Acute abdomen

CHAPTER 13 Acute abdomen



Basic principles 205

Medical causes of acute abdominal pain 211

Peritonitis 211

Intra-abdominal abscesses 213


Basic principles


Acute abdomen is the most common cause of emergency admission to a surgical unit. The term ‘acute abdomen’ is difficult to define but it indicates any non-traumatic disorder of acute onset in which the symptoms are predominantly abdominal and for which in some cases, urgent surgery may be indicated. In practice, it represents a spectrum of problems ranging from sudden onset of severe abdominal pain with a life-threatening underlying cause to minor abdominal symptoms of lengthy duration. The most important feature of the acute abdomen is to sort out the severe causes in need of urgent surgery (e.g. ruptured aortic aneurysm, perforated diverticulitis) from severe abdominal pain that does not require surgery (biliary colic, ureteric colic, pancreatitis); and also from those conditions that do not need urgent investigation and treatment (e.g. mild gastroenteritis, constipation). Prompt diagnosis is essential. A careful history and examination will indicate the cause of most acute abdomens.




History




Age

Certain conditions are more likely to occur in certain age groups, e.g. mesenteric adenitis in children, diverticulitis in the older patient.



Pain

This can be remembered from the mnemonic ‘SOCRATES’:


• Site: where did it start, has it moved?

• Onset: sudden, gradual

• Character: e.g. dull, vague, cramping, sharp, burning

• Radiation: e.g. loin to groin in ureteric colic

• Associated factors: e.g. vomiting, diarrhoea, fever, effect of movement, effect of micturition, etc.

• Timing: is the pain constant or intermittent; how long does the pain last?

• Exacerbations and relieving factors: what makes the pain better/worse?

• Severity.


Vomiting


• Did vomiting precede the pain?

• Frequency.

• Character, e.g. bile, faeculent, blood, coffee grounds.


Defaecation


• Constipation: absolute constipation with colicky abdominal pain, distension, and vomiting suggests intestinal obstruction.

• Diarrhoea: frequency, consistency of stools, blood, mucus, pus.


Fever

Any rigors.



Past history


• Previous surgery, e.g. adhesions may cause intestinal obstruction

• Recent trauma, e.g. delayed rupture of spleen

• Menstrual history, e.g. ectopic pregnancy.


Examination




General

Is the patient lying comfortably? Is the patient lying still but in pain, e.g. peritonitis? Is the patient writhing in agony, e.g. ureteric or biliary colic? Is the patient flushed suggesting pyrexia?



Pulse, temperature, respiration


Cervical lymphadenopathy

(e.g. mesenteric adenitis).



Chest

(e.g. referred pain from lobar pneumonia).



Abdomen



Inspection

Moves on respiration. Scars, distended, visible peristalsis (usually chronic obstruction in patient with very thin abdominal wall). Pain on coughing. Hernial orifices. Any obvious masses, e.g. pulsatile mass to suggest aortic aneurysm.



Palpation

Patient relaxed, lying flat, with arms by side. Be gentle and start as far from the painful site as possible. Check for guarding and rigidity. Rebound tenderness is unpleasant and should not be performed in the traditional manner of palpating the abdomen deeply and then suddenly withdrawing the examining hand. The presence of rebound tenderness can be inferred from more subtle signs such as percussing the abdomen, asking the patient to cough and asking whether bumps in the road during the ambulance journey were painful (hospitals always have speed bumps and can provide much information about an acute abdomen!). Check for masses, e.g. appendix mass, pulsatile expansile mass of aortic aneurysm. Check the hernial orifices.



Percussion

For example, tympanitic note with distension due to intestinal obstruction; dullness over bladder due to acute retention.



Auscultation

Take your time (30–60 s), e.g. silent abdomen of peritonitis, high-pitched tinkling bowel sounds of intestinal obstruction.



Rectal examination


This is just as important as the abdominal examination. It should be carried out in the left lateral position. Insert the well-lubricated gloved finger posteriorly into the sacral hollow. Move the finger around in the arc of a circle until it impinges on the peritoneum of the rectovesical or rectouterine pouch. If the patient winces with pain when the finger impinges on the peritoneum, this is a sign of peritonitis in the most dependent part of the pelvis. The pain disappears when the finger comes off the peritoneum as it completes the circle and returns to the sacral hollow. The correct annotation of a positive rectal examination should be ‘tender anteriorly’. ‘Tender high up in the right’ is inappropriate. There seems to be a misconception among medical students that you are feeling the area of the appendix. You are feeling for tenderness due to inflammation of the pelvic peritoneum caused by infected exudates draining to the most dependent part of the pelvis, i.e. the rectovesical or rectouterine pouch.



Vaginal examination


Discharge, tenderness associated with pelvic inflammatory disease, examine the uterus and adnexa, e.g. pregnancy, fibroids, ectopic pregnancy.



Investigations


• FBC: low Hb may indicate chronic bleeding; a raised white cell count with a neutrophil leukocytosis may indicate an inflammatory or infective process

• U&Es: fluid loss may result in renal impairment, vomiting may cause electrolyte abnormalities

• LFTs: may indicate gallstone pathology or hepatitis

• Amylase: a high amylase confirms the diagnosis of pancreatitis; a mildly raised amylase is also seen in ectopic pregnancy, perforated viscus, intestinal obstruction and intestinal ischaemia

• β-hCG: pregnancy/ectopic pregnancy – must be performed in all females of child-bearing age with iliac fossa pain

• CRP: inflammatory marker generally raised within 8 h of an inflammatory process – can be useful in difficult cases, e.g. suspected appendicitis of 12 h duration with a normal WCC and CRP is unlikely to be acute appendicitis

• ABG: generally only indicated in severely ill patients; it can give useful information on tissue perfusion by pH and lactate levels; PaO2 and PaCO2 can give important information for the anaesthetist prior to surgery

• CXR: exclude referred lesion, gas under diaphragm (→ Fig. 13.1)

• AXR: distended bowel with air/fluid levels, gallstones (10% are radio-opaque); calcified aorta, e.g. aneurysm; air in biliary tree (cholecystoduodenal fistula with gallstone ileus)

• USS: e.g. ovarian cyst, ectopic pregnancy, gallstones

• CT: useful in difficult cases – able to demonstrate free fluid, air, dilated bowel, pancreatitis

• KUB

• IVU for stones

• Angiography: e.g. acute GI haemorrhage of obscure cause, superior mesenteric embolus or thrombosis (duplex scanning may also be appropriate).

image

Figure 13.1 Gas (arrow) is seen under the right hemidiaphragm following perforation of a duodenal ulcer.



Causes




Some causes of the acute abdomen are shown in Table 13.1. These conditions are covered in the relevant chapters. (For information on the site of abdominal pain in relation to suspected pathology → Table 13.2.)


TABLE 13.1 Causes of acute abdomen






















































































Gastrointestinal  
Gut Acute appendicitis
Intestinal obstruction
Perforated peptic ulcer
Diverticulitis
Inflammatory bowel disease
Acute exacerbation of peptic ulcer
Gastroenteritis
Mesenteric adenitis
Meckel’s diverticulitis
Liver and biliary tract Cholecystitis
Cholangitis
Hepatitis
Biliary colic
Pancreas Acute pancreatitis
Spleen Splenic infarct and spontaneous rupture
Urinary tract Cystitis
Acute pyelonephritis
Ureteric colic
Acute retention
Gynaecological Ruptured ectopic pregnancy
Torsion of ovarian cyst
Ruptured ovarian cyst
Salpingitis
Severe dysmenorrhoea
Mittelschmerz
Endometriosis
Vascular Ruptured aortic aneurysm
Mesenteric embolus
Mesenteric venous thrombosis
Ischaemic colitis
Acute aortic dissection
Peritoneum Primary peritonitis
Secondary peritonitis
Abdominal wall Rectus sheath haematoma
Retroperitoneal Haemorrhage, e.g. anticoagulants

TABLE 13.2 Site of abdominal pain in relation to suspected pathology







































































Whole abdomen Generalized peritonitis and mesenteric infarction
Right upper quadrant Acute cholecystitis
Cholangitis
Hepatitis
Peptic ulceration
Left upper quadrant Peptic ulceration
Pancreatitis
Splenic infarct
Right lower quadrant Appendicitis
Ovarian cyst
Ectopic pregnancy
Pelvic inflammatory disease
Meckel’s diverticulum
Mesenteric adenitis
Ureteric colic
Rectus sheath haematoma
Right-sided lobar pneumonia
Left lower quadrant Sigmoid diverticular disease
Ovarian cyst
Ectopic pregnancy
Pelvic inflammatory disease
Ureteric colic
Rectus sheath haematoma
Left-sided lobar pneumonia
Radiating pain Peptic ulcer
Back Pancreatitis
Aortic aneurysm
Acute aortic dissection
Groin Ureteric colic
Testicular torsion

Related posts:

  1. Management of malignant disease
  2. An introduction to surgical techniques and practical procedures
  3. Abdominal wall and hernia
  4. Orthopaedics

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Jun 14, 2017 | Posted by in GENERAL SURGERY | Comments Off on Acute abdomen

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