Post-Exposure Prophylaxis: Acting Within 72 Hours of a Possible HIV Exposure

The urine lipoarabinomannan (LAM) test is reserved for tuberculosis diagnosis, and it has only been validated for patients with a CD4 count below 100. Below that threshold, a high tuberculosis bacterial burden allows the antigen to wash out into the urine; above it, the test loses sensitivity and specificity, so extrapolating it to every patient isn't supported. On stool testing for other opportunistic infections, a high viral load before treatment changes the normal gut flora, so a stool sample will often show excess normal flora and candida, which makes interpreting it for treatment decisions difficult specifically in HIV patients.

Yes. Cabotegravir, a longer-acting integrase inhibitor, combined with rilpivirine from the non-nucleoside reverse transcriptase inhibitor family, was studied in the TANGO trial and showed viral suppression sustained for close to three months from a single dose. Their half-life runs to about 24 to 26 weeks, so the combination is given as one intramuscular or subcutaneous injection every three months for patients who are already stable on oral therapy, as maintenance rather than as a starting regimen.

Opportunistic infections can be diagnosed at any stage; the WHO staging system, grade one through four, is built around exactly this, using the infection profile and CD4 level together. Oral thrush, for instance, usually appears at stage two, while reactive generalised lymphadenopathy sits at stage one. Sometimes the opportunistic infection is itself the first clue to an undiagnosed HIV infection, tuberculosis being the clearest example: finding it usually puts the patient at WHO stage three, and a very low viral load and CD4 count below 200 to 250 lets you further risk-stratify from there. Diagnosis runs on three legs: the clinical symptoms and signs, which organ is involved, and targeted sampling, such as testing sputum by GeneXpert for suspected pulmonary tuberculosis, or testing CSF, or serum cryptococcal antigen when CSF isn't accessible, for cryptococcal meningitis.

The early signs, known as acute HIV syndrome, look like a flu. Most patients who are symptomatic present with intermittent fever for two to three months, fatigue or weakness, weight loss, loss of appetite, cough, cold, sore throat, more frequent minor illnesses than usual, and loose motions or diarrhoea. This symptom complex over the first month or two is what we call acute HIV syndrome.