What are the possible causes and treatments for right inguinal pain in a patient of unknown age and medical history?

Right Inguinal Pain: Diagnostic Approach and Management

Right inguinal pain requires systematic evaluation beginning with assessment for life-threatening complications (incarceration/strangulation), followed by imaging with CT abdomen/pelvis or ultrasound to differentiate between inguinal hernia, infectious causes (lymphogranuloma venereum, granuloma inguinale), musculoskeletal pathology, and other etiologies.

Immediate Assessment for Emergent Conditions

First, rule out hernia complications requiring emergency surgery:

• Assess for signs of incarceration or strangulation: irreducibility, severe tenderness, erythema over the hernia, fever, tachycardia, leukocytosis, or abdominal wall rigidity 1
• Check laboratory markers: elevated lactate, CPK, and D-dimer levels predict bowel strangulation 1
• Time is critical: symptomatic periods >8 hours significantly increase morbidity, and delayed treatment >24 hours dramatically increases mortality 1
• If strangulation is suspected, proceed immediately to emergency surgical repair 1

Diagnostic Imaging Strategy

For non-emergent presentations, imaging clarifies the diagnosis:

• CT abdomen and pelvis with contrast is the primary imaging modality for right lower quadrant/inguinal pain with sensitivity of 95% and specificity of 94% for identifying pathology 2
• CT identifies appendicitis, hernias, infectious lymphadenopathy, and alternative diagnoses with high accuracy 2
• Ultrasound is appropriate for initial evaluation when hernia is suspected clinically, particularly useful for assessing reducibility and contents 3, 4
• CT with contrast can predict bowel strangulation with 56% sensitivity and 94% specificity based on reduced wall enhancement 1

Differential Diagnosis Framework

Inguinal Hernia (Most Common)

Clinical presentation:

• Groin bulge that increases with coughing/straining, may extend into scrotum 1
• Burning, gurgling, or aching sensation in groin with heavy/dragging sensation worsening throughout the day 3
• Bulge may disappear when prone 3
• Examine both groins bilaterally as contralateral patent processus vaginalis occurs in 64% of infants <2 months and 25-50% develop contralateral hernias 1

Management:

• All symptomatic inguinal hernias require surgical repair to prevent bowel incarceration and gonadal infarction 1
• Urgent surgical referral within 1-2 weeks of diagnosis 1
• Choice between open versus laparoscopic repair depends on patient age, comorbidities, hernia characteristics, and surgeon expertise 1

Infectious Causes (Lymphogranuloma Venereum)

When unilateral tender inguinal/femoral lymphadenopathy is present:

• Lymphogranuloma venereum (LGV) causes tender inguinal lymphadenopathy, usually unilateral in heterosexual men 2
• Diagnosis made serologically and by exclusion of other causes 2
• Treatment: Doxycycline 100 mg orally twice daily for 21 days (preferred regimen) 2
• Alternative: Erythromycin base 500 mg orally four times daily for 21 days 2
• Buboes may require aspiration through intact skin or incision/drainage to prevent ulceration 2
• Sex partners with contact during 30 days preceding symptom onset should be examined and treated 2

Musculoskeletal and Nerve-Related Causes

Consider when hernia is excluded:

• Iliopectineal bursitis 5
• Ilioinguinal or genitofemoral nerve entrapment (particularly post-surgical) 5, 6
• Anterior snapping hip syndrome 5
• Adductor-related groin pain 7
• Nerve blocks help determine which nerve (ilioinguinal, iliohypogastric, or genitofemoral) is involved in post-herniorrhaphy pain 6

Other Uncommon Causes

• Endometriosis in round ligament (women) 5
• Vascular compression (iliac aneurysm compressing genitofemoral nerve) 5
• Retroperitoneal masses causing nerve compression 5

Common Pitfalls to Avoid

• Failing to examine both groins: missing contralateral hernias or femoral hernias (which have higher strangulation risk) 1
• Delaying evaluation when strangulation signs present: this dramatically increases mortality 1
• Missing femoral hernias: these have higher risk of strangulation than inguinal hernias 1
• Not considering infectious causes: LGV presents with similar inguinal lymphadenopathy and requires specific antibiotic therapy 2
• Assuming all inguinal pain is hernia-related: multiple musculoskeletal and neurologic conditions mimic hernia pain 5, 7

Special Populations

Pregnant patients with LGV:

• Use erythromycin regimen (erythromycin base 500 mg orally four times daily for 21 days) 2
• Avoid doxycycline and sulfonamides 2

HIV-infected patients with LGV:

• Treat with standard regimens but may require prolonged therapy with delayed resolution 2
• Consider adding parenteral aminoglycoside (gentamicin) 2