Diagnosis: Two Concurrent Conditions

1. Tuberculous Peritonitis - explaining the ascites
2. Erythema Nodosum Leprosum (ENL) / Type 2 Leprosy Reaction - explaining the recurrent painful subcutaneous nodules

Part 1: Tuberculous Peritonitis

Why the diagnosis fits

• Moderate ascites with lymphocyte-predominant exudate (50-10,000 leukocytes/µL, majority lymphocytes)
• ADA of 64 U/L - well above the 30 U/L cutoff (sensitivity 94%, specificity 92% per Henry's Clinical Diagnosis textbook)
• CB-NAAT negative - this does not rule out TB peritonitis; AFB is rarely seen on ascitic fluid smears, and cultures are positive in only ~50% even with large-volume submissions

• Murray & Nadel's Textbook of Respiratory Medicine, p. 1429

Why she is at elevated risk for TB

Management of TB peritonitis

• Continue standard ATT: Isoniazid + Rifampicin + Pyrazinamide + Ethambutol for 2 months (intensive phase), then Isoniazid + Rifampicin for 4 months (continuation phase). Total duration: 6 months
• Note: Some guidelines recommend 9 months for peritoneal TB due to concerns about response
• Adjunctive prednisolone for peritoneal TB is debated; some guidelines use it to reduce adhesions, but given her prior steroid use and ENL history (see below), this requires individualized assessment
• Monitor with repeat imaging/clinical assessment at 6-8 weeks for response
• Remaining abdominal pain and nausea may be symptoms of peritonitis itself and should improve as treatment continues

Part 2: Erythema Nodosum Leprosum (ENL) - Type 2 Leprosy Reaction

The key diagnostic insight

ENL: Pink-to-red, tender nodular lesions on the arms. From Harrison's Principles of Internal Medicine, 22E.

• Occurs mostly during MDT, but also develops in untreated patients and after treatment completion
• Can recur episodically for months to years post-MDT
• Involves skin, nerves, and other organs (lymph nodes, liver, spleen, kidneys, eyes, testes)

Why ENL keeps recurring

"Leprosy reactions and new nerve damage may also occur after completion of multidrug treatment. While the risk diminishes with time, these manifestations can occur up to 3 years after the conclusion of therapy."

• Harrison's Principles of Internal Medicine, 22E, p. 1454

Management of ongoing ENL

• Thalidomide is potentially usable but requires mandatory pregnancy testing and two reliable forms of contraception - this must be discussed and documented before prescribing
• If thalidomide is not feasible, clofazimine (100 mg 3x/day, tapering) is the alternative long-term option for recurrent ENL
• Steroids may be needed for acute flares but require caution given the TB peritonitis co-diagnosis (steroids may be acceptable adjunctive therapy for TB peritonitis but at lower doses)

• NSAIDs for mild episodes
• Assess for nerve function impairment at each visit (ENL can cause silent neuritis - test for ulnar/median/posterior tibial nerve function)
• Monitor eyes for iridocyclitis/uveitis - a serious ENL complication
• Monitor renal function (ENL nephritis)

Putting It All Together: The Critical Connection

1. She had multibacillary leprosy (given the severity and bilateral limb involvement)
2. She developed ENL (Type 2 reaction) - manifesting as painful subcutaneous nodules + fever → appropriately treated with prednisone
3. Prolonged corticosteroid use for ENL suppressed her immune system and likely reactivated latent TB → leading to tuberculous peritonitis
4. She is now on ATT (correct), but her ENL continues post-MDT (expected and documented up to 3 years after therapy)

Immediate Action Plan

• Harrison's Principles of Internal Medicine, 22E, pp. 1452-1454
• Fitzpatrick's Dermatology, 5th ed., pp. 1489-1500
• Murray & Nadel's Respiratory Medicine, p. 1429

Latest Guidelines: Managing TB Peritonitis with Concurrent ENL

1. TB Peritonitis: Current Evidence-Based Recommendations

ATT Regimen (Standard, well-established)

2RHZE / 4RH - Rifampicin + Isoniazid + Pyrazinamide + Ethambutol for 2 months, then Rifampicin + Isoniazid for 4 months. Total: 6 months.

Assessing Response to ATT

• Do not rely solely on subjective symptom improvement - use objective markers
• 2-month assessment is the key checkpoint: look for reduction in ascites on imaging, improvement in constitutional symptoms
• ADA levels may not reliably track response (do not retest ADA as a response marker)
• In this patient, partial reduction of ascites at 2 weeks on ATT is a positive sign - full response takes 6-8 weeks

Adjunctive Corticosteroids in TB Peritonitis

2. ENL Management: Latest Evidence (2025-2026)

The Corticosteroid Risk Problem - A 2026 Warning

"Infections were the second most common adverse effect (15.5%) of corticosteroids in leprosy... Infections accounted for three-quarters of corticosteroid-associated mortality, predominantly due to tuberculosis, with 88.2% of corticosteroid-associated mortalities occurring in individuals with ENL."

• Lun et al., PLoS Negl Trop Dis, 2026 (PMID 41886473)

Preferred Steroid-Sparing Approaches for ENL in 2025-2026

• Drug of choice for chronic/recurrent ENL
• Blocks TNF-α production, targeting the immune complex-driven inflammation of ENL
• CRITICAL CONTRAINDICATION: Absolutely teratogenic - in this 28-year-old woman, mandatory pregnancy testing + dual reliable contraception must be confirmed before use
• Not appropriate if she could be pregnant or not willing to use strict contraception

• Preferred steroid-sparing agent when thalidomide cannot be used
• Anti-inflammatory via inhibiting phospholipase A2 and T-cell function
• Onset of action slow (6-12 weeks) - not suitable for acute flares
• Safe to use concurrently with ATT (no major interactions)

• PDE4 inhibitor - blocks downstream TNF-α, IL-17, IL-23
• A 2025 review + case report (Gayoso Cantero et al., Travel Med Infect Dis, 2025 - PMID 41093045) documents successful use in steroid-dependent, thalidomide-refractory ENL - enabling complete withdrawal of both corticosteroids and thalidomide
• No teratogenic risk (unlike thalidomide)
• May be the best option in a young woman with concurrent active TB where steroids and thalidomide both carry concerns
• Currently off-label for ENL; cost and access may be limiting factors

3. The Specific Challenge: Managing Both Simultaneously

The rifampicin interaction

• Rifampicin resistance acquisition: If the patient received rifampicin monthly (leprosy dose), and is now taking rifampicin daily (TB dose), this is an intensification - no problem
• However, if ENL recurs during active TB treatment and rifampicin is already being used, any ENL treatment decision must not compromise ATT adherence
• Rakotoarisaona et al. (2024, PMID 38645889) - Madagascar case series of 5 TB-leprosy coinfections - concluded: "Dermatologists should screen leprosy patients for latent/active TB before long-term corticosteroids, and rifampicin resistance is the greatest risk of combined treatment"

Practical Management Algorithm for This Patient

Active TB Peritonitis (on ATT)
        +
Recurrent/Chronic ENL
        ↓
Step 1: Continue full 6-month ATT (2RHZE/4RH) — non-negotiable
        ↓
Step 2: Assess ENL severity
  ├─ Mild (skin nodules only, no nerve involvement)
  │     → Clofazimine 100-300 mg/day (steroid-sparing, TB-safe)
  │     → NSAIDs for symptomatic relief
  │
  └─ Moderate-severe (neuritis, systemic symptoms, or
     risk of nerve damage)
        ↓
        Use MINIMUM effective corticosteroid dose
        Prednisolone 0.5-1 mg/kg/day (not full 2 mg/kg)
        Taper aggressively over 6-8 weeks (not 3 months)
        Avoid open-ended long-course steroids
        ↓
        Transition to steroid-sparing agent ASAP:
        ├─ Thalidomide 100 mg/day (if dual contraception confirmed)
        └─ Apremilast 30 mg BD (if thalidomide not feasible)

Monitoring Parameters

Summary of Evidence Levels