27 Nov 2020

11/4/20: West Nile Encephalomyelitis

PGY2 Lianne Ho presented a case of a 56 y/o male with history of CAD s/p PCI w/ 4 stents placed 7/2019, AFib, DM complicated by diabetic neuropathy and HTN presents with 3 months of increasing fatigue and weakness in the lower extremities.  Patient was in his usual state with chronic lower back pain and bilateral LE diabetic neuropathy (more numbness than pain) until 3 months ago when he started having fatigue.  Patient reports that 1 month prior to admission, he developed symptoms similar to viral gastroenteritis with fever, nausea, vomiting, diarrhea.  Around that time, he also developed sudden onset of RLE weakness.  He was treated with antibiotics by his PMD which resolved most of his GI symptoms but his RLE weakness remained.  ROS significant for fatigue and 30lb weight loss in last three months.  Home medications include atenolol, sotalol, clopidogrel, apixaban, losartan and oral antiglycemics.   He is an occasional user of tobacco and alcohol.  He owns a painter contractor business.  He did recently travel to Palm Desert where the patient experienced bilateral LE bug bites thought to be from ants.

Vitals: T 36.4, HR 95, RR 20, BP 130/90, O2 sat 100% on RA

Physical Exam significant for normal cardiac and pulmonary exam, neuro with RLE 2/5 hip flex/ext, 2/5 knee flex/ext, 2/5 ankle DF, 4/5 ankle PF; LLE 4-/5 hip flex/ext, 4-/5 knee flex/ext, 4-/5 ankle DF, PF; reflexes absent bilaterally, negative Babinski, clonus; sensation intact bilaterally.

CBC: WBC 9.3> Hb 12.1/Hct 35.7 <Plt 255 (MCV 87.1, RDW 13.4%)

CMP:

Na 137/K 3.7/Cl 101/HCO3 20/BUN 56/Cr 1.11 <Glucose 160 (Baseline Cr: 0.7)

ALP 92>T.protein 8/Albumin 4.1/AST 49/ALT 36/Tbili 0.6

Ca 8.8, Mg 1.9, Phos 2.8

Coags: PT 14.8, INR 1.1, PTT 27.6

Rheumatology was consulted given concern for possible dermatomyositis vs polymyositis vs vasculitis; however autoimmune panel including ANCA, CK, anti-Jo1 returned negative.

Imaging with MRI brain was negative for acute intracranial abnormalities.  MRI C/T spine showed scattered mild to moderate spinal canal stenosis, most notable at C3-4 where moderate spinal canal stenosis results in cord contact without cord signal abnormality.  There is also indentation of the ventral cord at T7-8 with mild spinal canal stenosis.  L4-5 left foraminal disc protrusion with mass effect on the left L4 exiting nerve root and the descending left L5 nerve root.

EMG study highly consistent with an active neurogenic process affecting multiple myotomes of the bilater LE and also the mid to low lumbar paraspinal muscles.

Infection workup was pursued with a LP that showed WBC 36 (predominant lymphocytes), glucose 84 and protein 180 (H).  CSF viral panel revealed West Nile IgM to be elevated.

Treatment: Patient was treated symptomatically and he improved enough to be accepted to acute rehab to continue with Physical Therapy.

Teaching points:

  1. West Nile Virus will have initial symptoms of fever, headache, GI symptoms and can progress to meningitis/encephalitis. Specific to West Nile is acute onset of asymmetric flaccid paralysis, extrapyramidal symptoms (upper > lower extremity) and Parkinsonian symptoms (eg rigidity).
  2. Diagnosis for West Nile encephalomyelitis is with CNS fluid.
  3. Treatment is supportive management. There has been unclear evidence to support treatment with glucocorticoids (clinical trial currently undertaking).

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