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Difficulty: HardInfectious Diseases

Match each clinical presentation in a patient with advanced HIV infection to the most likely central nervous system etiology.

  • A 35-year-old patient with a CD4 count of 80 cells/mm³ presents with fever, seizures, and hemiparesis. Brain MRI reveals multiple ring-enhancing lesions predominantly in the basal ganglia and cerebral cortex.Toxoplasma gondii encephalitis
  • A 42-year-old patient with a CD4 count of 30 cells/mm³ presents with focal neurologic deficits. Brain MRI demonstrates a solitary, large, weakly ring-enhancing periventricular lesion. Cerebrospinal fluid PCR is positive for Epstein-Barr virus.Primary central nervous system lymphoma
  • A 39-year-old patient with a CD4 count of 45 cells/mm³ develops progressive aphasia, ataxia, and hemiparesis without fever. Brain MRI demonstrates asymmetric, non-enhancing white matter lesions lacking mass effect.Progressive multifocal leukoencephalopathy
  • A 45-year-old patient with a CD4 count of 90 cells/mm³ presents with a 2-week history of severe headache, nausea, and photophobia. Lumbar puncture reveals an opening pressure of 320 mm H₂O and encapsulated budding yeast.Cryptococcal meningitis
  • A 50-year-old patient with prolonged, untreated HIV infection exhibits progressive memory loss, apathy, and psychomotor slowing over 6 months. Brain MRI shows diffuse cortical atrophy and symmetric periventricular white matter pallor.HIV-associated neurocognitive disorder

Answer

The correct pairings match each clinical vignette to its corresponding HIV-associated central nervous system complication based on CD4 count thresholds, distinct neuroimaging characteristics, and cerebrospinal fluid findings.
Each diagnosis represents a distinct opportunistic condition in advanced HIV, distinguishable by unique neuroimaging patterns (enhancing vs. non-enhancing, solitary vs. multiple, mass effect vs. no mass effect), focal versus global neurologic symptoms, and specific cerebrospinal fluid analysis findings.

Step-by-Step Solution

1
Analyze the first clinical vignette focusing on CD4 count (< 100 cells/mm³), symptoms (seizures, focal deficits), and MRI findings (multiple ring-enhancing lesions in basal ganglia).
Identified as Toxoplasma gondii encephalitis.
This is the most common cause of focal brain lesions in patients with AIDS, characterized classically by multiple enhancing lesions in the deep white matter and basal ganglia.
2
Analyze the second vignette focusing on the solitary, large periventricular mass and positive CSF Epstein-Barr virus PCR.
Identified as Primary central nervous system lymphoma.
Primary CNS lymphoma in HIV is an AIDS-defining malignancy heavily associated with EBV, presenting typically as a solitary, weakly enhancing periventricular mass.
3
Evaluate the third vignette noting the lack of mass effect, non-enhancing asymmetric white matter lesions, and subacute focal deficits.
Identified as Progressive multifocal leukoencephalopathy.
PML is a demyelinating disease caused by JC virus reactivation, classically appearing on MRI as patchy, non-enhancing white matter lesions without edema or mass effect.
4
Review the fourth vignette recognizing the high CSF opening pressure and presence of encapsulated budding yeast.
Identified as Cryptococcal meningitis.
Cryptococcal neoformans characteristically causes severe meningoencephalitis with highly elevated opening pressures; encapsulated budding yeast is pathognomonic on India ink or histopathology.
5
Assess the final vignette identifying the gradual cognitive decline combined with symmetric atrophy and white matter changes.
Identified as HIV-associated neurocognitive disorder.
HAND (including HIV dementia) presents with progressive cognitive and motor decline; MRI reflects generalized brain volume loss and diffuse, symmetric white matter signal abnormalities without focal lesions.

Key Concept

Differential diagnosis of central nervous system lesions and infections in patients with advanced HIV, utilizing neuroimaging, CD4 count, and CSF analysis.
Estimated Time:2m 0s
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Topics

Infectious Diseases

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