HIV infection is believed to have peaked in the late 1990s and to have stabilized recently. Globally, an estimated 38.4 million people were living with HIV at the end of 2021, with 1.5 million people newly infected.
Most people are infected through sexual contact, before birth or during delivery, during breast-feeding, or when sharing contaminated needles and syringes.
Diagnosis is established using an HIV antibody test and confirmed using a more specific test. Patients should be clinically staged according to World Health Organization or Centers for Disease Control and Prevention criteria.
Guidelines recommend that all patients infected with HIV, regardless of CD4 cell count, should start antiretroviral therapy (ART) as soon as possible.
Pre-exposure prophylaxis with daily oral antiretroviral therapy or long-acting intramuscular cabotegravir reduces the risk of HIV infection and is recommended in sexually active adults and people who inject drugs and who are at substantial ongoing risk of HIV exposure and acquisition.
Diagnosis and management varies between resource-intensive settings and resource-limited settings.
HIV infection is caused by a retrovirus that infects and replicates in human lymphocytes and macrophages, eroding the integrity of the human immune system over a number of years, culminating in immune deficiency and a susceptibility to a series of opportunistic and other infections as well as the development of certain malignancies.
At the initial consultation with the medical practitioner, an infected patient may be at any stage of the natural history from acute to chronic infection, ranging from asymptomatic through to severely ill. The initial assessment is key for prognosis and formulation of short- to long-term management plans.
AIDS (a syndrome of a constellation of infections, conditions, or malignancies) occurs as a result of HIV infection, and usually develops over 10-15 years.
This topic focuses on the diagnosis and initial management of nonpregnant adults with HIV infection. The management of treatment-experienced patients and special patient populations is beyond the scope of this topic. See Overview of HIV for details of our other topics.
History and exam
Key diagnostic factors
- fevers and night sweats
- weight loss
- skin rashes and post-inflammatory scars
- oral ulcers, angular cheilitis, oral thrush, or oral hairy leukoplakia
- wasting syndrome
- changes in mental status or neuropsychiatric function
- recent hospital admissions
- tuberculosis (TB)
- medical comorbidities
- sexual activity
- generalized lymphadenopathy
- Kaposi sarcoma
- genital STIs
- chronic vaginal candidiasis
- periodontal disease
- retinal lesions on fundoscopy
- shortness of breath on exertion, cyanosis on exertion, dry cough, silent chest on auscultation
Other diagnostic factors
- current and prior use of other substances
- peripheral neuropathy
- recurrent herpes simplex
- hepatomegaly or splenomegaly
- meningeal signs (bacterial or viral meningitis)
- people who inject drugs
- gay men and other men who have sex with men
- commercial sex worker
- transgender women
- unprotected receptive anal intercourse
- unprotected receptive penile-vaginal sexual intercourse
- percutaneous needle stick injury
- racial and ethnic minorities
- high maternal viral load (mother-to-child transmission)
- use of progestin-only injectable contraceptives
- herpes simplex virus type 2 (HSV-2) infection
1st investigations to order
- serum HIV enzyme-linked immunosorbent assay (ELISA)
- serum HIV rapid test
- HIV noninvasive tests
- serum Western blot
- serum p24 antigen
- serum HIV DNA polymerase chain reaction (PCR)
- CD4 count
- serum viral load (HIV RNA)
- drug resistance testing
- pregnancy test
- serum hepatitis B serology
- serum hepatitis C serology
- CBC with differential
- basic metabolic panel
- liver function tests (LFTs)
- random or fasting plasma glucose
- lipid profile
- human leukocyte antigen-B*5701 testing
Investigations to consider
- chest x-ray
- hepatitis A serology (IgG)
- toxoplasma serology (IgG)
- testing for sexually transmitted infections
- tuberculin skin test
newly confirmed infection
virologic or immunologic treatment failure
- Infectious mononucleosis
- Cytomegalovirus infection (CMV)
- Influenza infection
- Guidelines for the use of antiretroviral agents in adults and adolescents living with HIV
- Guidelines for the prevention and treatment of opportunistic infections in adults and adolescents with HIV
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