Annals of African Medicine

LETTER TO THE EDITOR
Year
: 2013  |  Volume : 12  |  Issue : 4  |  Page : 255--256

Silicotuberculosis: Importance of evaluation of serial radiographs


Binit Sureka, Aliza Mittal, Mahesh Kumar Mittal, Brij Bhushan Thukral 
 Department of Radiodiagnosis, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India

Correspondence Address:
Binit Sureka
Department of Radiodiagnosis, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi
India




How to cite this article:
Sureka B, Mittal A, Mittal MK, Thukral BB. Silicotuberculosis: Importance of evaluation of serial radiographs.Ann Afr Med 2013;12:255-256


How to cite this URL:
Sureka B, Mittal A, Mittal MK, Thukral BB. Silicotuberculosis: Importance of evaluation of serial radiographs. Ann Afr Med [serial online] 2013 [cited 2020 Sep 24 ];12:255-256
Available from: http://www.annalsafrmed.org/text.asp?2013/12/4/255/122697


Full Text

Sir,

A 46-year-old man, working in a stone-cutting factory for last 14 years presented with a history of breathlessness, chest discomfort, dry cough, sweating, malaise, and loss of weight since September 2006. On examination, patient was conscious, oriented, and afebrile. He was dyspneic without cyanosis, clubbing, or lymphadenopathy. On auscultation; fine crackles in bilateral upper and mid zones at the end of inspiration were present. Routine examination of blood and urine samples were normal except for raised erythrocyte sedimentation rate (40 mm/h). Sputum was negative for acid-fast bacilli. Mantoux test was reactive (15 × 17 mm).

Serial chest radiographs of the patient (since 2006) were reevaluated which revealed progressive gradual volume loss, pulled up hila, and increasingly dense conglomerate fibrotic masses in bilateral upper and mid zones leading to compensatory hyperinflation of lower zones over the past 6 years [Figure 1]. Provisional diagnosis of silicotuberculosis was made. Contrast-enhanced followed by high resolution computed tomography scan chest was done which confirmed the chest X-ray findings. In addition, it showed calcified lymph nodes in the mediastinum, calcification in bilateral lung parenchyma with conglomerate fibrotic masses showing areas of cavitation [Figure 2]. Lung biopsy was done from the lung lesion which showed silicotic nodules as well as acid-fast bacilli. These findings were consistent with the diagnosis of silicotuberculosis. The patient took early retirement due to disability, was started with antitubercular therapy, however the patient expired due to respiratory failure and cor pulmonale in February 2013.{Figure 1}{Figure 2}

Silicosis is caused by inhalation of fine particles of crystalline silicon dioxide (silica). [1] Worldwide, silicosis is the most common occupational lung disease. [2] The disease occurs in three clinical forms: Acute silicosis, accelerated silicosis, and classic (chronic) silicosis. Chronic (classic) silicosis is the most common form of the disease and follows exposure to silica for more than 10 years. Acute silicosis manifests as alveolar silicoproteinosis, occurs as a result of intense exposure within months to 5 years of exposure. Accelerated silicosis results from heavier exposure for duration of 5-10 years. Classic silicosis may be classified as either simple or complicated. Simple silicosis is defined by a radiographic pattern of small, irregular opacities, whereas complicated silicosis is characterized by large conglomerate opacities representing progressive massive fibrosis. [3] On chest radiographs, complicated silicosis shows symmetric opacities with a diameter of more than 1 cm, commonly in the middle and upper lung zone. On computed tomography scan of chest, high attenuation lung parenchyma often representing calcifications is seen with surrounding emphysema. [4] Peripheral eggshell calcified hilar and mediastinal lymph nodes are seen only in approximately 5% of cases of silicosis and is almost pathognomonic of this entity. Complications are carcinoma, tuberculosis, cor pulmonale, spontaneous pneumothorax, broncholithiasis, tracheobronchial obstruction, and hypoxemic ventilator failure. Twenty-five percentage of patients with acute or classic silicosis develop pulmonary tuberculosis and men with silicosis have a relative risk of tuberculosis that is 2.8 times that for men without silicosis. [5] Presence of asymmetric nodules, consolidation, cavitation, and rapid disease progression suggests concomitant tuberculosis in a known patient of silicosis. [3]

Through this case, we would like to highlight the importance of evaluation of old serial X-rays (to look for progression of the disease/fibrosis and not miss coexisting silicosis) in any similar patient with a suggestive occupational history as patients suffering from silicotuberculosis are often misdiagnosed leading to late onset of adequate treatment and possible fatal outcome. Since both diseases have a similar initial presentation, there is a strong possibility of concurrent existence of both diseases in one patient, it is important that the clinician in charge has adequate knowledge of diagnostic techniques in order to evaluate such patients.

References

1Adverse effects of crystalline silica exposure. American Thoracic Society Committee of the Scientific Assembly on Environmental and Occupational Health. Am J Respir Crit Care Med 1997;155:761-8.
2Cullen MR, Cherniack MG, Rosenstock L. Occupational medicine (1). N Engl J Med 1990;322:594-601.
3Chong S, Lee KS, Chung MJ, Han J, Kwon OJ, Kim TS. Pneumoconiosis: Comparison of imaging and pathologic findings. Radiographics 2006;26:59-77.
4Marchiori E, Souza AS Jr, Franquet T, Müller NL. Diffuse high-attenuation pulmonary abnormalities: A pattern-oriented diagnostic approach on high-resolution CT. AJR Am J Roentgenol 2005;184:273-82.
5Cowie RL. The epidemiology of tuberculosis in gold miners with silicosis. Am J Respir Crit Care Med 1994;150:1460-2.