Tuberculosis

M.W., a 36-year-old woman, is admitted to the hospital with a 2 month history of cough, which has recently become productive. She is also experiencing fatigue, night sweats, and has lost 15 pounds. Other medical problems include diabetes mellitus, which is controlled with 10 units of NPH insulin daily, and poor nutritional status secondary to frequent dieting. M.W. works as a volunteer in a nursing home several days a week. Recently, it was discovered that two patients who she had been caring for had undiagnosed active tuberculosis. M.W.’s physical examination was normal, but her chest radiograph revealed bibasilar infiltrates.

A tuberculin purified protein derivative (PPD) skin test, sputum collections for cultures and susceptibility testing, and a sputum AFB smear were ordered as part of M.W.’s diagnostic workup. Initial laboratory test findings were within normal limits. The result of her tuberculin PPD skin test, read at 48 hours, was a palpable induration of 14 mm. Her sputum smear was positive for AFB, and additional sputum cultures for M.tuberculosis were ordered to confirm the diagnosis of active TB disease.

Q1. What subjective and objective findings does M. W Q1. What subjective and objective findings does M.W. have that are consistent with active TB disease? History of cough (which gradually became productive), bibasilar infiltrates, fatigue, and night sweats are consistent with the classic symptoms of activeTB. The sputum may contain blood (hemoptysis) in patients with advanced cavitary disease, Anorexia from TB, along with frequent dieting, may have resulted in M.W.’s weight loss.

Objective Findings A positive sputum smear for AFB, a positive PPD skin test(14mm), and diabetes mellitus, which is a risk factor for TB.

Q2. What is tuberculin skin testing  Q2. What is tuberculin skin testing? How should the results be interpreted in M.W.? What other test may be useful in the diagnostic work-up of M.W.? The skin test is performed by injecting 0.1 mL of solution containing 5-TU PPD intracutaneously into the volar or dorsal surface of the fore arm. A distinct, pale elevation of the skin (a wheal) 6 to 10mm in diameter should be produced. An in duration ≥5 mm in diameter read 48 to 72 hours after injection is considered to be a positive reaction in an individual with a recent history of close contact with a person with active TB. Other tests ELISA for interferon gamma from T cells

 Q3. Because M.W.’s Mantoux PPD skin test is positive, does this confirm her diagnosis of active TB? No.M.W.’s positive reaction to 5-TU PPD alone does not confirm active TB. M.tuberculosis must be isolated from sputum, gastric aspirate, spinal fluid, urine, or tissue biopsy, depending on the site. Detection of AFB in stained smears.(grow slowly (i.e., once every 24hours).

Q4. Should M.W. be tested for HIV infection? Yes, testing should be considered because TB may be the first manifestation of HIV infection. (37% HIV develop TB)

No. A negative response will not exclude. False negatives occur Q5.Would a negative tuberculin skin test have eliminated the possibility of infection with M.tuberculosis in M.W.? No. A negative response will not exclude. False negatives occur Injecting too little antigen Error in recording Diseases affecting lymphoid organs Age(newborns, elderly) Corticosteroids,I mmunosuppressive agents

4 basic regimens started INH+RIF+PYZ+ETM(8weeks). Q6. M.W.’s HIV test was negative. How should treatment be initiated in M.W., pending the results of the sputum culture and susceptibility testing? Can she transmit infection during treatment? Effective treatment of TB requires a substantial period (minimum 6 months) of intensive drug therapy with at least two bactericidal drugs that are active against the organism. 4 basic regimens started INH+RIF+PYZ+ETM(8weeks). M.W.,who is diabetic and has a poor nutritional status, should also be given pyridoxine 25mg/day because she may be at greater risk for the development of INH-induced peripheral neuropathy. Considered non infective if improving symptoms with 3 sputum negative for AFB.

Patient adherence important Q7. Six weeks later, M.W.’s sputum cultures were positive for M.tuberculosis. Drug susceptibility tests demonstrated susceptibility to both INH and rifampin. What drug regimen should be used for continued therapy of M.W.? How long treatment should be continued? Patient adherence important After 8 weeks of DOT with 4Drug regimen, 2 drug regimen for another 18 weeks.

Prevent risk to community. Prevent relapse Q8. What exactly is DOT, and why is it important that it be used in M.W.? A health care provider or other responsible person observing as the patient ingests and swallows the TB medications. Mutual agreement Prevent risk to community. Prevent relapse

Multiple organisms are involved. Q9. Why is multiple drug therapy indicated for the treatment of active TB disease? What is the role of each drug in the treatment of TB? To kill organisms and prevent development of resistant strains od M.TB. Multiple organisms are involved. Sterilize the sputum and lesions as quickly as possible. Reduce infectiousness of the patient.

Hepatitis symptoms need to be investigated. Q10. What subjective and objective findings should be followed to ensure therapeutic efficacy and minimize drug toxicity? Should M.W. be followed closely after completion of her treatment regimen? ADRs due to INH, RiF. Hepatitis symptoms need to be investigated. Ask symptoms of peripheral neuropathy. Rifampin induced thrombocytopenea. Hematologic disturbances BUN, Hepatic enzymes, visual examination

No, Do not add a single drug. Check susceptibility. Q11. If M.W. does not respond to her current therapy, should one more drug be added to her regimen? No, Do not add a single drug. Check susceptibility. Empiric retreatment regimens may include a fluoroquinolone, an injectable agent (e.g.,streptomycin, amikacin, or capreomycin) , and an additional oral agent (e.g.,para-aminosalicylicacid, cycloserine, or ethionamide).