A 19-year-old healthy male fell into stagnant water of the intercostal waterway (salt water of South Florida), following a jet ski accident. He sustained minor superficial injuries but engulfed significant quantities of water and sediment. Two to three days later he developed meningitis-type symptoms necessitating hospital admission (e.g. bifrontal headaches, vomiting, a stiff neck and a temperature of 102 F. A CT scan on admission without contrast was negative. CBC and electrolytes were within normal limits as were BUN and creatinine. A lumbar puncture revealed markedly elevated white count in the cerebrospinal fluid (466 WBC with 85% neutrophils, 5% lymphocytes, a protein of 49 and normal glucose). He became progressively lethargic. On the 5th day he developed seizure activity. His subsequent CSF cultures were negative for bacterial organisms and fungi. Cryptococcal AG was negative. The clinical impression was: purulent leptomeningitis in which bacteria were not found. He was treated aggressively with Rocephin but became progressively worse. On the 6th day he was totally unresponsive with fixed and dilated pupils. He was placed on hyperventilation and later that day was declared brain dead. Life support was removed.
GROSS NEUROPATHOLOGIC FINDINGS:
The brain weight after fixation was 1630 grams. There was diffuse gyral flattening and sulcal narrowing. A thick leptomeningeal exudate covered the basal cisterns, particularly the perichiasmatic zone, the ventral pons, and the cisterna magna (Figure 1). Hippocampal unci were prominent and massive cerebellar tonsillar herniation with medullary compromise was evident (Figure 1). There was inflammatory exudate over the lower third of the gyri recti, but olfactory tracts and triangle showed no congestion or petechiae. The herniated cerebellar tonsils showed hemorrhagic necrosis along their tips (Figure 2 arrowhead). Coronal sections of the cerebral hemispheres revealed cortical hemorrhagic softenings, mostly in sulcal depths in the anterior frontal zone (Figure 3). Basal ganglia, thalami and mammillary bodies were grossly unremarkable. There was no hydrocephalus. The rostral brainstem was grossly unremarkable.