Lipoarabinomannan Antigen Assay (TB-LAM) for Diagnosing Pulmonary Tuberculosis in Children with Severe Acute Malnutrition in Mozambique

Abstract

Background Tuberculosis (TB) and malnutrition are important causes of morbidity and mortality in children in the developing world. Aims To assess the prevalence of pulmonary TB in severely malnourished children and evaluate TB detection using the urine lipoarabinomannan antigen assay (TB-LAM). Methods A retrospective analysis was conducted in all pediatric inpatients with severe acute malnutrition at a rural health center in Mozambique, from February to August 2018. All children underwent a physical examination and chest X-ray, and their nasopharyngeal aspirates and stool specimens were studied for mycobacterial culture and subjected to the Xpert MTB/RIF assay. TB-LAM tests were performed on urine. Results Of 45 included cases, 17 (37.8%) were clinically diagnosed as pulmonary TB. None of these were detected by the Xpert MTB test; 4 (8.9%) nasopharyngeal aspirates were TB-culture positive. Seventeen patients (37.8%)—all clinically diagnosed with TB—tested positive on the TB-LAM, while 23 (51.1%) were negative. In 5 (11.1%), the urine LAM was not done. Conclusion Although our sample size was small, TB was diagnosed and treated in more than a third of included children. The urine TB-LAM test showed a perfect correlation with clinical diagnosis of childhood TB. LAY SUMMARY Severe acute malnutrition makes children more vulnerable to tuberculosis (TB) infections, but it is difficult to detect TB in children because they cannot always cough up phlegm, which is used in diagnostic processes. This study aimed to find out how many severely malnourished children had TB in Gaza, Mozambique, and to test the accuracy of a less-used diagnostic test: the lipoarabinomannan assay (TB-LAM). Of the 45 severely malnourished children who were admitted to our hospital, 17 were diagnosed with TB by their doctor. The TB-LAM corroborated the clinical diagnosis in all cases, while the other tests (Xpert MTB/RIF assay) and cultures failed to detect most of them. Overall, more than a third of severely malnourished children had TB, and the TB-LAM test—a simple, point-of-care method—was a highly accurate way to diagnose them. While larger studies are needed to confirm these results, our findings suggest that the TB-LAM could vastly improve TB diagnosis in malnourished children.

Predictors of unfavourable tuberculosis treatment outcome in Bilene District, Gaza Province, Mozambique: A retrospective analysis, 2016 - 2019

“…The study could not evaluate nutritional factors, although previous studies have indicated an association between TB and nutritional status that may affect treatment outcomes. [12,23] Future studies should look to integrate findings from the TB register and HIV database for TB/HIV co-infected patients and collect socioeconomic and nutritional status for a complete evaluation of prognostic factors.…”

Accuracy of upper respiratory tract samples to diagnose Mycobacterium tuberculosis: a systematic review and meta-analysis

“…From included manuscripts (appendix pp 26–33 for study characteristics; appendix p 5 includes full methodological details and results by study), we classified types of upper respiratory tract sampling into four groups: laryngeal swabs (32 studies 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ), nasopharyngeal aspirate (ten studies 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ), oral swabs (18 studies 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ), and other (mouthwash three studies, 71 , 72 , 73 nasal swabs one study, 74 saliva four studies, 75 , 76 , 77 ,…”

Growth and anemia among children with tuberculosis infection at different sites in Southwest China

“…Existing data demonstrate that malnutrition is common among children with TB ( 6 , 7 , 9 , 21 ) and vice versa ( 22 , 23 ), with mortality tending to increase when these two diseases co-occur ( 24 ). In our survey, children in the TPA group had a higher incidence of malnutrition, reaching 69.5% (82/118).…”