Acute Abdomen causes, symptoms, types and treatment

Acute Abdomen refers to a sudden onset of severe abdominal pain that typically requires urgent medical evaluation and often surgical intervention. It is a medical emergency with a broad range of potential causes, including inflammatory, obstructive, vascular, and traumatic conditions.

Acute Abdomen

Acute abdomen is a critical condition that requires prompt assessment and intervention. Timely diagnosis and management can significantly reduce morbidity and mortality.

Acute abdomen: Any serious acute intra-abdominal condition attended by sudden, spontaneous severe pain in the abdomen that is less than 24 hours in duration. Acute surgical abdomen: Pain arising in a previously apparently healthy person that lasts more than six hours.

Causes of acute abdomen:

Surgical Causes of Acute Abdomen

GIT Disorders:

• Non-specific abdominal pain (43%).
• Appendicitis (24%).
• Small & large bowel obstruction (5%).
• Perforated peptic ulcer (3%).
• Bowel perforation.
• Diverticulitis (2%).
• Gastritis and gastroenteritis.

Liver, Spleen & Biliary tract Disorders:

• Acute cholecystitis (9%).
• Acute cholangitis.
• Hepatic abscess.
• Ruptured hepatic tumour.
• Spontaneous rupture of the spleen.
• Splenic infarct.

Pancreatic Disorders: Acute pancreatitis (2%).

Urinary Tract Disorders:

• Renal colic (4%).
• Renal infarct.

Gynecological Disorders:

• Ruptured ectopic pregnancy.
• Twisted ovarian tumour.
• Ruptured ovarian follicle cyst.
• Pelvic inflammatory disease (PID).

Vascular Disorders:

• Ruptured aneurysm.
• Mesenteric vascular occlusion.

Peritoneal Disorders: Peritonitis or Intra-abdominal abscess.

Post-operative Causes:

• Bleeding or Abscess.
• Anastomotic leak.
• Bowel obstruction.
• Abdominal compartment syndrome.

Medical Causes of Acute Abdomen

Endocrine and Metabolic Disorders:

• Uremia.
• Diabetic crisis.
• Addisonian crisis.
• Acute intermittent porphyria.
• Hereditary Mediterranean fever.

Hematological Disorders: Sickle cell crisis.

Toxins and Drugs:

• Lead poisoning.
• Food poisoning.

Infections and Inflammatory Disorders:

• Henoch-Schonlein purpura.
• Systemic lupus erythematosis (SLE).
• Polyarthritis.

Tropical Diseases:

• Typhoid.
• Malaria.
• Tuberculous (TB) peritonitis.
• Amebiasis.
• Worm infestations.

Cardiac/Pulmonary Disorders:

• Pleurisy.
• Pneumonia.
• Cardiac disease. (e.g. myocardial infarction – MI).

Nervous System Disorders:

Disease of the spine affecting nerve roots.

Common Acute Abdominal Conditions in Infants and Children

• Acute appendicitis.
• Non-specific mesenteric adenitis.
• Intussusception.
• Intestinal volvulus.
• Meckel’s diverticulitis.

Common Causes of Pain According to Site:

1. diffuse (generalized) abdominal pain:

• GUT Perforation.
• Mesenteric ischemia.
• Abdominal Aortic Aneurysm (AAA).
• Acute pancreatitis.
• Diabetes mellitus (DM).

2. Localized abdominal pain:

Clinical diagnosis:-

History-Taking/Symptoms

1. Abdominal pain

location and character of pain.

• Visceral pain → dull, poorly localized (distension, inflammation, or ischemia).
• Parietal pain → sharper, better localized.
• Kidney/ureter → flank pain.
• Referral of pain (pain away from origin).

Onset

• Sudden (hemorrhage, perforation, or torsion).
• Gradual (inflammation).

2. GI symptoms

• Nausea, vomiting (bilious or bloody).
• Constipation is the rule in most acute abdomen (due to ileus or obstruction).
• Diarrhea (?? bloody).
• Both, nausea and diarrhea? Medical?
• Change in symptoms with eating?

3. Constitutional symptoms

• Fever Chills.
• Jaundice (passage of clay stools and dark urine denotes obstructive jaundice).

4. History-Taking

• Non-steroidal anti-inflammatory drug (NSAID) use (e.g. for duodenal ulcer).
• Drinking alcohol (pancreatitis).
• Prior surgeries (adhesions…).
• Hernia (obstruction, strangulation).
• Urine output (dehydration).

Clinical Examination

• General examination.
• Vital signs.
• Abdominal examination.
• Examination of hernial orifices.
• PR examination.
• Scrotal examination.

Investigations:

Laboratory Test

1. Complete blood count (CBC): Leukocytosis or anemia.
2. Electrolytes: Vomiting causes acidosis and dehydration.
3. Amylase: Pancreatitis
4. Renal function test
5. Liver function tests (LFTs): Jaundice-hepatitis.
6. Urine analysis: UTI – stones – hematuria.
7. Stool analysis.

Imaging Studies

1. Plain X-ray (supine and erect): Obstruction – free air – stones.
2. Ultrasound: Cholecystitis – gynecological pathology – collection.
3. CT scan: Diagnostic.
4. CT angiography: Ischemia, bleeding, aortic aneurism.

treatment:

Primary Care

• Monitoring vital signs and pain assessment.
• Foley’s urinary catheter.
• Nothing orally (NPO) until surgical intervention is ruled out.
• Nasogastric (NG) tube with low continuous suction.
• IV fluids or nutritional support.
• Analgesia for pain.

Specific treatment (according to the diagnosed cause)

Decision to Operate (Indications of Surgery)

1. Peritonitis: Tenderness, rebound tenderness, involuntary guarding.
2. Severe/unrelieved pain
3. Vitally unstable (hemorrhage or sepsis): Tachycardia, hypotensive, white count.
4. Intestinal ischemia, including strangulation.
5. Pneumo-peritoneum.
6. Complete or high-grade obstruction.

Individual Causes of Acute Abdomen

Acute Appendicitis (the most common cause)

Clinical picture: This depends on the appendix’s site.

• Occur at any age.
• Pain starts in the umbilicus and then shifts to the right iliac fossa.
• Pain before vomiting.

investigations:

• Laboratory Test: High WBC counts with the shift to the left (leukocytosis).
• Imaging Studies: Ultrasound is used to exclude other pathologies, especially in females. e.g. Ectopic pregnancy or torsion ovarian cyst.

Treatment: Appendectomy.

Perforated Peptic Ulcer

clinical picture:

• Sudden onset.
• Commonly in the duodenum, (DU > GU with a ratio of 6:1.
• The ulcer may be acute or chronic.
• Board-like rigidity.
• History of precipitating factor e.g. NSAID.

investigation:

• Plain X-ray (KUB) shows air under the diaphragm (pneumo-peritoneum).
• Treatment: suturing and omental patch.

Acute Cholecystitis

clinical picture :

• Diffuse or colicky right hypochondrial pain with overlying tenderness and rigidity.
• examination: Difficult to feel the gall bladder (GB).

investigation: Ultrasound (US): cholecystitis – gall stones.

Treatment: cholecystectomy.

Acute Pancreatitis

clinical picture:

• History of precipitating factors e.g. alcohol intake and hyperlipidemia
• Severe epigastric pain and may be referred to the back.
• Profuse vomiting.
• The patient may be shocked.

investigation:

1. Laboratory Test:

• Serum amylase within 12 hours (elevated).
• Serum lipase (elevated) is more diagnostic.

2. Imaging Studies: US and CT scans are diagnostic.

 Acute Diverticulitis

Clinical Picture:

• Rare before 40 years.
• Sigmoid is commonly affected.

investigation:

• Diagnosis relies on clinical presentation.
• CT scan is a diagnostic.
• Gastrograffin enema may be helpful.

Acute Intestinal Obstruction (refer to lecture on Intestinal Obstruction)

clinical picture:

• The four cardinal symptoms of bowel obstruction are pain, vomiting, absolute constipation, and distention.
• Rain is very severe and referred to as epigastrium, umbilical or hypogastrium.
• associated symptoms: fever, dehydration up to hypovolemic shock.

Symptoms according to site and cause of obstruction: In general the higher up the gut, the more severe symptoms.

small bowel obstruction:

causes: Hernia, adhesions, intussusception, cancer & volvulus.

1. Obstruction Proximal Small Intestine:

• Vomiting Very early, frequent and violent, green and bilious.
• Distension is minimal and not an early feature.

2. Obstruction Distal Small Intestine

• Pain is less severe than proximal small bowel obstruction.
• Vomiting and distension delayed.

Large Bowel Obstruction

• causes: volvulus, colon cancer, impacted fecal matter, etc.
• Distension is an early feature except in intussusception.
• Pain less acute, shock and vomiting late.
• Can be due to strangulation of the bowel where tenderness on applying pressure is positive.

Simple Bowel Obstruction

• Colicky abdominal pain.
• Abdominal distension.
• No fever.
• Absolute constipation + vomiting.
• Multiple air-fluid levels on plain X-ray.

diagnosis:

1. CT scan (standard).
2. Plain X-ray.

Strangulated/Bowel Obstruction

• Severe pain not relieved by NG tube.
• May be absent distention.
• Fever and tachycardia.
• Localized tenderness and guarding.
• Leukocytosis.

Vascular Acute Abdomen

1. Mesenteric Ischemia:

types:

• Acute mesenteric ischemia: Usually acute occlusion of the superior mesenteric artery (SMA) by a thrombus or an embolus.
• Chronic mesenteric ischemia: The patient is typically a smoker vasculopathy with severe atherosclerotic vessel disease.

clinical picture:

• The patient is over 50 years, with valvular or atherosclerotic heart disease.
• Arrhythmia or history of myocardial infarction (MI).
• Bleeding per rectum may be the early manifestation.

investigations: CT angiography is diagnostic.

2. Ruptured abdominal aortic aneurysm (AAA).

3. Ischemic colitis: Any inflammation, obstructive, or ischemic process can progress to perforation.

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