|Year : 2017 | Volume
| Issue : 2 | Page : 50-51
Pulmonary Silicotuberculosis in A Stone Miner
Mukesh Kumar Tiwari1, Manish Shankar2, Kalyan Kumar Saha3
1 Senior Resident Department of Pneumonology, Indira Gandhi Institute of Medical Sciences, Sheikhpura, Patna -14, Bihar, India
2 Assistant Professor, Department of TB & Chest, Indira Gandhi Institute of Medical Sciences, Sheikhpura, Patna -14, Bihar, India
3 Senior Resident, Department of General Medicine, Indira Gandhi Institute of Medical Sciences, Sheikhpura, Patna -14, Bihar, India
|Date of Web Publication||11-Dec-2020|
Mukesh Kumar Tiwari
Senior Resident, Department of Pneumonology, Indira Gandhi Institute of Medical Sciences, Sheikhpura, Patna-14, Bihar
Source of Support: None, Conflict of Interest: None
We are presenting a case of a patient a former stone miner, male, 45 years old, who developed silicosis after almost a decade of occupational exposure to silica dust in stone mining industry. He was detected to have sputum positive pulmonary tuberculosis 4 years after leaving the profession. The case affirms that silicosis is increasingly associated with tuberculosis. The history of occupational exposure to inciting agent, radiological features (conventional chest X-ray and computerized tomography) and microbiological examination of sputum help in diagnosing the case, correctly. In comparison to general population tuberculosis morbidity is more pronounced in silicosis.
Keywords: Pulmonary tuberculosis, silicosis; Tubeaculosis.
|How to cite this article:|
Tiwari MK, Shankar M, Saha KK. Pulmonary Silicotuberculosis in A Stone Miner. J Indira Gandhi Inst Med Sci 2017;3:50-1
| Introduction|| |
The earth crust contains abundant amount of silica (silicon dioxide). Amorphous form of silica is relatively non toxic. It is crystalline form, which is predominantly deposited in lung and can lead to various manifestations of pneumoconiosis ranging from infiltrations and nodular opacities mainly in upper lobes to progressive massive fibrosis., Silicosis is a disease caused by inhalation and deposition of crystalline form of silica in lung mainly in interstitium. Mining, milling, foundry, sandblasting, glass and ceramic industry workers are mainly at risk population., Almost all forms of pneumoconiosis are at increased risk of tuberculosis but this relation in silicosis is even stronger. The diagnosis of silicotuberculosis is difficult if based only on radiological features. Microbiological examination of sputum is extremely helpful in this aspect. Here, we are presenting a case of sputum positive pulmonary silicotuberculosis.
| Case Report|| |
The patient is a 45 years old male, non-smoker, who was working in a stone mining industry from the age of 30 to 41 years. He developed shortness of breath 4 years ago which compelled him to leave the job. The conventional x ray chest done 4 years back showed bilateral upper zone nodular opacities. High resolution computerized tomography confirmed the diagnosis of pneumoconiosis. Afterwards he was under conservative management for the same. He came in our observation in early May 2017 with complaints of cough with expectoration and intermittent low grade fever from last 2 months. Spirometry was showing restrictive features with FVC of 46%. CT scan of thorax showed bilateral upper lobe fibrocavitary and nodular changes. The changes were more pronounced in right upper lobe. Because of high likelihood of tuberculosis he was sent for Cartridge Based Nucleic Acid Amplification Test (CBNAAT) of sputum. CBNAAT revealed high Mycobacterium tuberculae load without rifampicin resistance. Antitubercular drugs (category I-Rifampicin, Isoniazid, Pyrazinamide, Ethambutol) had been started on 23rd May 2017. The patient was symptomatically better in his next visit.
|Figure 1: Fibrocavitory changes along with nodular opacities in Rt. upper lobe.|
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| Discussion|| |
The exposure of silica dust results in impairment of macrophage function. It also hampers cell mediated immunity. It leads to increase in B cell number and reduced T cell number. These changes are primarily responsible for increased susceptibility to tuberculosis in silicosis. Even prolonged exposure of silica dust sans silicosis also increases the risk of tuberculosis. The association between the two entities has been proved in various analytical and epidemiological studies. The risk is directly proportional to the amount and duration of the exposure and lastly to the age of the patient as elderly persons are more at the risk of developing silicotuberculosis. This association may play a role in increasing incidence of tuberculosis in industrialized nations besides HIV.
Diagnosis of Tuberculosis in a preexisting case of silicosis may be quite delayed as symptomatology and initial laboratory finding may be misdiagnosed to be due to silicosis alone. The rate of sputum smear positivity is also low as the bacilli may remain harboured by surrounding fibrosis. This can also lead to delayed response to antitubercular drugs. Important differential diagnosis of the case includes pulmonary tuberculosis, fibrobronchiectasis, resolving cavitatory pneumonia like staphylococcal and klebsiella pneumonia, allergic bronchopulmonary aspergillosis, Wegener’s granulomatosis etc.
Conventional radiography and CT scan are complementary to the diagnosis of silicotuberculosis. Preexisting nodular opacities associated with recent appearance of new opacities as well as cavitory and fibrotic changes increases the possibility of active silicotuberculosis .
Pulmonary silicotuberculosis is a occupational lung disease with great medico-legal importance. In western countries it has to be reported to both judicial and workers’ compensation authorities.
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