A quick approach to Tuberculosis
Summary
Tuberculosis is a bacterial infection caused most commonly by Mycobacterium tuberculosis. It may have pulmonary and extra-pulmonary manifestations. Patients should be initiated on treatment once a diagnosis (GexeXpert, AFB smear, TB Culture, urine LAM, clinical) is made. The treatment consists of an intensive phase (RHZE) and a continuation phase (RH). The continuation phase is usually 2 months and the intensive phase is usually 6 months. Before moving from one phase to another, sputum smear microscopy should be performed in order to assess if the patient is NEGATIVE or POSITIVE.
Who gets treatment
- Patient with bacteriological confirmation of TB, either via GeneXpert, AFB smear or TB culture
- Patient with symptoms (Coughing > 2/52, Fever > 2/52, Weight loss, Drenching night sweats) and signs with radiological evidence with/without bacteriological confirmation
- Positive urine LAM test (Done in patients with CD4 < 200)
Baseline Evaluation and Investigations
- Sputum GeneXpert, AFB smear (Microscopy), TB Culture. Read this article on how to approach a patient that you suspect has a lower respiratory tract infection secondary to TB.
- Urine LAM (for dissimianted TB)
Diagnostic:
Others
- BMI
- Alcohol screen
- Urine dipstick (glucose and ketones)
- Pregnancy test, if indicated (woman of child bearing age not on any oral contraceptive agents)
- Liver Function Tests
- Chest X-Ray
- HIV testing, if the status is unknown
Monitoring
- Ask for symptoms
- Assess BMI, remember that these patients may be underweight.
- Contact Tracing (Look for other household members that may also be infected) and screen for TB disease. Assess those who may benefit from Isoniazid preventative therapy.
- Discuss information regarding family planning.
- Assess adherence (count their pills as well), review their clinic cards to check if they are attending their appointments, side effects of treatment
- Review other co-morbidities, and manage them accordingly.
- Follow up results of any pending investigations!
- Perform bacteriological monitoring: Important dates to keep in mind (7 weeks, 11 weeks, and 23 weeks). On these three dates, you will be sending sputum samples in order to monitor the TB treatment. Hence, it is important to keep track of how many weeks the patient is on treatment.
Treatment
- Once the patient is diagnosed: Notify the patient (there’s a book for this), then if down referring to another clinic/hospital then fill in the correct forms.
- Decide/Assess the following: (1) Total treatment duration, (2) phases of treatment (3) correct medication to use and prescribe (4) correct follow up
- Total treatment duration: Pulmonary TB is treated for 6 months (24 weeks). In severe forms of TB/disseminated TB (meningitis, TB bones/joints, military TB) then treatment may be extended to 9 months. If the patient has TB meningitis OR TB pericarditis then high dose steroids should be given as prednisone 1-2mg/kg daily for 4/52 and then you taper the steroid over 2/52.
- Phases: TB is treated in two different phases (Intensive phase and Continuation phase). The intensive phase comes first, usually for 2 months with RHZE usually as a fixed dosed combination (one tablet). Then the patient begins the Continuation phase, for at least 4 months in pulmonary TB with RH only. Sometimes, depending on the type of TB (eg. TB meningitis) the duration of the Continuation phase is extended to 7 months instead of 4 months.
- Medications: The intensive phase includes RHZE (150/75/400/275mg) while the continuation phase includes RH (150/75mg). The TB treatment should be calculated and prescribed as “mg/kg”. However, these medications are so common that they come in pre-existing combinations called Rifafour (RHZE) and Rifinah (RH).
- Once the patient is TB positive (GeneXpert positive Rifampicin sensitive OR Culture positive Rifampicin sensitive) start the patient on RHZE (150/75/400/275mg) PO daily for 2 months. You NEED to follow them up BEFORE the end of the intensive phase ends which is on week 7. On week 7, you will see the patient and take a sputum sample for smear microscopy. If at week 7 the sputum is negative, then it means that the patient is “NEGATIVE” and they can begin the continuation phase of treatment. The continuation of treatment begins at the END of week 8 (2 months intensive phase) and you need to prescribe RH (150/75mg) PO daily for 4 months. You will follow up the patient accordingly, but at week 23 then another sputum sample for smear microscopy needs to be taken in order to decide if the patient is really NEGATIVE. If NEGATIVE at 23 weeks, then stop the treatment at 24 weeks (6 months) and discharge the patient as “CURED”. If POSITIVE at 23 weeks then stop the TB treatment and register the patient as “Treatment failure”. Because the patient is still POSITIVE, you want to check the sensitivity/resistance with a LPA (Line Probe Assay) and DST (Drug Sensitivity Testing). If the sensitivity/resistance testing shows that the bacilli are susceptible then restart the TB treatment + counsel the patient. If the sensitivity/resistance testing shows that the bacilli are drug-resistant then you should refer the patient to an MDR-TB unit.
- On the other hand, what if the patient’s sputum test is POSITIVE for TB smear microscopy at week 7? This means that the patient has TB that was not adequately treated during the initial intensive phase. Hence, check for the patient’s compliance and send ANOTHER sputum for LPA (Line Probe Assay) and DST (Drug Sensitivity Testing). This patient needs to be registered as POSITIVE, and EXTEND the Intensive phase by 1 more month (Hence the treatment is now for 3 months). You will then repeat the sputum smear microscopy at 11 weeks and check for culture and DST results. If the patient is NEGATIVE and drug-susceptible start them on the continuation phase RH (150/75mg) PO daily for 4 months at the end of the 12 weeks. Register them as NEGATIVE and repeat the smear microscopy at 23 weeks (just as written above). If the patient at 11 weeks is either NEGATIVE/POSITIVE BUT resistant to any medication then you should refer the patient to the MDR-TB unit.
Common Side Effects
- Jaundice/Hepatotoxicity: This is caused by Rifampicin, Isoniazid or Pyrazinamide. Mx: Do a liver function test and follow the DILI guidelines.
- Visual impairment/loss: This is caused by Ethambutol. Mx: Stop ethambutol and do not start it again. Refer the patient to a ophthalmologist.
- Orange/Red coloured urine: This is caused by Rifampicin. Mx: Reassure the patient
- Peripheral neuropathy: This is caused by Isoniazid
- Joint Pains: This is caused by Pyrazinamide. Mx: Treat it symptomatically with analgesia such as NSAIDs
- Skin Rash: This is caused by Rifampicin, Isoniazid, Pyrazinamide: The management depends according to the severity.
Treatment Interruption
Interruption Period:
- < 1 month: Continue treatment and just add the missed doses at the end of the treatment phase.
- 1 – 2 months: Continue treatment BUT also collect sputum for GeneXpert. If the results are POSITIVE and sensnitve to Rifampicin then continue with the treatment and then add the missed doses at the end of the treatment phase. If resistant, stop the treatment, register the patient as “RR-TB” then refer to the MDR unit.
- > 2 months: Treat this patient as a new patient, collect sputum, and treat accordingly (SENSITIVE vs RESISTANT)
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