Pulmonary & Extrapulmonary TB

1. Background/Cultural Points:

   Tuberculosis, pulmonary and extrapulmonary, is ubiquitous in Cambodia. Cambodia ranks 21st (2011) on the list of 22 “High-Burden” TB countries in the world. An estimated 64% of Cambodians are infected with TB (world-wide, approximately 1 in every 3 people is infected; in Cambodia 2 in every 3 people are). Since 2000, approximately 13,000 Cambodians die of TB per year. A national DOTS program was launched in 1994 and reaches all provinces now with varying success (national detection rate is 60%). MDR TB is present in Cambodia, but very uncommon. HIV prevalence is 8% among TB infected patients (while only 0.8% HIV rate in the general population, all ages; 2% among reproductive-age adults).

   At MMC, we most often see more complicated cases of TB, such as: pulmonary TB that was initially sputum negative, undiagnosed extrapulmonary TB, and chronic lung damage from previous TB. A difficult challenge can be diagnosing and treating extrapulmonary TB because of the difficulty with microbiological testing and accessing medications (Extrapulmonary TB is not a public health threat, so it is more difficult for patients to get a diagnosis and treatment through the national program). The rule at MMC is, in any unclear patient case, “Think TB”.

2. Work-Up/Diagnosis & Lab:

   1. If pulmonary TB is suspected, ask the patient his/her history of seeking care. It is common that patients have already accessed care. If pulmonary TB is suspected and sputums have not yet been checked or were checked but negative (or incomplete/inadequate), complete a referral form for the national system. The National TB Center (CENAT) is our preferred referral point in Phnom Penh.
   2. If pulmonary TB is suspected and sputums are negative, check a CXR (at Calmette Hospital).
   3. If extrapulmonary TB is suspected, order blood work and other diagnostics as needed. A referral letter to Pulmonology/Infectious Disease at KSF (Russian) Hospital may be the most likely to succeed.
   4. PPD skin testing is available (at MMC or NIPH), but false-negatives due to malnutrition and false-positives due to previous BCG vaccination often make interpretation difficult.
   5. All patients should be tested for HIV.
   6. All patients suspicious for TB should be given a mask to wear at triage.

3. Management/Education/Treatment:

   1. If TB is confirmed (either XR evidence or, preferably, sputum evidence), the patient should be referred with a letter and the evidence of their TB to their local Health Center to be enrolled in DOTS.
   2. If TB is not confirmed but highly suspected, and enrollment in the national program has failed or is likely to fail, order appropriate pre-treatment labs and perform pre-treatment fundoscopy and visual acuity check, then begin empiric 1 month treatment through MMC.
   3. Pre-treatment labs should include careful screening for Hep B and C which are common in Cambodia. Rapid B/C tests are available at MMC.
   4. Preferred regimen is weight-based WHO/Cambodia MOH protocol using “RHZE” (Rifampin, INH (Isoniazid), Pyrazinamide, Ethambutol) as first line and adding Streptomycin for second line (such as “defaulters”).
   5. Consider adding Vitamin B6 25mg/d prophylaxis for peripheral neuropathy. Avoid excessively high-doses of B6, which can, ironically, cause neuropathy.
   6. Cases of suspected MDR TB should be reported to CDC at National Institute of Public Health in Tuol Kork, PP.
   7. Remember to educate the patient regarding: informing contacts, wearing a mask in the house until sputum negative (or cough free), medication side effects, completing an entire treatment course and not missing any doses. (Ideally, patient should sign a contract to complete treatment.)

4. Follow-Up:

   1. Initial follow up should typically be in 1-2 weeks, then spaced to 1 month. If a patient responds to 1 month empiric treatment of TB, he/she should be continued 6-9 months, preferably through referral to national system with referral letter from MMC. If a patient does not respond to empiric therapy by 1 month, discontinuation of TB meds should be considered.
   2. Ministry of Health has a standard of care for TB booklet, available in English in MMC library
   3. Sanford Guide TB treatment table has appropriate weight-based protocol.