Abdominal pain, acute in adults

Probability diagnosis

Acute gastroenteritis

Acute appendicitis

Mittelschmerz/dysmenorrhoea

Irritable bowel syndrome

Biliary colic/renal colic

Peptic ulcer

Serious disorders not to be missed

Vascular:

• myocardial infarction (esp. inferior)

• splenic infarction

• ruptured AAA

• dissecting aneurysm aorta

• mesenteric artery occlusion

Cancer:

• of bowel with large or small bowel obstruction

Infection:

• acute cholecystitis

• acute salpingitis

• peritonitis/spontaneous bacterial peritonitis

• ascending cholangitis

• intra-abdominal abscess

Other:

• pancreatitis

• ectopic pregnancy

• small bowel obstruction/strangulated hernia

• sigmoid volvulus

• perforated viscus (esp. perforated peptic ulcer)

Pitfalls (often missed)

Acute appendicitis (atypical)

Myofascial tear/muscle wall pain

Pulmonary causes:

• pneumonia

• pulmonary embolism

Faecal impaction (elderly)

Acute diverticulitis

Herpes zoster

Acute hepatitis

Inflammatory bowel disease

Rarities:

• porphyria

• lead poisoning

• haemochromatosis

• haemoglobinuria

• Addison disease

Masquerades checklist

Depression

Diabetes (ketoacidosis)

Drugs (e.g. NSAIDS, iron tablets, narcotics, cytotoxics)

Anaemia (sickle cell)

Spinal dysfunction (referred)

UTI (inc. urosepsis)

Is the patient trying to tell me something?

May be very significant. Consider Munchausen syndrome, sexual dysfunction and abnormal stress.

Key history

Pain has to be analysed according to the usual SOCRATES features. In respect to associated symptoms and signs, special attention has to be paid to anorexia, nausea or vomiting, micturition, bowel function, menstruation and drug intake.

Key examination

A useful checklist is:

• general appearance

• oral cavity

• vital parameters incl. temperature, pulse

• abdominal examination: inspection, auscultation, palpation and percussion (in that order)

• rectal examination

• inguinal region

• vaginal examination (if appropriate)

• urine analysis

Key investigations

• FBE

• ESR/CRP

• Serum lipase or amylase

• Urine MC

• LFTs

• H. pylori tests

• Faecal blood

Consider:

• imaging including plain X-ray, ultrasound, IVU, CT scan and others according to suspected conditions

• upper GI endoscopy

Diagnostic tips

• Upper abdominal pain is caused by lesions of the upper GIT.

• Lower abdominal pain is caused by lesions of the lower GIT or pelvic organs.

• Early severe vomiting indicates a high obstruction of the GIT.

• Acute appendicitis features a characteristic ‘march’ of symptoms:

  • pain → anorexia, nausea → vomiting.