Winning Abstracts from the 2009 Medical Student Abstract Competition: Cryptococcal Meningoencephalitis Masquerading as a Brainstem Stroke
Evan Hardegree, ACP Medical Student Member, Michael Moffitt, MD, PhD, Department of Medicine, Texas A&M Health Science Center College of Medicine/Scott & White Memorial Hospital, Temple, TX
Cryptococcal meningoencephalitis is rare among HIV-negative, immunocompetent patients, and is uniformly fatal if untreated, making its diagnosis in such patients both challenging and essential.
A 48 year old male presented with a six-week history of global headache associated with diplopia, dysphagia, emesis, and weight loss of forty pounds. Following onset of his headache, he had experienced severe hypertension requiring antihypertensive medication, followed by collapse and altered mental status. His past medical history was unremarkable; however, he worked outside as an air conditioner installer in southeast Texas. On examination, he had diplopia with bilateral abduction deficits, dysdiadochokinesia, difficulty with finger-to-nose testing, and unsteady gait. His vital signs and initial labs were normal. His cranial nerve abnormalities (dysphagia, diplopia, eye abduction deficits) suggested brainstem infarction, but MRI revealed only a small subacute cerebellar infarct. Thus, lumbar puncture was performed, and CSF analysis revealed glucose of 18 mg/dl, protein of 74.7 mg/dl, and a white blood cell count of 514/mm³, with 95% lymphocytes. Cryptococcal antigen was positive, CSF culture confirmed Cryptococcus neoformans, and he was diagnosed with cryptococcal meningoencephalitis. Further testing showed he was HIV-negative, with a normal immune profile. He was treated for six weeks with amphotericin B and flucytosine, showing significant clinical improvement, and was discharged on oral fluconazole suppression therapy.
This is a fascinating case of an immunocompetent man who contracted cryptococcal meningoencephalitis, likely from exposure to fungal spores while working outdoors as an air conditioner installer. Increased intracranial pressure caused the headache, nausea, altered mental status, and multi-cranial nerve dysfunction, as well as the hypertensive episode, which was probably due to the Cushing reflex. The appropriate diagnosis was challenging, as this man's history of a hypertensive episode followed by altered mental status, dysphagia, and Abducens Nerve paresis suggested malignant hypertension leading to brainstem stroke. His significant smoking history and family history of stroke further supported this notion. However, MRI findings were inconsistent with this diagnosis, and other possibilities had to be considered. His unremarkable past medical history, immunocompetent state, and lack of fever, lymphadenopathy, and leukocytosis all decreased our suspicion of infectious etiologies. Certainly, fungal meningoencephalitis was not initially a strong consideration. Nonetheless, he had evidence of central nervous system dysfunction without a clear cause, and infectious and neoplastic etiologies had not yet been ruled out. Thus, using a broad differential diagnosis and a systematic approach, lumbar puncture was the next logical step. This revealed the definitive diagnosis and illustrated the importance of keeping an open mind and using a systematic approach in working up such cases.