⚠️ Pain may be absent or muted in certain high-risk groups - elderly patients, those on long-term steroids, diabetics, and the very frail. Always think: is the patient moribund/in extremis? If so → follow ABC, call for senior/surgical help early, gain IV access, give oxygen, start IV crystalloids, provide analgesia, and send urgent bloods (including lactate, FBC, U&E, amylase, and cross-match if haemorrhage is suspected). 👉 If shocked with bleeding → get 2 wide-bore lines, activate major haemorrhage protocol, consider urgent O negative blood. 👉 If septic → IV antibiotics + fluids without delay.

🚑 Acute Abdominal Pain – Emergency Management Summary
🔴 ABCDE + NEWS, Nil by mouth, early senior review 🩻 Initial investigations: Erect CXR / AXR, ECG, FBC/U&E/CRP/Lactate 💉 Get 2 large-bore IV lines, send bloods, start IV fluids ± antibiotics ⚠️ Red flags: high NEWS, peritonism (silent/rigid abdomen), haemodynamic instability → escalate immediately Special diagnostic triggers: Abdominal pain + low BP → think sepsis Abdominal pain + low BP + >50 yrs → leaking AAA Abdominal pain + fertile female → ectopic pregnancy Abdominal pain + AF/MI → ischaemic bowel Abdominal pain + gallstones/alcohol → pancreatitis

🚑 Acute Abdominal Pain – Emergency Management Summary

🔴 ABCDE + NEWS, Nil by mouth, early senior review
🩻 Initial investigations: Erect CXR / AXR, ECG, FBC/U&E/CRP/Lactate
💉 Get 2 large-bore IV lines, send bloods, start IV fluids ± antibiotics
⚠️ Red flags: high NEWS, peritonism (silent/rigid abdomen), haemodynamic instability → escalate immediately
Special diagnostic triggers:
- Abdominal pain + low BP → think sepsis
- Abdominal pain + low BP + >50 yrs → leaking AAA
- Abdominal pain + fertile female → ectopic pregnancy
- Abdominal pain + AF/MI → ischaemic bowel
- Abdominal pain + gallstones/alcohol → pancreatitis

📖 Acute Abdomen – Key Principles

Sudden onset severe abdominal pain (<24h) → always assume potentially lethal pathology until proven otherwise
Expert assessment + early surgical involvement crucial
Pain localisation often follows embryological origin:
- 🌐 Foregut → Epigastrium
- 🌐 Midgut → Peri-umbilical
- 🌐 Hindgut → Below umbilicus

🧠 Pathophysiological Background

Parietal peritoneum richly innervated → inflammation causes localised pain, guarding & rigidity
Visceral pain → poorly localised, dull (e.g. appendicitis starts peri-umbilical)
When parietal peritoneum becomes involved → pain localises (e.g. appendicitis to RIF at McBurney’s point)
Always examine hernial orifices to exclude strangulated hernia

🔎 Common Causes of Acute Abdominal Pain

Cause	Clinical Features	Diagnostic Tests	Management
Appendicitis	RIF pain, anorexia, fever, rebound tenderness	FBC, US/CT	Appendicectomy ± antibiotics
Cholecystitis	RUQ pain, post-prandial, fever	US, LFTs	Cholecystectomy
Pancreatitis	Epigastric pain radiating to back, vomiting	Amylase/lipase, CT	IV fluids, analgesia, NBM
Ectopic Pregnancy	Lower pain, bleeding, missed period	hCG, TV ultrasound	Methotrexate or surgery
AAA (ruptured)	Shock, back/abdo pain, pulsatile mass	Bedside US, CT angio	Resuscitation + vascular surgery

🧾 Additional Diagnostic Pearls

📉 Silent abdomen + rigidity → peritonitis → surgical emergency
🧪 Amylase 3× ULN → pancreatitis (but can rise in perforation, ectopic, DKA)
📍 Pain radiation clues:
- Shoulder → diaphragmatic irritation
- Back → AAA or pancreatitis
- Periumbilical → appendicitis (early)
🚺 All women of child-bearing age → pregnancy test mandatory

🧰 Investigations

Bloods: FBC, U&E, CRP, LFTs, Ca, glucose, amylase/lipase, group & save
Urine dip ± culture; urine pregnancy test
ECG – exclude ACS
Imaging: AXR (limited), CXR (free air, pneumonia), CT abdo (most useful), USS (biliary/gyne)
Blood cultures if sepsis suspected
Special: CT angiography (mesenteric ischaemia), porphobilinogen (acute porphyria)

🫁 Causes of Free Sub-diaphragmatic Gas on AXR

Perforated viscus (peptic ulcer, diverticulitis, appendix)
Gas-forming infection
Iatrogenic (post-laparoscopy)
Pleuroperitoneal fistula

⚡ Acute Management – Principles

Stabilise → ABC, O2, IV access, fluids, catheter, NG tube if obstruction
3L/day crystalloids minimum in pancreatitis/obstruction
Correct electrolytes, insulin infusion if DKA
Early antibiotics if sepsis or perforation suspected
Urgent senior surgical review
CT abdo for diagnosis, laparotomy if peritonitis/rupture
DVT prophylaxis unless contraindicated

🔪 Surgical Management

Do not delay surgery except for resuscitation
Broad-spectrum IV antibiotics (e.g. Tazocin ± Gentamicin ± Metronidazole)
Remove infarcted/perforated tissue
Repair perforations, drain abscesses, lavage peritoneum
Massive haemorrhage protocol if bleeding

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Assessing Abdominal Pain