Abdominal distention

Epidemiology

Differential Diagnosis

Ascites

An abnormal collection of fluid in the peritoneal cavity. Broadly speaking, the causes can be split into transudate, exudate and chylous (obstruction of the lymphatics).

• Transudate (<3g protein in fluid) - heart failure, hypoalbuminaemia (nephrotic syndrome, liver failure), constrictive pericarditis
• Exudate (>3g protein in fluid) - malignancy (pancreatic cancer, colon cancer), infection (peritonitis), TB, Budd-Chiari syndrome (obstruction of the hepatic vein), myxoedema
• Chylous (milky white ascites) - malignant involvement of para-aortic lymph nodes by lymphoma, testicular tumour

Bowel obstruction

• Mechanical
  • intraluminal: meconium ileus, intussusception, gallstones, colon cancer, faecal impaction;
  • bowel wall: atresia, gut stenosis, Meckel's diverticulum, imperforate anus, bowel stricture, IBD, diverticulitis, colon cancer, endometriosis;
  • extraluminal: abdominal abscess, tumour, adhesions (from previous surgery).
• Non-mechanical (bowel stops working for some reason) -
  • abdominal: postoperative, pernitonitis, vascular occlusion;
  • systemic: hypokalaemia, hypomagnesaemia, DKA, hypothyroidism, uraemia;
  • drugs: anticholinergics, TCAs, anti-Parkinsonians; reflex: postpartum, renal colic, retroperitoneal haemorrhage; fractured vertebrae.

Enlarged organs

This is more seen as an abdominal mass, but your organs can get bigger: hepatomegaly, splenomegaly, bladdermegaly, stomachmegaly etc. (I may have made the last two up). The uterus also enlarges in fibroids.

Non-pathological

Being fat and/or preggers.

Clinical and Associated Features

Ascites

• Heart failure - orthopnoea (short of breath when lying down), PND, ankle oedema, tachycardia, pulsus alternans, reduced pulse volume, raised JVP, bibasal crackles, hepatomegaly, ascites
• Nephrotic syndrome - heavy proteinuria, hypoalbuminaemia, generalised oedema. Oedema - periorbital, genital, affected by gravity; transudative ascites; pleural effusions; abdominal discomfort, hypovolaemia, peritonitis; diarrhoea and vomiting; can present in kids
• Liver failure - ascites, jaundice, susceptibility to bleeding (haemorraghic diathesis), hepatic encephalopathy (neuro problems which get worse as the encephalopathy worsens)
• Percarditis - chest pain (substernal/precordial radiating to neck and shoulders, pain worsened by swallowing, inspiration, coughing, lying flat; fever; non-productive cough; weakness. Dyspnoea and orthopnoea are worse in tamponade.
• Fibroma - Meig's syndrome: fibroma, ascites and pleural effusion (weirdly mostly on the left).
• Cancer/IBD - weight loss, alternating constipation and diarrhoea, blood in stools, tiredness
• TB - weight loss, blood in stools, diarrhoea, tiredness, fever
• Budd-Chiari syndrome - ascites, jaundice, hepatomegaly and renal failure

Bowel Obstruction

• Mechanical - abdominal pain (usually cramp), vomiting (especially late in high obstructions), constipation, distention (especially with low obstruction)
• Non-mechanical (paralytic ileus - the bowel just ain't working baby) - no pain or tenderness, distention, no flatus or faeces, no bowel sounds, vomiting, high nasogastric output.