WHERE DO OPPORTUNISTIC INFECTIONS AND CANCERS OCCUR?

Symptomatic HIV infection is mainly caused by the emergence of opportunistic infections and cancers that the immune system would normally prevent. These can occur in almost all the body systems, but common examples are featured in the table below. As the table below indicates, symptomatic HIV infection is often characterised by multi-system disease. Treatment for the specific infection or cancer is often carried out, but the underlying cause is the action of HIV as it erodes the immune system. Unless HIV itself can be slowed down the symptoms of immune suppression will continue to worsen. System Examples of Infection/Cancer Respiratory system Pneumocystis Carinii Pneumonia (PCP) Tuberculosis (TB) Kaposi's Sarcoma (KS) Gastro-intestinal system Cryptosporidiosis Candida Cytomegolavirus (CMV) Isosporiasis Kaposi's Sarcoma Central/peripheral Nervous system HIV Cytomegolavirus Toxoplasmosis Cryptococcosis Non Hodgkin's lymphoma Varicella Zoster Herpes simplex Skin Herpes simplex Kaposi's sarcoma Varicella Zoster Find out more about opportunistic infections.

STAGE 4: Progression from HIV to AIDS

As the immune system becomes more and more damaged the illnesses that occur become more and more severe leading eventually to an AIDS diagnosis. At present in the UK an AIDS diagnosis is confirmed if a person with HIV develops one or more of a specific number of severe opportunistic infections or cancers. In the US, someone may also be diagnosed with AIDS if they have a very low count of T helper cells in their blood. It is possible for someone to be very ill with HIV but not have an AIDS diagnosis. WHO clinical staging of HIV disease in adults and adolescents (2006 revision) In resource-poor communities, medical facilities are sometimes poorly equipped, and it is not possible to use CD4 and viral load test results to determine the right time to begin treatment. The World Health Organization has therefore developed a staging system for HIV disease based on clinical symptoms.

Clinical Stage I:

• Asymptomatic
• Persistent generalized lymphadenopathy

Clinical Stage II:

• Moderate unexplained* weight loss (under 10% of presumed or measured body weight)**
• Recurrent respiratory tract infections (sinusitis, tonsillitis, otitis media, pharyngitis)
• Herpes zoster
• Angular chelitis
• Recurrent oral ulceration
• Papular pruritic eruptions
• Seborrhoeic dermatitis
• Fungal nail infections

Clinical Stage III:

• Unexplained* severe weight loss (over 10% of presumed or measured body weight)**
• Unexplained* chronic diarrhoea for longer than one month
• Unexplained* persistent fever (intermittent or constant for longer than one month)
• Persistent oral candidiasis
• Oral hairy leukoplakia
• Pulmonary tuberculosis
• Severe bacterial infections (e.g. pneumonia, empyema, pyomyositis, bone or joint infection, meningitis, bacteraemia)
• Acute necrotizing ulcerative stomatitis, gingivitis or periodontitis
• Unexplained* anaemia (below 8 g/dl), neutropenia (below 0.5 billion/l) and/or chronic thrombocytopenia (below 50 billion/l)

Clinical Stage IV***:

• HIV wasting syndrome
• Pneumocystis pneumonia
• Recurrent severe bacterial pneumonia
• Chronic herpes simplex infection (orolabial, genital or anorectal of more than one month's duration or visceral at any site)
• Oesophageal candidiasis (or candidiasis of trachea, bronchi or lungs)
• Extrapulmonary tuberculosis
• Kaposi sarcoma
• Cytomegalovirus infection (retinitis or infection of other organs)
• Central nervous system toxoplasmosis
• HIV encephalopathy
• Extrapulmonary cryptococcosis including meningitis
• Disseminated non-tuberculous mycobacteria infection
• Progressive multifocal leukoencephalopathy
• Chronic cryptosporidiosis
• Chronic isosporiasis
• Disseminated mycosis (extrapulmonary histoplasmosis, coccidiomycosis)
• Recurrent septicaemia (including non-typhoidal Salmonella)
• Lymphoma (cerebral or B cell non-Hodgkin)
• Invasive cervical carcinoma
• Atypical disseminated leishmaniasis
• Symptomatic HIV-associated nephropathy or HIV-associated cardiomyopathy