Serum HIV testing is required for the diagnosis. In addition, HIV characterization of the cere- ﬂuid versus in the plasma. Neuroimaging (i.e., magnetic resonance imaging [MRI]) may reveal reduction in total brain volume, cortical thinning, reduction in white matter volume, and patchy areas of abnormal white matter (hyperintensities). MRI or lumbar puncture may be helpful to exclude a specific medical condition such as cryptococcus infection or herpes en- cephalitis that may contribute to CNS changes in the context of AIDS. Specialized techniques such as diffusion tensor imaging may reveal damage to specific white matter tracts.
Functional Consequences of Major or Mild
Neurocognitive Disorder Due to HIV Infection
Functional consequences of major or mild NCD due to HIV infection are variable across individuals. Thus, impaired executive abilities and slowed information processing may substantially interfere with the complex disease management decisions required for ad- herence to the combined antiretroviral therapy regimen. The likelihood of comorbid dis- ease may further create functional challenges.
In the presence of comorbidities, such as other infections (e.g., hepatitis C virus, syphilis), drug abuse (e.g., methamphetamine abuse), or prior head injury or neurodevelopmental conditions, major or mild NCD due to HIV infection can be diagnosed provided there is ev- idence that infection with HIV has worsened any N CDs due to such preexisting or comorbid conditions. Among older adults, onset of neurocognitive decline related to cerebrovascular disease or neurodegeneration (e.g., major or mild NCD due to Alzheimer’s disease) may need to be differentiated. In general, stable, ﬂuctuating (without progression) or improving neurocognitive status would favor an HIV etiology, whereas steady or stepwise deter- ioration would suggest neurodegenerative or vascular etiology. Because more severe im- munodeficiency can result in opportunistic infections of the brain (e.g., toxoplasmosis; cryptococcosis) and neoplasia (e.g., CNS lymphoma), sudden onset of an NCD or sudden worsening of that disorder demands active investigation of non-HIV etiologies.
HIV disease is accompanied by chronic systemic and neuro-inﬂammation that can be as- sociated with cerebrovascular disease and metabolic syndrome. These complications can be part of the pathogenesis of major or mild NCD due to HIV infection. HIV frequently co- occurs with conditions such as substance use disorders when the substance has been in- jected and other sexually transmitted disorders.
Due to Prion Disease
A. The criteria are met for major or mild neurocognitive disorder.
B. There is insidious onset, and rapid progression of impairment is common.
C. There are motor features of prion disease, such as myoclonus or ataxia, or biomarker evidence.
Major or Mild Neurocognitive Disorder Due to Prion Disease 635
D. The neurocognitive disorder is not attributable to another medical condition and is not better explained by another mental disorder.
Coding note: For major neurocognitive disorder due to prion disease, with behavioral dis- turbance, code first 046.79 (A81.9) prion disease, followed by 294.11 (F02.81) major neurocognitive disorder due to prion disease, with behavioral disturbance. For major neu- rocognitive disorder due to prion disease, without behavioral disturbance, code first 046.79 (A81.9) prion disease. followed by 294.10 (F02.80) major neurocognitive disorder due to prion disease, without behavioral disturbance.