59. Abdominal distension

Question 1

6 Fs of abdominal distension (2 only in women)

Answer 1

Fat
Flatus
Foetus
Faeces (constipation/ obstruction)
Fluid (ascites)
Fibroids

Question 2

Ascites.

a) Causes - most common? Other?
b) Detectable volumes - clinically? - on USS?
c) O/E: i) signs of ascites, ii) signs of liver disease
d) Investigations
e) management

Answer 2

a) Liver cirrhosis (75%), malignancy (UGI, LGI, pancreas, liver primary and secondary, ovary)
- Any cause of fluid overload: CCF, nephrotic syndrome, protein-losing enteropathy (hypoalbuminaemia)
- Inflammatory causes: pancreatitis, TB

b) Clinical: > 1500mL, USS: < 500mL

c) - Ascites: distension, shifting dullness, fluid thrill (large)
- Liver disease: jaundice, muscle wasting, Dupuytren’s, gynaecomastia, spider naevi, palmar erythema, asterixis

d) - Bloods: FBC, ESR, LFTs, clotting, renal function, possibly tumour markers (e.g. CA-125, AFP)
- USS:
- ?CXR - heart failure, effusions, etc.
- CT - if malignancy suspected
- Ascitic tap: differentiates transudative vs exudative causes; can diagnose SBP

e) - Treat any underyling cause
- Salt restriction
- Diuretics: spironolactone (monitor for hyperkalaemia) best in cirrhosis (+/- furosemide)
- Surgery: Transjugular intrahepatic portal shunt (TIPS) or therapeutic ascitic tap

Question 3

Ascitic tap (paracentesis): exudative vs transudative

Answer 3

Serum-ascites albumin gradient (SA-AG):

• SA-AG ≥11 g/L: (TRANSUDATIVE) - likely causes - cirrhosis, cardiac failure, nephrotic syndrome
• SA-AG <11 g/L: (EXUDATIVE) - likely causes - malignancy, pancreatitis and tuberculosis

Question 4

Bowel obstruction.

a) Causes - mechanical and non-mechanical (ileus)
b) 4 cardinal features + signs o/e
c) Management
d) When is surgery indicated?

Answer 4

a) - Mechanical: adhesions, tumour, hernia, inflammation (IBD, diverticulitis), abscess, gallstones, bezoar, enlarged bladder (retention)
- Non-mechanical: post-surgical, trauma, acute infection/sepsis, acute MI/CVA, hypokalaemia, hypercalcaemia, uraemia

b) Distension, pain (usually central, colicky), absolute constipation, vomiting
- Signs: tympanic percussion, tinkling (mechanical) or absent (ileus) bowel sounds, check for hernias and scars from previous surgery

c) - Nil by mouth, NG tube and fluids (‘drip and suck’)
- Fluid balance: catheterise, monitor for dehydration
- Bloods: FBC, UEs/creatinine (dehydration/AKI), clotting, group and save, crossmatch, lactate (bowel ischaemia)
- Erect CXR - assess for perforation (pneumoperitoneum)
- CT abdomen
- Surgery if required

d) - Bowel ischaemia
- Peritonitis
- Perforation
- Poor response to conservative management

Question 5

Investigating abdominal distension.

a) Bedside
b) Bloods
c) Imaging
d) Special tests

Answer 5

a) - Urine dip: may show haematuria in patients with tumours of kidney or bladder.
- Pregnancy test.

b) - FBC: raised WCC in infection or malignancy, anaemia with fibroids/ malignancy.
- UEs: renal dysfunction; hypokalaemia or uraemia may cause non-mechanical bowel obstruction.
- LFTs: liver failure, tumours, hypoalbuminaemia
- Tumour markers: CA-125, AFP, CA-19-9, etc.

c) - Abdominal XR: constipation, large bowel pathology, bowel obstruction.
- Barium enema
- Abdominal USS

d) - Sigmoidoscopy, colonoscopy.
- Ascitic tap
- Faecal calprotectin (IBD)
- Hydrogen breath test (lactose intolerance)

Question 6

IBS: Rome III criteria.

a) Symptom duration
b) Core symptom
c) Must be associated with …?
d) Supporting symptoms (at least 2)
e) Common extra-intestinal symptoms
f) Investigations

Answer 6

a) 6 month history
b) Abdominal pain or discomfort
c) Associated with change of bowel habit OR relieved by defecation
d) Bloating or distension; altered stool passage (straining, urgency, tenesmus); symptoms aggravated by eating; passage of mucus rectally
e) Nausea, back pain, urinary frequency, headaches, depression, lethargy, dyspareunia

f) Must fulfil positive criteria (not just diagnosis of exclusion)
- Bloods: FBC, CRP, UEs, coeliac serology, CA-125
- Faecal calprotectin (if possible IBD)
- Sigmoidoscopy/colonscopy - if risk of colon Ca

Question 7

IBS management.

a) Dietary
b) Other conservative approaches
c) Drugs

Answer 7

a) - Regular fluids
- Limit caffeine, alcohol and fizzy drinks
- Fibre (increase in constipation; decrease in diarrhoea)
- Avoid sorbitol (diarrhoea)
- Low FODMAP diet
- Involve dietician; keep food diary

b) Exercise, psychological support, self-management, stop smoking, avoid alcohol, weight loss

c) - Diarrhoea: loperamide
- Constipation: laxatives (avoid lactulose)
- Pain: antispasmodics (mebeverine, hyoscine butylbromide)
- Antidepressants: SSRI, TCAs