HIV-associated dementia

HIV-associated dementia (HAD), previously referred to as AIDS dementia complex (ADC), corresponds to a neurological clinical syndrome seen in patients with HIV infection. The associated imaging appearance is generally referred to as HIV encephalopathy.

Terminology

The terms HIV dementia complex, AIDS dementia complex (ADC), HIV-associated dementia (HAD) and HIV encephalopathy (HIE) are being replaced by more clear definitions for the spectrum HIV-associated neurocognitive disorder (HAND). The progressive impairment formerly described as AIDS dementia complex is now referred to as HIV-associated dementia (HAD) ^4,5. 

Clinical presentation

The clinical syndrome of HIV-associated dementia comprises of a combination of cognitive, behavioral and motor dysfunction like gait disturbance and tremors. While there is some individual variation, frequent manifestations include: inattention and reduced concentration, apathy and dulling of personality, psychomotor slowing, marked motor slowing and ataxia. 

Radiographic features

CT

Imaging findings include:

• diffuse and symmetric cerebral atrophy, out of proportion in keeping with the age of the patient 

• symmetric periventricular and deep white matter hypoattenuation

MRI

• symmetric periventricular and deep white matter T2 hyperintensity with relative sparing of the subcortical white matter and posterior fossa structures

• confluent or patchy

• no mass effect

• no enhancement

MR spectroscopy

MR spectroscopy shows decreased N-acetyl aspartate and increased choline peaks and changes in the glutamate and glutamine levels. 

Treatment and prognosis

Severity is related to the patient's viral load and can regress with antiretroviral therapy (ART). Superimposed infection may lead to fulminant disease. Overall prognosis is not good, generally leading to death in less than a year ⁵.

History and etymology

The term AIDS dementia complex was introduced by Bradford Navia, an American neurologist, and colleagues in 1986 ⁴. It was renamed "HIV-associated dementia" by Antinori et al. in 2007 ^5,6.

Differential diagnosis 

• progressive multifocal leukoencephalopathy (PML)

• HIV-associated CD8+ encephalitis

• cerebral small vessel disease

  • subcortical arteriosclerotic encephalopathy

  • cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

• leukodystrophies