HIV Involving Nervous System
CNS INVOLVEMENT OF HIV:
- Cerebral involvement:
- AIDS dementia complex
- Vacuolar myelopathy
- HIV -1 associated neuronopathy is characterized by
- infiltration of macrophages into the CNS
- formation of microglial nodule
- multinucleated giant cell
- Astrocyte activation and damage
- neuronal loss particularly in Hippocampus, Basal ganglia, Caudate nucleus.
PATHOLOGICAL FEATURES OF BRAINS IN AIDS :
Gross:
- Encephalitis: frontal /temporal cortical atrophy
Histology:
- Meningitis with mild lymphocytic infiltrates and scanty perivascular inflammation
Features of giant cell (HIV) encephalitis are:
- Presence of microglial nodules
- Pericapillary aggregates of multinucleated giant cells having generous or scanty neoplasm
- Perivascular lymphocytic cuffing
In leukoencephalopathy:
- there is diffuse demyelination
- infiltration of macrophages and multinucleated giant cells.
Toxoplasmosis
- Most common space occupying lesion in HIV infected
- CT scan – multiple contrast-enhancing lesions, tend to be peripheral, predilection for the basal ganglia
- Sing
- le lesions are atypical of toxoplasmosis
MENINGITIS IN AIDS:
- Opportunistic infections occurs with CD4 counts below 200.
- Most common organism that causes acute meningitis in an AIDS patients is Cyptococcus neoformans.
Creutzfeldt-Jakob Disease
- Caused By prion Protein
- On light microscopy
- spongiform degeneration
- astrogliosis.
CNS Tumors
| Astrocytoma | Oligodendroglioma | Ependymoma |
|
Origin from astrocytes Most common primary brain tumor in adults GFAP Positive Glioblastoma multiforme is grade IV astrocytoma Crosses midline (Butterfly Glioma) Pseudopallisading Necrosis Common in white matter |
Origin From oligodendrocytes Fried Egg Appearance Chicken wire pattern of capillaries Slow growing |
Usually in ventricular system Ependymal rosettes Perivascular pseudorossettes Often causes hydrocephalus |
CNS LYMPHOMA:
Primary CNS lymphoma
- relatively common type of lymphoma in AIDS patients
- shows multicentric mass lesions in the brain and meninges
- derived from B-lymphocytes
Presenting symptoms include
- seizures
- headache
- cranial nerve deficits
- The lesions are often multicentric.
- Primary CNS lymphoma is typically a late manifestation of AIDS (median CD4 count 40/μl).
Ependymomas
- Tumors derived from ependymal cells
- Produce rosettes or perivascular pseudorosettes
Melanoma
- Neoplasm arising from transformation of melanocytic cells.
SEIZURES IN AIDS:
It may be due to:
- HIV encephalopathy(24-47%)
- Cerebral Toxoplasmosis(28%)
- Cerebral lymphoma(4%)
- Cryptococcal meningitis(13%)
Progressive multifocal leukoencephalopathy(1%)
- It is due to Polyoma JC Virus
- In immunocompromised states.
- Demyelination and Astrogliosis are a feature.
Treatment :
- The mainstay of definitive therapy is chemotherapy including high-dose methotrexate.
- A single dose of rituximab is generally administered prior to cytotoxic chemotherapy
Exam Question
- Progressive multifocal leukoencephalopathy is the least common cause of seizures in AIDS
- Pathologic features of brain in AIDS includes microglial nodule, Pericapillary aggregates of multinucleated giant cells having generous or scanty neoplasm , Perivascular lymphocytic cuffing, demyelination and infiltration of macrophages and multinucleated giant cells.
- Cryptococcus neoformans is the most common cause of acute meningitis in an AIDS patient
- Primary CNS lymphoma shows multicentric mass lesions in the brain and meninges derived from B-lymphocytes
- Diffuse white matter pallor, Perivascular infiltrates of lymphocytes and macrophages, Foci of necrosis, gliosis and / or demyelination, Microglial nodules, macrophages and multinucleated cells e the Histopathological features of HIV encephalitis
- Perivascular lymphocytes & microglial nodules are seen in HIV encephalitis
- Primary CNS lymphoma is the Most common CNS neoplasm in HIV patient
- HIV associated neuronal loss occurs particularly in Hippocampus, Basal ganglia, Caudate nucleus.
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