Winning Abstracts from the 2009 Medical Student Abstract Competition: Cryptococcal Meningoencephalitis Masquerading as a Brainstem Stroke
Authors:
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
Introduction:
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.
Case Presentations:
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/mm鲁, 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.
Discussion:
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.