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Uncal herniation secondary to bacterial meningitis in a newborn
Uncal Herniation Secondary to Bacterial Meningitis in a Newborn S t e v e n K. F e s k e , M D * , E n r i q u e J. C a r r a z a n a , M D * , W i l l i a m J. K u p s k y , MD*, a n d J o s e p h J. V o l p e , M D *
A newborn with bilateral uncal herniation secondary to acute bacterial meningitis is reported. The findings of previous neuropathologic studies of neonatal bacterial meningitis are reviewed and the factors most likely responsible for the relative rarity of herniation in this disease in newborns are discussed. Feske SK, Carrazana EJ, Kupsky WJ, Volpe JJ. Uncal herniation secondary to bacterial meningitis in a newborn. Pediatr Neurol 1992;8:142-4.
Introduction Herniation of brain tissue is rare in newborns. In the two largest series of autopsied infants with bacterial meningitis [1,2], specific note is made of the absence of herniation despite severe brain edema; however, because appropriate intervention at the early signs of impending herniation may prevent death, it is important to recognize that herniation may occur in the newborn with bacterial meningitis. We report a 5-day-old infant with bilateral uncal herniation secondary to acute bacterial meningitis. Case Report This patient was born at 37 weeks gestation, weighing 2,300 gm, to an 18-year-old G1, P0 woman after an uncomplicated pregnancy. Membranes had ruptured spontaneously 8 hours before delivery. On the fourth day of life, the infant developed fever, grunting respirations, a brief apneic episode, and arching of the back. An evaluation for sepsis included a peripheral leukocyte count of 2,000/mm 3 with a left shift (i.e., 23% neutrophils, 21% band forms, 11% metamyelocytes, 2% myelocytes). Cerebrospinal fluid (CSF) examination revealed 4,650 leukocytes/mm3, 250 erythrocytes/mm3, an undetectable glucose c o n -
From the Departments of *Neurology and *Pathology; Children's Hospital; Harvard Medical School; Boston, Massachusetts.
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centration, and Grain-positive cocci with Gram stain. Culture of CSF later grew group B streptococcus. Ampicillin (300 mg/kg/day) and gentamicin (5 mg/kg/day) were administered and she was transferred to Children's Hospital. On arrival she was awake but irritable, with opisthotonic posturing, jaundice, and a ten~, bulging anterior fontanel. Head circumference was 32 cm. No local neurologic signs were observed. A latex fixation assay of the CSF confirmed group B streptococcal infection. On the fifth day of life, she was extremely irritable. Later that day she became obtunded, respirations were irregular, and pupils were asymmetric and minimally responsive to light. Mechanical ventilation was required. Cranial computed axial tomography revealed diffuse brain hyp(ntensity, with loss of demarcation of cortical gray and subcortical white matter, and small ventricles, compatible with diffuse cerebral edema. A neurologic consultation was requested. On neurologic examination she was lying still with eyes closed. There was slight withdrawal of legs to tactile stimulation but no response to light or sound. Spontaneous respirations were irregular while on the ventilator. Head circumference had increased to 33 cm. The anterior fontanel was bulging and the cranial sutures separated. The left pupil was 6 mm, right pupil 4 ram, and neither reacted to light. The optic discs were sharp, but no retinal venous pulsations were observed. There was spontaneous asymmetric posturing with the left arm flexed over the chest and the right arm extended. The legs were symmetrically flexed. Deep tendon reflexes were depressed throughout and there was a left extensor plantar response. With hyperventilation causing a decrease of Pco2 from 45 mm Hg to 22-33 mm Hg, the pupils constricted to 3 mm and a sluggish light reflex was elicited. After mannitol (I gm every 4 hrs) and furosemide (3 mg) were administered, there was increased urine output; however, the osmolality reached only 280 mOsm/L. Throughout the next day the degree of pupillary dilatation fluctuated with no change in responsiveness. Ampicillin administration was discontinued and penicillin, 375,000 units every 12 hrs, was begun. Despite antibiotics, hyperventilation, mannitol, furosemide, and phenobarbital, she died on the sixth day of life. At autopsy, the cerebrum, cerebellum, and brainstem all were covered by a dense gray-green purulent teptomeningeal exudate. The cerebrum was soft and swollen. Both unci had herniated through the tentorial notch, the left more than the right, and the parahippocampal gyri were deeply grooved (Fig I ). The herniated left uncus indented the superior surface of the left cerebellar hemisphere. The midbrain was compressed by the herniated unci and shifted slightly to the right; the aqueduct was obliterated by the compression (Fig 2). There was also bilateral cerebellar tonsillar herniation with necrosis of the tonsils and compression of the medulla (Fig 3). The cut brain was softened due to brain edema. The lateral ventricles were reduced to thin slits and no hemorrhage or abscess was found. No abnormalities of cranial bones or sutures were observed. Microscopic examination confirmed the presence of an acute bacterial leptomeningitis which extended focally into the cerebral parenchyma. Moreover, there was purulent exudate within the lateral ventricles and patchy perivascular neutrophilic cuffing with infiltration into the surrounding white matter. Cerebral cortex, white matter, deep gray nuclei, cerebellum, and brainstem disclosed diffuse edema and acute neuronal and glial necrosis.
Discussion Herniation of cerebral or cerebellar tissues outside of their supratentorial or infratentorial compartments due to
Communications should be addressed to: Dr. Feske; Department of Neurology; Children's Hospital; 300 Longwood Avenue; Boston, MA 02115. Received July 10, 1991; accepted November 11, 1991.
Figure 1. Ventral view of formalin-fixed brain disclosing massively swollen orbitofrontal and temporal gyri and damaged herniated portions of the medial temporal lobes (small arrows). Note the presence of a purulent exudate in the subarachnoid space on the inferior surface of the left temporal lobe (large arrow). The friable surface of the right temporal lobe was damaged during removal. The cerebellar folia also appear swollen.
acute bacterial meningitis and increased intracranial pressure (ICP) is rare in the newborn. In 1966, Berman and Banker described the neuropathology of bacterial menin-
Figure 2. View of the superior surfaces of the cerebellum and the cut section of compressed midbrain. The lumen of the cerebral aqueduct (small arrow) has been obliterated. The superior surface of the left cerebellar hemisphere demonstrates a large area of indentation (large arrow)from the herniated left uncus.
gitis in 25 infants who died within the first 28 days of life [1]. The 16 brains examined within the first week of illness (their "acute" stage) were swollen and hyperemic, yet no cerebral or cerebellar herniation was demonstrated. In 1978, Bortolussi et al. reviewed the autopsies of 20 patients with neonatal bacterial meningitis and reported "the absence of tentorial or cerebellar hemiations" [2]. In a review of the literature, we found only a single patient, a 2-week-old male infant, with anterior fontanel herniation due to bacterial meningitis [3]. The factors accounting for the relative rarity of herniation in acute bacterial meningitis in newborns compared to older infants and children are unknown. We suggest that the major factor is an increased cranial compliance because of the presence of open, distensible cranial sutures. The latter allow an increase in intracranial volume to occur without the increase in ICP that would develop in a fixed intracranial compartment. Berman and Banker cited as a crucial factor "the newborn's ability to relieve intracranial pressure by widening the cranial sutures" [1]. Bortolussi et al. drew a similar conclusion from their neuropathologic study [2]. Consistent with the formulation of the importance of increased cranial compliance in the newborn is the demonstration that major increases in ICP also are unusual with the brain swelling associated with neonatal hypoxic-ischemic encephalopathy [4] or with neonatal posthemorrhagic hydrocephalus [5]. Moreover, in a study of the effects of acute bacterial meningitis on ICP in infants, ICP was markedly elevated during the first 2 days of illness in older infants but not in newborns [6]. Our patient demonstrates the uncommon failure of the newborn's increased cranial compliance to prevent serious deleterious effects of brain edema in acute bacterial meningitis. No clear explanation for the herniation was found. Possible reasons for herniation may include abnormalities of the cranium that reduce normal compliance and an
Figure 3. View of the inferior surfaces of the cerebellum and the cut section of medulla. The cerebellar tonsils are necrotic and distorted (arrows) and the medulla is compressed (above).
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exceptional degree or rate of brain swelling. As observed above, at autopsy no abnormalities of the cranial bones or sutures accompanied the major brain edema in our patient. There was severe brain edema and swelling that developed over the 2-day course of her illness with only a slight increase in head circumference. Because the brain was so friable at autopsy, the weight was not obtained before fixation; therefore, we cannot quantify the degree of edema. Because we know that massive enlargement of the cranium can develop over the course of a chronic increase in ICP in infants, we must assume that the rapid rate of development of severe brain edema was critical. It is likely that containment by the dura rather than the cranium was responsible for the herniation. This finding, however, does not distinguish our patient from others with bacterial meningitis in whom brain swelling is severe and acute. This patient underscores the need to delineate the possible beneficial and detrimental effects of proposed interventions for the prevention or treatment of brain edema and elevated ICP in meningitis, such as hyperventilation and dexamethasone [7,8]. Finally, this patient demonstrates that when uncal herniation does develop in the newborn,
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it may present with the familiar clinical warning signs observed in older children and adults. References [1] Berman PH, Banker BQ. Neonatal meningitis: A clinical and pathological study of 29 cases. Pediatrics 1966;38:6-24. 12] Bortolussi R, Krishnan C, Armstrong D, Tovichayathamrong P. Prognosis for survival in neonatal meningitis: Clinical and pathological review of 52 cases. CMA J 1978; I 18:165-8. [3] Gibson NE Anterior fontanelle herniation. Pediatrics 1975;56: 466-8. [4] Lupton BA, Hill A, Roland EW, Whitfield ME Flodmark O. Brain swelling in the asphyxiated term newborn: Pathogenesis and outcome. Pediatrics 1988;82:139-46. [5] Hill A, Volpe JJ. Normal pressure hydrocephalus in the newborn. Pediatrics 1981 ;68:623-9. 16] M c M e n a m i n J, Volpe JJ. Bacterial meningitis in infancy: Effects on intracranial pressure and cerebral blood flow velocity. Neurology 1984;34:500-4. [7] Asbwal S, Stringer W, Tomasi L, Schneider S, Thompson J, Perkin R. Cerebral blood flow and carbon dioxide reactivity in children with bacterial meningitis. J Pediatr 1990;117:523-30. [8] American Academy of Pediatrics Committee of Infectious Diseases. Dexamethasone therapy fl)r bacterial meningitis in infants and children. Pediatrics 1990;86:130-3.
A newborn with bilateral uncal herniation secondary to acute bacterial meningitis is reported. The findings of previous neuropathologic studies of neonatal bacterial meningitis are reviewed and the factors most likely responsible for the relative rarity of herniation in this disease in newborns are discussed. Feske SK, Carrazana EJ, Kupsky WJ, Volpe JJ. Uncal herniation secondary to bacterial meningitis in a newborn. Pediatr Neurol 1992;8:142-4.
Introduction Herniation of brain tissue is rare in newborns. In the two largest series of autopsied infants with bacterial meningitis [1,2], specific note is made of the absence of herniation despite severe brain edema; however, because appropriate intervention at the early signs of impending herniation may prevent death, it is important to recognize that herniation may occur in the newborn with bacterial meningitis. We report a 5-day-old infant with bilateral uncal herniation secondary to acute bacterial meningitis. Case Report This patient was born at 37 weeks gestation, weighing 2,300 gm, to an 18-year-old G1, P0 woman after an uncomplicated pregnancy. Membranes had ruptured spontaneously 8 hours before delivery. On the fourth day of life, the infant developed fever, grunting respirations, a brief apneic episode, and arching of the back. An evaluation for sepsis included a peripheral leukocyte count of 2,000/mm 3 with a left shift (i.e., 23% neutrophils, 21% band forms, 11% metamyelocytes, 2% myelocytes). Cerebrospinal fluid (CSF) examination revealed 4,650 leukocytes/mm3, 250 erythrocytes/mm3, an undetectable glucose c o n -
From the Departments of *Neurology and *Pathology; Children's Hospital; Harvard Medical School; Boston, Massachusetts.
142
PEDIATRIC NEUROLOGY
Vol. 8 No. 2
centration, and Grain-positive cocci with Gram stain. Culture of CSF later grew group B streptococcus. Ampicillin (300 mg/kg/day) and gentamicin (5 mg/kg/day) were administered and she was transferred to Children's Hospital. On arrival she was awake but irritable, with opisthotonic posturing, jaundice, and a ten~, bulging anterior fontanel. Head circumference was 32 cm. No local neurologic signs were observed. A latex fixation assay of the CSF confirmed group B streptococcal infection. On the fifth day of life, she was extremely irritable. Later that day she became obtunded, respirations were irregular, and pupils were asymmetric and minimally responsive to light. Mechanical ventilation was required. Cranial computed axial tomography revealed diffuse brain hyp(ntensity, with loss of demarcation of cortical gray and subcortical white matter, and small ventricles, compatible with diffuse cerebral edema. A neurologic consultation was requested. On neurologic examination she was lying still with eyes closed. There was slight withdrawal of legs to tactile stimulation but no response to light or sound. Spontaneous respirations were irregular while on the ventilator. Head circumference had increased to 33 cm. The anterior fontanel was bulging and the cranial sutures separated. The left pupil was 6 mm, right pupil 4 ram, and neither reacted to light. The optic discs were sharp, but no retinal venous pulsations were observed. There was spontaneous asymmetric posturing with the left arm flexed over the chest and the right arm extended. The legs were symmetrically flexed. Deep tendon reflexes were depressed throughout and there was a left extensor plantar response. With hyperventilation causing a decrease of Pco2 from 45 mm Hg to 22-33 mm Hg, the pupils constricted to 3 mm and a sluggish light reflex was elicited. After mannitol (I gm every 4 hrs) and furosemide (3 mg) were administered, there was increased urine output; however, the osmolality reached only 280 mOsm/L. Throughout the next day the degree of pupillary dilatation fluctuated with no change in responsiveness. Ampicillin administration was discontinued and penicillin, 375,000 units every 12 hrs, was begun. Despite antibiotics, hyperventilation, mannitol, furosemide, and phenobarbital, she died on the sixth day of life. At autopsy, the cerebrum, cerebellum, and brainstem all were covered by a dense gray-green purulent teptomeningeal exudate. The cerebrum was soft and swollen. Both unci had herniated through the tentorial notch, the left more than the right, and the parahippocampal gyri were deeply grooved (Fig I ). The herniated left uncus indented the superior surface of the left cerebellar hemisphere. The midbrain was compressed by the herniated unci and shifted slightly to the right; the aqueduct was obliterated by the compression (Fig 2). There was also bilateral cerebellar tonsillar herniation with necrosis of the tonsils and compression of the medulla (Fig 3). The cut brain was softened due to brain edema. The lateral ventricles were reduced to thin slits and no hemorrhage or abscess was found. No abnormalities of cranial bones or sutures were observed. Microscopic examination confirmed the presence of an acute bacterial leptomeningitis which extended focally into the cerebral parenchyma. Moreover, there was purulent exudate within the lateral ventricles and patchy perivascular neutrophilic cuffing with infiltration into the surrounding white matter. Cerebral cortex, white matter, deep gray nuclei, cerebellum, and brainstem disclosed diffuse edema and acute neuronal and glial necrosis.
Discussion Herniation of cerebral or cerebellar tissues outside of their supratentorial or infratentorial compartments due to
Communications should be addressed to: Dr. Feske; Department of Neurology; Children's Hospital; 300 Longwood Avenue; Boston, MA 02115. Received July 10, 1991; accepted November 11, 1991.
Figure 1. Ventral view of formalin-fixed brain disclosing massively swollen orbitofrontal and temporal gyri and damaged herniated portions of the medial temporal lobes (small arrows). Note the presence of a purulent exudate in the subarachnoid space on the inferior surface of the left temporal lobe (large arrow). The friable surface of the right temporal lobe was damaged during removal. The cerebellar folia also appear swollen.
acute bacterial meningitis and increased intracranial pressure (ICP) is rare in the newborn. In 1966, Berman and Banker described the neuropathology of bacterial menin-
Figure 2. View of the superior surfaces of the cerebellum and the cut section of compressed midbrain. The lumen of the cerebral aqueduct (small arrow) has been obliterated. The superior surface of the left cerebellar hemisphere demonstrates a large area of indentation (large arrow)from the herniated left uncus.
gitis in 25 infants who died within the first 28 days of life [1]. The 16 brains examined within the first week of illness (their "acute" stage) were swollen and hyperemic, yet no cerebral or cerebellar herniation was demonstrated. In 1978, Bortolussi et al. reviewed the autopsies of 20 patients with neonatal bacterial meningitis and reported "the absence of tentorial or cerebellar hemiations" [2]. In a review of the literature, we found only a single patient, a 2-week-old male infant, with anterior fontanel herniation due to bacterial meningitis [3]. The factors accounting for the relative rarity of herniation in acute bacterial meningitis in newborns compared to older infants and children are unknown. We suggest that the major factor is an increased cranial compliance because of the presence of open, distensible cranial sutures. The latter allow an increase in intracranial volume to occur without the increase in ICP that would develop in a fixed intracranial compartment. Berman and Banker cited as a crucial factor "the newborn's ability to relieve intracranial pressure by widening the cranial sutures" [1]. Bortolussi et al. drew a similar conclusion from their neuropathologic study [2]. Consistent with the formulation of the importance of increased cranial compliance in the newborn is the demonstration that major increases in ICP also are unusual with the brain swelling associated with neonatal hypoxic-ischemic encephalopathy [4] or with neonatal posthemorrhagic hydrocephalus [5]. Moreover, in a study of the effects of acute bacterial meningitis on ICP in infants, ICP was markedly elevated during the first 2 days of illness in older infants but not in newborns [6]. Our patient demonstrates the uncommon failure of the newborn's increased cranial compliance to prevent serious deleterious effects of brain edema in acute bacterial meningitis. No clear explanation for the herniation was found. Possible reasons for herniation may include abnormalities of the cranium that reduce normal compliance and an
Figure 3. View of the inferior surfaces of the cerebellum and the cut section of medulla. The cerebellar tonsils are necrotic and distorted (arrows) and the medulla is compressed (above).
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exceptional degree or rate of brain swelling. As observed above, at autopsy no abnormalities of the cranial bones or sutures accompanied the major brain edema in our patient. There was severe brain edema and swelling that developed over the 2-day course of her illness with only a slight increase in head circumference. Because the brain was so friable at autopsy, the weight was not obtained before fixation; therefore, we cannot quantify the degree of edema. Because we know that massive enlargement of the cranium can develop over the course of a chronic increase in ICP in infants, we must assume that the rapid rate of development of severe brain edema was critical. It is likely that containment by the dura rather than the cranium was responsible for the herniation. This finding, however, does not distinguish our patient from others with bacterial meningitis in whom brain swelling is severe and acute. This patient underscores the need to delineate the possible beneficial and detrimental effects of proposed interventions for the prevention or treatment of brain edema and elevated ICP in meningitis, such as hyperventilation and dexamethasone [7,8]. Finally, this patient demonstrates that when uncal herniation does develop in the newborn,
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it may present with the familiar clinical warning signs observed in older children and adults. References [1] Berman PH, Banker BQ. Neonatal meningitis: A clinical and pathological study of 29 cases. Pediatrics 1966;38:6-24. 12] Bortolussi R, Krishnan C, Armstrong D, Tovichayathamrong P. Prognosis for survival in neonatal meningitis: Clinical and pathological review of 52 cases. CMA J 1978; I 18:165-8. [3] Gibson NE Anterior fontanelle herniation. Pediatrics 1975;56: 466-8. [4] Lupton BA, Hill A, Roland EW, Whitfield ME Flodmark O. Brain swelling in the asphyxiated term newborn: Pathogenesis and outcome. Pediatrics 1988;82:139-46. [5] Hill A, Volpe JJ. Normal pressure hydrocephalus in the newborn. Pediatrics 1981 ;68:623-9. 16] M c M e n a m i n J, Volpe JJ. Bacterial meningitis in infancy: Effects on intracranial pressure and cerebral blood flow velocity. Neurology 1984;34:500-4. [7] Asbwal S, Stringer W, Tomasi L, Schneider S, Thompson J, Perkin R. Cerebral blood flow and carbon dioxide reactivity in children with bacterial meningitis. J Pediatr 1990;117:523-30. [8] American Academy of Pediatrics Committee of Infectious Diseases. Dexamethasone therapy fl)r bacterial meningitis in infants and children. Pediatrics 1990;86:130-3.