Download Acquired Immunodeficiency Syndrome(AIDS)

Acquired Immunodeficiency Syndrome(AIDS)
By
Dr. Nusrum Iqbal
EPIDEMIOLOGY
•AIDS was first described in 1981 as a clinical entity
•HIV was described as the causative organism in 1983
•Worldwide up to 16000 new cases/day
•Predominantly concentrated in developing countries
•Majority of the infections are transmitted via semen, cervical secretions and blood
The Virus (Biology)
•HIV belongs to the lentivirus group of the retrovirus family.
•Types
HIV-1
HIV-2 (exclusively in West Africa)
•HIV1 is a single strand of RNA enclosed in a protein envelope
•Viral replication is dependent upon a DNA polymerase(reverse transcriptase) which is
responsible for copying the viral RNA into DNA
•Incorporation of DNA then takes place into the host cell genome(T-helper CD4 cell
genome)
•Additional transcription of the DNA results in new viral particles that are extruded from
the cell membranes
Risk Factors/Mode of transmissions
•Sexual intercourse (homosexual vs Bisexual)
•Intravenous Drug Abusers
•Blood transfusion
•Hemophiliacs and recipients of other blood products
•Sexual partners of these groups
•Contaminated needles (IVDA, needlestick injury)
•Vertical Transmission (mother to fetus- 30-50% )
In Africa, hetrosexual transmission is most common
Pathogenesis
•T-helper cell coordinates the immune response of T & B lymphocytes, monocytes and
macrophages
•Both quatitative and qualitative defects lead to both cell mediated and humoral impaired
immunity
•HIV is also neurotropic
•Macrophages engulf and plays a role in its dissemination in the CNS
•The host cellular receptor that is recognized by the HIV is CD4 molecule
•This interraction of HIV and CD4 molecule leads to the entry of HIV into the cell
Laboratory diagnosis
Diagnosed by
virus-specific antibodies
direct identification of viral material
HIV enzyme immunoassay-screening test--ELISA technique (99.9% sensitive) detection
of IgG to envelope comp-gp20
Western-Blot---detects Antibody to HIV proteins--confirmatory test (99.9% specific)
HIV isolation--culture, p24 antigen detection by EIA or HIV gemone detect by PCR
p24 antigen represents active HIV replication
Physical Examination
•Low grade fever
•Marked weight loss
•Fascial seborrhea
•Diffuse lymphadenopathy
•Splenomegaly
•oral candidiasis
•Evidence of present or past herpes zoster
Clinical Features
Nonspecific features include
•Asymptomatic for years
•Persistent fevers and chills
•Drenching night sweats
•Fatigue
•Unintentional weight loss
•Depression
•Apathy
•Memory loss and personality changes
Specific Clinical features
FEVER
•Most common complaint
•Blood cultures should be drawn for bacteria, fungus, atypical mycobacteria and CMV
•Lymphoma when organomegaly and marked lymphadenopathy present
•Chest X-ray for pneumocystis carinii infection
•Serum cryptococcal antigen for fungal infection
Weight
•Decrease in the muscle mass
•Decrease in the fat
•Increase TNF leads to decrease in lipoproptein lipase activity
•Anorexia, nausea, and vomiting
•Malabsorption
•Diarrhea
•Increase metabolic rate
Lymphadenopathy
•It is a common finding
•Biopsy indicated in the presence of fever, or marked enlargement of a single node.
•Extensive differential diagnosis including atypical mycobacteria, disseminated
tuberculosis, toxoplasmosis and histoplamosis.
Skin lesions
•Pruritis and folliculitis common
•kaposi’s sarcoma most frequent in homosexuals and bisexual men and far less common
in intravenous drug abusers
–appear as nodular dark red or purple lesins
–frequently on head or neck, though they can occur anywhere including the respiratory
tract and gastrointestinal tract and cause localized bleeding.
–Chemotherapy may be effective
–cryptococcus and histoplamosis may cause necrotic cutaneous ulcers or papules
Dyspnea
•Pneumocystic carinii pneumonia is most common etiology (75%)
•usually present as subacute illness with constitutional symptoms: fever, night sweats and
progressive non productive cough.
•Chest X-ray typically shows diffuse interstitial infiltrates although many radiographic
appearances are possible.
•Diagnosis with cyst or trophozites in sputum or bronchio alveolar lavage (98%)
•Treatment with either trimethoprim sulphamethoxazole or pentamidine.
Other causes of pulmonary disease
•Tuberculosis( drug resistant, apical infiltrates on CXR
•atypical mycobacteria(mycobacterium avium cellulare)
•disseminated fungal disease (cryptococcus, histoplasma, coccioides
•encapsulated bacteria with streptococcus and hemophilus
•pulmonary lymphoma is less common
•pulmonary kaposi’s sarcoma
Dysphagia
•Candidal esophagitis, often in the presence of oral thrush, treatment with fluconazole or
ketoconazole.
•Esophageal herpetic ulcers are treated with acyclovir.
•Esophageal CMV ulcers are treated with gancyclovir
•idiopathic HIV ulcers are treated with oral prednisolone
Diarrhea
•Distinguish between high volume watery (small bowel infection) versus small volume,
bloody with tenesmus (colonic infection)
•Small bowel infections are most commonly cryptosposridium, microsporidium, giardia
and entamoeba histolytica
•other small bowel infections that may be accompanied by bacteremias include
salmonella, shigella and campylobacter
•Colitis is most frequently caused by CMV
•Proctitis may be caused by infection of the “gay bowel syndrome” with treponema,
herpes, gonorrhea
Headache
•Symptoms of CNS infections is often only headache; it should be evaluated since many
oppurtunistic infections possible
•Toxoplasma is the most common finding with patients presenting with headache,
confusion and seizures
–CT shows classic single or multiple ring enhancing lesions
–Treatment is with pyrimethamine and sulfadiazine; life long maintenance medication is
required
Other CNS lesions include, CNS lymphoma, Progressive multifocal
leukoencephalopathy, Herpes simplex encephalitis, CMV encephalitis, Mycobacterial or
fungal brain abscesses, cryptococcal meningitis
Crypotoccal Meningitis
•Headache with meningeal signs should prompt the search for cryptococcal meningitis
•Diagnosis made with CSF identification of cryptococcal antigen on india ink stain
•Candidal esophagitis, often in the presence of oral thrush Treatment with fluconazole or
ketoconazole
•Esophageal herpetic ulcers are treated with acyclovir
•Esophageal CMV ulcers are treated with gancyclovir
•Idiopathic HIV ulcers are treated with oral prednisone
Dementia (Mental Status Change)
•Early HIV encephalopathy with depression and apathy
•Neurological examination is usually unremarkable at this point
•Distinguish dementia from depression with progressive infection, paraparesis,
incontinence and global dementia occur
•CT scan reveals diffuse atrophy. CT scan is not specific but it is done to rule out mass
lesions
Blindness
•CMV retinitis can cause rapid visual loss and is treated with gancyclovir, Retinal cotton
wool spots may be sen in patients with pneumocystis
•Disseminated candidiasis or toxoplasmosis may also cause visual disturbances
Hematologic abnormalities
•Immune thrombocytopenia resembling ITP
•Amenia of chronic disease
•Lymphocytopenia
•Polyclonal gammopathy
Therapy
•Antiviral therapy with AZT with CD4 count under 500
•with CD4 count under 200 in addition to pneumocysits prophylaxis is given
•Vaccination with pneumococcal vaccine, influenza vaccine and hepatitis vaccine is
advised
•Patients are also at risk for reinfection for tuberculosis and syphilis
•Prophylaxis for mycobacterium avium intracellulare when CD4 count under 100
•If CD4 count decreases to < 50/4L then death can occur