HIV Encephalopathy vs PML

Listed are the pathologies that closely resemble each other, and these pathologies are the favourite questions in final FRCR part A exam.

HIV vs PML

	HIV Encephalopathy	Progressive Multifocal Leukoencephalopathy (PML)
1	Commonly frontal region	Commonly posterior (parietal) region
2	Usually in white matter, centrum semiovlae	Characteristically involve subcortical U-fibers
3	Characteristically spare grey matter	Affects grey matter
4	Cerebral atrophy Confluent white matter oedema	Mild cortical atrophy Single/Multiple hypodense white matter w/o mass effect/oedema ↓T1; ↑T2/FLAIR
5	Tend not to enhance	No contrast enhancement
6	Bilateral but Asymmetrical
7	Due to HIV	Due to reactivation of JC virus (John Cunningham)
8	Progressive dementia	Seen in 2-4% of AIDS cases Poor prognosis (death in ¬6mo)
9	Demyelinating plaques	Destruction of oligodendrocytes => demyelination
10	-	A/w Autoimmune disease, Sarcoidosis Immunosuppressive Rx, Transplantation Lympho/myeloproliferative disease Nontropical sprue, Whippel disease TB, AIDS, Carcinoma