Acute Abdomen

Mohammed Al Sebayel

Essentials

The ‘acute abdomen’ is defined as a sudden onset of severe abdominal pain of less than 24 hours duration.

Structured approach
Initial assessment of acute surgical problem

Does it need immediate and prompt surgical intervention, or urgent medical therapy.
critically unwell, give oxygen, start suitable initial steps, and call for help early before going into detail on the history and examination.

Grade of Operative Surgical Urgency in Acute abdomen:

Immediate action: bleeding

Rupture aortic aneurysm
Bleeding ulcer (gastric or duodenal)
Trauma.
Rupture ectopic. (ask menstrual period, pregnancy, …)

Emergency action: Perforations

(peptic ulcer, small or large bowel perforation, diverticular disease, Inflammatory bowel disease, Bowel obstruction, Mesenteric Ischemia

Urgent action: Inflammation

Colic……..Biliary Colic ……Acute Cholecystitis
Peritonism (localized Peritonitis)…… Acute Appendicitis

Non urgent: Biliary Colic without cholecystitis and renal colic

Colic Colic is an abdominal pain that crescendos to become very severe and then goes away completely. This is most typically seen in either ureteric obstruction or bowel obstruction.

Biliary ‘colic’ is not a true colic as the pain does not go away completely, instead getting periodically better and worse (colloquially termed ‘waxes and wanes’)

Presentations Requiring Immediate /Urgent Surgery

The most serious cause of intra-abdominal bleeding is a Ruptured Abdominal Aortic Aneurysm (AAA) which requires swift referral to the vascular team and immediate surgical intervention.
Other common causes usually involve a slower rate of bleeding, but with urgent surgery still required, include Ruptured Ectopic Pregnancy, bleeding Peptic Ulcer and Trauma.
These patients will typically go into hypovolemic shock. Clinical features include tachycardia and hypotension, pale and clammy on inspection, and cool to touch with a thread pulse.

Indications for Urgent Operation IHOP

Ischemia - 4 HR until death -
Hemorrhage
Obstruction
Perforation (Perforated Viscus)

Somatic	Visceral
• Nociceptors are involved	• Involves hollow organ and smooth muscle nociceptors that are sensitive to stretching, hypoxia and inflammation
• Often well localized	• Pain is usually referred, poorly localized, vague and diffuse
• Usually described as throbbing or aching	• May be associated with autonomic symptoms (e.g., pallor, sweating, nausea, blood pressure and heart rate changes)
• Can be superficial (skin, muscle) or deep (joints, tendons, bones)

PAIN:

Site.
Onset and progression.
Character.
Referred.

Referred Pain:

Biliary Colic: to right shoulder or scapula
Renal colic: to groin
Appendicitis: periumbilical to right lower quadrant (RLQ)
Pancreatitis: to back
Ruptured aortic aneurysm: to back or flank
Perforated ulcer: to RLQ (right paracolic gutter)
Hip pain: to groin

Most Common Presentations of Surgical Pain

Sudden onset with rigid abdomen = perforated viscus
Pain out of proportion to physical findings = ischemic bowel (Abdomen soft lax with extreme pain)
Vague pain that subsequently localizes = appendicitis or other intra-abdominal process that irritates the parietal peritoneum
Waves of colicky pain = bowel obstruction

Acute Abdomen by region

In all patients presenting with an acute abdomen, order the following:

KEY TESTS FOR SPECIFIC DIAGNOSIS

ALP, ALT, AST, bilirubin - liver
Lipase/ amylase - pancreatic
Urinalysis - kidney
β-hCG (in women of childbearing age) - in women
Troponins - heart
Lactate - tissue perfusion

KEY TESTS FOR OR PREPARATION

CBC, electrolytes, creatinine, glucose
INR/PTT
CXR (if history of cardiac or pulmonary disease)
ECG if clinically indicated by history or if >69 years and no risk factors

Laboratory TestsY

The investigations in all cases of the acute abdomen share the same generic outline:

Urine dipstick – for signs of infection or haematuria ±MC&S. Include a pregnancy test for all women of reproductive age.
ABG – useful in bleeding or septic patients, especially for the pH, pO2, pCO2, and lactate for signs of tissue hypoperfusion, as well as a rapid hemoglobin.
Routine bloods – FBC, U&Es, Liver Function, CRP, amylase.
Consider measuring serum calcium in suspected pancreatitis.
Do not forget a group & save (G&S) if the patient is likely to need surgery soon.
Blood cultures – if considering infection as a potential diagnosis
Note: Any amylase / lipase 3x greater than the upper limit is diagnostic of pancreatitis. Any raised value lower than this may also be due to another pathology, such as perforated bowel, ectopic pregnancy, or diabetic ketoacidosis (DKA)

Investigation:

Imaging In the emergency setting, every patient with abdominal pain should have an ECG to exclude myocardial infarction. Other imaging modalities that may be initially requested include:

Ultrasound:

Kidneys, ureters and bladder (‘KUB’) – for suspected renal tract pathology
Biliary tree and liver – for suspected gallstone disease
Ovaries, fallopian tubes and uterus – for suspected tubo-ovarian pathology

Radiological:

An erect chest X-ray (eCXR) – for evidence of bowel perforation.
CT imaging, depending on the suspected underlying diagnosis

D- Aortic Aneurysm

Perforation - air - can be found normally after surgery

CT scan for varying degrees of diverticular disease (1) diverticulum in the sigmoid colon (2) degree of diverticulitis present (3) abscess formation, secondary to ongoing diverticulitis