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| Hydrocephalus | ||
| Etiology •There are two types of hydrocephalus - communicating and noncommunicating. •In communicating hydrocephalus, CSF can expand into the subarachnoid space but fibrosis of the meninges or arachnoid granulations prevents it from draining into the superior sagittal sinus. •In noncommunicating hydrocephalus, CSF cannot get to the subarachnoid space because its flow is blocked by gliosis of the aqueduct, fibrosis of the foramina of Luschka and Magendie or a colloid cyst of the third ventricle. | ||
| Pathogenesis •In spite of the fact that CSF pathways are blocked CSF is formed at a normal rate so the ventricles have to dilate at the expense of the white matter particularly but also the grey matter since the CSF has no place to be resorbed. •Hydrocephalous ex vacuo is enlargement of the ventricles due to atrophy of brain substance, not increased intracranial pressure., | ||
| Epidemiology •Hydrocephalus is often an accompaniment of a meningomyelocoele or Arnold-Chiari malformation. •It can also be caused by isolated stenosis of the Aqueduct of Sylvius due to in utero viral infection. •Meningitis can cause communicating hydrocephalus. | ||
| General Gross Description •In hydrocephalus, there is blockage of flow of the Cerebrospinal fluid (CSF) with enlargement of ventricles at the expense of the white matter and grey matter. •Examples: | ||
| General Microscopic Description •May be due to gliosis of the aqueduct of Sylvius or fibrosis of the leptomeninges, foramina of Lushcka or Magendie, or arachnoid (Paccinonian) granulations. •Ventricles show loss of ependyma. •Examples: | ||
| Clinical Correlation •Infants have large heads as well ventricles because of their flexible skull. •Older children and adults develop headache and signs of increased intracranial such as lethargy or a dilated pupil. •Must place a shunt tube into the lateral ventricles and extend it to the peritoneal cavity or atrium of the heart to drain excess fluid. A pressure valve is used in the shunt to regulate flow •Children with hydrocephalus if unshunted are retarded. | ||
| References • Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 1300-1301. • Poirer J et.al. Manual of basic neuropathology. Philadelphia: Saunders, 1990, pp. 202-203. Please be patient during transfer. Medline will open in a new window. To return, close the Medline Window Hydrocephalus
| Synopsis by: M. L. Grunnet M.D. (TX2000M33320)[60]
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