Friday, January 25, 2013

HIV Patient With Confusion and Disorientation

Clinical Vignette: A 42-year-old HIV-seropositive man presents to Casualty with a two-week history global headache. His partner
says that he has become increasingly confused and disorientated. The patient's latest CD4 count, taken three weeks ago, was 50 cells/mm3. He had chosen not to take antiretroviral therapy, but was taking co-trimoxazole as prophylaxis against Pneumocystis carinii pneumonia.
On examination he had mild weakness of his left arm and leg in all muscle groups and a right homonymous hemianopia. Fundoscopy was normal with no evidence of papilloedema.
A CT scan of his brain showed several areas of low attenuation in both cerebral hemispheres, but there was no enhancement with contrast and no mass effect. What is the most likely diagnosis?

  1. Cerebral lymphoma
  2. Cerebral toxoplasmosis
  3. HIV encephalopathy
  4. Neurosyphilis
  5. Progressive multifocal leukoencephalopathy

Answer to clinical vignette|case: (5)

The most likely diagnosis is Progressive multifocal leukoencephalopathy (PML), a demyelinating disease
seen in advanced HIV/AIDS and caused by the JC virus.
Cerebral lymphoma and cerebral toxoplasmosis are often associated with mass effect on CT brain scanning. In CNS lymphoma there is usually a solitary lesion. Cerebral toxoplasmosis is frequently associated with multiple lesions that show ring enhancement with iv contrast.
HIV encephalopathy may be associated with confusion, but is not associated with this CT appearance.
This is not a typical presentation of neurosyphilis in any of its forms.