A 32-year-old man from Mumbai presents to the STI clinic with a 2-week history of fever, generalized lymphadenopathy, and a maculopapular rash over the trunk. He reports unprotected sexual contact with multiple partners over the past 3 months. On examination, he has cervical and axillary lymphadenopathy, hepatosplenomegaly, and oral candidiasis. His CD4+ count is 450 cells/µL. Rapid HIV antibody test is negative, but HIV RNA (viral load) is 850,000 copies/mL. What is the most likely explanation for this clinical presentation?

Explanation

## Clinical Diagnosis: Acute Retroviral Syndrome **Key Point:** Acute retroviral syndrome (ARS) occurs 2–4 weeks after HIV acquisition and presents with fever, lymphadenopathy, rash, and constitutional symptoms. The hallmark is a **negative or indeterminate antibody test with detectable high viral load** — the "window period" before seroconversion. ### Pathophysiology 1. Rapid viral replication during early infection (viral load often >100,000 copies/mL) 2. Massive CD4+ T-cell destruction and immune activation 3. Antibody production lags behind viremia by 1–3 weeks 4. Window period: viral RNA detectable before antibodies appear ### Clinical Features of ARS | Feature | Frequency | |---------|----------| | Fever | 80–90% | | Lymphadenopathy | 70–90% | | Rash (maculopapular) | 40–80% | | Oral/esophageal candidiasis | 5–10% | | Hepatosplenomegaly | 10–20% | | Myalgia/arthralgia | 50–70% | **High-Yield:** CD4 count in ARS is typically 200–500 cells/µL; the patient's count of 450 is consistent with acute infection, not chronic AIDS. **Clinical Pearl:** The negative antibody test with high viral load is pathognomonic for the window period. This is why fourth-generation (Ag/Ab) tests and NAT (nucleic acid testing) are superior for early detection. **Mnemonic for ARS diagnosis:** **FEVER-RASH-LYMPH-WINDOW** — Fever, Rash, Lymphadenopathy + negative Ab test = Window period (acute infection). ### Why This Is NOT IRIS IRIS occurs after antiretroviral therapy initiation in patients with advanced immunosuppression (CD4 <50). This patient is newly diagnosed and has not started ART. ### Why This Is NOT Chronic AIDS with OI While oral candidiasis suggests advanced immunosuppression, the acute presentation with high fever, rash, and constitutional symptoms is more consistent with acute viremia than chronic AIDS.