A 15-year-old male patient was admitted to a hospital due to a 4-week history of fever and intermittent, diffuse abdominal pain.
The patient had first presented with diffuse, intermittent abdominal pain and diarrhea after eating barbecue many times over the course of 2 weeks. Two days after the first presentation of these symptoms, he had a high fever, with a maximum temperature of 39 C. His symptoms did not remit after 4 weeks. So he went to a local hospital and was treated with an unidentified antibiotic. His diarrhea was relieved, but the fever and abdominal pain did not improve. Approximately 10 days later, he was transferred to our hospital for further investigation and management of suspected inflammatory bowel disease (IBD).
He was living in a village in Heilongjiang Province, a northern province in China where the incidence of human brucellosis has increased substantially. In addition, the patient had a history of eating barbecue. He denied having a history of exposure to contaminated water or going to epidemic areas. His mother had suffered from pulmonary tuberculosis about 10 years ago. He had lost approximately 5 kg of weight over the previous month and he was only 41 kg in weight and 174.5 cm in height (body mass index [BMI] 13.5) when admitted to our hospital.
On physical examination, his temperature was 37.2 C, intestinal peristalsis had decreased to 2 to 3 times per minute, and suspicious tenderness was detected in the right and left upper quadrants of the abdomen. Other vital signs and elements of the examination were normal. The laboratory investigations revealed anemia, a high erythrocyte sedimentation rate, and an elevated C-reactive protein level; the laboratory test results are shown in Table 1. A stool specimen was positive for occult blood. A tuberculin skin test was negative, as was an interferon gamma release assay (T-spot. tuberculosis) for Mycobacterium tuberculosis. A Widal-Felix test was negative. Negative test results were found for antibodies to IBD, antinuclear antibody, and extractable nuclear antigens.
A transabdominal US examination was performed to investigate the cause of the abdominal pain. The US showed a thickened hypoechoic bowel wall in the terminal ileum (0.55 cm), with thickening mainly in the mucosal and submucosal layers. The 5-layer structure of the bowel wall remained identifiable (Fig. 1). Additionally, color Doppler US showed increased flow signals in the bowel walls and luminal narrowing. The ileocaecal structure was intact. Notably, multiple hypoechoic lymph nodes (maximum diameter: 1.8 cm) with a thickened cortex were detected in the abdominal cavity, especially in the right lower quadrant; some of these lymph nodes were fused together. Furthermore, a spectral analysis of the Doppler signals of arteries supplying the gastrointestinal tract (i.e., celiac trunk and superior mesenteric arteries) was performed. The results showed a dramatically increased flow velocity (peak systolic velocity: 643 cm/s) in the origin of the superior mesenteric artery (SMA) and celiac artery (CA) (Fig. 2), which suggested significant stenosis. A computed tomography (CT) scan of the intestine confirmed the above findings; the scan showed a thickened bowel wall in the ileocaecal area and terminal ileum, with an abnormal enhancement of the mucosal surface (Fig. 1) and remarkably enlarged lymph nodes near the iliac vessels in the right lower quadrant of the abdomen. An aortic computed tomographic angiography showed moderate narrowing in the beginning of the SMA and slight narrowing in the beginning of the CA (Fig. 2). Incidentally, the CT scan revealed an enlarged spleen with multiple wedged areas of low attenuation under the membrane (Fig. 3), and a similar lesion was also found in the inferior pole of the left kidney; these were suspected to be areas of infarction.
The patient underwent an endoscopic examination. The examination revealed many irregular ulcers in the narrowed lumen of the terminal ileum. Additional pathological features of the terminal ileum included inflammatory exudate, granulation tissue, and mucosal lymphoid hyperplasia, which collectively suggested severe acute and chronic inflammation of the intestinal mucosa.
Due to the patient's signs and symptoms, he was considered to be suffering from an intestinal infection rather than from IBD. Subsequently, additional history was obtained. He had eaten undercooked roast lamb and beef many times during the 2 weeks before he began to feel uncomfortable. No pathogenic microorganism was found in endoscope biopsy tissues of the patient. Cytomegalovirus DNA and IgM antibody were negative on multiple blood tests. In addition, cytomegalic inclusion body was not present in the tissue sample from endoscopic biopsy.
Brucellosis was suspected because the patient came from Heilongjiang Province, which is a northern province in China where the incidence of human brucellosis has risen substantially. A blood sample was sent for serological testing, and the Brucella standard tube agglutination (STA) test was twice positive at a dilution of 1:160. In addition, the Rose-Bengal plate test was positive for brucellosis. Two Brucella spp. blood cultures were collected and all results were negative.
According to his symptoms (i.e., fever, abdominal pain), imaging results (i.e., splenomegaly, splenic and renal infarction), history of eating undercooked roast lamb and beef, and STA continuously twice positive at a dilution of 1:160 and Rose-Bengal test results, Brucellosis was highly suggestive. Unfortunately, multiple Brucella spp. blood culture were undertaken and turned out to be negative. Neither Brucella Coombs test nor PCR analysis was further undertook. For the suspicion of that the abdominal artery stenosis was caused by embolism from endocarditis, a transthoracic echocardiogram was performed. There was no sign of endocarditis. No cardiac murmur or sign of embolism was found in physical examination. The patient received minocycline (doxycycline was unavailable) plus rifampicin to treat brucellosis and there was a significantly improvement after 4 weeks treatment. Further transesophageal echocardiogram has not been arranged. Finally, the patient was diagnosed as brucellosis. The narrowing of the SMA and CA was suspected to be vasculitis secondary to the brucellosis.
Doxycycline is considered as the first-line therapy for Brucellosis; however, it is currently unavailable in Beijing. Minocycline combined with rifampicin were used instead. The patient was given oral minocycline and rifampicin for 12 weeks totally. After 3 weeks of treatment, he had no fever or abdominal pain. After another 7 weeks, follow-up CT and US examinations showed remarkable improvements in the bowel. Positron emission tomography (PET) was used for further investigation of the intestine inflammation. The results showed mildly increased metabolic activity in the terminal ileum and adherent lymph nodes (Fig. 1), which was indicative of an inflammatory disease instead of a malignancy. The areas of splenic infarction were smaller than they were previously, and renal perfusion appeared normal (Fig. 3). The CT results showed that the narrowed lumens of the SMA and CA had not improved. However, the Riolan artery, a collateral circulation between the SMA and inferior mesenteric artery (IMA), had opened (Fig. 2). Two months later, the splenic and renal lesions were barely perceptible. Due to the suspected secondary vasculitis, he was treated with minocycline and rifampicin for another 8 weeks, but there was little improvement in the noted arterial stenosis (Fig. 2). Additional laboratory test results are shown in Table 1.