|Year : 2020 | Volume
| Issue : 5 | Page : 470-474
Yield of direct sputum smear examination in pulmonary tuberculosis suspect cases with hemoptysis
Sushil Kumar Munjal1, Karnail Singh2, Ritu Singhal3, Amartya Chakraborti2
1 Department of Tuberculosis and Chest Diseases, National Institute of Tuberculosis and Respiratory Diseases, New Delhi, India
2 Department of Tuberculosis and Respiratory, National Institute of Tuberculosis and Respiratory Diseases, New Delhi, India
3 Department of Microbiology, National Institute of Tuberculosis and Respiratory Diseases, New Delhi, India
|Date of Submission||25-Sep-2019|
|Date of Decision||25-Nov-2019|
|Date of Acceptance||06-Jan-2020|
|Date of Web Publication||7-Sep-2020|
Room Number 6, Doctors Hostel, National Institute of Tuberculosis and Respiratory Diseases, Sri Aurobindo Marg, New Delhi - 110 030
Source of Support: None, Conflict of Interest: None
Introduction: Hemoptysis is one of the cardinal symptoms of pulmonary tuberculosis (PTB) as per the Revised National Tuberculosis Control Programme 2016 guidelines. Hemoptysis in tuberculosis patients usually occurs in those who have a large bacillary load like that in a cavity. Direct smear done from the sputum of a PTB suspect with hemoptysis should have a higher diagnostic yield due to the greater bacillary load in such patients. Keeping this intention in mind, our study was conducted to systematically inquire into the efficacy of a cheap and easily available test like direct sputum smear examination in PTB suspect cases of hemoptysis. Materials and Methods: This was a prospective, hospital-based, analytical study, conducted on 100 PTB suspects with hemoptysis, who were attending the Outpatient and Emergency Department of National Institute of Tuberculosis and Respiratory Diseases, New Delhi, India. Patients were enrolled over a period of 8 months. All patients underwent routine clinical and radiological evaluation and sputum examination in the form of direct smear by Ziehl–Neelsen (ZN) staining and mycobacterium growth indicator tube (MGIT) culture. Results: Most of the patients (25%) belonged to the age bracket 16–25 years followed by 24% of patients who belonged to the age group of 26–35 years. Fifty-two percent of patients had the cavity in their chest X-ray findings in which mostly were the unilateral cavity (39%). Direct sputum microscopy was found to be positive in 56% of patients. In comparison to MGIT, it had a sensitivity of 79% and a positive predictive value of 92%. Conclusion: Direct smear examination in hemoptysis patients should be a first line essential investigation as it is a good, cheap, easily available, and quick test. The yield of the test increases if the patient is young, male, with a previous history of antitubercular therapy intake and cavitary lesions on the radiological findings.
Keywords: Hemoptysis, pulmonary tuberculosis suspect, yield of sputum direct smear, Ziehl–Neelsen staining
|How to cite this article:|
Munjal SK, Singh K, Singhal R, Chakraborti A. Yield of direct sputum smear examination in pulmonary tuberculosis suspect cases with hemoptysis. Med J DY Patil Vidyapeeth 2020;13:470-4
|How to cite this URL:|
Munjal SK, Singh K, Singhal R, Chakraborti A. Yield of direct sputum smear examination in pulmonary tuberculosis suspect cases with hemoptysis. Med J DY Patil Vidyapeeth [serial online] 2020 [cited 2020 Sep 29];13:470-4. Available from: http://www.mjdrdypv.org/text.asp?2020/13/5/470/294356
| Introduction|| |
India is the second-most populous country in the world, and one-fourth of the global incidence of tuberculosis (TB) cases occurs in India annually. As per the World Health Organization (WHO) Global TB Report 2017, an estimated 10.4 million people fell ill with TB in 2016, out of which 2.4 million occurred in India. Hemoptysis is one of the cardinal symptoms of pulmonary tuberculosis (PTB) as per the Revised National Tuberculosis Control Programme (RNTCP) 2016 guidelines. Although hemoptysis is a less common symptom than other PTB-related symptoms such as cough, fever, night sweats, and weight loss, it occurs in an estimated 15%–28% of PTB patients.,, Hemoptysis in TB patients usually occurs in those who have a large bacillary load like that in a cavity. Hence, direct smear done from the sputum of a PTB suspect with hemoptysis should have a higher diagnostic yield due to the greater bacillary load in such patients. Keeping this intention in mind, our study was conducted to systematically enquire into the efficacy of a cheap and easily available test like direct smear examination in PTB suspect cases with hemoptysis. The study included only those cases who presented clinicoradiologically as TB. As studies regarding direct smear examination in patients with hemoptysis are lacking, this study can open the new systematic inquiry in the diagnosis of PTB in hemoptysis.
| Materials and Methods|| |
The aim of this study is to evaluate the yield of direct sputum smear examination in PTB suspect cases with hemoptysis.
The objectives are as follows:
- To assess the early diagnosis of TB in hemoptysis
- To assess the risk factors and its association with a yield of direct microscopy in PTB suspect with hemoptysis
- To evaluate the result of direct microscopy for the diagnosis of the PTB suspect cases with hemoptysis.
Type of the study
The study design involves a prospective, observational study.
Duration of the study
The duration of the study was approximately 1 year.
The study was conducted at the National Institute of Tuberculosis and Respiratory Diseases (NITRD), New Delhi, India.
The inclusion criteria are as follows:
- Age of the patient more than 18 years
- PTB suspects with hemoptysis.
As per the treatment and operational guidelines RNTCP 2016, PTB suspects or presumptive PTB refers to a person with cough >2 weeks, fever >2 weeks, significant weight loss, and hemoptysis any abnormalities in chest radiography. Significant weight loss was defined as the loss of weight of at least 10% of the bodyweight within the past 6 months.
The exclusion criteria are as follows:
- Spurious hemoptysis
- Lung malignancy with hemoptysis (confirmed by biopsy or suspected radiologically)
- Not willing to be a part of this study.
- All the PTB suspects with hemoptysis who reported for the treatment at the Outpatient Department (OPD) and Emergency Department of National Institute of Tuberculosis and Respiratory Diseases, New Delhi, India, were recruited for this study. 100 patients were enrolled in this study.
Required research committee approval and Institute Ethical Clearance were obtained before commencing this study. The Institute Ethical Clearance Committee letter number was NITRD/PGEC/2017/6113, dated September 29, 2017. In OPD and Emergency Department of our institute, written informed consent forms were distributed and explained to the PTB suspect cases presenting with hemoptysis. After receiving informed consent in the patient's regional language, detailed clinical history and examination of the patient were done, and appropriate blood tests and radiological tests were done as per the decision of the treating doctor. Two samples of coughed out blood were collected: one in sterile sputum collection container and another in the Falcon tube. The coughed out blood collected in a sterile container was examined with the ZN stain method. The other sample collected in the Falcon tube was processed for MGIT culture growth in the microbiology laboratory of our institute. Considering sputum for Mycobacterium Growth Indicator Tube (MGIT) as the gold standard for acid-fast bacilli (AFB) detection, the detection rates of Ziehl–Neelsen (ZN) staining in hemoptysis were compared and analyzed with respect to the clinical factors. The severity of hemoptysis was divided into mild, moderate, or severe depending on the amount of bleeding. It was called mild if ɶ ml of blood was expectorated per day or there was only streaking or flecks of blood in the sputum. Hemoptysis was moderate if bleeding was between 30 and 200 ml/day and severe if bleeding occurred in excess of 200 ml/day. Massive hemoptysis was defined as blood loss of 200–600 ml or more within 48 h or as much as to cause hemodynamic disturbance.
The recorded observations were entered in Epi Data software, CDC, Atlanta, USA., and the collected data were consolidated on Microsoft Excel sheets and further analyzed in Epi Info 126.96.36.199, CDC, Atlanta, USA. version and the Statistical Package for the Social Studies (SPSS) for Windows, version 20, IBM Corporation, USA. P < 0.05 was considered statistically significant. The data were also presented with the help of different types of charts and bar diagrams. Quantitative variables were analyzed and presented with their descriptive statistics.
| Results|| |
The mean age of our study group was 37.94 ± 14.39 years (mean ± standard deviation). Twenty-five percent of patients belonged to the age bracket 16–25 years, whereas 24% of the patients belonged to the age group of 26–35 years. Sixty-five percent of our enrolled patients fell in ʔ years of age group. 72/100 (72%) of the enrolled patients were male, whereas the rest 28 (28%) were female. Classifying the patients according to their socioeconomic status by the Kuppuswamy scale revealed that the majority (51%) belonged to the lower class followed by upper-lower class (20%), lower-middle class (15%), upper-middle class (10%), and upper class (4%). Addiction to smoking was found in 45% of patients, whereas alcoholism was seen in 29% of patients. Type 2 diabetes mellitus was seen in 9% of patients, whereas hypertension was seen in 2% of patients. Sixty-five percent of patients had previous history of antitubercular therapy (ATT) intake, whereas 35% of patients were treatment naive at presentation. On chest X-ray (CXR), cavities were seen in 52% of patients. Other radiological features found in the patients are given in [Table 1].
Most of the patients had moderate hemoptysis (80%), whereas 18% had mild hemoptysis. Only 2% of patients had severe hemoptysis, and no patient had massive hemoptysis. Of 100 patients studied, direct smear microscopy for AFB was positive in 56 (56%) of patients while it was negative in 44 (44%). Microbiologically confirmed PTB by the virtue of positive MGIT culture was seen in 63 (63%) of patients, leading to an extra diagnosis of 7/63 (11.11%) cases. Nontuberculous mycobacteria (NTM) were isolated in 8 (8%) of isolates, but the culture was considered negative with respect to the yield of Mycobacterium bacilli. Speciation of NTM was carried out in the microbiology laboratory but was outside the scope of our study and hence was not recorded. The association of sputum smear results with the various clinicoradiological factors is given in [Table 2]. From [Table 2], we can say that PTB suspect patients with hemoptysis who have cavity in CXR, history of previous ATT, and having moderate-to-severe hemoptysis have a statistically significant higher rate of having sputum smear positive results. [Table 3] depicts the comparative parameters between direct smear and sputum MGIT cultures of PTB suspects with hemoptysis.
|Table 2: Association between direct sputum smear status with various clinicoradiological parameters|
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|Table 3: Comparison between direct sputum smear and sputum Mycobacterium Growth Indicator Tube culture as diagnostic tests|
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| Discussion|| |
This was a prospective, hospital-based, analytical study, conducted on PTB suspects with hemoptysis, who were attending OPD and emergency of a tertiary referral hospital for TB and respiratory diseases. A total of 100 patients were included to study the yield of Mycobacterium tuberculosis in PTB suspect cases with hemoptysis. Eighty-six percent of our enrolled patients fell in ʔ years of age group. In a meta-analysis review by Pérez-Guzmán et al., 12 studies were analyzed to evaluate the differences in the younger and older (>60 years) PTB patients in respect of clinical, radiological, and laboratory features. Of 12 studies, in 5 studies, hemoptysis was found to be more common in the younger age group (<60 years). In another study by Achkar and Joseph, risk factors for the occurrence of hemoptysis in patients with PTB were evaluated. The occurrence of hemoptysis was more common in the age group of 24–46 years (P = 0.003). The younger age group as an independent risk factor for hemoptysis in PTB was found. The results of above-quoted studies were similar to our study. It can be hypothesized that due to more aggressive immune response in the younger age group as compared to older ones, more pulmonary damage occurs in the younger ones, leading to more occurrence of hemoptysis in the younger age group. A male preponderance was also found in our study. The proportion of culture positivity for M. tuberculosis was also more in males as compared to females. A meta-analysis review by Pérez-Guzmán et al. revealed male predominance in all 12 studies. Similarly, a retrospective study by Tan et al. revealed 72.5% of male PTB patients presented with hemoptysis. The reason for the higher frequency of PTB in enrolled male patients who presented with hemoptysis could be differential exposure to environments contaminated with MTB, less competent immune potency due to male sex hormone (testosterone) and more smoking habits.
In our study, of 100 patients with hemoptysis, 65 patients had a past history of ATT intake. Proportions of patients with microbiologically confirmed PTB (66% vs. 58%) and cavitary lesions (58% vs. 40%) were more in patients who had taken ATT in past as compared to the patients who had no exposure to ATT. Similarly, in a study by Tan et al., proportion of hemoptysis and cavitary lesions were more in retreatment cases of PTB than new treatment cases. Therefore, it can be inferred that retreatment cases with cavitary lesions have more tendency to present with hemoptysis, and chances of PTB relapse are more in these patients. We also found that the majority (52%) of our patients had cavitary lesions in their CXRs. There was a statistically higher direct sputum smear positivity rate in patients with cavities in their CXRs in comparison to patients with other radiological features such as b/l extensive consolidation or parenchymal involvement, fibrosis, and pleural thickening. TB cavities usually result from liquefied caseous necrotic lesions. Most TB cavities have collagen and caseous cheesy material in the outer and inner layers, respectively, and granulation tissues containing a lot of capillaries in between them. There is incomplete thrombosis in the blood vessels in the middle layer, which can be disrupted by TB infection leading to hemoptysis and eventually heavy hemoptysis.
Most TB cavities have Rasmussen's aneurysms, and their rupture often leads to moderate-to-severe hemoptysis. For TB patients without cavities, less blood vessels are disrupted and thus less hemoptysis, especially moderate-to-severe hemoptysis cases. This is concordant with the findings in this study. Therefore, cavitary TB is an important and very reasonable risk factor for PTB. Different TB lesions contain different amount of M. tuberculosis bacilli. There are about 102–105 bacilli in a solid TB lesion, whereas the bacilli in a TB cavity are between 107 and 109. As caseous TB lesions liquefy, M. tuberculosis first multiplies in macrophages, and extracellular bacilli in the solid caseous TB lesions are suppressed. M. tuberculosis can also be neutralized easily by the macrophages in the living tissue. Once the caseous TB lesions liquefy, the necrotic lesions can then be exhausted to form cavities. The extracellular M. tuberculosis in the solid caseous TB lesions and those in the cavities then proliferate rapidly because of oxygen-rich environments. Large amounts of M. tuberculosis bacilli are in the cavities connected with bronchi and are expelled outside by cough. This has led to the higher smear positive rates in patients with cavities in our study.
In our study, direct sputum smear leads to the diagnosis of 56% of PTB patients, whereas MGIT culture leads to an excess detection of 11.1% of cases. Sputum smear had a high sensitivity of approximately 80% with respect to MGIT, which is the gold standard. In Negi et al.'s study, the sensitivity of pulmonary samples in diagnosing TB was compared with other diagnostic modalities such as polymerase chain reaction (PCR), BACTEC, and Lowenstein-Jensen medium. The sensitivity of direct sputum smear by ZN stain was 50%. In Shoukrie et al.'s study, in which 2783 PTB suspects were enrolled, the sensitivity of direct sputum smear as a diagnostic tool came out to be 47%. In the multicenter study by Hanna et al. to look into the yield of MGIT 960 systems, 2210 respiratory samples underwent direct smear and cultures and the sensitivity of direct smear came out to be 47%. The sensitivity of direct sputum smear in our study group is much higher mainly because of the greater bacillary load of our patients as discussed previously. Although MGIT is the gold standard at present to identify M. tuberculosis, it takes 4–6 weeks to declare a sample negative. Cartridge based nucleic acid amplification tes (CBNAAT) has a very low turn around time, but it is not indicated in samples mixed with blood. This is because blood contains many naturally occurring inhibitors of PCR such as heme, leukocyte DNA, and IgG. Hence, in PTB suspect patients suffering from hemoptysis, direct sputum smear with ZN staining remains an accurate, viable, and sensitive diagnostic modality. The high positive predictive value of 92.73% of direct smear also indicates that the rates of false positivity in our study were quite low. This may be due to the fact that the Microbiology Department of our institute is a Supra-National Reference Laboratory (SNRL) for TB and its expertise in sample collection, handling, and staining had minimized errors.
This study was carried out in a limited period of approximately 12 months duration, single centric, and only 100 patients were enrolled. It is suggested that a larger multicentric study with more number of patients may be carried out to further validate the results of our study. Direct smear microscopy requires a high degree of expertise for better results. As this study was done in a SNRL for TB in India, the results may vary in the periphery with less expert technicians. Direct microscopy in this study was done using ZN stain. The sensitivity may be improved with fluorescent microscopy using Auramine-Rhodamine dye.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]