Acute abdomen in the adult

• Decisions on the need for further investigations and on the urgency of treatment, and beginning treatment quickly, as necessary, are of primary importance.
• Abdominal computed tomography (CT) is a basic investigation of an acute abdomen, unless cholecystitis is suspected, in which case abdominal ultrasonography should be performed.

• Surgical causes: see table T1.
• Gynaecological causes: see table T2 and the article Lower abdominal pain of gynaecological origin (Lower abdominal pain of gynaecological origin)
• Other causes: see table T3.

Table 1. Surgical causes and diagnostic clues for acute abdomen

• See picture (Perforation, free air in the abdominal cavity)

Table 2. Gynaecological causes for acute abdomen; examples and clues

(Lower abdominal pain of gynaecological origin)

Table 3. Non-surgical causes for acute abdomen (examples)

History

• Pain history
• Any underlying diseases and regular medication
• History of abdominal surgery
• Is this a new acute problem or an exceptionally severe exacerbation of prolonged pain?
• Vomiting, nausea, bladder and bowel function
• Obstipation is most often chronic. A change in bowel habits is an important symptom.

Clinical examination

• An always careful general examination
  • Auscultation of the heart and lungs
  • Measurement of blood pressure and heart rate
  • General neurological examination
• Inspection of the abdomen
  • Form and plumpness of the abdomen
  • Surgical scars
  • Skin changes
  • Hernias (visible or palpable)
• Palpation of the abdomen
  • Abdominal wall (tender or pain-free, soft or tense suggesting peritoneal irritation, guarding)
  • The location of maximal pain
  • Palpable masses, hernial orifices, tautness and ascites
• Palpation of the genitals
  • Hernias
  • Pain or swelling of the testes or epididymis
  • Scrotal hydrocele
• Digital rectal examination
  • Palpable masses, bleeding
  • Prostate: size, consistency, nodules
  • Any faeces in the rectal ampulla, the colour of the faeces

Laboratory tests

• If the patient is unwell or clearly ill, further investigations should be arranged without waiting for laboratory results.
• Today, accident and emergency clinics commonly use laboratory packages.
• It is usually sufficient to do basic blood count with platelet count, CRP, chemical screening of urine, in suspected pancreatitis plasma pancreatic amylase, in suspected cholecystitis ALT, ALP, bilirubin, glucose, sodium and potassium. Also note blood glucose and, as necessary, blood gas analysis.
• If a cardiac cause is suspected, an electrocardiogram (ECG) and TnI/TnT test should always be taken.
• In women below 50, hCG should be tested.
• Normal laboratory results do not exclude conditions such as mesenteric ischaemia; if this is suspected, laboratory results should not be waited for.

Imaging

• Ultrasound examination
  • The primary examination in the diagnostic workup for acute cholecystitis
  • Ultrasonography (or "sonopalpation") is also useful when performed by a doctor on call (Ultrasonographic examinations).
• Abdominal CT scan is the primary imaging method in the diagnostic workup of abdominal pain
  • If there is clear suspicion of pancreatitis, to improve the diagnostic results CT should preferably only be performed 72–94 hours after the onset of symptoms.
  • In patients over 70, the possibility of mesenteric ischaemia should be kept in mind and the arterial phase included in imaging..
• Chest x-ray as necessary
  • Look for pleural effusion, pericarditis or heart failure, pulmonary infections or shadows.

• During the diagnostic investigations, the degree of metabolic disorder should be assessed and fluid therapy should be started before transport to a hospital, unless the distance is very short.
• Start measuring urine output.
• A nasogastric tube should be inserted without hesitation if the patient keeps vomiting.