A 38-year-old woman comes to the emergency department with 7 days of fatigue and headache that has worsened in intensity today. She also reports an episode of vomiting. The patient is accompanied by her roommate, who has noted no confusion or personality changes. On physical examination she is awake, alert, and conversant. Her temperature is 38.3 C (101 F) and pulse is 84/min. Her neck is supple. Oropharynx examination shows thrush. Lungs and cardiovascular examination is normal. Neurological examination shows no focal deficits. Ophthalmological examination shows bilateral papilledema. An MRI of the brain is normal. A rapid HIV test is positive. Which of the following is most likely to establish a diagnosis?

Question

A 38-year-old woman comes to the emergency department with 7 days of fatigue and headache that has worsened in intensity today.  She also reports an episode of vomiting.  The patient is accompanied by her roommate, who has noted no confusion or personality changes.  On physical examination she is awake, alert, and conversant.  Her temperature is 38.3 C (101 F) and pulse is 84/min.  Her neck is supple.  Oropharynx examination shows thrush.  Lungs and cardiovascular examination is normal.  Neurological examination shows no focal deficits.  Ophthalmological examination shows bilateral papilledema.  An MRI of the brain is normal.  A rapid HIV test is positive.  Which of the following is most likely to establish a diagnosis?

Quizplus · Accepted Answer

11ec25c8_d461_aafb_bc81_377a62ae4d4c_MD0003_00 The patient presents with fevers, headaches, and signs of elevated intracranial pressure (eg, vomiting, papilledema). In immunocompromised patients with HIV, this is most consistent with cryptococcal meningitis, typically seen in patients with CD4 counts <100/mm³. Cryptococcus neoformans is an invasive fungus acquired by the inhalation of spores that primarily causes pulmonary disease. Immunocompromised patients can develop central nervous system infection leading to meningoencephalitis. The classic presentation is indolent (eg, progressing over days to weeks), and neck stiffness and photophobia are absent in the majority of patients. Diagnosis is established through cryptococcal antigen testing of cerebrospinal fluid (CSF). CSF India Ink stain or culture on Sabouraud agar may also identify the organism. Other features include an elevated opening pressure, low glucose, high protein, and a lymphocytic pleocytosis (although white cells may be reduced in HIV patients). Increased intracranial pressure develops due to the occlusion of CSF flow by the organism. Neuroimaging is performed to exclude mass lesions, although C neoformans infection rarely causes mass lesions in patients with HIV. If no such lesion is found, a lumbar puncture can be performed; it both provides diagnostic confirmation and offers therapeutic value in the relief of elevated intracranial pressure. Some patients require serial lumbar punctures in addition to antifungal therapy to control intracranial pressure. (Choice B) Cytomegalovirus typically causes retinitis (eg, floaters, blurry vision) in patients with HIV who have CD4 counts <50/mm³. Papilledema is usually not seen and MRI may show periventricular enhancement. (Choice C) Herpes simplex virus 1 (HSV-1) infection can cause encephalitis in both immunocompetent and immunocompromised patients. Cognitive and personality changes, as well as focal neurological deficits and/or seizures, are more common in HSV infection due to the temporal lobe involvement (seen on MRI). Absence of these features suggests cryptococcal meningoencephalitis as the more likely diagnosis in this patient. (Choice D) JC virus causes progressive multifocal leukoencephalopathy, an opportunistic infection seen in patients with HIV that can be detected on polymerase chain reaction testing of cerebrospinal fluid. Neuroimaging usually shows patchy areas of white matter consistent with demyelination. (Choice E) Serum toxoplasma antibody tests for prior exposure to Toxoplasma gondii. Reactivation of T gondii in patients with AIDS most commonly presents with a ring-enhancing mass lesion seen on neuroimaging. Educational objective: Patients with HIV who have subacute-onset of low-grade fever, headache, and signs of increased intracranial pressure should be evaluated for cryptococcal meningitis. Diagnosis is established by detection of the cryptococcal antigen or isolation of the organism in cerebrospinal fluid. References: New insights into the prevention, diagnosis, and treatment of cryptococcal meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/22763808) HIV-associated cryptococcal meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/18090038)

A 38-Year-Old Woman Comes to the Emergency Department with 7