What is the appropriate management for an 18-year-old female presenting with left inguinal pain, tenderness on palpation, leukocytosis, and anemia?

Management of Left Inguinal Pain in an 18-Year-Old Female with Leukocytosis and Anemia

This patient requires urgent imaging with ultrasound or CT to differentiate between gynecologic pathology (ovarian torsion, tubo-ovarian abscess, ectopic pregnancy), lymphadenitis from sexually transmitted infection, or appendicitis, followed by targeted antimicrobial therapy based on findings.

Immediate Diagnostic Priorities

Imaging Strategy

• Pelvic/transvaginal ultrasound is the preferred initial imaging modality for premenopausal women with inguinal pain, as it effectively evaluates gynecologic causes while avoiding radiation exposure 1
• If ultrasound is non-diagnostic or suggests non-gynecologic pathology, proceed to CT abdomen/pelvis with IV contrast (rated 8/9 by ACR) for comprehensive evaluation of appendicitis, abscess, or other intra-abdominal pathology 1
• The leukocytosis (13,900 WBC) combined with localized tenderness suggests an infectious or inflammatory process requiring imaging confirmation 1

Critical Differential Diagnoses to Exclude

Gynecologic emergencies (most likely in this demographic):

• Ovarian torsion: Requires immediate surgical intervention to prevent ovarian loss
• Tubo-ovarian abscess from pelvic inflammatory disease: The combination of inguinal pain and leukocytosis is consistent with this diagnosis
• Ectopic pregnancy: Must be excluded with β-hCG testing before any imaging

Infectious lymphadenitis:

• Enlarged painful inguinal nodes can indicate sexually transmitted infections, particularly lymphogranuloma venereum (LGV), herpes simplex virus, or syphilis 2
• LGV classically presents with tender unilateral inguinal/femoral lymphadenopathy in young sexually active individuals 2

Appendicitis:

• Though typically right-sided, left inguinal pain can occur with pelvic appendicitis or referred pain 1

Targeted Physical Examination Findings

Essential examination components:

• Palpate inguinal lymph nodes for size, tenderness, and consistency—enlarged painful nodes suggest STI including syphilis or HSV 2
• External genital examination looking for ulcers (HSV, syphilis, chancroid), vesicles, or discharge 2
• Assess for peritoneal signs (guarding, rebound)—their presence mandates immediate surgical evaluation 1
• Bartholin gland examination (4 and 8 o'clock positions)—swelling and tenderness suggest gonorrhea or chlamydia infection 2

Treatment Algorithm Based on Findings

If Lymphadenitis from STI is Confirmed:

For Lymphogranuloma Venereum (most common cause of inguinal lymphadenopathy in young sexually active patients):

• Doxycycline 100 mg orally twice daily for 21 days 2
• Alternative: Erythromycin base 500 mg orally four times daily for 21 days 2
• Buboes may require aspiration through intact skin to prevent ulceration 2

For concurrent genital ulcers (HSV or syphilis):

• Obtain viral culture for HSV and serologic tests for syphilis 2
• Test for urethral/cervical chlamydia and gonorrhea 2

If Pelvic Inflammatory Disease/Tubo-ovarian Abscess:

Empiric antibiotic coverage for gonorrhea and chlamydia:

• Ceftriaxone 250 mg IM single dose PLUS doxycycline 100 mg orally twice daily for 10-14 days 3
• If abscess >3-4 cm on imaging, percutaneous drainage combined with antibiotics 1

If Appendicitis is Confirmed:

For abscess >3 cm:

• Percutaneous catheter drainage with antibiotics, followed by interval appendectomy 2
• Success rates of 70-90% with PCD avoiding immediate surgery 2

Addressing the Anemia (Hb 10.1 g/dL)

Evaluation and Management:

• This mild anemia in an 18-year-old female warrants investigation for iron deficiency, particularly given menstrual blood loss as a common cause 2
• Confirm with repeat hemoglobin; if persistent, begin oral iron 60-120 mg/day 2
• The combination of severe anemia with extreme leukocytosis can occur with iron deficiency, though this patient's leukocytosis is more likely infectious 4
• Follow-up in 4 weeks—if no response to iron therapy, obtain MCV, RDW, and serum ferritin 2

Critical Pitfalls to Avoid

• Never dismiss inguinal lymphadenopathy in sexually active adolescents—always test for STIs including LGV, which requires 21 days of doxycycline, not the standard 7-10 day course 2
• Do not perform CT without first obtaining β-hCG in any woman of reproductive age 1
• Avoid attributing all symptoms to a single diagnosis—this patient has both acute infection (leukocytosis, inguinal pain) and chronic anemia requiring separate evaluation 2
• If peritoneal signs develop, immediate surgical consultation is mandatory regardless of imaging findings 1

Follow-up Strategy

• Re-evaluate at 48-72 hours to confirm clinical improvement with antibiotic therapy 3
• If no improvement after 72 hours, obtain cultures and consider imaging if not yet performed 3
• Screen sex partners if STI is confirmed—those with contact within 30-60 days preceding symptom onset require examination and treatment 2
• Address the anemia separately with iron supplementation and dietary counseling, with follow-up in 4 weeks 2