A 46-year-old female was brought to the emergency department by her husband after being found unresponsive at home. The patient had been experiencing intermittent fever episodes and dry cough for two weeks. She was seen by her primary care physician and prescribed Azithromycin for an upper respiratory tract infection (URI). Physical examination in the ED revealed a patient responsive only to painful stimuli, with equally reactive pupils and upgoing plantar reflexes. Head CT was obtained and showed a large area of vasogenic edema in the anterior left frontal lobe with midline shift. Subsequent MRI of brain revealed extensive T2 signal mainly within the white matter of the left frontal lobe and periventricular white matter of both cerebral hemispheres likely representing vasogenic edema with midline shift. Lumbar puncture was deferred due to extensive vasogenic edema and increased intracranial pressure. Given the fever and altered mental status, central nervous system infection was suspected; broad spectrum antibiotics and acyclovir were initiated. Patient was intubated for airway protection and transferred to the intensive care unit. Further imaging studies including MR venogram, chest, abdomen and pelvis CT scan were unremarkable. EEG was negative for epileptiform foci. Neurology service evaluated case and severe form ADEMS was suspected and steroid therapy was initiated.
On the fifth day of hospitalization, she was noted to have a non-reactive left pupil; subsequent head CT scan revealed worsening edema with left uncal herniation, for which underwent left decompressive hemicraniectomy and left frontal brain biopsy. The worsening vasogenic edema while on steroids prompted initiation of plasmapheresis. Brain biopsy revealed mild perivascular chronic inflammation and reactive glial cells without evidence of viral infection, neoplastic process, white matter demyelination or vasculitis. Given the recent viral URI and biopsy findings, ADEM was strongly suspected. She completed five cycles of plasmapheresis with gradual neurologic recovery. She was discharged to acute rehabilitation facility with minor neurological deficits after twenty-six days of hospital stay with tapering dose of steroids.
Discussion:
Acute disseminated encephalomyelitis (ADEM) is a rare autoimmune demyelinating disease of the central nervous system frequently triggered by viral infections or vaccines. ADEM usually produces an acute onset of multifocal neurologic symptoms, often with impaired consciousness or encephalopathy. ADEM is more frequent in children and rarely occurs in middle-aged adults, makes our case a diagnostic and therapeutic challenge due to the lack of cases described in the literature.
Conclusions:
Even though ADEM is rare in adults, it should be contemplated when there is a close temporal association between a viral infection and acute multifocal neurological deficits or encephalopathy.