🩺 Abdominal Pain

Abdominal pain is one of the most common presentations in UK emergency departments and primary care, encompassing a vast spectrum of aetiologies from benign self-limiting conditions to life-threatening surgical emergencies. It is classically categorised by the surgical sieve and anatomical location (nine regions or four quadrants). Effective management relies on distinguishing between visceral pain (dull, poorly localised) and parietal pain (sharp, localised, indicating peritoneal irritation). The clinical priority is the 'Acute Abdomen', requiring rapid identification of perforation, haemorrhage, or obstruction.

A structured history should follow the SOCRATES acronym to define the pain's nature. Sudden onset 'thunderclap' abdominal pain suggests a vascular event like an AAA rupture or bowel perforation. Colicky pain often implies obstruction of a hollow viscus (ureter, bile duct, or bowel). Associated symptoms provide vital clues: vomiting (high obstruction or pancreatitis), change in bowel habit (malignancy or diverticulitis), and urinary symptoms (UTI or nephrolithiasis). A menstrual and gynaecological history is mandatory for female patients.

Initial assessment must focus on the ‘ABC’ and signs of peritonism, such as guarding, percussion tenderness, and rebound tenderness. Observe for 'stilled' patients (peritonitis) versus 'writhing' patients (renal or biliary colic). Palpation should look for specific signs like Murphy’s (cholecystitis), Rovsing’s (appendicitis), or Grey-Turner’s/Cullen’s (haemorrhagic pancreatitis). A digital rectal examination (DRE) is essential if pelvic pathology or bowel obstruction is suspected. Always check hernial orifices and examine the external genitalia in males.

Acute Appendicitis, Biliary Colic/Cholecystitis, Acute Pancreatitis, Diverticulitis, Perforated Peptic Ulcer, Ectopic Pregnancy, Ruptured AAA, Bowel Obstruction, Mesenteric Ischaemia, Gastroenteritis.

Haemodynamic instability (tachycardia, hypotension), board-like rigidity (peritonitis), pulsatile abdominal mass (AAA), fever with severe pain (sepsis), and unexplained weight loss or rectal bleeding (malignancy).

Bedside tests include a pregnancy test, urinalysis, and ECG to rule out atypical MI. Bloods should include FBC (leucocytosis), CRP (inflammation), U&Es (dehydration/renal function), LFTs, amylase/lipase (pancreatitis), and Group and Save if surgery is likely. Imaging is guided by clinical suspicion: an erect chest X-ray can show free air under the diaphragm (perforation), while an AXR may show dilated bowel loops in obstruction. Ultrasound is first-line for RUQ or pelvic pain, whereas CT Abdomen/Pelvis is the gold standard for diagnosing acute surgical pathology like diverticulitis or ischaemic bowel.

In any woman of childbearing age presenting with lower abdominal pain, an ectopic pregnancy must be excluded with a urinary hCG, even if they deny being sexually active. For suspected appendicitis, the migration of pain from the periumbilical region to the right iliac fossa (RIF) has high diagnostic specificity. Always remember the 'two above/two below' rule: check the thorax (pneumonia/MI) and the scrotum (testicular torsion) in patients presenting with unexplained abdominal pain. Chronic pain that improves with defecation and is associated with bloating strongly suggests IBS.

Clinicians must be able to differentiate surgical emergencies requiring immediate laparotomy from medical causes. Understand the significance of the 'Surgical Sieve' (Vindicated - Vascular, Infective, Neoplastic, etc.) to ensure a broad differential. Recognition of the 'Acute Abdomen' and the need for early senior surgical input is a core MLA requirement. Always maintain a high index of suspicion for AAA in older patients with sudden back or flank pain.