|Year : 2006 | Volume
| Issue : 3 | Page : 22-23
White cerebellum sign - A case report and review of literature
S Dwarakanath, A Bansal, S Rudrappa, S Gopal, NK Venkataramana
Department of Neurosurgery, Manipal Institute for Neurological Disorders (MIND), Bangalore, India
Manipal Institute for Neurological Disorders, Airport Road, Bangalore - 560 017
Source of Support: None, Conflict of Interest: None
'White cerebellum sign' is a classic yet uncommon radiological finding in severe pediatric head injury. We present a case of a 7-year-old child who had this finding on computed tomography. We also discuss the possible etiogenesis and review the relevant literature.
Keywords: pediatric head injury; white cerebellum sign.
|How to cite this article:|
Dwarakanath S, Bansal A, Rudrappa S, Gopal S, Venkataramana N K. White cerebellum sign - A case report and review of literature. J Pediatr Neurosci 2006;1, Suppl S1:22-3
'White cerebellum sign' is a classic radiologic finding seen usually in extra cerebral cause of hypoxia. We report a 7-year-old child with this radiological finding due to a severe head injury and review its possible etiogenesis and other relevant literature.
| » Case report|| |
A 7-year-old girl child was brought to emergency services with history of fall from a height of around 12 ft. On examination she was E1 V1 M2. The pupils were bilaterally dilated and not reacting to light. The initial computed tomography (CT) scan (1 h after fall) revealed a thin right FTP acute subdural hematoma with diffuse cerebral edema [Figure - 1]A, B. She was intubated and electively ventilated in the intensive care unit. She was started on cerebral decongestants and anticonvulsants. In spite of this she deteriorated to E1Vt M1 for which a repeat CT scan was performed (14 h after initial trauma). It revealed completely hypodense cerebral hemispheres while the cerebellum was hyper dense i.e. 'White cerebellum sign' [Figure - 2]A, B. A magnetic resonance angiography was performed [Figure - 3]A, B which revealed absence of flow in bilateral ICA distal to level of petrous bone. The child did not improve and was declared dead at around 24 h after the initial trauma.
| » Discussion|| |
Diffuse brain swelling is seen in 10-20% of severe head injuries and is twice as common in children when compared to adults. The brain in diffuse bilateral cerebral edema typically exhibits homogenously decreased attenuation along with loss of gray white matter interface. Thus, the cerebellum appears relatively hypodense compared to the cerebral hemispheres i.e. 'white cerebellum sign'. The white cerebellum sign has also been described as a variant of the reversal sign. However, the term 'Reversal sign' has been mainly limited to imaging findings of reversal of gray matter and white matter densities of the cerebral hemispheres along with increased density of thalamus, brainstem and cerebellum.
However, this sign has been mainly seen as either an early sign or sequel of nonaccidental extra cranial hypoxia. It usually indicates extra cerebral hypoxia and has been primarily seen in methods of death such as smothering or strangulation. It can occur also in other causes of death such as drowning and smoke inhalation. Sometimes this sign may be the only suitable indication of child abuse though it is not pathognomonic. Trauma as an etiologic factor is rare, Kin Han analysed 20 children with the 'reversal sign' and found that nine cases were due to hypoxia/anoxia incidents, seven due to child abuse, two due to accidental trauma, one bacterial encephalitis and one due to degenerative encephalitis. The outcome was poor as a majority expired, while those who survived had profound neurologic deficits.
The genesis of this white cerebellum sign has been a matter of debate. Myers suggested a mechanical factor for relative presentation of central areas of brain. In animal experiments, he postulated that central preservation is due to transtentorial herniation during acute edema state. Bird et al. reporting three children with the reversal sign suggested that this sign could be from distention of deep medullary veins caused by partial obstruction of venous outflow in elevated intracranial pressure. Myers suggested chemical and metabolic factors could be related to pathophysiology of reversal sign. It was postulated that elevated serum (brain) glucose during anoxia/ischemia cause preferential damage to the cerebral hemispheres. However, Harwood-Nash suggested that this white cerebellum sign is due to primitive ' diving' reflex, which is seen, in hibernating animals and during diving to great depth.
The brain protects itself from ischemia by two different mechanisms. The first emanates from the oxygen - sensitive sympatho - excitatory reticulospinal neurons of the RVLM. The second is represented by the intrinsic neurons of the cerebellar fastigial nucleus and mediates a conditioned central neurogenic neuroprotection. This is mediated by excitation of the intrinsic neurons of the fastigial nucleus and is independent of first mechanism. These two mechanisms initiate the systemic components of the oxygen-conserving (Diving) reflex within seconds of excitation. The rCBF is increased greatly without changing rCGB and thus, brain is provided rapidly with oxygen.
| » Conclusion|| |
White cerebellum sign is an uncommon radiologic finding seen mainly in cases of pediatric hypoxia. The possible etiogenesis is ill understood with probable explanations including the primitive diving reflex. It usually represents severe anoxic - ischemic brain injury and carries a poor prognosis.
| » References|| |
|1.||Osborn AG. "Craniocerebral Trauma": In : Osborn AG (editor) Diagnostic Neuroradiology, 1st Edn, Chapter: Elseiver; 1994. p. 199- 247. |
|2.||Harwood- Nash DC. Abuse to Pediatric Central Nervous system. AJNR Am J Neuroradiol 1992;13:569-75. |
|3.||Han BK, Towbin RB, De Courten-Myers G, McLaurin RL, Ball WS Jr. Reversal sign in CT: Effect of Anoxia / Ischemic cerebral injury in children. AJR 1990;154:361-8. [PUBMED] |
|4.||Myers RE. Experimental models of perinatal brain damage: relevance to human pathology. In : Gluck L (ed), Intrauterine asphyxia and the develop brain. Yearbook Med: Chicago; 1977. p. 37-97. |
|5.||Bird CR, Drayer BP, Gillies FH. Pathophysiology of reverse edema in global cerebral ischemia. AJNR Am J Neuroradiol 1989;10:95-8. |
|6.||Myers RE, de Courten - Myers GM. Metabolic principles of patterns of perinatal brain injury, In : Crawford JW, ed. Risks of labour. Wiley: New York; 1985. p. 119-46. |
|7.||Reis DJ, Golanov EV, Galea E, Feinstein DL. Central neurogenic neuroprotection: central neural systems that protect the brain from hypoxia and ischemia. Ann N Y Acad Sci 1997;835:168-86. [PUBMED] |
[Figure - 1], [Figure - 2], [Figure - 3]