Winning Abstracts from the 2014 Medical Student Abstract Competition: Influenza vaccine induced CNS demyelination in a fifty year old male
All Authors: Aaron Sacheli, Raymond Bauer M.D. (St. John Hospital & Medical Center, Detroit MI)
Acute disseminated encephalomyelitis (ADEM) describes a demyelinating condition of the central nervous system. It is known that 75% of cases arise from post-infectious and post-immunization events with annual incidence rates ranging from 0.4 to 0.8 per 100,000. While rare, it remains an important clinical consideration in patients with neurologic symptoms in the context of recent vaccination.
A fifty year-old, Caucasian male, presented with a course of progressive, focal, left-sided neurologic deficits within twenty-four hours after influenza vaccination. The patient has a non-contributory past medical history. Physical examination demonstrated no significant findings, except for definitive left sided weakness (3/5) and hypertonicity. Sensation to pain, temperature and vibration was intact.
The full evaluative course initially focused on a working diagnosis of acute stroke. Chest X-ray, computed tomography (CT) of the head, and CT angiography of the head and neck were all unremarkable. Carotid duplex demonstrated carotid stenosis less than 40% on the right and the left. Subsequent magnetic resonance imaging (MRI) of the brain showed scattered non-specific foci of white matter gliosis, from possible arteriopathy or venopathy. MRI of the cervical, thoracic and lumbar spine proved benign.
Cerebrospinal fluid (CSF) sample was completely normal by laboratory evaluation, and gram stain was negative with no growth on culture after seven days. Additionally, cytological analysis showed no evidence of malignancy, and there were no oligoclonal bands. Cardiology work-up, including an EKG and an echocardiogram, was normal. Post-vaccination ADEM appeared to best encompass this patient's clinical picture.
A five day course of, twice daily, intravenous methylprednisone (500mg) was prescribed, followed by a 12 day tapered course of, once daily, oral prednisone (20mg). Additionally, the patient was referred for comprehensive inpatient rehabilitation. The 12 day course of rehabilitation treatment consisted of intense Activities of Daily Living, gait, and transfer training, as well as strengthening exercises. His Functional Independence Measure score improved from 74 to 106.
Few case reports of ADEM have been noted following influenza vaccination, but only in the young and in the elderly. This report, to our knowledge, in addition to being a rare clinical occurrence, is the first to describe ADEM within twenty-four hours of influenza vaccination and the first in a middle aged patient. Though uncommon, ADEM may be encountered at both the in-patient and primary care level given the wide contingent of influenza vaccinated patients. Prompt medical management and plans for comprehensive and focused rehabilitation are pivotal to favourable clinical outcomes in these patients.