What is the diagnosis and treatment for a female patient with right inguinal pain for 4 days?

Right Inguinal Pain in a Female: Diagnosis and Management

Initial Diagnostic Approach

The first priority is to obtain a pregnancy test (serum β-hCG) and perform targeted imaging based on the most likely differential diagnosis, as right inguinal pain in females encompasses gynecologic, gastrointestinal, urologic, and musculoskeletal etiologies. 1

Critical History and Physical Examination Elements

• Pain characteristics: Painless lumps suggest granuloma inguinale or malignancy, while tender lumps indicate lymphogranuloma venereum (LGV) or reactive lymphadenopathy 2
• Sexual history: Recent sexual contact within 30-60 days raises concern for sexually transmitted infections causing inguinal lymphadenopathy 1, 2
• Associated symptoms: Nausea, vomiting, fever, vaginal discharge, or urinary symptoms help narrow the differential 1
• Palpable findings: Fixed or matted lymph nodes require biopsy rather than empiric antibiotics due to concern for metastatic disease 2
• Bulge characteristics: A bulge that disappears when prone suggests inguinal hernia 3

Pregnancy Status Determines Imaging Strategy

• If β-hCG positive: Ultrasound is the initial imaging modality of choice to avoid fetal radiation exposure 1
• If β-hCG negative: CT abdomen and pelvis with IV contrast is usually appropriate for nonspecific right lower quadrant/inguinal pain, with 95% sensitivity and 94% specificity for appendicitis, plus excellent detection of alternative diagnoses 1
• MRI abdomen and pelvis: May be appropriate when CT is contraindicated or for pregnant patients, with 85-98% sensitivity for appendicitis and ability to identify alternative diagnoses in 52% of cases 1

Differential Diagnosis by Category

Gynecologic Causes

• Ovarian pathology: Hemorrhagic cysts, ovarian torsion, or adnexal masses 1
• Pelvic inflammatory disease (PID): Consider with fever, cervical motion tenderness, or vaginal discharge 1
• Endometriosis: Can involve the round ligament and present as inguinal pain 4
• Ectopic pregnancy: Must be excluded with positive β-hCG 1

Infectious/Lymphatic Causes

• Lymphogranuloma venereum (LGV): Tender unilateral inguinal/femoral lymphadenopathy, often without visible genital ulcer at presentation 1
• Granuloma inguinale: Painless, beefy red ulcerative lesions with secondary inguinal swelling 1
• Chancroid: Painful genital ulcers with tender inguinal lymphadenopathy 2

Gastrointestinal Causes

• Appendicitis: Most common surgical emergency, CT has 95% sensitivity 1
• Diverticulitis, colitis, inflammatory bowel disease: Identified on CT in patients with RLQ pain 1

Musculoskeletal/Other Causes

• Inguinal hernia: Bulge with cough impulse, may cause burning or dragging sensation 3
• Nerve entrapment: Ilioinguinal or genitofemoral nerve compression 4
• Iliopectineal bursitis: Uncommon but treatable cause 4

Treatment Based on Diagnosis

For Sexually Transmitted Inguinal Lymphadenopathy

Doxycycline 100 mg orally twice daily for 21 days is the first-line treatment for LGV, the most common sexually transmitted cause of inguinal lymphadenopathy. 1, 2

• Alternative regimen: Erythromycin base 500 mg orally four times daily for 21 days (for pregnant/lactating women or doxycycline contraindications) 1, 2
• Buboes management: May require aspiration through intact skin or incision and drainage to prevent ulceration 1, 2
• Partner treatment: Examine and treat sexual contacts within 30 days before symptom onset 1, 2

For Granuloma Inguinale

• First-line: Trimethoprim-sulfamethoxazole one double-strength tablet orally twice daily for minimum 3 weeks 1, 2
• Alternative: Doxycycline 100 mg orally twice daily for minimum 3 weeks 1
• Continue therapy until all lesions completely heal 1

For Inguinal Hernia

• Surgical referral for symptomatic hernias, though small minimally symptomatic hernias may be observed 3
• Ultrasound can confirm diagnosis when physical examination is equivocal 3

For Appendicitis or Other Surgical Emergencies

• Urgent surgical consultation based on CT findings 1
• In patients with CT-confirmed non-appendiceal diagnoses, 41% required hospitalization and 22% underwent surgical or image-guided intervention 1

Critical Follow-Up and Red Flags

• Reassess at 3-7 days: If no improvement with antibiotics, reconsider diagnosis, check for coinfection, HIV status, or antimicrobial resistance 2, 5
• HIV testing: Recommended at initial diagnosis and 3-month follow-up for patients with genital ulcers or inguinal lymphadenopathy 5
• Biopsy indication: Fixed/matted nodes or failure to respond to appropriate antibiotics within 7 days requires tissue diagnosis 2, 5
• Clinical follow-up: Continue until complete resolution of signs and symptoms 1, 2

Common Pitfalls to Avoid

• Do not assume single pathogen: Coinfections occur in 10-25% of genital ulcer/lymphadenopathy cases 5
• Do not continue empiric antibiotics indefinitely: Obtain tissue diagnosis after 7 days of treatment failure 5
• Do not miss pregnancy: Always obtain β-hCG before imaging to guide appropriate modality selection 1
• Do not delay imaging: In nonspecific RLQ/inguinal pain, CT frequently identifies conditions requiring hospitalization or intervention 1