DiagnosisCrohn’s disease of small intestine with intestinal obstructionICD 10 Code: K50.012Please note that some of the investigations refer to IBD which is an umbrella term for both Crohn’s disease and ulcerative colitis.Patient presentationMr JR, a 22 year old male, presented to A&E with a 3-day history of diffuse abdominal pain, vomiting and complete constipation. A diagnosis of stricture of the small bowel secondary to Crohn’s disease was made.Several weeks previously the patient had attended GP complaining of a 2-month history of diarrhea and abdominal pain.
He had no other relevant past medical history and took no regular medication. He has no known allergies. He has no family history of IBD or other bowel disorders.
He was awaiting specialist referral.He lives with his parents and works as an events manager. He is an ex-smoker of 2 pack years.
He drinks 20 units of alcohol a week and smokes cannabis at weekends.On examination, 5 days after his admission, his abdomen is soft and not distended but is diffusely tender, although he notes it has improved considerably since admission. No other abnormalities were noted.
InvestigationsThe GP had sent him for the following investigations:- Coeliac screen which had come back negative- FBC which was normal- CRP which was elevated- Fecal calprotectin which was elevated (exact figures unavailable)Following hospital admission, the following tests were performed:- CT scan which showed stricturing causing obstruction. It also showed bowel wall thickening and skip lesions which is characteristic of Crohn’s disease- Colonoscopy which showed skip lesions and cobblestoning. This led to the diagnosis of Crohn’s disease.- Histology was taken but results were not available.- CRP was elevated at 157 mg/L (normal range <10)- U were normal- FBC was normal aside from a slightly elevated white cell count of 12.1 x10?/L (normal range 4-11)Sensitivity and specificity of fecal calprotectinNICE guidelines recommend the measurement of fecal calprotectin in adults with lower GI symptoms to distinguish between IBS and IBD only if colorectal cancer is not suspected. If the test comes back at above positive (above 50 micrograms/g), they should be sent for specialist assessment within 4 weeks.
There is no gold standard technique for the diagnosis of Crohn’s disease but it is rather a combination of endoscopic, histological, radiological and biochemical investigations. A meta-analysis of 13 studies has been conducted into the sensitivity and specificity of fecal calprotectin. Of the 13 studies analysed, six where in adults (n=670) and seven in children and teenagers (n=371). For adults, the sensitivity was found to be 93% (95% confidence interval: 85% to 97%) and specificity to be 96% (95% CI: 79% to 99%). For children and teenagers, the sensitivity was found to be 92% (95% CI: 84% to 96%) and the specificity 76% (95% CI: 62% to 86%). (1)Disease detailsCrohn’s disease is a chronic inflammatory bowel disease that is relapsing-remitting in nature. It can affect anywhere from the mouth to the anus but is particularly likely to affect the terminal ileum. Unlike ulcerative colitis, Crohn’s disease has skip lesions; areas of healthy bowel interspaced between diseased areas.
Histologically, it appears transmural and granulomatous. (2) (3)Patients typically present with abdominal pain, prolonged diarrhea, perianal lesions, blood in stool, bowel obstruction, fever and fatigue. (2) However, Crohn’s disease can have extra-intestinal manifestations such as iritis, arthritis, erythema nodosum and pyoderma gangrenosum.
(3)The aetiology of Crohn’s disease is largely unknown but genetic factors have been found to play a role. Known risk factors are family history, white ancestry, smoking, use of NSAIDs, recurrent URTIs, OCP use and diets high in refined sugars. Bimodal age distribution for onset: first peak between 15 and 40 years and second between 60 and 80 years. There are no known occupational risks for Crohn’s disease.