Gastroenterology & Hepatology
Question 54 of 180
A 37 year old woman presents to the Emergency Department with a one week history of worsening diarrhoea. She is currently being investigated by her General Practitioner for weight loss and diarrhoea. A barium enema arranged by the GP last month has shown “cobblestoning”, rose thorn ulcers and colonic strictures at intermittent points throughout the colon. What is the diagnosis?
Answer:
Crohn’s disease only located in the distal colon can appear indistinguishable from ulcerative colitis (UC) except on histology. Findings may include a thickened bowel wall with a 'cobblestoned' appearance due to deep ulcers and swelling of the issue. Crohn’s disease affects the entire thickness of the bowel wall – this is why it more often leads to complications such as strictures, deep fissures and fistulae.Inflammatory Bowel Disease
Gastroenterology & Hepatology
Last Updated: 12th February 2021
Inflammatory bowel disease (IBD) is a lifelong condition, typified by periods of relapse and remission with recurrent cycles of inflammation.
Definitions
- Crohn's disease is a chronic, relapsing-remitting, non-infectious inflammatory disease of the gastrointestinal tract. The inflammation involves discrete parts of the gastrointestinal tract, anywhere from the mouth to the anus; these are called 'skip lesions' because they leave normal areas in between. The full thickness of the intestinal wall is inflamed, in contrast to the inflammation in ulcerative colitis, which is limited to the intestinal mucosa.
- Ulcerative colitis is a chronic, relapsing-remitting, non-infectious inflammatory disease of the gastrointestinal tract. It is characterised by diffuse, continuous, superficial inflammation of the large bowel limited to the intestinal mucosa, and usually affects the rectum with a variable length of the colon involved proximally.
Clinical features
- Symptoms
- Unexplained persistent diarrhoea (frequent loose stools for more than 4–6 weeks), including nocturnal diarrhoea
- Faecal urgency and/or incontinence
- Blood or mucus in the stool
- Tenesmus (persistent, painful urge to pass stool even when the rectum is empty)
- Pre-defecation pain, which is relieved on passage of stool
- Abdominal pain or discomfort
- Non-specific symptoms such as fatigue, malaise, anorexia, or fever
- Weight loss, faltering growth or delayed puberty in children
- Symptoms of complications e.g. fistulae or bowel obstruction
- Signs
- Pallor, clubbing, aphthous mouth ulcers
- Abdominal tenderness or mass
- Perianal pain or tenderness, anal or perianal skin tag, fissure, fistula, or abscess
- Signs of malnutrition and malabsorption
- Extra-intestinal manifestations, including abnormalities of the joints, eyes, liver, and skin
Extra-intestinal manifestations
- Extra-intestinal manifestations related to disease activity include:
- Pauciarticular arthritis
- This affects fewer than five large joints, such as the ankles, knees, hips, wrists, elbows, and shoulders. It is usually asymmetric, acute, and self-limiting (lasting for weeks rather than months), and joints tend not to be permanently damaged. There is often associated enthesitis (inflammation where a tendon attaches to a bone), tenosynovitis (inflammation of a tendon and its sheath), or dactylitis (inflammation of an entire finger or toe).
- Erythema nodosum
- Tender, red or violet subcutaneous nodules, 1–5 cm in diameter. Usually on the anterior tibial area or extensor surfaces of the legs or arms.
- Aphthous mouth ulcers
- Painful, clearly defined, round or ovoid, shallow ulcers of the smooth surfaces of the mouth and underside of the tongue.
- Episcleritis
- Red eye with injected sclera and conjunctiva. May be painless or painful, itching or burning.
- Metabolic bone disease (osteopenia, osteoporosis, osteomalacia)
- Osteoporosis occurs in up to 30% of men and women with IBD. Contributing factors include age, corticosteroid treatment, smoking status, low physical activity, extensive small bowel disease or resection, and nutritional deficiencies. Osteopenia is a precursor of osteoporosis causing reduced bone mineral density. Osteomalacia is a condition of defective bone matrix mineralisation resulting from vitamin D malabsorption.
- Venous thromboembolism
- The risk of VTE is increased in IBD and the risk is greatest during active disease.
- Pauciarticular arthritis
- Extra-intestinal manifestations not related to disease activity include:
- Axial arthritis
- This affects the sacroiliac joint (sacroiliitis) or spine (spondylitis), causing buttock and back pain.
- Polyarticular arthritis
- This affects five or more joints, such as the small joints of the hands. It is usually symmetrical and persistent, and it damages the affected joints.
- Pyoderma gangrenosum
- Single or multiple erythematous papules or pustules develop into deep ulcers containing sterile pus unless they are secondarily infected. Occurs anywhere, most commonly on the shins, and often at the site of previous trauma.
- Psoriasis
- A systemic, immune-mediated, inflammatory skin disease which typically has a chronic relapsing-remitting course, and may have nail and joint involvement.
- Uveitis (also known as 'iritis' or 'iridocyclitis').
- Uveitis is usually bilateral, with an insidious onset and chronic course. It presents as a painful red eye, with injected conjunctiva, blurred vision, photophobia, and headache.
- Hepatobiliary conditions, such as primary sclerosing cholangitis, pericholangitis, steatosis, autoimmune hepatitis, cirrhosis, and gallstones.
- They often present as an incidental finding of abnormal liver function tests, rather than as biliary symptoms.
- Others
- Rare extra-intestinal manifestations of inflammatory bowel disease include bronchiectasis, bronchitis, hyperhomocysteinemia, pancreatitis and renal stones.
- Axial arthritis
Complications
- Psychosocial impact — for example on school, work, or leisure activities.
- Toxic megacolon — a potentially life-threatening complication with segmental or total non-obstructive dilatation of the colon accompanied by escalating abdominal pain and systemic symptoms, which may require colectomy. Typically there is dilatation of the transverse colon on abdominal X-ray. It may occur spontaneously as a result of relapse, or be precipitated by infection, hypokalaemia, hypomagnesaemia, medical bowel preparation, or the use of anti-diarrhoeal drugs.
- Bowel obstruction — suggested by lack of passing stool or flatus, abdominal pain, distension, or vomiting.
- Bowel perforation — may complicate acute severe colitis and may be associated with inappropriate total colonoscopy investigation or toxic megacolon if colectomy has been inappropriately delayed.
- Intestinal strictures — where the intestine narrows and partially or completely obstructs the passage of bowel contents.
- Fistulas — where the bowel wall is perforated, allowing faecal matter to track through to adjacent organs, such as the intestine, bladder, vagina, abdominal wall, or perianal skin.
- Significant haemorrhage - especially if the disease affects the colon.
- Anaemia — may be due to iron deficiency (through blood loss or nutritional deficiency), vitamin B12 or folate deficiency (through decreased absorption), anaemia of chronic disease, or drug-associated anaemia.
- Malnutrition, faltering growth, and delayed pubertal development (in children) — may be due to reduced oral intake, increased nutrient requirements, increased gastrointestinal losses and malabsorption, long-term corticosteroid use, and drug-nutrient interactions.
- Increased risk of malignancy in the small and large intestine.
- Perianal disease — a frequent complication of colonic and ileocolonic disease, characterised by fissures, fistulae, or abscesses.
Differential diagnosis
- Infective colitis
- Pseudomembranous colitis (Clostridium difficile infection)
- Microscopic colitis
- Intestinal ischaemia
- Acute appendicitis
- Diverticulitis
- Coeliac disease
- Irritable bowel syndrome
- Anal fissure
- Malignancy (such as colorectal cancer, small bowel cancer, and lymphoma)
- Endometriosis
- Laxative misuse
Investigations
If a diagnosis of IBD is suspected, consider arranging the following investigations:
- Serum full blood count — anaemia may be due to blood loss, malabsorption, or malnutrition; an increased platelet count may suggest active inflammation.
- Serum inflammatory markers such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) — may be raised if there is active inflammation or an infectious complication.
- Serum urea and electrolytes — to assess for electrolyte disturbance and signs of dehydration.
- Serum liver function tests, including albumin — a low serum albumin may indicate protein-losing enteropathy and reflects disease activity and severity as well as nutritional status.
- Serum ferritin, vitamin B12, folate, and vitamin D levels — may be nutritional deficiencies due to malabsorption or intestinal losses.
- Thyroid function tests — to exclude hyperthyroidism.
- Coeliac serology — to exclude coeliac disease.
- Stool microscopy and culture, including Clostridium difficile toxin — to exclude infective gastroenteritis or pseudomembranous colitis.
- Faecal calprotectin (a faecal white cell marker, for adults) — if raised may suggest active inflammation (compared with a normal result which is expected in irritable bowel syndrome).
- Additional tests if extra-intestinal manifestations such as pancreatitis, inflammatory arthritis, or primary sclerosing cholangitis are suspected, depending on clinical judgement.
Specialist investigations may include:
- Colonoscopy with histology of multiple intestinal biopsy specimens, which allows classification of disease extent and severity.
- Upper intestinal endoscopy for children and young people, and if there are upper gastrointestinal tract symptoms in adults.
- Magnetic resonance enterography (MRE) of the small bowel and additional small bowel imaging.
- Pelvic MRI to evaluate suspected perianal disease, to allow definition of the extent and location of abscesses and fistulas.
- Computed tomography (CT) to stage disease and look for extraluminal complications, such as abscesses and fistulas.
- Abdominal ultrasound to assess bowel thickness and dilatation (suggesting obstruction), abscesses, fistulas, and strictures.
- Plain abdominal X-rays to identify small bowel or colonic dilatation, which may indicate complications such as bowel obstruction and toxic megacolon.
Management
- Suspected IBD:
- Arrange emergency hospital admission if the person is systemically unwell with symptoms of bloody diarrhoea, fever, tachycardia, or hypotension.
- Do not prescribe anti-diarrhoeal drugs if the clinical diagnosis is uncertain, as they may precipitate toxic megacolon.
- If hospital admission is not indicated, arrange an urgent referral to secondary care (paediatric gastroenterologist for children or gastroenterologist for adults) for confirmation of the diagnosis and initiation of specialist drug treatments. Options include:
- Corticosteroids
- Aminosalicylates e.g. mesalazine and sulfasalazine
- Calcineurin inhibitors e.g. tacrolimus or ciclosporin
- Immunosuppressive drugs e.g. thiopurines (azathioprine, mercaptopurine) or methotrexate (second-line)
- Biologic therapy e.g. anti-tumour necrosis factor alpha monoclonal antibody agents infliximab and adalimumab
- Specialist enteral nutritional supplementation
- Confirmed IBD flare-up:
- Arrange an emergency hospital admission if the person has a suspected flare-up of IBD and is systemically unwell with severe symptoms, such as:
- Severe diarrhoea (more than 6–8 stools a day).
- Fever, dehydration, tachycardia, or hypotension.
- Severe abdominal pain.
- Suspected intestinal obstruction or intra-abdominal or perianal abscess.
- Cachexia with body mass index (BMI) less than 18.5 kg/m2, or unintended sudden weight loss.
- Raised inflammatory markers and/or anaemia.
- Persistent symptoms despite optimal management in primary care.
- Arrange an emergency hospital admission if the person has a suspected flare-up of IBD and is systemically unwell with severe symptoms, such as:
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
