A TEENAGER WITH CHRONIC DIARRHOEA
History
Levi is a 14-year-old boy who presents to the paediatric rapid referral clinic with a 3-week history of diarrhoea and cramp-like abdominal pain. He has no blood or mucus in his stool and has had no vomiting. His appetite is poor and he has lost 3.5 kg in 3 weeks. He has intermittent fevers. The family recently returned from France where his father contracted diarrhoea, from which he is now recovering. There is no other medical history of note. His mother suffers from irritable bowel syndrome.
Examination
He looks generally unwell. There is no anaemia, jaundice, clubbing or lymphadenopathy. His temperature is 37.9C. There is generalized abdominal tenderness but no guarding or rebound. There is no organomegaly. Inspection of the mouth and anus is normal. His pubertal assessment shows him to have testes that are 5 mL in volume and pubic hair and genitalia that are Tanner stage 2. His weight, at 35 kg, is on the second centile and his height, at 151 cm, is on the ninth centile (mid-parental height is on the 50th centile).
INVESTIGATIONS
Normal
Haemoglobin 10.9 g/dL 14–18 g/dL
White cell count 15.2 109/L 4.0–11.0 109/L
Platelets 623 109/L 150–400 109/L
Mean cell volume 70 fL 76–96 fL
Erythrocyte sedimentation rate (ESR) 87 mm/h 15 mm/h
C-reactive protein (CRP) 36 mg/L 6 mg/L
Ferritin 14 ng/ml 20–300 ng/ml
Albumin 31 g/L 35–50 g/L
Urea and electrolytes Normal
Stool – no bacterial growth, no ova, cysts or parasites
Questions
• What is the most likely diagnosis?
• What investigations would you do?
• What is the initial treatment?
The most likely diagnosis is Crohn’s disease. The most important differentials are an infective enteropathy (e.g. Campylobacter, Yersinia, Giardia) and ulcerative colitis. Tenderness may be over the terminal ileum in the right iliac fossa, but can also be generalized, and signs may mimic those of an acute abdomen. The father’s resolving diarrhoea is most likely to be coincidental. The irritable bowel syndrome does not lead to weight loss, fevers and abnormal blood results, as in this case. It is very important to examine the anus in cases of suspected Crohn’s, as perianal disease (e.g. skin tags, abscess, fistula) is present in 45 per cent of patients. Clubbing may also be present. This child has a degree of growth failure and delayed puberty, which is common in adolescents with Crohn’s disease. The microcytic anaemia in Crohn’s is due to a combination of gastrointestinal blood loss, an insufficient dietary intake and inadequate iron absorption. The white cell count and platelets are often raised. The ESR and CRP are usually elevated and the albumin is often low due to malabsorption and protein loss in the stool. The most common extraintestinal manifestation (10 per cent) is arthritis, typically affecting large joints. The most common dermatological manifestations are erythema nodosum and pyoderma gangrenosum. All patients require an expert ophthalmic examination, which may reveal episcleritis or uveitis.
Causes of chronic diarrhoea (14 days)
Infection
• Bacterial (Salmonella, Campylobacter)
• Protozoal (e.g. Giardia)
• Post-gastroenteritis diarrhoea
Malabsorption
• Lactose intolerance
• Cow’s milk protein intolerance
• Cystic fibrosis • Coeliac disease
Gastrointestinal disorders
• Crohn’s disease
• Ulcerative colitis
Miscellaneous
• Toddler’s diarrhoea/irritable bowel syndrome
• Drugs (e.g. laxatives, antibiotics, chemotherapy)
• Immunodeficiency
A colonoscopy with colonic and terminal ileal biopsies should be performed. An upper gastrointestinal endoscopy should also be done in all new cases of suspected Crohn’s disease, as clinically significant upper tract disease can be present in the absence of upper gastrointestinal symptoms. The goals of treatment are to achieve clinical remission and to promote growth with adequate nutrition. Patients with mild disease are treated with preparations of 5-aminosalicylic acid, e.g. sulphasalazine, antibiotics such as metronidazole and nutritional therapy. If there is no response, corticosteroids and immunosuppressive therapy with 6-mercapto purine or methotrexate can be tried. The latter two agents can also have corticosteroid-sparing effects. Surgery is considered when medical therapy fails. Indications include intractable disease with growth failure, obstruction (due to strictures or adhesions), abscess drainage, fistula, intractable haemorrhage and perforation.
KEY POINTS
• The perianal area should always be examined in cases of suspected Crohn’s disease.
• Growth failure and delayed puberty are common in Crohn’s disease.
• Colonoscopy and upper gastrointestinal endoscopy are key investigations.
• Initial treatment consists of preparations of 5-aminosalicylic acid, antibiotics and nutritional therapy.
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