• CLINICAL INFECTIOUS DISEASES
• CHEMISTRY
• VIRUS

In the published literature on Eastern equine encephalitis, a description of serum creatine kinase changes has not been found. Here, in three cases of Eastern equine encephalitis, there was a consistent pattern of levels of serum creatine kinase consisting of an increase to a maximum and then a decline.

Case 1: A man in his 70s was admitted to hospital 4 days after onset of headache and speaking difficulty. Medications included furosemide 10 mg, spironolactone 12 mg, hydrochlorothiazide 12 mg and simvastatin 10 mg/day. Physical examination demonstrated lethargy, meningeal signs and left upper extremity paresis and lower extremity paresis. Laboratory reported cerebrospinal fluid containing Eastern equine encephalitis virus nucleic acid meeting the criteria for a confirmed case.1 Elevation of serum total creatine kinase (CK) (normal 20–200 units/L) was noted 4 days after, and peaked 7 days after, onset of symptoms (figure 1). Creatinine kinase – myocardial isoenzyme (CK-MB) levels were 3.1, 2.7, 1.9, 3.1, 13.9, 4.9, 2.6 and 2.9 ng/mL (normal 0.0–5.0) (figure 1). Serum troponin T levels were 0.1 and 0.1 ng/mL (normal 0.0–0.1). MRI of the brain shows abnormal left basal ganglia and bilateral caudate, thalamus, putamen and temporal lobes. At 5 days, parkinsonian rigidity developed. At 11 days, coma and apneic episodes developed. At 16 days after onset of symptoms, the patient was pronounced dead. Autopsy was not performed.2