Abdominal distension

20 Abdominal distension



Michael Cox



Case


A 32-year-old woman presents with a 6-day history of progressive abdominal distension and nausea. She had recently been an inpatient with an episode of acute pancreatitis. The aetiology of the pancreatitis was familial pancreatitis, with her grandmother, father and one brother having episodes of recurrent pancreatitis. She looked well, was afebrile and was not jaundiced or pale. Abdominal examination revealed a moderately distended abdomen that was tense but not tender. The bowel sounds were normal. There was evidence of shifting dullness and a fluid thrill. A provisional diagnosis of ascites was made.


Laboratory blood tests were all normal in particular the amylase, lipase, liver function tests and albumin. A CT scan confirmed marked ascites. The pancreas was slightly enlarged but well perfused with a slightly prominent pancreatic duct. There were no loculated fluid collections or evidence of pseudocyst formation. A diagnostic aspiration of the fluid revealed it was straw-coloured. Analysis confirmed it was an exudate with no cells and an amylase of over 100 000 I/U (serum ascites–albumin gradient < 11 g/L). This confirmed the clinical suspicion of pancreatic ascites.


The following day an ERCP was performed. The pancreatic duct was dilated at 4 mm with no obvious stricture. There was a leak of contrast from the region of the distal body into the peritoneal cavity. An endoscopic pancreatic stent was inserted with good drainage noted. Over the next 3 days the abdominal distension resolved and she was discharged home. Three weeks later a follow-up CT scan confirmed complete resolution of the ascites and a relatively normal pancreas with the stent in situ. She remained well and the stent was removed after 6 months. Unfortunately, she had further episodes of recurrent acute pancreatitis over the next 4 years and is likely to develop chronic pancreatitis.



Preliminary Examination of the Abdomen


The traditionally taught five causes of generalised abdominal distension (the ‘five Fs’) are: flatus, fluid, faeces, fetus and fat. To this list should be added a sixth: massive organomegaly or ‘filthy big tumour’.


For the patient presenting with generalised abdominal distension, a preliminary abdominal examination is worthwhile before a detailed history is taken to determine which of the ‘six Fs’ is the most likely cause. The reason for this departure from the usual sequence of history followed by examination is that history taking can be greatly simplified if the clinician has some prior idea of the underlying problem.



1. Flatus


The cause of flatus is gaseous distension of the bowel often secondary to a bowel obstruction or paralytic ileus. There is generalised hyper-resonance to percussion. Any fluid contained within the distended bowel associated with a bowel obstruction or ileus is clinically undetectable. It lies posteriorly with the patient lying supine and is not percussible. It is contained within bowel loops and cannot shift. Auscultation of the abdomen may reveal hyperactive bowel sounds with mechanical obstruction and absent or just a few ‘tinkly’ bowel sounds with paralytic ileus.



2. Fluid or ascites


Intraperitoneal fluid collection is associated with dullness to percussion in the flanks with the patient lying supine. The dullness is described as shifting dullness because the upper limit of the dullness moves in relation to the abdominal wall as the patient is rolled onto the side. Massive ascites is also associated with a fluid thrill felt in one flank after tapping in the other. The distension is less globally distributed with ascites than with gaseous distension of the abdomen, with the effect that the flanks tend to sag.



3. Faeces


Stool can accumulate in the colon to produce abdominal distension. This can cause gaseous distension of more proximal bowel. The degree of distension tends to be less than can occur with ascites or bowel obstruction. The faeces can be recognised as firm to hard lumps that are indentable when prodded with the tip of the examining finger (Ch 11). The segments of colon overlying the brim of the pelvis on the left and right sides may be more prominent to the examining hand.



4. Fetus


Pregnancy and the associated enlarged uterus produce a globular firm mass, which arises out of the pelvis so that the examining hand cannot palpate an inferior border. In early pregnancy, the swelling is confined to the lower abdomen. The mass may reach as high as the epigastrium in late pregnancy. Further, bony fetal parts, such as the head and back, may be identifiable to palpation and fetal heart sounds may be heard on auscultation.



5. Fat


Within the abdomen, fat commonly produces abdominal distension. It is known colloquially as ‘pot belly’ or ‘beer gut’. It does not have characteristic features on clinical examination except that other parts of the body are usually also obviously fat. Obesity is so prevalent that a previously obese patient may present with further distension due to one of the other ‘five Fs’. Evaluation by physical examination is always more difficult under these circumstances.



6. Filthy big tumour (massive organomegaly)


Features of massive organomegaly are covered in Chapter 19.



History and Further Examination


A classification of the causes of abdominal distension is presented in Table 20.1 and relevant symptoms are listed in Table 20.2. The duration of abdominal distension and its association with abdominal pain are key questions. Thus, abdominal pain should not usually be expected to be a feature, except with abdominal distension due to gas in bowel obstruction; with the other causes, there may be milder discomfort due to stretching of the parietal peritoneum or the capsule of an organ. Localised pain can occur with organ swelling. Similarly, the speed of development for most causes is slow, except with abdominal distension from gas, in which case it can be fast. Tense swelling of the abdomen due to fluid or a large tumour can cause increased intraabdominal pressure leading to heartburn, nausea, vomiting or dyspnoea (from elevation of the diaphragm). The specific clinical features for each cause are described below.


Table 20.1 Classification of causes of abdominal distension: the ‘six Fs’











































































































Cause Example Distension
1. Flatus (gaseous distension)    
Bowel obstructed    
Open   Generalised
Closed Sigmoid volvulus Localised
  Caecal volvulus Localised
Bowel not obstructed    
  Paralytic ileus Generalised
  Pseudo-obstruction Generalised
  Irritable bowel syndrome Generalised
  Acute gastric dilatation Localised
  Gas bloat Generalised
2. Fluid (ascites) See Table 20.3 for detail Generalised
3. Faeces   Localised
4. Fat   Generalised
5. Fetus   Localised
6. Filthy big tumour (organomegaly)    
Liver See Chapter 19 Localised
Spleen See Chapter 19 Localised
Ovary Ovarian cyst Localised
Uterus Fibroids Localised
Kidney Polycystic kidney Localised
Hydronephrosis – Localised
Bladder Obstructed bladder Localised
Mesentery Tumour Localised
Retroperitoneum Tumour Localised or generalised

Table 20.2 Possible symptoms with abdominal distension
































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May 30, 2016 | Posted by in GASTROENTEROLOGY | Comments Off on Abdominal distension

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Symptom Relevance/significance
Abdominal pain:
• abdominal tightness/vague generalised ache;

• colicky (periumbilical or lower abdominal).
Non-specific

Bowel obstruction
Nausea/vomiting Bowel obstruction
Anorexia Non-specific, malignancy, cirrhosis
Loss of weight Non-specific, malignancy, cirrhosis
Bowel habit (recent and usual) Bowel obstruction, constipation
Respiratory symptoms Secondary to elevation of the diaphragm
Previous history of malignant disease As a possible cause of ascites
Alcohol or drug abuse As a cause of liver disease and ascites
Jaundice