Koch's Abdomen — Further Management

Step 1 — Confirm the Diagnosis

Ascitic Fluid Analysis (if ascites present)

Patients with lymphocytic ascites + fever → TB until proven otherwise; afebrile + lymphocytic → consider malignancy (10× more common). — Sleisenger & Fordtran's Gastrointestinal and Liver Disease

Imaging

• CT abdomen: Peritoneal thickening/enhancement, omental caking, matted bowel loops, mesenteric lymph nodes with central caseation (hallmark), ascites
• Chest X-ray / CT chest: look for pulmonary TB (concurrent in ~40%)

Serology

• QuantiFERON-Gold / Mantoux: Detect TB exposure, but poor sensitivity for active peritoneal TB, especially in endemic areas or BCG-vaccinated individuals

Tissue Biopsy (Gold Standard)

• Laparoscopy: Nearly 100% sensitive — reveals "white miliary nodules" on peritoneum, allows biopsy for histology (caseating granulomas) and culture
• Use when ascitic fluid analysis is inconclusive or cytology is negative (to exclude malignancy)
• CT-guided biopsy of lymph nodes/omentum is an alternative

Step 2 — Baseline Workup Before Starting Treatment

• HIV testing and other blood-borne virus screening
• Liver function tests (LFT) — baseline (repeat during therapy)
• Renal function
• Colour vision baseline (before ethambutol)
• Audiometry (if injectable agents planned)
• Assess for other sites of TB (chest, spine, urogenital)
• Identify drug interactions (especially if patient on anticonvulsants, anticoagulants, antiretrovirals)

Step 3 — Antitubercular Treatment (ATT)

Standard Regimen (Drug-Sensitive TB)

"A 6-month treatment course of isoniazid, rifampin, pyrazinamide, and ethambutol for the first 8 weeks, followed by isoniazid and rifampin for the next 4 months, is considered adequate." — Sleisenger & Fordtran's Gastrointestinal and Liver Disease

Drug-Resistant TB (MDR/XDR)

• Requires specialist referral
• Injectable agents (amikacin, capreomycin) + oral agents per susceptibility (cycloserine, ethionamide, PAS, fluoroquinolones, linezolid)
• Treatment prolonged (18–24 months)

Step 4 — Special Considerations

Hepatotoxicity

• All four first-line drugs are potentially hepatotoxic
• Monitor LFTs regularly — especially in patients with cirrhosis, where drug modification may be needed
• Stop ATT if LFTs rise >3× ULN with symptoms or >5× ULN asymptomatic

Rifampicin Drug Interactions (P450 inducer)

HIV Co-infection

• Start ATT first, then ART (after 2–8 weeks) to avoid immune reconstitution inflammatory syndrome (IRIS)
• Rifabutin may replace rifampicin if on protease inhibitors

Cirrhotic Patients

• Higher risk of developing TB peritonitis
• Drug-induced hepatitis more likely — use safer alternatives (e.g., streptomycin-based regimens in severe liver disease under expert guidance)

Step 5 — Directly Observed Therapy (DOT)

• ATT must be administered under supervised/DOT protocols
• Erratic or incomplete treatment leads to MDR-TB — a major public health risk
• Public health notification is mandatory

Step 6 — Surgical Indications

Surgery for abdominal TB complications should ideally be done after ATT has been initiated for 4–6 weeks to reduce inflammation, except in emergencies.

Response Monitoring

• Clinical improvement (fever, weight, pain) expected within 2–4 weeks
• Repeat imaging (ultrasound/CT) at 2–3 months
• Persistent or worsening disease despite ATT → consider drug resistance, wrong diagnosis (malignancy), or poor adherence

Summary Flowchart

Ultrasound suggests Koch's abdomen
        ↓
Ascitic fluid analysis (ADA, AFB, cytology, lymphocyte count)
        ↓
CT Abdomen + Chest X-ray
        ↓
Baseline bloods (LFT, RFT, HIV)
        ↓
Laparoscopy ± biopsy (if diagnosis uncertain)
        ↓
Confirm TB → Start 2HRZE / 4HR under DOT
        ↓
Monitor (LFT, clinical, imaging)
        ↓
Surgery if complications (obstruction, perforation, abscess)

• Sleisenger & Fordtran's Gastrointestinal and Liver Disease — Tuberculous Peritonitis
• Bailey & Love's Short Practice of Surgery 28th Ed. — Mycobacterial Infection Management
• Recent systematic reviews: PMID 40533676 — Abdominal TB in children (2025); PMID 40963962 — Misdiagnosis patterns (2025)