Burst abdomen: an unusual complication of silicosis in pregnancy

Abstract

We present a case of silicosis in a 37-year-old pregnant woman, a second gravida with previous caesarean section. She was referred to our hospital at 42 weeks of gestation with breathlessness and oligohydramnios. She had worked in a glass and talc powder factory for 11 years and was diagnosed as having silicosis 2 years prior; she was on treatment. Following admission, she was evaluated for dyspnoea and underwent emergency Caesarean section for poor cervical dilation. She developed a burst abdomen on the third postoperative day with loops of gangrenous bowel protruding outside the abdomen. Emergency laparotomy with ileal resection and ileostomy was carried out. She was discharged on day 14 and is on follow-up. To the best of our knowledge, this is the first case of silicosis in pregnancy presenting with an unusual complication.

Background

Silicosis is a known occupational pulmonary hazard that results from inhalation of silicon dioxide, or silica in crystalline form. Workers with potential for exposure are miners, tunnel drillers, quarry workers, sand blasters, stone carvers, ceramic workers and silica flour production workers.¹ Exposure to crystalline dust leads to inflammation and scarring of lung tissue, and, ultimately, respiratory insufficiency.² The disease may be quite severe and progressive despite discontinuation of exposure. We report a case of a patient with silicosis in pregnancy with burst abdomen after caesarean section.

Case presentation

A 37-year-old gravida 2, with one living baby, at 42 weeks of gestation was referred to our hospital as a case of previous lower segment caesarean section with breathlessness and oligohydramnios. She was diagnosed with silicosis 2 years prior during a routine check-up and was started on formoterol fumarate and budesonide inhaler. She had worked in a glass factory for 6 years and later in a talc powder company for 5 years. There was no history of tuberculosis, bronchial asthma or heart disease. On examination, the patient's vitals were stable and cardiovascular and respiratory system examination revealed no abnormalities. The uterus was term size, cephalic and relaxed, and fetal heart rate was good. On vaginal examination, the cervix was uneffaced and the os was closed. Chest X-ray showed hard miliary infiltration (figure 1).

Figure 1.

Chest X-ray showing bilateral hilar nodular opacity and egg shell shadow.

An emergency lower uterine caesarean section was performed due to history of caesarean section with oligohydramnios and poor cervical dilation. A live 2400 g small-for-term baby was delivered. The postoperative period was uneventful for 48 h, but on postoperative day 3, the patient developed a burst abdomen with loops of gangrenous bowel leaking out (figure 2). Laparotomy was carried out; there was a 25 cm gangrenous ileal segment about 10 cm from the ileocolic junction, so ileal resection and ileostomy were performed. The patient was discharged on postoperative day 14 and is on follow-up.

Figure 2.

Burst abdomen with gangrenous loop of intestine.

Discussion

Silicosis is the most prevalent chronic occupational lung disease, and is encountered in mining and quarrying of hard rock, anthracite, coal and metals. It is an irreversible and chronic fibrotic disease of the lungs caused by inhalation, retention and pulmonary reaction to large amounts of silica dust, usually in the form of α quartz. The prevalence of silicosis is increased in developing countries, including Brazil, China, India and Vietnam. In India, the prevalence is increased in, for instance, workers in Kolar Gold Fields, Karnataka, and there is a high risk of silicosis in the slate pencil and agate grinding industry.³ Our patient had a total of 11 years of exposure to silica dust while working in a glass factory and later in a talc powder company.

The most common presentation of silicosis is in the form of uncomplicated chronic silicosis. Chronic silicosis develops only after decades of repeated exposure to high concentrations of silica dust. Dyspnoea on exertion is considered to be the most frequent and directly related symptom of silicosis.⁴ There can be coughing and sputum production from non-specific bronchitis or from cigarette smoking. Chest pain and haemoptysis indicate the likely complication of tuberculosis. Acute silicosis presents with dyspnoea, fatigue, weight loss, fever and pleuritic pain. Rarely, bilateral pneumothorax has also been reported.⁵ This is the first case reported of an acute complication of silicosis in pregnancy.

Silicosis is diagnosed by radiological features distinct from other fibrotic disease, by occupational exposure to a substantial amount of silica or silicotic nodules, and/or involvement of hilar lymph nodes. Patients with silicosis have a homogenous ground glass appearance and nodular infiltrates or consolidation on chest radiographs, as seen in our patient (figure 1). Radiologically, there is a close resemblance between silicosis and miliary tuberculosis. However, the size of the nodules seen in tuberculosis is smaller than those seen in silicosis. The radiographs of patients with silicosis usually exhibit an increased translucency compared to general loss of translucency in tuberculosis.⁶ Pulmonary function tests performed in silica exposure patients may show restrictive as well as obstructive changes.⁴ Peak expiratory flow and forced vital capacity are both reported to be reduced in chronically exposed individuals.⁷ Bronchoalveolar lavage (BAL) study is rarely indicated. The amount of mineral dust in BAL fluid cells is related to the intensity of exposure and duration of employment. Lung biopsy is, rarely, indicated. This is particularly important when lung malignancy is suspected as a complication.

Moreover, silicosis is not only a respiratory disease, but also can be associated with other disorders. Tuberculosis is a common complication reported in Indian studies.⁸ There is increased susceptibility to pulmonary tuberculosis and, rarely, to fungal infection. It is thought that macrophage dysfunction caused by the presence of silica appears to cause increased susceptibility to tuberculosis and other infections.^{9 10} It has been reported that silicosis is associated with lupus-like autoimmune disease and could complicate existing diseases such as lung cancer.¹¹ Chronic silicosis gradually leads to development of pulmonary hypertension, chronic corpulmonale and chronic respiratory failure. The onset of these complications is rapid in the case of massive fibrosis.

Though pregnancy does not appear to affect the course of silicosis, there is still a risk of acute progression of the disease due to alteration in immunity, causing fetal complication and maternal morbidity. Complications in our case were fetal growth restriction, oligohydramnios with mild meconium-stained liquor, which may be due to obstructive airway disease due to silicosis, a burst abdomen, which may be the result of lowered immune response, and chronic cough due to long-term progression of the disease.

The wound-healing process consists of four highly integrated and overlapping phases: haemostasis, inflammation, proliferation and tissue remodelling or resolution. Silicosis can impair wound healing; the macrophages, which are important for wound healing as they promote the inflammatory response and clear apoptotic cells, are destroyed due to the interaction of silica, and may affect the proliferative phase of wound healing. Another possible cause for wound disruption in our patient could be due to the intake of steroid medication for silicosis. Systemic steroids have anti-inflammatory effects, suppress cellular wound response, and are responsible for fibroblast proliferation and collagen synthesis.

There is no specific treatment for silicosis and therapy is directed largely at the complications of the disease. Corticosteroids and aluminium citrate have been used with varying success in silicosis.¹² In our patient, steroids were started soon after the diagnosis and she was on inhaler preparations throughout pregnancy. Comorbid conditions, such as chronic obstructive pulmonary disease, should be identified and managed. It is recommended that patients with silicotuberculosis should receive at least four antimycobacterial drugs, such as isoniazid, rifampicin and pyrazinamide for 2 months followed by two antituberculosis drugs for 9 months or longer. The exact duration remains debateable. Steroid inhalers can be continued in pregnancy and complications of silicosis should be closely observed, and, if tuberculosis is diagnosed, antituberculosis drugs should be started immediately. Even though there is no specific management for silicosis in pregnancy, each case should be closely observed throughout pregnancy and postdelivery or postoperatively to prevent maternal morbidity and mortality.

Prevention of complications remains the main goal of silicosis management. It comprises primarily of medical screening, which includes periodic examinations by chest X-rays, sputum examination for tubercle bacilli and spirometry. Health education is important to get the active cooperation of those workers at risk. Elimination and suppression of dust at work places, and measures such as use of masks and improved ventilation, should be undertaken to avoid and control dust exposure.

Learning points.

• Silicosis in pregnancy is rare and though pregnancy does not appear to affect the course of silicosis, the complications of silicosis leading to infections, pulmonary hypertension, chronic corpulmonale and chronic respiratory failure, should be closely observed to prevent maternal morbidity and mortality.

• There is increased susceptibility to pulmonary tuberculosis and other infections, and if tuberculosis is diagnosed, antituberculosis drugs should be started immediately.