Hidden in Plain Sight: Intestinal Tuberculosis Perforated a Man’s Gut in a Low-TB Country

A 41-year-old Nepalese man living in Japan arrived at a hospital with abdominal pain, nausea, and vomiting that had begun after dinner the previous evening. Within seventy-two hours, his bowel had perforated, spilling intestinal contents into his peritoneal cavity and forcing an emergency laparotomy. The culprit was not a tumor or a flare of inflammatory bowel disease but intestinal tuberculosis, a disease so uncommon in modern Japan that clinicians rarely place it high on their differential lists. The case, published as an open-access report in Clinical Case Reports, illustrates how tuberculosis can still surprise physicians in countries where the infection has become statistically rare, and how rapidly an indolent infection can convert into a life-threatening surgical emergency.

Intestinal tuberculosis is a form of extrapulmonary tuberculosis that falls within the broader category of gastrointestinal tuberculosis, which itself accounts for only roughly one to three percent of all tuberculosis cases worldwide. In most patients it follows a chronic, smoldering course marked by nonspecific complaints such as abdominal pain, weight loss, fever, diarrhea, constipation, or bloody stools. Acute presentations are the exception rather than the rule, and the clinical picture closely mimics Crohn’s disease and gastrointestinal malignancy, both of which share a predilection for the ileocecal region. That overlap makes definitive diagnosis difficult without tissue, and the median time from symptom onset to diagnosis has been reported at approximately thirteen weeks. In the Japanese patient, the interval between the first symptoms and perforation was measured in days.

The patient’s background offered subtle but important clues. He had lived in Japan for a year and a half after moving from Nepal, a country with a high tuberculosis burden, and he had lost about six kilograms over the preceding year despite maintaining a body mass index of 29.7 kilograms per square meter. He had no history of diabetes, malignancy, autoimmune disease, immunosuppressive therapy, or recent antibiotic use, and both his HIV antibody test and serum beta-D-glucan assay were negative. When he presented to the hospital, his temperature was 38.1 degrees Celsius, his abdomen was distended and soft, with tenderness in the lower abdomen but no rebound tenderness. His white blood cell count of 8,800 per microliter, with 7,234 neutrophils and 1,118 lymphocytes, and a C-reactive protein level of 1.03 milligrams per deciliter were only modestly abnormal, providing little to suggest the catastrophe unfolding within his small bowel.

Contrast-enhanced computed tomography of the abdomen supplied the first strong signal. The scan revealed continuous dilatation and symmetric thickening of the small intestinal wall, increased density of the surrounding fat, and enlarged mesenteric lymph nodes. Multiple para-aortic nodes measuring more than one centimeter were also visible. Chest radiography and chest computed tomography showed no active pulmonary lesions, meaning the intestinal disease was not accompanied by the classic lung findings that usually trigger suspicion of tuberculosis. The patient was admitted, managed with fasting, rehydration, and a nasogastric tube, and started on empiric cefmetazole, an antimicrobial choice consistent with the hospital’s protocol for presumed intra-abdominal infection in a patient without prior antibiotic exposure or recent hospitalization.

Over the next two days the clinical course deteriorated sharply. Abdominal pain worsened on the second hospital day and failed to improve by the third. Repeat laboratory testing showed a C-reactive protein concentration that had surged to 32.86 milligrams per deciliter, alongside a procalcitonin level of 1.46 nanograms per milliliter, a pattern consistent with bacterial peritonitis. A repeat contrast-enhanced computed tomography scan demonstrated free air within the abdominal cavity, the radiographic signature of gastrointestinal perforation, together with increased peri-intestinal fat density and fluid collections indicating an intra-abdominal abscess. The diagnosis of small intestinal perforation was made, and the patient was taken to the operating room for emergency surgery.

At laparotomy, the surgical team encountered feculent peritonitis with a fibrinous exudate that was most prominent in the pelvis. A two-millimeter perforation was identified in the distal ileum, surrounded by roughly thirty centimeters of edematous bowel. The affected segment was resected and intestinal continuity was restored with a stapled side-to-side anastomosis. The peritoneal cavity was irrigated with twenty liters of saline, three drains were placed, and the abdomen was closed in layers. The resected bowel then became the key to the diagnosis, because the differential diagnosis at this stage still included intestinal tuberculosis, Crohn’s disease, and malignant tumor.

The imaging features argued against some of these alternatives. The lesion was located in the ileocecal region, where intestinal tuberculosis most commonly localizes, typically involving a short segment of bowel. The symmetric wall thickening favored tuberculosis, whereas the asymmetric thickening highly specific for Crohn’s disease was absent, as were the skip lesions characteristic of that condition. Lymph nodes larger than one centimeter are more often seen in intestinal tuberculosis than in its mimics. Malignant tumors, meanwhile, are far more common in the large intestine than in the small bowel, and no mass lesion was identified on axial or coronal contrast-enhanced images, although the authors acknowledged that small-bowel tumors can occasionally escape detection on imaging. Definitive classification therefore awaited pathology.

Histopathological examination of the resected small intestine settled the question. Microscopy revealed epithelioid granulomas with caseous necrosis and Langhans giant cells, the pathological hallmarks of tuberculosis, visible on hematoxylin and eosin staining at magnifications of 200 and 400 times. A tuberculosis polymerase chain reaction test performed on the ascitic fluid returned a positive result, confirming the microbiological diagnosis of intestinal tuberculosis causing perforation. The isolate proved sensitive to all major first-line drugs, allowing prompt initiation of standard anti-tuberculosis chemotherapy: a four-drug regimen of isoniazid, rifampicin, ethambutol, and pyrazinamide for the first two months, followed by a two-drug regimen of isoniazid and rifampicin for the subsequent four months.

The recovery was uncomplicated. No drug side effects were observed during treatment, the abdominal pain resolved, and the C-reactive protein level normalized. A contrast-enhanced computed tomography scan performed three months after the start of therapy showed that the intra-abdominal abscess had resolved and the enlarged lymph nodes had decreased in size. The patient completed the full six months of treatment and experienced no recurrence. This favorable trajectory is consistent with the broader literature, which indicates that anti-tuberculosis therapy generally proceeds smoothly once the diagnosis is made and appropriate drugs are administered, underscoring that the principal barrier in such cases is recognition rather than treatment.

The case carries a sobering epidemiological message. Japan became a low-burden tuberculosis country in 2021, and national case numbers continue to decline, which means clinicians there encounter intestinal tuberculosis ever less frequently and are correspondingly less likely to suspect it in patients presenting with abdominal symptoms. Yet global migration means that people from high-burden countries such as Nepal continue to live in low-burden settings, and they may carry forms of tuberculosis that clinicians rarely see. Intestinal perforation complicates four to 7.6 percent of intestinal tuberculosis cases and carries a mortality rate as high as thirty percent, making early recognition a matter of survival. The authors note that a previously reported patient who presented with obstruction from abdominal tuberculosis avoided perforation through diagnostic surgery, and they suggest that in their own patient the combination of characteristic computed tomography findings and a year of unexplained weight loss might likewise have allowed earlier diagnosis and prevention of the perforation. Their warning to colleagues is explicit: even subtle signs such as weight loss should not be overlooked, and in patients from high-burden countries presenting with abdominal symptoms and suggestive imaging, intestinal tuberculosis must remain on the differential list, because the disease can progress from obstruction to perforation within a matter of days.

Subject of Research: A case of intestinal tuberculosis causing small bowel perforation in a Nepalese migrant living in a low tuberculosis-burden country

Article Title: Intestinal Perforation Caused by Intestinal Tuberculosis of a Nepalese Man Living in a Low Tuberculosis‐Burden Country: A Case Report

Article References: Matsushita, S., Kanata, K., Matsushita, S., Ito, Y., Ichijo, K., & Uehara, M. (2026). Intestinal Perforation Caused by Intestinal Tuberculosis of a Nepalese Man Living in a Low Tuberculosis‐Burden Country: A Case Report. Clinical Case Reports, 14(9), Article e73521. https://doi.org/10.1002/ccr3.73521

Image Credits: AI Generated

DOI: 10.1002/ccr3.73521

Keywords: intestinal tuberculosis, bowel perforation, extrapulmonary tuberculosis, Nepal, Japan, case report, ileocecal region, computed tomography, granulomas, anti-tuberculosis therapy, low-burden country, differential diagnosis