4/21/2009 Case 4: Rabies (by bat)

Presented by: Dr. Sharer (sent by Dr. Miller) - University of Missouri

Clinical History:

Case involves an episode preceding tremor onset by about a month wherein a wild bat kept as a pet by the patient bit him on the ear.  The patient sought no treatment or further evaluation (even though he was living with a nurse).  Following a presumptive diagnosis of rabies, coma was induced using the “Milwaukee protocol” (pharmacologically induced coma with ketamine, lorazepam, midazolam) that seeks to preserve neurons.  Apparently this has only been successful in one patient.  The skin biopsy presumably used immunofluorescence for diagnosis.  Autopsy was done with full body suits and respirators, and otherwise universal precautions were taken.  Dr. Miller reports that nobody attending the autopsy has yet fallen ill, as of April 2009 (the autopsy was done in November 2008).

Diagnostic Notes:

Histologically, Negri bodies are present in Purkinje neurons and in pyramidal neurons in the hippocampus, reconfirming the clinical diagnosis of rabies, which currently in the United States is usually spread by bats.  Histology also showed some perivascular chronic inflammation in the brain, but virus was not seen by electron microscopy, only lamellar inclusion bodies, a normal finding in Purkinje cells given as a “bonus question” by Dr. Miller (nobody in attendance knew what they were).  The patient’s course included renal problems, and the virus apparently can affect renal tubular epithelial cells.

Slide Image:

view high resolution slide image