We know that HIV attacks T helper cell and makes the failure of cell mediated immunity. Besides destroys immune system HIV also destroys Central Nervous System (CNS) too. This condition is called HIV-associated encephalopathy. On this condition patients can get dementia or delirium.
HIV enters the brain through HIV-infected monocytes and other infected CD4+ cells. Then it infects other cells (such as microglia, oligodendrocytes, astrocytes, and neurons). HIV enters the CNS by transcytosis of endothelial cells. In immunohistochemistry studies, HIV is located in basal ganglia, subcortical regions, and frontal cortex. This condition makes people can get cognitive impairment, motor deficiencies, behavioral disorder. Without treatment this condition may get worse progressively (mean survival rate 3-6 months).
In infants, this condition is difficult to diagnose. Physical examination findings are often normal. Manifestation of this condition may not be noticeable until age 2-3 years. At this time, children may present with cognitive impairment, masklike facies, acquired microcephaly, and pseudobulbar and corticospinal tract signs. Common findings in older children and adolescents are impaired attention, decreased linguistic and scholastic performance, psychomotor slowing, emotional lability, and social withdrawal. Examination findings are similar to those in adults with ADC.
Criteria for HIV-associated progressive encephalopathy
The American Academy of Neurology defines HPE as the presence, for at least 2 months, of at least one of the following progressive findings in a pediatric patient with no concurrent illness, other than HIV infection, that could explain the findings :
- Failure to attain, or loss of, developmental milestones or loss of intellectual ability verified by standard developmental or neuropsychological tests
- Acquired microcephaly as demonstrated by head circumference measurement or brain atrophy on serial computed tomography (CT) or magnetic resonance imaging (MRI) imaging in children younger than 2 years of age
- Acquired symmetrical motor deficits manifested by 2 or more of the following: paresis, pathological reflexes, ataxia or gait disturbance
So, we must take more concern about this condition in children. Manifestation is not as clearly as adult.
Reference:Niranjan N Singh, MD, DNB. 2011. HIV encephalopathy and AIDS dementia complex. emedicine.medscape.com.