Interesting case of dual pathology: Crohn’s disease and Peutz-Jeghers syndrome

Background

The prevalence of Crohn’s disease (CD) is 157 per 100 000 people with up to 1/3 of patients being diagnosed before the age of 21.1 Peutz-Jeghers syndrome (PJS) is a rare, autosomal dominant disorder estimated to affect between 1 in 50 000 and 1 in 200 000 people, which is characterised by gastrointestinal polyposis, skin pigmentation and a greatly increased risk of certain cancers.2 3

This case presents an interesting dual pathology which is rarely seen. To our knowledge, there have only been two previous case reports in the literature of PJS coexisting with inflammatory bowel disease (IBD).4 5 This case represented a patient who had become very unwell with unmanaged and unrecognised IBD, which culminated in severe malnutrition requiring initial parental support.

This case highlights the importance of not allowing a pre-existing diagnosis to draw clinical suspicion away from other pathology that may coexist.

Case presentation

An 18-year-old male farmer was referred to a tertiary colorectal service with a 2-month history of severe abdominal pain and weight loss of over 14 kg. He described the pain as central, colicky and worse after eating. He presented severely malnourished with a body mass index of 17. He described abdominal pain on eating, bloody stools and increased stool frequency up to 10 times per day.

During early childhood, he presented with constipation and rectal prolapse, and subsequent endoscopy revealed colonic polyps with histology compatible with PJS. He had the typical perioral pigmentation of this condition, and clinical diagnosis was made. Genetic analysis revealed a mutation in the STK11 gene, confirming a genetic diagnosis of PJS. In October 2016 he underwent a left hemicolectomy as a result of complications of his polyps. He had had four previous laparotomies for management of intussusception.

On examination, he was clearly in pain and was thin and pale. He had lost significant muscle mass. There was obvious perioral pigmentation. His abdomen was not distended; it bore scars of previous surgery with no evidence of hernias. There was mild tenderness diffusely, with no peritonism and no palpable masses. There was no anal fissure.

Investigations

Differential diagnosis

The differential diagnosis in this patient was wide. His occupation placed him at increased risk of zoonoses. Common zoonotic pathogens associated with dairy farming include Shiga-toxin producing E. coli (E. coli O157:H7), Salmonella, Cryptosporidium parvum, Listeria and Campylobacter. Tuberculosis was considered in light of the fevers, night sweats and weight loss. Other infections, including brucellosis, parasitosis and yaws were all possibilities. It was also important to evaluate for immunosuppression, such as by HIV, as this can radically alter the list of likely infective pathogens.

PJS greatly increases the risk of a number of malignancies, both intestinal and extra-intestinal. The lifetime risk of developing cancer is thought to be in excess of 90%.6 As such, it was important to consider gastrointestinal malignancy as a cause for his altered bowel habit with bloody stool, weight loss and night sweats, though this patient’s history was quite acute.

Colicky abdominal pain, worse after eating, can lead to consideration of intermittent small bowel obstruction, particularly given the tendency for intussusception in PJS. Subsequent ischaemia or infarction of bowel can produce bloody diarrhoea and severe abdominal pain.

Considering this range of possibilities, the microbiological, radiological and endoscopic findings were all vital in arriving at the final diagnosis.

Treatment

Following all the investigations above that confirmed ileo-colonic Crohn’s disease, he was started on a course of intravenous steroids to induce remission, which improved his symptoms including his bowel frequency.

The case was discussed at the IBD multidisciplinary meeting, and we decided to start infliximab for maintenance of remission. He received the first infliximab infusion as an inpatient, with no adverse effects. Further doses were arranged for outpatient settings, alongside a tapering course of steroids.

His weight on admission was 56 kg. He was malnourished and unable to maintain an adequate oral intake. He was referred to the nutritional team. A peripherally inserted central catheter was inserted on admission and he received parental nutrition (PN) every night to ensure his nutritional requirements were met. After his course of steroids, he had an appetite and was more able to tolerate food with an adequate oral intake. He received dietetic advice and support, and his PN was stopped on discharge.

Outcome and follow-up

The introduction of medical therapy while he was an inpatient (corticosteroids for induction of remission, infliximab for maintenance of remission) for his CD transformed him. His weight increased by 21 kg, with resolution of bloody diarrhoea. He started eating and drinking freely.

On discharge, he was maintained on infliximab and tapering steroids as an outpatient. Once the steroid taper was complete, azathioprine was added to maintain remission, in combination with infliximab.

In light of his PJS, surveillance for the development of malignancy was needed. The upper gastrointestinal endoscopy during this admission was normal. As described above, the colonoscopy had shown only post-inflammatory polyps, rather than PJS-related polyps. The capsule endoscopy had demonstrated a number of polyps in the small bowel, of approximately a centimetre. A magnetic resonance enterography has been planned for further surveillance of these. He has been scheduled for further surveillance endoscopies in 2021.