The Impact of Nutrition on TB Treatment Outcomes

December 2008

Case History

A 49 year old male was diagnosed with recurrent pulmonary tuberculosis after presenting to an emergency room with a 3 month history of malaise, chills, subjective fevers, shortness of breath, productive cough; and weight loss over the past year. A sputum specimen was positive for AFB and grew M. tuberculosis susceptible to all first line drugs. The chest radiograph was abnormal with bilateral patchy alveolar opacifications in the upper lobes and a CT scan of the chest noted tree-in-bud parenchymal opacifications and consolidation bilaterally, cavitation in the right apex and right lower lobe, and diffuse centrilobular nodules in both lungs. The patient was coughing and appeared malnourished and chronically ill. His height was 5'7½" and weight at diagnosis was 114lbs. His BMI was 18 (underweight). Labs indicated anemia, with a borderline low serum folate level (3.6, normal >5.4), and iron deficiency (iron 28, normal range 50-160).

His previous episode of tuberculosis was treated by directly observed therapy 7 years earlier. Because of a presumed allergic reaction to pyrazinamide (PZA), he received treatment with isoniazid (INH), rifampin (RIF), and ethambutol (EMB) alone. For unclear reasons, treatment was stopped after only 8 months despite a slow clinical and bacteriological response. His weight gain was poor and sputum cultures took more than 2 months to convert to negative.

Treatment was reinstituted with the standard four drug daily regimen of INH, RIF, EMB, and PZA but he was not able to tolerate the PZA and it was discontinued. Without PZA, a minimum of 9 months of treatment was planned. After 2 months of treatment, he had not gained any weight and during the third month he only gained 1 pound. A CBC indicated mild anemia. Serum drug levels showed a rifampin level of 8.01mcg/ml which was at the low end of normal (8-21 mcg/ml normal range), and a border line low INH level of 3.14 mcg/ml (normal 3 5). Rifampin was increased to 750 mg daily. Repeat rifampin serum drug levels were normal at 20.17 mcg/ml. The patient tolerated the increased rifampin dose without any evidence of toxicity so INH was increased to 450 mg daily. Repeat levels were within normal limits.

Sputum smears and cultures were positive through the third month of therapy but converted to negative before the fourth month. Treatment was complicated by poor appetite, intermittent nausea, and vomiting after taking his TB medications. He improved with decreased cough, resolution of fevers and night sweats, and increased energy. After 4 months of treatment, he had gained 2 additional pounds and his appetite improved. By the fifth month, the weight was 119lbs, but his chest x-ray showed increased lucencies, necrosis, and cavitations. His weight increased further by month 7 of treatment but he continued to note mild daily nausea and at least 2 episodes of vomiting each week.

Treatment was extended to 12 months due to treatment without PZA, slow clinical and bacteriological response, and extensive radiographic disease. He continued on daily therapy throughout the course of his treatment.

Teaching Points

This patient had several risk factors for a poor treatment outcome. We will note these but focus our discussion on the impact of nutrition on TB treatment outcomes.

Researched and written by: Catalina Navarro, RN, BSN; Debbie Onofre, RN, MSN, Heartland National TB Center

Footnotes

Resources

Khan A, Sterling TR, Reves R, Vernon A, Horsburgh CR: Tuberculosis Trials Consortium. Lack of weight gain and relapse risk in a large tuberculosis treatment trial. Am J Respir Crit Care Med 2006;174:344-348.

Yew WW, Leung CC. Prognostic significance of early weight gain in underweight patients with tuberculosis. Am J Respir Crit Care Med 2006; 174:236-237.

American Thoracic Society; Centers for Disease Control and Prevention; Infectious Diseases Society of American. Treatment of tuberculosis. Am J Respir Crit Care Med 2003; 167:603-662.

Heartland National TB Center provides a Medical Consultation Line that is staffed Monday to Friday, 8:00 AM to 5:00 PM (CST). After business hours, voice mail is available and will be returned in one business day.

Heartland National TB Center
2303 SE Military Drive
San Antonio, Texas 78223
Phone: 1 (800) TEX-LUNG
Fax: (210) 531-4590
http://www.heartlandntbc.org/