Oxford Handbook of Genitourinary Medicine, HIV, and Sexual
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Clinical staging
Early in the epidemic, before HIV was discovered, diagnosis of AIDS was largely based on finding Pneumocystis jiroveci (previously P.carinii) pneumonia (PCP) or Kaposi’s sarcoma. HIV antibody testing led to patients being identified as having asymptomatic infection, AIDS-related complex, or AIDS. The Centers for Disease Control and Prevention (CDC) devised a classification system, revised in 1993, based on clinical features, AIDS-defining illnesses, and CD4 counts (Table 37.1). The CD4 count is a useful predictor for the development of opportunistic infections (OIs) and malignancies, but it should be recognized that this may be influenced by other factors such as inter-current infection.
This system was originally designed as a categorization tool for public health purposes and was not intended for staging.
Category A
Asymptomatic HIV infection
Persistent generalized lymphadenopathy
Acute retroviral syndrome
Category B
Bacillary angiomatosis
Candidiasis:
oral
recurrent vaginal
Cervical dysplasia/carcinoma in situ
Constitutional symptoms
Oral hairy leukoplakia
Herpes zoster
Idiopathic thrombocytopenic purpura
Listeriosis
Pelvic inflammatory disease
Peripheral neuropathy
Category C (AIDS-defining conditions)
CD4 count <200cells/μL
Candidiasis:
pulmonary
oesophageal
Cerebral toxoplasmosis
Cervical cancer
Coccidioidomycosis
Cryptosporidiosis
Cytomegalovirus
Herpes simplex:
chronic (>1 month)
oesophageal
HIV encephalopathy
Histoplasmosis (extrapulmonary)
Isosporiasis
Lymphoma
Mycobacterium avium complex
Mycobacterium tuberculosis
Pneumocystis jiroveci
Pneumonia (recurrent)
Progressive multifocal leucoencephalopathy
Salmonella (septicaemia, recurrent)
Wasting syndrome due to HIV
Natural history of untreated HIV infection
Characterized by progressive loss of immune function allowing the development of some virulent bacterial infections, certain opportunistic infections, and malignancies that define AIDS (Fig. 37.1). Progression rate varies depending on interactions between host, viral, and environmental factors. The average time between HIV acquisition and AIDS is ~10 years if untreated.
Schematic representation of progression of HIV infection with time. Reproduced with permission of Professor Giuseppe Pantaleo, Centre Hospitalier Universitaire Vaudois.
The course of the disease can be divided into five continuous stages: 1° infection followed by early, middle, advanced, and late stages. There is significant individual variation between patients in the same clinical stage.
1° HIV infection: disseminates widely in the body at seroconversion, usually with a very high VL and a rapid CD4 cell ↓ which is spontaneously but not fully reversible.
Early stage: CD4 count >500cells/μL. After 1° stage viraemia ↓ (rarely becoming undetectable). Usually asymptomatic apart from generalized lymphadenopathy and certain skin disorders (e.g. seborrhoeic dermatitis, aphthous ulcers, eosinophilic dermatitis, and psoriasis) which may deteriorate or appear for the first time.
Middle stage: CD4 count 200–500cells/μL. Mostly asymptomatic/mildly symptomatic. Skin disorders of early stage may worsen. Recurrent herpes simplex infection, varicella zoster, diarrhoea, weight loss, and intermittent fever may develop. Lung infections caused by community-acquired organisms such as Streptococcus pneumoniae, Haemophilus influenzae, and Mycobacterium tuberculosis become more common.
Advanced stage: CD4 count 50–200cells/μL. ↑ VL with classical manifestations of AIDS, especially PCP, Kaposi’s sarcoma, lymphomas, and Mycobacterium avium complex (MAC) infection.
Late stage: CD4 count <50cells/μL. Very high levels of viraemia. Further development of conditions associated with severe immune deficiency, e.g. CMV retinitis, disseminated MAC. Neurological manifestations ↑ due to 1° brain lymphoma, multifocal leukoencephalo-pathy, and dementia. HIV wasting disease is commonly seen at this stage.
