Case Study 37 By Chris Sanders

History of Present Illness 86 y.o. male Mosquito bite Swelling around right eye Bit 96 hours ago Severe periorbital edema Mild fever Mild headache

Review of Systems Alert and oriented Doctor suspects arthropod Follow up appointment with neurologist and infections diseases specialist OTC ibuprofen Ice to swollen area

Acute Viral Encephalitis What is the pathophysiology of swelling in this case? Why is the application of ice helpful to relieving swelling in this case? Based on the patient’s location when he received the mosquito bite, what are several possible diagnoses? Based on incubation period only, identify two potential types of encephalitis in this patient. Are any of the infections that you listed above in your answer to question 3 potentially serious?

Clinical Course Confused Disoriented Mild tremors Severe headache

Previous Medical History 18 months S/P cadaveric renal transplantation ESRD secondary to DM type 1, diagnosed 10 yrs CAD COLD x 6 yrs Asthma DM type 1 diagnosed at 13

Medications Nitroglycerin SR 6.5 mg po Q 8h Nitroglycerin 0.4 mg SL PRN Theo-Dur 100 mg po BID Albuterol MDI 2 puffs QID PRN Atrovent MDI 2 puffs BID Cyclosporine 250 mg po BID Prednisone 10 mg po QD Mycophenolate mofetil 1500 mg po BID Insulin: NPH insulin 16 u @ breakfast and Lispro Blood Glucose (mg/dL) Units @ breakfast Units @ lunch Units @ supper Units @ Bedtime <80 4 - 81-150 5 8 151-200 6 9 1 201-250 7 2 10 251-300 3 11 301-350 12 351-400 13 >400 14

Three of the drugs listed above are of particular concern in this patient. Which three drugs should cause concern and why should they cause concern?

Nitroglycerin Dizziness, headaches, lightheadedness Theo-Dur Dizziness, headaches, lightheadedness Albuterol Dizziness, headaches Atrovent Headache, eye pain Cyclosporine/Prednisone Suppresses immune system Mycophenolate mofetil Suppresses immune system

PE and Lab Tests Disoriented, pale, mild tremors, appears ill BP 150/95 P 105 and regular RR 17 and unlabored T 100.5º F Warm and pale skin No rash observed

PE and Lab Tests Cont. PERRLA EOM intact Fundi reveal old laser scars bilaterally w/o hemorrhages and occasional hard exudates bilaterally Ears and nose unremarkable with no bulging of TMs Mucous membranes dry Mild non-exudative pharyngitis present Wears dentures

PE and Lab Tests Cont. Thyroid normal Cervical and axillary lymph nodes palpable (~2cm) Sinus tachycardia Chest normal Abd normal Rect normal Ext normal

PE and Lab Tests Cont. Disoriented Mild tremor in both hands DTRs 2+ (+) Kernig sign (+) Brudzinski sign Muscular strength 3/5 Decreased sensation in feet (diabetic neuropathy)

Suggest a reasonable explanation for the laser scars in the eyes? Suggest a reasonable pathophysiologic explanation for the patient’s enlarged lymph nodes. Although not routine practice, why were this patient’s feet carefully examined for lesions? What is suggested by the positive Kernig and Brudzinski signs?

Lumbar Puncture Results Significant lymphopenia Mild diffuse cerebral edema with no intra-cerebral bleeding CSF lymphocytosis Normal glucose No CSF RBCs Moderately elevated protein Normal lactic acid Gram stain (-) Bacterial culture (-) IgM antiviral antibody (+) Enzyme Immunoassay with Plaque Reduction Neutralization Test West Nile Virus

Based on all the available clinical evidence above, what is a likely diagnosis for this patient’s condition? What is an appropriate treatment approach for this patient?