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Referral and warning signs
When to refer
- Development of symptoms suggestive of active TB disease while on TPT.
- Signs or symptoms suggestive of significant drug toxicity (e.g., jaundice, severe rash, persistent vomiting, severe neuropathy).
- Known contact of an MDR-TB patient (requires specialist consultation for preventive options).
- Patients with complex co-morbidities or potential drug interactions requiring specialist management.
Red flags
- Development of cough, fever, weight loss, or night sweats while on TPT
- Jaundice
- Severe or persistent peripheral neuropathy symptoms
- Severe skin rash
Signs and symptoms
- Not applicable - TPT is for individuals WITHOUT signs/symptoms of active TB disease.
- Eligibility requires screening for and absence of: Cough, Fever, Weight loss, Night sweats.
Risk factors
- Being a Person Living with HIV (PLHIV)
- Being a close contact (especially household contact) of a person with bacteriologically confirmed pulmonary TB.
- Children < 5 years who are contacts of PTB cases.
- Other immunosuppressed conditions (though guidelines focus on PLHIV/contacts).
Diagnosis
Clinical assessment
Eligibility assessment involves identifying individuals belonging to target groups (PLHIV, contacts). Crucial Step: Rule out active TB disease using a systematic symptom screen (absence of current cough, fever, weight loss, night sweats).
Investigations
- TB Symptom Screen: Mandatory for all potential TPT candidates.
- Chest X-ray: May be used to help rule out active pulmonary TB if symptom screen is unclear or in specific populations (though not routinely required for asymptomatic PLHIV/contacts in high-burden settings).
- Tuberculin Skin Test (TST) / Interferon-Gamma Release Assay (IGRA): Can confirm latent infection but generally NOT required to initiate TPT in high-risk groups (PLHIV, child contacts <5) in high-burden settings like Uganda, once active TB is excluded.
- Rule out contraindications to TPT medications (e.g., active liver disease, severe peripheral neuropathy, history of severe hypersensitivity).
Diagnostic criteria
Identification as eligible high-risk individual (PLHIV, TB contact) AND systematic exclusion of active TB disease (primarily via symptom screen).
Management
Non-pharmacological management
- Counseling: Explain LTBI vs active TB, purpose of TPT, importance of adherence, potential side effects.
- Adherence Support: Strategies to ensure completion of the full course.
Pharmacological treatment
- Regimen Choice (Based on Uganda Guidelines 2023 Summary/Dosing Chart - refer to full NTLP guidelines for specifics):
- - Preferred for PLHIV (>2yrs) & Contacts (>2yrs): 3HP = Rifapentine + Isoniazid once weekly for 3 months.
- - Preferred for Child Contacts <1yr: 1HP = Rifapentine + Isoniazid once daily for 1 month (only if history of contact with TB case and active TB excluded).
- - Preferred for Adolescents >13yrs/Adults (Alternative): 1HP = Rifapentine + Isoniazid once daily for 1 month.
- - Alternative/Commonly Used: 6H = Isoniazid daily for 6 months.
- - Alternative: 3RH = Rifampicin + Isoniazid daily for 3 months.
- Co-medication:
- - Pyridoxine (Vitamin B6) 25mg daily: Co-administer with all Isoniazid-containing TPT regimens to prevent peripheral neuropathy.
- Dosing: Based on weight bands as per UCG/NTLP dosing chart.
- Contraindications: Active TB disease, contact of known MDR-TB patient (requires specialist consultation for alternative prevention), severe liver disease, hypersensitivity to TPT drugs.
Monitoring
- Regular clinical follow-up (e.g., monthly) to:
- - Assess for and reinforce adherence.
- - Screen for symptoms of active TB disease.
- - Monitor for adverse drug reactions (esp. hepatotoxicity - jaundice, nausea/vomiting, abdominal pain; peripheral neuropathy - tingling/numbness).
- - Routine LFT monitoring usually not required unless baseline liver disease, high alcohol intake, pregnancy, or symptoms develop.
Complications
- Adverse drug reactions: Isoniazid-induced hepatitis (rare but serious), peripheral neuropathy (preventable with Pyridoxine), rash. Rifapentine/Rifampicin: hepatitis, rash, flu-like syndrome, drug interactions.
- Development of active TB if screening was inadequate, adherence poor, or infection was already drug-resistant.
- Development of drug resistance if active TB was missed and treated with inadequate regimen (e.g., INH monotherapy).
Prevention
- TPT itself is a primary prevention strategy against developing active TB disease in those with latent infection.
Patient education
- Difference between latent TB infection (sleeping germs) and active TB disease.
- Purpose of TPT is to prevent active disease.
- Critical importance of completing the full course of medication for it to be effective.
- How to take the medication correctly.
- Potential side effects (especially liver symptoms, nerve symptoms) and the need to report them immediately.
- Reassurance that TPT does not treat active TB.
- Importance of attending follow-up appointments.
Uganda-specific notes
TPT targeted primarily at PLHIV and child contacts <5 years, plus other contacts based on programmatic priorities. 3HP is an increasingly preferred shorter regimen. Ensure Pyridoxine is co-prescribed with INH. Active TB exclusion relies heavily on symptom screening. Adherence support is key.
References
- Uganda Clinical Guidelines (UCG) 2023
Chapter 5, Section 5.3.2.3, 5.3.2.5 (Dosing Chart)
- National Guidelines for Programmatic Management of Latent TB Infection (NTLP)
(Refer to latest NTLP document)