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 ABDOMINAL PAIN

 Acute abdominal pain: step-by-step assessment4

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• medical conditions, e.g. diabeticketoacidosis, myocardial infarction,adrenal crisis, pneumonia

• any condition associated with repeatedvomiting, e.g. intestinal obstruction,gastroenteritis.

2 Generalised peritonitis?

Generalised peritonitis occasionally resultsfrom acute pancreatitis but is usually themanifestation of a perforated hollow viscus,e.g. stomach, duodenum or colon. Suspectit if there is severe, non-colicky abdominalpain that is worse on movement, coughing

or deep inspiration, and which is associatedwith inflammatory features and general-ised abdominal rigidity. The patient willusually be lying still, taking shallow breaths,and will be in obvious distress or discom-fort; reconsider the diagnosis if the patientappears well or is moving freely.

Patients require aggressive resuscitation,antibiotics and immediate surgical referral.Free air under the diaphragm on erect CXR

(present in 50–75% of cases) confirms thediagnosis; if CXR non-diagnostic considercontrast CT (Fig. 4.4). Serum amylase mayhelp to differentiate perforation from pan-creatitis. A very high index of suspicion isrequired in the elderly and in patientstaking systemic steroids; signs are oftensubtle, so reassess frequently.

1 Evidence of shock?

Rapidly identify patients who are shockedwith hypotension and evidence of tissuehypoperfusion (see Box 28.1, p. 249).

Remember that young, fit patients canoften maintain BP in the face of major fluidlosses; in these patients hypotension occurslate, so look carefully for early featuressuch as ↑HR, ↑RR, narrow pulse pre-ssure, anxiety, pallor, cold sweat or light-headedness on standing ± postural ↓BP.

If the patient has overt or incipientshock, secure two large-bore IV lines;send blood for cross-match, U+E, FBC,

amylase and LFTs; and begin aggressiveresuscitation.

The diagnoses to consider first are ruptureof an AAA, ectopic pregnancy or otherviscus, as these may require immediate sur-gical intervention.

• Suspect ruptured AAA in any patientwith known AAA, a pulsatile abdominalmass or risk factors e.g. male >60 years,

who experiences sudden-onset, severeabdominal/back pain followed rapidlyby haemodynamic compromise.

• Suspect ruptured ectopic pregnancy inany pregnant woman or woman ofchild-bearing age with recent-onsetlower abdominal pain or PV bleeding;perform an immediate bedsidepregnancy test.

• Consider splenic rupture in any shocked

patient with abdominal pain who has ahistory of recent trauma, e.g. road trafficaccident.

If any of these diagnoses is suspected,arrange immediate surgical review prior toimaging.

In the absence of these conditions,perform an ECG, CXR, urinalysis and ABG,continue to assess for an underlying cause,as described below, and refer for urgent

surgical review. Other important diagnosesto consider include:

• perforated viscus• mesenteric ischaemia• acute inflammatory conditions, e.g.

pancreatitis, colitis, cholangitis Fig. 4.4  Free air under the diaphragm.