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| Edema |
| Etiology •May be due to tumor, trauma, infection, metabolic disease, vascular disease or toxins. |
| Pathogenesis •There are two types of edema - vasogenic and cytotoxic. •In vasogenic edema, seen in infection, vascular disease trauma and tumor, the blood brain barrier is defective and fluid enters the interstitial space. •In cytotoxic edema the Na-K pump breaks down as does Calcium transport so fluid enter the cells including neurons. •In both cases astrocytes swell., |
| Epidemiology •See etiology. |
| General Gross Description •Edema causes brain swelling with flattening of gyri and narrowing of the sulci. •It can also cause subfalcial transtentorial and foramen magnum herniation with shift of the cingulate gyrus under the falx in asymmetrical swelling and uncal grooving and tonsillar hernation. •The brain generally has a congested appearance. |
| General Microscopic Description •Microscopically edema is characterised by vacuolization or spongy change of the neuropil and pericellular vacuolization as well as pallor of the tissue and swollen astrocytes. •In cytoxic edema neurons and myelin sheaths may also be swollen. |
| Clinical Correlation •Severe cerebral edema produces increased intracranial pressure with headache and lethargy at first followed by coma, third nerve palsy (dilatation of the pupils and hemiparesis) due to compression of the cerebral peduncle containing the corticospinal tract against the tentorium. •This is followed by decerebrate rigidity with folding of the arms and extension of the legs. |
| References • Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 1299-1300. • Greenfield's Neuropathology, 6th ed. Graham DI, Lantos PL (ed), New York: Arnold, 1997, pp. 166-173. |
| Edema |
| Synopsis by: M.L. Grunnet M.D. (TX2000M36500)[400] |
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