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Introduction:
Recognized in 1982 – dreaded disease of the20th century
40 million (WHO) in 2000 - India 5 million
HIV is a retrovirus that grows in T Helper Lymphocytes
leading to their progressive depletion & susceptibility to
opportunistic infection
With earlier, more accurate and specific diagnosis of HIV
infection , longevity resulting in more affliction of other systems
Reduction/prevention of opportunistic infection most
significant development in management of HIV. Full blown AIDS can be
postponed even to 10 years.
With no vaccine yet available, behavioral changes appear to
be the only way to reduce the prevalence of HIV infection
Today it is possible to preserve health and prolong life
Treatment still imperfect, costly and demanding
Post exposure prophylaxis (Zidovudine ) ???
Transmission in health workers only thro’ cuts from
contaminated needles and splashes on mucous membrane from blood, semen,
breast milk, cervicovaginal secretions and CSF. Saliva alone has not been
proved to be a transmitting agent.
Refusal to treat HIV patient US Supreme Court ruling
CDC universal precautions triple latex gloving, thimble
protection
Specific effects on the CNS:
40 TO 70% of HIV infected patients develop symptomatic
neurological disorders often debilitating and life threatening. Autopsy
studies reveal 90% CNS involvement
Diagnosis difficult as those with HIV infection may also
have coexisting alcoholism, diabetes, migraine, cervical spondylosis, HNP
etc. all of which are common in the general population
Localization complex as multiple levels may be involved
simultaneously or sequentially
Clinically, often mild neurological changes are overlooked
in the face of other life threatening problems
Drug induced, metabolic and nutritional factors could
account for many neurological manifestations rather than HIV infection of
the CNS per se
30%-40% present with neurological signs and symptoms at time
of AIDS diagnosis, 12% have some complaint of neurological dysfunction
and 10% have no neurological complaints.
Nitric Oxide implicated as a potential mediator of BBBB in
AIDS
Neurological complications length of stay and total
hospital charges for HIV infected patients (16.3 vs 9.3 days,)
Decision making for treating AVM etc.
Diagnosis:
CSF studies for identifying HIV virus, and various other
opportunistic infective pathogens with appropriate PCR.
Serum immunoglobulin studies – indirect evidence
Quantitative measurement of HIV antigen
Detailed CD4 Cell count
CT/MRI
Stereotactic biopsy - safe and effective.
Algorithm for evaluation of AIDS patient with neurological
diseases.
Impact of ‘neurological AIDS’
1995: # Equal to those with epilepsy, > Parkinson’s
disease, 11000 stereotactic biopsy’s in AIDS patients in the USA >>
incidence of malignant astocytoma, meningiomas
Poll of neurosurgeons in the US in ’89 indicated that 90%
would perform a surgical procedure if it would have a +ve impact on
patient care
The future : Astroglial cells represent
a target for HIV infection in the central nervous system.. However,
activation of the nuclear factor NF-kappaB and its binding to HIV long
terminal repeat (LTR) can induce HIV replication. Moreover, nitric oxide
(NO) can affect NF-kappaB activation in glial cells. NO may reduce HIV
replication in human astroglial cells by inhibiting HIV-1 LTR
transcriptional activity. t NO donors reduce viral replication in
HIV-1-infected human astrocytoma T67 cells, taken as an astroglial model.
Furthermore, using transfected T67 cells, NO donors inhibit HIV-1 LTR
transcriptional activity. These results suggest that the use of
NO-releasing drugs may represent a potential in HIV replication in
astrocytes.
Specific nervous system involvement:
Type of involvement depends on HIV viral load, sub type of
the virus, resultant specific depletion of specific type of Helper
Lymphocytes and prior exposure to preventive drugs e.g. Lymphoma more
common when CD4 count is less than 50 to 100 cells
HIV Dementia – mild cognition impairment to frank dementia
Encephalitis
Toxoplasmosis (? Empirical Chemotherapy before biopsy, ? ¯
incidence with prior antimicrobial prohylaxis) focal / diffuse meningo encephalitis,
blood vessel thrombosis à infarction à necrosis à mass effect. Incidence
12%-13% Respond clinically and radiologically Pyrimethamine and
Sulfadiazine 1 yr survival
Cytomegalo virus detection of CMV DNA in CSF. Treatment –
GANCICLOVIR, FOSCARNET, CIDOFOVIR HAART (Highly Active Antiretroviral
Therapy) has ¯ incidence of CMV disease in AIDS.
CMV retinitis à Blindness
Atypical herpes simplex virus
Subacute measles encephalitis (SME)
Epstein-Barr virus and Kaposi's sarcoma
Meningitis
Cryptococcal – 10% of AIDS Patients develop this, More
common among African-Americans, Typical meningitis not seen in 70%. CT
mostly normal. Diagnosis CSF analysis. Inspite of amphotericin B /
5-flucytosine mortality 20%.
Tuberculous – 4 million world wide with TB + HIV. Resistant
strains of TB more common. 2/3 mass lesion, 1/3 meningitis. Mycobacterium
avium more common in AIDS patients. Facial palsy, peripheral neuropathy
associated – very poor survival
Fungal – Candida albcans – abscess excision with
amphotericin B: coccidioides immitis also rapidly progressive.
Bacterial – Listeria monocytgenes most common. Nocardia
asteroids also common.
Meningoencephalitis
Myelitis
Primary CNS Lymphoma – more common in AIDS population.
Median survival 3-4 months. Radiation Chemotherapy.
Non Hodgkin’s Lymphoma
Progressive Multifocal Leucoencephalopathy (Papova virus
infection) – dementia, blindness aphasia hemiperasis, ataxia – hypodense
areas without mass effect occurs in 4%-5% of AIDS Patient. Survival 2
months. Intrathecal cytosine arabinoside.
Neurosyphilis
Vacuolar Myelopathy – diffused degeneration of thoracic
spinal cord? B12 deficiency. – spastic paraparesis, ataxia bowel bladder
involvement
Myopathy
Distal Symmetric Polyneuropathy – more common with
DIDANOSINE, ZALCITABINE and STAVUDINE.
Inflammatory Demyelinating Polyneuropathy
Mononeuropathy multiplex
Progressive polyradiculopathy
Spinal extradural Leiomyoma
Recurrent brain abscess
Brain Tuberculoma
CAT scratch fever à painful radiculopathy
Cerebravascular complications – infarction, hemorrhage.
Drug induced neurological complications – extra pyramidal,
acute myelopathy, startle myoclonus, dysphasia and delirium – as new
drugs are constantly being developed neurological drug induced complication
will become more.
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