Infectious Disease · Sexually Transmitted Infections
The facts most likely to be tested
Primary infection with HSV-2 typically presents as painful genital ulcers on an erythematous base accompanied by tender inguinal lymphadenopathy.
The gold standard for diagnosis of active lesions is PCR testing of the lesion swab, which has higher sensitivity than viral culture.
Tzanck smear showing multinucleated giant cells with intranuclear inclusions is a classic, though less sensitive, diagnostic finding.
Acyclovir, valacyclovir, or famciclovir are the first-line treatments for both initial episodes and suppressive therapy for recurrent outbreaks.
Asymptomatic viral shedding is a hallmark of HSV-2, allowing for transmission even in the absence of visible genital lesions.
Neonatal transmission risk is highest during primary maternal infection near the time of delivery, necessitating cesarean section if active lesions are present.
Aseptic meningitis is the most common neurological complication associated with primary HSV-2 infection, particularly in women.
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A 24-year-old female presents to the clinic complaining of severe vulvar pain and dysuria for the past 3 days. She reports a new sexual partner 2 weeks ago. Physical examination reveals multiple shallow, painful ulcers on an erythematous base on the labia majora and bilateral tender inguinal lymphadenopathy. She has no history of similar symptoms.
What is the most appropriate next step in management to confirm the diagnosis?
PCR testing of the lesion swab
The patient's presentation of painful genital ulcers and lymphadenopathy is classic for primary HSV-2 infection, and PCR is the most sensitive and preferred diagnostic test.
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Etiology / Epidemiology
Primarily transmitted via sexual contact; high prevalence in sexually active adults with multiple partners.
Clinical Manifestations
Presents as painful grouped vesicles on an erythematous base; primary outbreaks are often systemic.
Diagnosis
PCR is the gold standard; viral culture is less sensitive.
Treatment
Valacyclovir is the first-line treatment; avoid in severe renal impairment.
Prognosis
Lifelong latent infection in sacral ganglia; risk of neonatal transmission during delivery.
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Epidemiology & Etiology
HSV-2 is a double-stranded DNA virus primarily transmitted through direct mucosal contact. It is a leading cause of genital ulcer disease worldwide. Incidence is highest in populations with high-risk sexual behaviors and history of other STIs.
Pertinent Anatomy
The virus establishes latency in the sacral dorsal root ganglia. Reactivation travels down the sensory nerve axons to the genital skin or mucosa.
Pathophysiology
Primary infection involves viral replication in epithelial cells, leading to cell lysis and inflammation. The virus then migrates via retrograde axonal transport to the sacral ganglia. Reactivation occurs due to stress, immunosuppression, or hormonal changes, causing recurrent outbreaks.
Clinical Manifestations
Initial infection often presents with prodromal burning or tingling followed by painful grouped vesicles on an erythematous base. Patients may experience inguinal lymphadenopathy, fever, and dysuria. Aseptic meningitis is a rare but serious neurological complication of primary infection.
Diagnosis
PCR is the gold standard for detection of viral DNA from lesion swabs. Tzanck smear showing multinucleated giant cells is historically relevant but lacks sensitivity and specificity compared to modern molecular testing.
Treatment
Valacyclovir is the preferred first-line agent for both episodic and suppressive therapy. Renal dose adjustment is mandatory for patients with impaired function. For severe or disseminated disease, IV Acyclovir is indicated.
Prognosis
Infection is chronic and incurable. Suppressive therapy reduces transmission risk by approximately 50%. Pregnant patients require monitoring for neonatal herpes, which carries high morbidity.
Differential Diagnosis
Syphilis: painless chancre
Chancroid: painful ulcer with suppurative lymphadenopathy
Lymphogranuloma venereum: transient ulcer with massive inguinal buboes
Behçet syndrome: oral and genital ulcers with uveitis
Contact dermatitis: pruritic rash without viral prodrome