Acute HIV infection

Acute HIV infection

Acute HIV infection

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Acute HIV Infection - The Great Mimic

  • Acute Retroviral Syndrome (ARS): A symptomatic seroconversion illness occurring 2-4 weeks after HIV exposure, driven by a massive burst of viremia.
  • Presentation: Mimics a mononucleosis-like or flu-like illness (fever, lymphadenopathy, pharyngitis, rash, myalgia). Its non-specific nature makes it the “great mimic.”
  • Pathophysiology: Reflects the initial seeding of HIV in lymphoid tissues.

Diagnostic Pearl: During the early "window period," standard antibody tests are often negative. Diagnosis requires direct viral detection via HIV RNA or p24 antigen assays.

Symptoms of Acute HIV Infection

Pathophysiology - Viral Onslaught

  • Entry: HIV's gp120 binds to the host's CD4 receptor, then to a co-receptor-either CCR5 (early, M-tropic) or CXCR4 (late, T-tropic).
  • Replication: Viral RNA is reverse-transcribed into DNA, which is then integrated into the host genome by the enzyme integrase.
  • Consequences: Leads to massive viral replication (↑ viremia) and a sharp, transient drop in CD4+ T-cell count.

HIV Life Cycle: Entry, Reverse Transcription, Integration

⭐ Within days of infection, HIV establishes a latent reservoir in lymphoid tissues (e.g., GALT), which is a major barrier to cure.

Clinical Presentation - Flu's Deceptive Cousin

Appears 2-4 weeks post-exposure, mimicking infectious mononucleosis.

  • Core Symptoms (Mono-like):
    • Fever, widespread lymphadenopathy, pharyngitis, myalgia.
  • Key Dermatologic Signs:
    • Generalized maculopapular rash.
    • Painful mucocutaneous ulcers (oral, genital).
  • Neurologic Involvement:
    • Aseptic meningitis is a classic, though less common, finding.

Maculopapular rash in acute HIV seroconversion syndrome

⭐ During the acute phase "window period," standard HIV antibody tests may be negative. Diagnosis requires HIV RNA or p24 antigen testing.

Diagnosis - Pinpointing the Enemy

  • Diagnostic Challenge: The "window period" where viral replication is high, but antibody tests are negative.
  • Primary Test: Use a 4th generation HIV-1/2 antigen (p24)/antibody combination immunoassay.
  • Window Period Confirmation: If the initial screen is positive but antibody differentiation is negative, HIV RNA (viral load) PCR is the crucial next step to detect the virus directly.

⭐ The p24 antigen is the first serological marker to appear, detectable as early as 2 weeks post-infection, bridging the diagnostic gap before antibodies are reliably produced.

Management - Early Strike ART

  • Principle: Initiate antiretroviral therapy (ART) immediately for all patients with acute HIV, regardless of CD4 count.
  • Rationale:
    • ↓ HIV transmission risk to others.
    • ↓ Risk of progression to AIDS and non-AIDS-defining complications.
    • May reduce the size of the latent viral reservoir.
  • Standard Regimen: 2 NRTIs (Nucleoside Reverse Transcriptase Inhibitors) + 1 INSTI (Integrase Strand Transfer Inhibitor).
    • Example: Bictegravir/Tenofovir Alafenamide/Emtricitabine.

High-Yield: Early ART initiation not only preserves immune function but also significantly decreases the risk of cardiovascular, renal, and liver disease, which are major causes of morbidity in people with HIV.

High-Yield Points - ⚡ Biggest Takeaways

  • Presents as a mononucleosis-like syndrome approximately 2-4 weeks after initial exposure.
  • Characterized by a very high viral load (HIV RNA) and the presence of p24 antigen.
  • Standard antibody tests are often negative during this early "window period" of seroconversion.
  • Symptoms are non-specific: fever, generalized lymphadenopathy, sore throat, and a maculopapular rash.
  • This acute phase represents a period of extremely high infectivity and viral transmission.

Practice Questions: Acute HIV infection

Test your understanding with these related questions

A 19-year-old university student presents to the student clinic with painful joints. He states that over the past week his right wrist has become increasingly stiff. This morning he noticed pain and stiffness in his left ankle and left knee. The patient has celiac disease and takes a daily multivitamin. He says he is sexually active with multiple male and female partners. He smokes marijuana but denies intravenous drug abuse. He recently traveled to Uganda to volunteer at a clinic that specialized in treating patients with human immunodeficiency virus (HIV). He also went on an extended hiking trip last week in New Hampshire. Physical exam reveals swelling of the right wrist and a warm, swollen, erythematous left knee. The left Achilles tendon is tender to palpation. There are also multiple vesicopustular lesions on the dorsum of the right hand. No penile discharge is appreciated. Arthrocentesis of the left knee is performed. Synovial fluid results are shown below: Synovial fluid: Appearance: Cloudy Leukocyte count: 40,000/mm^3 with neutrophil predominance Gram stain is negative. A synovial fluid culture is pending. Which of the following is the patient’s most likely diagnosis?

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Flashcards: Acute HIV infection

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Reactivation of CMV from mononuclear cells occurs via _____

TAP TO REVEAL ANSWER

Reactivation of CMV from mononuclear cells occurs via _____

immunosuppression (organ transplant, AIDS patients)

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