may sometimes be a causative factor. Rudolph et al.12 reported that in infants with neonatal respiratory distress the catheter entered the portal vein in 5 of 15 attempts to reach the inferior vena cava through the umbilical vein. The portal vein could easily be injured during exchange transfusions. Exchange transfusion is a common proceciure and neonatal sepsis is not rare; hence the risk of portal-vein thrombosis in later life might be considerable. It could only be assessed by a prospective study, now provided by Thompson and Sherlockwho have diligently traced 470 children subjected to umbilical vein catheterisation between 1950 and 1960. Reassuringly, they found no instance of portal-vein thrombosis in this series, nor in 86 children who had had significant neonatal sepsis between 1955 and 1960. Encouraging as these figures are to the pxdiatrician, umbilical thrombophlebitis was evidently associated with prolonged umbilical venous catheterisation, and it is advisable to avoid this route for intravenous infusions. The routine use of parenteral antibiotics to cover exchange transfusions is best avoided, but swabbing the umbilical stump before and after catheterisation indicates the antibiotic sensitivities of the possible pathogens, and, should evidence of infection appear, early and effective treatment can be given.10 cocci
NOT HOT AIR
PATIENTS’ beliefs are often discounted, but not always wrong. Bronchitics and asthmatics sometimes complain that cold air aggravates their symptoms. And doctors who have themselves wheezed on exchanging a warm bed for a cold car in the early hours accept this even if they cannot explain it. Others are more sceptical because they believe that cold dry air becomes warm and moist as it passes along the upper respiratory tract on its way to the
lungs. But experimental evidence supports the voices of experience rather than the protests of theory. Wells et al. 13 demonstrated a rise in pulmonary air-flow resistance in sensitive patients suddenly exposed to cold air at -30°C. More recently, Millar et al. 14 measured forced expiratory volume in five normal subjects and ten asthmatic patients before, during, and after a period of 7 minutes in a refrigerated room with a temperature of -2U°C and a relative humidity of 35%. There was no significant change in the Henderson, R. J., Chalmers, J. A., Wood, J. J. Obstet. Gynœc. Br. Commonw. 1964, 71, 443. 9. Lipsitz, P. J., Cornet, J. M. Pediatrics, 1960, 26, 657. 10. Tizard, J. P. M. Proc. R. Soc. Med. 1962, 55, 772. 11. Oski, F. A., Allen, D. M., Diamond, L. K. Pediatrics, 1963, 31, 297. 12. Rudolph, A. M., Drorbaugh, J. E., Auld, P. A. M., Rudolph, A. J., Nadas, A. S., Smith, C. A., Hubbell, J. P. ibid. 1961, 27, 551. 13. Wells, R. E., Walker, J. E. C., Hickler, R. B. New Engl. J. Med. 1960, 263, 268. 14. Millar, J. S., Nairn, J. R., Unkles, R. D., McNeil, R. S. Br. J. Dis. Chest, 1965, 59, 23. 8.
usually employed. They will receive six weeks of orientation similar to that provided by the Commonwealth schools, under the supervision of the local clinical tutor or area director of postgraduate medical education. At the end of their six weeks’ training it should be easy to provide them with house-officer appointments in the hospitals or groups to which they have been attached. In the Birmingham region 50% of junior hospital staff are overseas graduates. In some regions the proportion is even higher. The Birmingham experience will interest everyone facing the same situation.
PORTAL-VEIN THROMBOSIS IN INFANTS
THE type of portal
hypertension which offers the greattherapeutic challenge in its treatment arises from portal-vein thrombosis, which is not uncommon in the neonatal period. In the absence of liver-disease these children withstand the recurrent bleeding from varices remarkably well. The natural history of neonatal portal-vein thrombosis has been outlined by Clatworthy and Boles.l The child passes through a phase of ascites at about six months, which may be followed by a remission of several years, during which splenomegaly and portasystemic collaterals appear, before bleeding from oesophageal varices supervenes. Portacaval anastomosis is made difficult by the small size of vessels, and the surgeon often has to transect varices to control haemorrhage. This is seldom more than a temporary solution, and by cutting off the main outlet of the portal flow, and so elevating venous pressure further, transection may precipitate ascites or accentuate the growth of rectal varices, which in turn bleed. These problems have stimulated reflection upon the aetiology and prophylaxis of portal thrombosis in the newborn. Although adult patients with portal hypertension usually have liver-disease, this is not so in early childhood when extrahepatic causes predominated2 Careful pathological studies indicate that the cavernomatous transformation of the portal vein, often found in children with extra-hepatic portal obstruction, is a consequence of portalvein thrombosis rather than of a hamartoma or developmental abnormality. 34 At necropsy the thrombosed portal vein can often be identified in, or adjacent to, the cavernoma. The umbilical vein joins the left branch of the portal vein, and umbilical and intra-abdominal sepsis are generally believed to be important causes of neonatal portal-vein thrombosis. Of the 21 infants and children with extrahepatic portal obstruction reported by Hsia and Gellis,5 4 had had omphalitis or peritonitis in the neonatal period, and 5 others sepsis elsewhere, which by causing dehydration may have predisposed to thrombosis. Shaldon and Sherlock6 obtained a definite history of neonatal umbilical sepsis in 9 of 16 children with obstruction of the extrahepatic portal system in childhood, and sepsis had occurred in the neonatal period in 12 of the 23 patients under twenty years of age with portal-vein thrombosis described by Thompson and Sherlock.’ Staphyloest
1. 2. 3. 4. 5. 6. 7.
Clatworthy, H. W., Boles, E. T. Ann. Surg. 1959, 150, 371. Walker, R. M. The Pathology and Management of Portal Hypertension. London, 1959. Gibson, J. B., Richards, R. C. J. Path. Bact. 1955, 70. 81. Parker, R. A., Seal, R. M. E. ibid. p. 97. Hsia, D. Y. Y., Gellis, S. S. Am. J. Dis. Child. 1955, 90, 390. Shaldon, S., Sherlock, S. Lancet, 1962, i, 63. Thompson, E. N., Sherlock, S. Q. Jl Med. 1964, 33, 465.
frequently colonise the normal umbilical stump, but seldom give rise to infection,But catheterisation of the umbilical vein may introduce them into the portal vein, and Lipsitz and Cornet9 found that 45% of cultures of umbilical venous blood gave a growth of staphylococci, Escherichia coli, or Aerobacter aerogenes in 13 healthy infants. In recent years reports of extrahepatic portal-vein obstruction following exchange transfusion have appeared. Tizard 10 described 3 cases, and Oski et al.ll described 4 following this procedure, usually with antibiotic cover, and not always with obvious umbilical sepsis. Thus, trauma, rather than infection, may sometimes be a causative factor. Rudolph et al.12 reported that in infants with neonatal respiratory distress the catheter entered the portal vein in 5 of 15 attempts to reach the inferior vena cava through the umbilical vein. The portal vein could easily be injured during exchange transfusions. Exchange transfusion is a common proceciure and neonatal sepsis is not rare; hence the risk of portal-vein thrombosis in later life might be considerable. It could only be assessed by a prospective study, now provided by Thompson and Sherlockwho have diligently traced 470 children subjected to umbilical vein catheterisation between 1950 and 1960. Reassuringly, they found no instance of portal-vein thrombosis in this series, nor in 86 children who had had significant neonatal sepsis between 1955 and 1960. Encouraging as these figures are to the pxdiatrician, umbilical thrombophlebitis was evidently associated with prolonged umbilical venous catheterisation, and it is advisable to avoid this route for intravenous infusions. The routine use of parenteral antibiotics to cover exchange transfusions is best avoided, but swabbing the umbilical stump before and after catheterisation indicates the antibiotic sensitivities of the possible pathogens, and, should evidence of infection appear, early and effective treatment can be given.10 cocci
NOT HOT AIR
PATIENTS’ beliefs are often discounted, but not always wrong. Bronchitics and asthmatics sometimes complain that cold air aggravates their symptoms. And doctors who have themselves wheezed on exchanging a warm bed for a cold car in the early hours accept this even if they cannot explain it. Others are more sceptical because they believe that cold dry air becomes warm and moist as it passes along the upper respiratory tract on its way to the
lungs. But experimental evidence supports the voices of experience rather than the protests of theory. Wells et al. 13 demonstrated a rise in pulmonary air-flow resistance in sensitive patients suddenly exposed to cold air at -30°C. More recently, Millar et al. 14 measured forced expiratory volume in five normal subjects and ten asthmatic patients before, during, and after a period of 7 minutes in a refrigerated room with a temperature of -2U°C and a relative humidity of 35%. There was no significant change in the Henderson, R. J., Chalmers, J. A., Wood, J. J. Obstet. Gynœc. Br. Commonw. 1964, 71, 443. 9. Lipsitz, P. J., Cornet, J. M. Pediatrics, 1960, 26, 657. 10. Tizard, J. P. M. Proc. R. Soc. Med. 1962, 55, 772. 11. Oski, F. A., Allen, D. M., Diamond, L. K. Pediatrics, 1963, 31, 297. 12. Rudolph, A. M., Drorbaugh, J. E., Auld, P. A. M., Rudolph, A. J., Nadas, A. S., Smith, C. A., Hubbell, J. P. ibid. 1961, 27, 551. 13. Wells, R. E., Walker, J. E. C., Hickler, R. B. New Engl. J. Med. 1960, 263, 268. 14. Millar, J. S., Nairn, J. R., Unkles, R. D., McNeil, R. S. Br. J. Dis. Chest, 1965, 59, 23. 8.