Abdominal Distension and Bloating

oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

Abdominal distension may be generalised or may be localised to a discrete mass or enlargement of an organ. The main causes of generalised abdominal distension are easily remembered by the five Fs:

  • Fat (obesity)
  • Faeces (constipation)
  • Fetus (pregnancy)
  • Flatus (gastrointestinal)
  • Fluid (ascites)

The most common causes are:

  • Obesity
  • Pregnancy
  • Irritable bowel syndrome[1]
  • Constipation
  • Fibroids
  • Enlarged bladder

Non-obstructive causes

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Mechanical bowel obstruction

Nonmechanical bowel obstruction

  • Vascular insufficiency: thrombosis, embolism.
  • Retroperitoneal irritation: renal colic, neoplasm, infection.
  • Extra-abdominal infection: sepsis, pneumonia, empyema, spinal osteomyelitis.
  • Metabolic/toxic: hypokalaemia, uraemia, lead poisoning.
  • Chemical irritation: perforated peptic ulcer, pancreatitis, biliary peritonitis.
  • Miscellaneous: excessive intraluminal gas, intra-abdominal infection, trauma, mechanical ventilation, other causes of peritoneal inflammation, severe pain and non-steroidal anti-inflammatory drugs (NSAIDs).

Right upper quadrant

  • Hepatomegaly, hepatoma, liver cancer.
  • Gall bladder - eg, mucocele, empyema, secondary to carcinoma of pancreas.
  • Right colon - eg, colonic carcinoma, faeces, caecal volvulus, intussusception.
  • Right kidney - eg, polycystic kidney, hydronephrosis, cyst, renal tumour, tuberculosis.

Left upper quadrant

  • Splenomegaly.
  • Stomach: stomach cancer, gastric distension (eg, pyloric stenosis).
  • Pancreas - eg, pseudocyst, carcinoma.
  • Left kidney - eg, polycystic kidney, hydronephrosis, cyst, tumour, tuberculosis.
  • Colon - eg, carcinoma, faeces, diverticular mass.

See separate articles Right Upper Quadrant Pain and Left Upper Quadrant Pain for further detail.

Epigastrium

  • Abdominal wall - eg, lipoma, hernia.
  • Stomach - eg, carcinoma, distension due to pyloric stenosis.
  • Pancreas - eg, pseudocyst, carcinoma.
  • Transverse colon - eg, carcinoma, faeces, diverticular mass.
  • Hepatomegaly.
  • Retroperitoneum - eg, aortic aneurysm, lymphadenopathy.
  • Omentum - eg, secondaries from stomach or ovary.

Umbilical

  • Hernia, paraumbilical or umbilical.
  • Stomach - eg, carcinoma.
  • Transverse colon - eg, carcinoma, faeces, diverticular mass.
  • Small bowel - eg, Crohn's disease.
  • Omentum - eg, secondaries from stomach or ovary.
  • Retroperitoneum - eg, aortic aneurysm, lymphadenopathy.

Right and left lower quadrants

Suprapubic

  • Careful history taking and abdominal examination are essential. Clinical assessment will usually indicate the nature of abdominal distension (ie whether ascites, gastrointestinal gas, pregnancy, etc) but further investigations are often required to determine the precise aetiology.
  • Resonance on percussion may be misleading because there may be bowel overlying a solid tumour or enlarged organ.
  • Weight loss associated with abdominal distension suggests malignancy.
  • Constipation needs to be fully evaluated to establish any underlying cause.
  • Obesity may make examination very difficult to provide a clear assessment and an ultrasound scan may then be required, irrespective of the likely cause of distension.
  • FBC: raised white cell count in infection or malignancy, anaemia with abnormal vaginal bleeding associated with fibroids, or as a consequence of malignancy.
  • U&Es: renal dysfunction; hypokalaemia or uraemia may cause nonmechanical bowel obstruction.
  • LFTs: liver failure, cholestatic hyperbilirubinaemia with carcinoma of pancreas, hypoalbuminaemia associated with ascites.
  • Urinalysis: may show haematuria in patients with tumours of kidney or bladder.
  • Pregnancy test.
  • Abdominal X-ray, barium enema: constipation, large bowel pathology, bowel obstruction.
  • Abdominal ultrasound.
  • Sigmoidoscopy, colonoscopy.
  • Further investigations may include CT scan and paracentesis.
  • Any patient who presents with abdominal distension without a clear diagnosis requires referral.
  • Referral will also be required for any patient with a serious underlying cause but for many patients the cause is benign.

Bloating is a very common and subjective ailment which can effect patients of all ages. It can be associated with any of the causes of abdominal distension but it is most commonly associated with irritable bowel syndrome. Bloating can have a major impact both socially and psychologically. It is incompletely understood and inadequately treated.

For further information see related separate article Irritable Bowel Syndrome

Further reading & references

  1. Chang L, Lee OY, Naliboff B, et al; Sensation of bloating and visible abdominal distension in patients with irritable bowel syndrome. Am J Gastroenterol. 2001 Dec;96(12):3341-7.
  2. Hsu SJ, Huang HC; Management of ascites in patients with liver cirrhosis: recent evidence and controversies. J Chin Med Assoc. 2013 Mar;76(3):123-30. doi: 10.1016/j.jcma.2012.11.005. Epub 2013 Jan 23.
  3. Sharma D, Srivastava M, Babu R, et al; Laparoscopic treatment of gastric bezoar. JSLS. 2010 Apr-Jun;14(2):263-7. doi: 10.4293/108680810X12785289144566.
  4. Seo AY, Kim N, Oh DH; Abdominal Bloating: Pathophysiology and Treatment. J Neurogastroenterol Motil. 2013 Oct;19(4):433-453. Epub 2013 Oct 7.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Colin Tidy
Current Version:
Peer Reviewer:
Dr Adrian Bonsall
Document ID:
1569 (v22)
Last Checked:
21/03/2014
Next Review:
20/03/2019