Patil Shital, Narwade Swati, Mirza Mazhar
Department of Pulmonary Medicine, MIMSR Medical College, Latur, India.
Department of Obstetrics & Gynecology, Government Medical College, Latur, India.
J Transl Int Med. 2017 Sep 30;5(3):174-181. doi: 10.1515/jtim-2017-0030. eCollection 2017 Sep.
Lower lung field tuberculosis (LLF TB) is an atypical presentation of tuberculosis (TB). LLF TB is common, and a proportionate number of non-resolving pneumonia cases are diagnosed to have pulmonary TB.
The prospective observational study was conducted during June 2013 to December 2015 in the Department of Pulmonary Medicine, MIMSR Medical College, Latur, India; the objective of the study is clinical, microbiological, and radiological presentation of LLF TB and the comparison of yield of conventional diagnostic techniques and bronchoscopy-guided modalities in LLF TB. Additional important objective of the study is to find LLF TB in patients with nonresolving pneumonia (NRP). A total of 2,600 patients with pulmonary TB were included in the study after inclusion and exclusion criteria. Ethical clearance was taken from the ethical committee of the institutional review board. Consent was taken from the patients before inclusion in the study. Statistical analysis was done using chi-square test.
In the present study, 300 (11.53%) cases of LLF TB of total 2600 pulmonary tuberculosis were included, females constitutes 66.66% (200/300) with mean age of 58.4 ± 11.8 years and males constitutes 33.34% (100/300) with mean age of 56.8 ± 10.6 years. Constitutional symptoms were observed as cough in 93% cases, fever in 83% cases, shortness of breath in 72% cases, anorexia in 91% cases, and weight loss in 84% cases. Radiological assessment of study cases documented the involvement of right lower zone in 84% cases and left lower zone in only 16% cases. In the studied LLF TB cases, 57 cases (20.66%) were diagnosed by routine sputum microscopic examination for acid fast bacilli (AFB) and 80 cases (28%) were diagnosed by induced sputum microscopic examination for AFB. In the study of 170 LLF TB cases, head-to-head comparison between conventional diagnostic techniques (sputum microscopy and Induced sputum microscopy for AFB) made diagnosis in 60 cases, while bronchoscopy-guided sampling techniques (BAL for AFB and BAL for Gene Xpert MTB/RIF) made diagnosis in 155 cases (91.17%) ( < 0.00001). Comorbid conditions such as human immunodeficiency virus (HIV) coinfection in 36 cases (12.00%), Diabetes mellitus in 64 cases (21.33%), and chronic kidney disease (CKD) in 22 cases (7.33%) were observed. Comorbidities were observed in 41.67% of the studied cases and found very significant assessment to have successful treatment outcome ( < 0.00001). In the study of 300 LLF TB cases, 60 cases were having NRP pattern. In LLF TB cases with NRP pattern, bronchoscopy-guided bronchial wash microscopy for AFB made diagnosis in 18 cases (42%), while bronchoscopy-guided BAL for Gene Xpert MTB/RIF made diagnosis in 58 cases (96.66%) ( < 0.00001).
LLF TB is usually underdiagnosed because of diverse clinical and radiological presentation, less diagnostic yield of conventional diagnostic modalities, and these modalities used routinely and universally. Bronchoscopy-guided diagnostic techniques are superior, sensitive, and reliable to confirm LLF TB. Gene Xpert MTB/RIF in bronchial wash samples is found to be best diagnostic modality in evaluating LLF TB and should be used routinely to have successful treatment outcome. A proportionate number of NRP cases are having LLF TB and a high index of suspicion is a must while evaluating these cases.
下肺野结核（LLF TB）是结核病（TB）的一种非典型表现。LLF TB很常见，相当一部分未愈肺炎病例被诊断为肺结核。
前瞻性观察性研究于2013年6月至2015年12月在印度拉图尔MIMSR医学院肺病科进行；该研究的目的是观察LLF TB的临床、微生物学和放射学表现，并比较LLF TB中传统诊断技术和支气管镜引导方法的诊断率。该研究的另一个重要目的是在未愈肺炎（NRP）患者中发现LLF TB。经过纳入和排除标准后，共有2600例肺结核患者纳入该研究。获得了机构审查委员会伦理委员会的伦理批准。在患者纳入研究前获得了其同意。使用卡方检验进行统计分析。
在本研究中，2600例肺结核患者中包括300例（11.53%）LLF TB病例，女性占66.66%（200/300），平均年龄58.4±11.8岁，男性占33.34%（100/300），平均年龄56.8±10.6岁。观察到的全身症状包括：93%的病例有咳嗽，83%的病例有发热，72%的病例有呼吸急促，91%的病例有厌食，84%的病例有体重减轻。对研究病例的放射学评估显示，84%的病例右下肺区受累，仅16%的病例左下肺区受累。在研究的LLF TB病例中，57例（20.66%）通过常规痰涂片抗酸杆菌（AFB）显微镜检查确诊，80例（28%）通过诱导痰涂片AFB显微镜检查确诊。在对170例LLF TB病例的研究中，传统诊断技术（痰涂片显微镜检查和诱导痰涂片AFB显微镜检查）共诊断出60例，而支气管镜引导采样技术（支气管肺泡灌洗术检测AFB和支气管肺泡灌洗术检测Gene Xpert MTB/RIF）诊断出155例（91.17%）（P<0.00001）。观察到合并症，如36例（12.00%）合并人类免疫缺陷病毒（HIV）感染，64例（2l.33%）合并糖尿病，22例（7.33%）合并慢性肾脏病（CKD）。41.67%的研究病例存在合并症，且发现其对治疗成功结局有非常显著的影响（P<0.00001）。在对300例LLF TB病例的研究中，60例有NRP模式。在有NRP模式的LLF TB病例中，支气管镜引导的支气管灌洗AFB显微镜检查诊断出18例（42%），而支气管镜引导的支气管肺泡灌洗术检测Gene Xpert MTB/RIF诊断出58例（96.66%）（P<0.00001）。
由于临床和放射学表现多样、传统诊断方法的诊断率较低以及这些方法的常规和普遍使用，LLF TB通常诊断不足。支气管镜引导的诊断技术在确诊LLF TB方面更优越、敏感且可靠。支气管灌洗样本中的Gene Xpert MTB/RIF被发现是评估LLF TB的最佳诊断方法，应常规使用以获得成功的治疗结局。相当一部分NRP病例患有LLF TB，在评估这些病例时必须保持高度怀疑。
