Necrobiotic Pulmonary Nodules in Ulcerative Colitis
Extraintestinal symptoms of inflammatory bowel disease (IBD) impact up to half of all patients. Pulmonary consequences of IBD are less common, with the majority involving the upper airways, resulting in bronchitis and bronchiectasis. Necrobiotic pulmonary nodules, especially those with necrotizing disease, are extremely rare. Its detection is critical since it can mimic viral, autoimmune, or vasculitic disorders.
The findings in this case are consistent with those previously documented in IBD-associated lung nodules. They are frequently bilateral, have a necrotic granulomatous infiltration on histology, and ultimately react favorably to steroid therapy.
This case report describes a 19-year-old male with a known history of ulcerative colitis. He was discovered to have bilateral lung nodules during computed tomography imaging.
Case report
The patient, a 19-year-old man with a known history of ulcerative colitis (UC), complained of bloody stools, and lethargy. And accidental weight loss for two weeks. Before this, he had been diagnosed with UC two months earlier, when he displayed similar symptoms. Colonoscopy at the time revealed broad involvement throughout the colon, including the rectum.
He had been prescribed 1.2 g of mesalamine twice a day for the condition. Symptom control had been adequate (mild disease according to severity classification) until this emergency department visit. Upon admission, he denied having fever, chills, chest pain, shortness of breath, cough, abdominal pain, nausea, or vomiting.
Upon initial examination, the patient was hemodynamically stable. His physical examination revealed conjunctival pallor, but the remainder of his examination, including the abdominal examination, was normal.
Investigations
His laboratory test results revealed a baseline hemoglobin level of 9.3 gm/dL. And a white blood cell count of 10,600 cells/μL. His serum lipase, aspartate transaminase, alanine transaminase, alkaline phosphatase, and bilirubin levels were all within normal limits. Stool tests were negative for the presence of common diarrheal bacteria.
An abdominal computed tomography (CT) scan indicated diffuse colon thickening. As well as many ill-defined lesions at the lungs’ bases, which were suspected to be infectious or embolic in origin. He had been given intravenous hydration with normal saline and medication for suspected sepsis.
The following day, he had a flexible sigmoidoscopy, which indicated pancolitis, indicating a flare-up of his UC. Abdominal and thoracic CT scans were performed to better define the lesions (Figure 1). This showed scattered cavitating pulmonary nodules on both sides, ranging in size from 0.2 to 1.6 cm. The infectious workup, which included blood cultures, interferon-gamma release assay for tuberculosis, urine histoplasma antigen, serum cryptococcal antigen, blastomyces antibody, and coccidioides antibody, was negative. Testing for human immunodeficiency virus also came out negative.
A rheumatologic workup was then performed. It revealed a positive antinuclear antibody Scl-70 antibodies, anticentromere antibodies, and antineutrophil cytoplasmic autoantibody (ANCA) all tested positive.
The nodules were biopsyed under interventional radiology guidance. The biopsy showed the presence of large histiocytes and fibrinous debris. Necrobiotic pulmonary nodules were diagnosed in the setting of IBD. The patient was released on 40 mg of prednisone daily in addition to mesalamine. A second thoracic CT after a one-month follow-up demonstrated almost full elimination of the pulmonary nodules and better control of his UC.
Discussion
Patients with necrobiotic pulmonary nodules are typically young (<30 years) with IBD and respiratory symptoms. The majority of cases mentioned in the literature show the presence of active luminal illness. Although our patient was within the specified age range and had active colitis. He had no respiratory symptoms and was thus detected accidentally. His asymptomatic presence is critical since many of these nodules can function as a source of infection. A complete respiratory assessment may thus be indicated in an IBD patient.
The conventional radiological result described is a diffuse interstitial lung disease with the presence of bilateral pulmonary nodules of 8 to 30 mm, many of which are known to be subpleural in origin, as was the situation in our patient.
Histopathology of the nodules nearly always demonstrates the presence of a chronic infiltration. Along with the presence of necrotic material, frequently with the presence of histiocytes.
The case is significant because it can masquerade as other autoimmune and viral phenomena. Differentials include granulomatosis polyangiitis, sarcoidosis, and infectious emboli. Distinguishing one from the other is difficult since differences might be subtle and require extensive examination. For example, in granulomatosis with polyangiitis, the ANCA is largely of the proteinase 3 (PR3-ANCA) subtype. But in UC, the ANCA is peripheral (p-ANCA). Ruling out sarcoidosis may prove more difficult and may have to rely on bronchoalveolar lavage testing and Gallium-67 scanning.
Although a few cases in the literature showed spontaneous remission. The majority of symptomatic individuals necessitated the use of immunomodulatory medications such as prednisone and mesalazine. The generally utilized regimen was prednisone at 1 g/kg/day, which resulted in a considerable reduction in the size of the lung nodules.