Acute Abdomen

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Abdominal Examination Signs

History

• Danforth sign: Shoulder pain on inspiration → Hemoperitoneum

Inspection

• Cruveilhier sign: Varicose veins at umbilicus → Portal hypertension
• Cullen sign: Periumbilical bruising → Hemoperitoneum
• Grey Turner sign: Local discoloration near umbilicus and flanks → Acute pancreatitis
• Ransohoff sign: Yellow discoloration of umbilical region → Ruptured common bile duct

Palpation

• Aaron sign: Pain in epigastrium or anterior chest with firm pressure at McBurney point → Acute appendicitis
• Bassler sign: Sharp pain by compressing appendix between abdominal wall and iliacus → Chronic appendicitis
• Blumberg sign: Rebound tenderness → Peritoneal inflammation
• Carnett sign: Loss of abdominal tenderness when muscles contract → Intrabdominal source of abdominal pain
• Chandelier sign: Extreme pelvic pain with cervical movement → Pelvic inflammatory disease
• Courvoisier sign: Palpable gallbladder when jaundiced → Periampullary mass
• Fothergill sign: Abdominal wall mass palpable with rectus contraction → Rectus muscle hematoma
• Iliopsoas sign: Pain on raising leg against resistance → Retrocecal acute appendicitis
• Murphy sign: Pain with inspiration while pressing on right upper abdomen → Acute cholecystitis
• Obturator sign: Pain with flexion and external rotation of right thigh → Pelvic abscess or appendicitis
• Rovsing sign: Pain in McBurney point on left-sided palpation → Acute appendicitis
• ten Horn sign: Pain caused by gentle traction of right testicle → Acute appendicitis

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ACUTE ABDOMEN

Introduction

• Acute abdomen refers to signs and symptoms of abdominal pain and tenderness.
• Often indicates an underlying surgical problem requiring prompt diagnosis and treatment.
• History and physical examination remain crucial, complemented by laboratory and radiologic studies.
• Non-surgical conditions can also present as an acute abdomen.

Epidemiology

• Age, gender, and surgical history affect the differential diagnosis.
  • Young patients: Appendicitis, mesenteric adenitis.
  • Older patients: Biliary tract disease, diverticulitis, intestinal ischemia.

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Anatomy and Physiology

Types of Abdominal Pain

1. Visceral Pain
   • Vague and poorly localized.
   • Localized to epigastrium, periumbilical region, or lower abdomen.
   • Originates from foregut, midgut, or hindgut.
   • Usually due to distention of a hollow organ.
2. Parietal Pain
   • Sharp and well-localized.
   • Corresponds to nerve roots supplying the peritoneum.
   • Due to peritoneal irritation.
3. Referred Pain
   • Perceived at a distant site from the source.
   • Common patterns:
     • Left Shoulder: Heart, left hemidiaphragm, spleen, tail of pancreas.
     • Right Shoulder: Gallbladder, liver, right hemidiaphragm.
     • Scrotum/Testicles: Ureter issues.

Peritoneal Response to Insult

• Introduction of bacteria or contents into peritoneal cavity leads to:
  • Fluid outpouring from peritoneal surfaces.
  • Increased blood flow and permeability.
  • Formation of a fibrinous exudate.
• Results in:
  • Loss of intestinal motility (ileus).
  • Formation of adhesions to localize inflammation.
  • Localized abscesses: Sharp, localized pain with normal peristalsis.
  • Diffuse processes: Generalized pain with absent bowel sounds.

Peritonitis

• Recognized by severe tenderness, possibly with rebound tenderness and guarding.
• Causes:
  • Infection: Commonly gram-negative organisms or anaerobes.
  • Non-infectious inflammation: e.g., pancreatitis.
• Primary Peritonitis:
  • Children: Caused by Pneumococcus or hemolytic Streptococcal species.
  • Adults on peritoneal dialysis: Commonly E. coli, Klebsiella.

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Differential Diagnosis

Non-Surgical Causes (Box 46.1)

• Endocrine and Metabolic:
  • Uremia
  • Diabetic/Addisonian crisis
  • Acute intermittent porphyria
  • Hyperlipoproteinemia
  • Hereditary Mediterranean fever
• Hematologic:
  • Sickle cell crisis
  • Acute leukemia
• Toxins and Drugs:
  • Lead poisoning
  • Heavy metal poisoning
  • Narcotic withdrawal
  • Black widow spider bites

Surgical Causes (Box 46.2)

• Hemorrhage:
  • Arterial aneurysm rupture
  • Aortoduodenal fistula
  • Bleeding diverticulum
  • Hemorrhagic pancreatitis
  • Ruptured ectopic pregnancy
  • Solid organ trauma
• Infection:
  • Appendicitis
  • Cholecystitis
  • Diverticulitis
  • Hepatic abscess
  • Meckel diverticulitis
  • Psoas abscess
• Ischemia:
  • Mesenteric thrombosis/embolism
  • Ischemic colitis
  • Strangulated hernia
  • Ovarian/Testicular torsion
• Obstruction:
  • Small bowel obstruction
  • Incarcerated hernias
  • Intussusception
  • Inflammatory bowel disease
  • Volvulus (Sigmoid/Cecal)
• Perforation:
  • Gastrointestinal ulcer
  • Perforated diverticulum
  • Boerhaave syndrome

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History

Importance of Detailed History

• Essential for accurate differential diagnosis.
• Focus on:
  • Onset and nature of pain.
  • Associated symptoms: Nausea, vomiting, anorexia.
  • Symptom sequence: Did symptoms begin before or after the pain?
  • Progression of pain.

Pain Characteristics

• Localization:
  • One finger point: Localized, parietal pain.
  • Hand over area: Diffuse, visceral pain.
• Intensity and Severity:
  • Sudden, severe pain: Suggests perforation or ischemia.
  • Gradual worsening: Suggests inflammation (e.g., cholecystitis).
• Pattern:
  • Progressive vs. Intermittent:
    • Infections: Progressive worsening.
    • Colicky pain: Obstruction or biliary colic.

Location and Radiation

• Solid Organs:
  • Pain in corresponding abdominal quadrant.
• Small Bowel:
  • Periumbilical pain.
• Colon:
  • Pain between umbilicus and pubic symphysis.
• Appendicitis:
  • Starts as diffuse periumbilical, shifts to right lower quadrant at McBurney's point.
• Referred Pain Examples:
  • Liver inflammation: Right shoulder pain.
  • Genitourinary issues: Flank pain radiating to scrotum/labia.

Aggravating and Alleviating Factors

• Eating:
  • Worsens pain in obstruction, biliary colic, pancreatitis.
  • May relieve pain in peptic ulcer disease.
• Movement:
  • Peritonitis: Pain worsens with movement; patients may flex knees to reduce pain.

Associated Symptoms

• Nausea and Vomiting:
  • May result from severe pain or obstruction.
  • Vomiting before pain: Often non-surgical causes.
  • Pain before vomiting: Suggests surgical acute abdomen.
• Bowel Habits:
  • Constipation/Obstipation:
    • May indicate obstruction.
    • Absence of flatus/bowel movements suggests complete obstruction.
  • Diarrhea:
    • Associated with infectious enteritis, inflammatory bowel disease.
    • Bloody diarrhea may indicate colonic ischemia.

Past Medical and Surgical History

• Previous Illnesses:
  • Similar past pain (e.g., renal stones) can guide diagnosis.
• Prior Surgeries:
  • Appendectomy, cholecystectomy narrow differential diagnosis.
• Abdominal Scars:
  • Indicate prior procedures affecting current condition.

Medications and Substance Use

• Medications:
  • Narcotics:
    • May cause obstipation, mask pain, alter mental status.
    • Can cause sphincter of Oddi spasm, worsening biliary/pancreatic pain.
  • NSAIDs:
    • Associated with gastric inflammation and perforation.
  • Steroids:
    • Reduce inflammatory response, masking symptoms.
  • Immunosuppressants:
    • Increase infection risk, blunt symptoms.
  • Anticoagulants:
    • Risk of bleeding, complicate surgery.
• Recreational Drugs:
  • Cocaine, methamphetamines:
    • Cause vasospasm, leading to cardiac or intestinal ischemia, severe hypertension.

Special Considerations in Women

• Gynecologic History is crucial.
• Conditions to consider:
  • Ectopic pregnancy
  • Pelvic inflammatory disease
  • Mittelschmerz (ovulation pain)
  • Endometriosis
• Advanced Imaging:
  • MRI and CT scans improve diagnostic accuracy in women.

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Summary

• Acute abdomen requires prompt and accurate evaluation.
• History and physical examination are the cornerstones of diagnosis.
• Consider both surgical and non-surgical causes.
• Imaging studies aid but do not replace clinical assessment.
• Special populations (e.g., women, elderly, immunocompromised) may present differently and require tailored evaluation.

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Physical Examination

Importance

• Essential step in evaluating the acute abdomen.
• Provides valuable information to guide diagnosis and therapy.
• Cannot be replaced by imaging studies.

Steps of Physical Examination

1. General Inspection
   • Assess overall severity upon entering the room.
   • Look for signs like diaphoresis, pallor, dyspnea, and decreased alertness.
   • Observe patient's movement:
     • Peritoneal inflammation: Patient remains still to minimize pain.
     • Non-peritoneal pain: Patient may fidget to find comfort.
2. Inspection of the Abdomen
   • Examine contour and skin.
     • Distension may indicate:
       • Intestinal obstruction
       • Ascites
       • Masses
   • Identify surgical scars and correlate with history.
   • Look for skin abnormalities:
     • Erythema, blistering: Suggest soft tissue infections.
     • Ecchymosis: May indicate necrotizing infections or trauma.
3. Auscultation
   • Perform before percussion or palpation.
   • Listen for vascular bruits:
     • May indicate arterial stenosis or arteriovenous fistulas.
   • Bowel sounds:
     • Ileus: Decreased or absent sounds.
     • Mechanical obstruction: High-pitched, tinkling sounds.
   • Note: Bowel sounds have low sensitivity; correlate with history and other findings.
4. Percussion
   • Assess for organ size and presence of air or fluid.
   • Dullness in right upper quadrant:
     • Identifies the liver; estimate size.
   • Localized dullness:
     • May indicate an intraabdominal mass.
   • Tympany (hyperresonance):
     • Suggests gas-filled structures.
     • Tympany over the liver area may indicate free intraperitoneal air.
   • Fluid wave test:
     • Suggests ascites.
   • Detecting Peritonitis:
     • Percussion tenderness: Severe pain upon percussion.
     • Jostling maneuvers:
       • Percussing flank or heel elicits pain.
     • More reliable than rebound tenderness.
5. Palpation
   • Most informative part of the exam.
   • Technique:
     • Begin with superficial palpation away from the pain.
       • Assess for anterior masses or fluid collections.
     • Proceed to deep palpation.
       • Assess for intraabdominal pain, masses, organ enlargement.
   • Findings:
     • Diffuse tenderness: Suggests extensive inflammation.
     • Localized tenderness: Helps identify the source of pain.
     • Use quadrant location to narrow differential diagnosis.

Guarding

• Voluntary Guarding:
  • Patient tenses muscles anticipating pain.
  • To reduce:
    • Have patient lie supine with knees bent.
    • Instruct to take deep breaths during palpation.
• Involuntary Guarding:
  • Muscle rigidity despite relaxation techniques.
  • Sign of peritonitis.

Special Signs and Maneuvers

• Murphy's Sign:
  • Assesses for acute cholecystitis.
  • Technique:
    • Deep palpation under right rib cage during inspiration.
    • Positive if inspiration stops due to pain.
• Psoas Sign:
  • Suggests appendicitis.
  • Pain on extension of the right hip.
• Obturator Sign:
  • Suggests appendicitis.
  • Pain on internal rotation of a flexed right thigh.
• Rovsing's Sign:
  • Pain in right lower quadrant when pressing on the left side.
  • Indicates right-sided peritoneal irritation.

Additional Examinations

• Digital Rectal Exam:
  • Checks for bleeding, masses, obstruction.
• Pelvic Exam (in women):
  • Identifies gynecologic sources of pain.
  • Important as some women with suspected appendicitis may have gynecologic pathology.

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Laboratory Studies

Purpose

• Narrow down the differential diagnosis.
• Identify infection, bleeding, organ dysfunction, or metabolic disturbances.

Complete Blood Count (CBC)

• White Blood Cell (WBC) Count:
  • Elevated or decreased in acute abdomen.
  • Left shift (increased immature cells) indicates infection.
• Hemoglobin and Hematocrit (H&H):
  • Low levels suggest bleeding.
  • High levels may indicate dehydration.

Complete Metabolic Panel (CMP)

• Electrolytes:
  • Sodium, Potassium, Calcium.
  • Abnormalities may indicate fluid loss or endocrine disorders.
• Renal Function Tests:
  • Blood Urea Nitrogen (BUN), Creatinine.
• Liver Function Tests (LFTs):
  • Elevated enzymes suggest hepatic or biliary issues.
  • Consider viral hepatitis panels if cause is unclear.
• Amylase and Lipase:
  • Elevated in pancreatitis.

Arterial Blood Gas (ABG) and Lactate

• Lactic acidosis:
  • Indicates hypoperfusion.
  • Raises concern for mesenteric ischemia.

Urine Studies

• Urinalysis:
  • Bacteria, WBCs, leukocyte esterase: Indicates urinary tract infection.
  • Red blood cells (RBCs): May suggest kidney stones or glomerular disease.
  • Casts: Indicate renal pathology.
• Pregnancy Test:
  • Urine hCG in women of childbearing age to rule out pregnancy complications.

Additional Tests (as needed)

• Stool Studies:
  • For patients with diarrhea.
  • Test for pathogens, ova, parasites, and Clostridium difficile toxin.
• HELLP Syndrome Assessment:
  • In pregnant women with:
    • Right upper quadrant pain
    • Elevated liver enzymes
    • Low platelets
  • Requires urgent diagnosis and treatment.

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Diagnostic Imaging

General Considerations

• Use after forming a working differential diagnosis.
• Choose the most appropriate modality to minimize costs and radiation exposure.

Ultrasound (US)

• Advantages:
  • Non-invasive, no radiation, cost-effective.
• Best for:
  • Right upper quadrant pain:
    • Evaluates gallbladder for:
      • Gallstones
      • Wall thickening
      • Pericholecystic fluid
  • Appendicitis in children and pregnant women.
  • Gynecologic issues:
    • Transvaginal US preferred over transabdominal.
• Limitations:
  • Affected by patient's body habitus, bowel gas, and operator skill.

Plain Radiographs (X-rays)

• Uses:
  • Detecting free air under diaphragm (suggests perforation).
  • Evaluating for bowel obstruction:
    • Air-fluid levels
    • Dilated loops of bowel
  • Identifying volvulus:
    • Cecal volvulus: "Comma-shaped" appearance.
    • Sigmoid volvulus: "Coffee bean" sign.
• Limitations:
  • Low diagnostic accuracy for some conditions.
  • Less informative than CT scans.

Computed Tomography (CT)

• Primary tool for detailed abdominal imaging.
• Advantages:
  • Comprehensive view of abdomen and pelvis.
  • Less dependent on operator skill.
• Technique considerations:
  • Without contrast: For kidney stones.
  • With oral and IV contrast: For bowel obstruction, appendicitis.
• Diagnostic Accuracy:
  • High sensitivity and specificity for many conditions.
  • Reduces negative surgery rates (e.g., appendectomy).
• Impact on Management:
  • Can significantly change diagnosis and treatment plans.
  • Especially useful in elderly patients.

Low-Dose CT

• Purpose: Reduce radiation exposure.
• Findings:
  • Comparable diagnostic accuracy to standard-dose CT.
  • Consider in children and patients needing frequent imaging.

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Diagnostic Laparoscopy

Role

• Used when other diagnostic methods are inconclusive.
• Offers direct visualization and can be therapeutic.

Indications

• Persistent uncertainty after imaging and laboratory tests.
• Select cases where minimally invasive exploration is appropriate.

Safety and Efficacy

• Safe in elderly patients with no increase in morbidity or mortality.
• Can be performed in patients with sepsis if precautions are taken:
  • Maintain intraabdominal pressure below 12 mm Hg.
  • Administer appropriate antibiotics before the procedure.

Contraindications

• Absolute:
  • Irreversible sepsis.
  • Surgeon's lack of experience with laparoscopy.
• Relative:
  • Severely dilated bowel may hinder visualization.

Advantages

• Allows for immediate diagnosis and treatment.
• Minimally invasive with potential for faster recovery.

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Intraabdominal Pressure Monitoring

Importance

• Increased intraabdominal pressure can cause or result from an acute abdomen.
• Abdominal compartment syndrome (ACS):
  • Intraabdominal pressure >20 mm Hg.
  • Life-threatening due to:
    • Decreased venous return
    • Reduced tidal volumes
    • Visceral ischemia

Normal Intraabdominal Pressure

• Ranges between 5–7 mm Hg.
• Factors that can artificially increase pressure:
  • Abdominal obesity
  • Accessory muscle respiration
  • Upright positioning

Measurement

• Bladder catheter pressure monitoring is used.
• WSACS Recommendations:
  • Instill 25 mL of saline into the bladder.
  • Patient supine; transducer zeroed at the midaxillary line.
  • Measure pressure at end of expiration.

Grading of Intraabdominal Hypertension (Table 46.2)

• Grade I: 12–15 mm Hg
• Grade II: 16–20 mm Hg
• Grade III: 21–25 mm Hg
• Grade IV: >25 mm Hg

Treatment

• Primary ACS (due to intraabdominal disease):
  • Decompressive laparotomy.
  • Address the underlying cause.
  • May require temporary abdominal closure.
• Secondary ACS (due to extra-abdominal cause):
  • Initial medical management if no organ damage:
    • Correct fluid balance.
    • Evacuate intraluminal contents.
    • Relax abdominal wall with sedation and pain control.
    • Drain peritoneal fluid.
  • Low threshold for surgery if condition worsens.

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Differential Diagnosis

Importance

• Should be continuously refined throughout evaluation.
• Guides selection of laboratory and imaging tests.
• Aim to narrow down to one or two potential diagnoses.

Determining Need for Surgical Intervention

• Identify if the cause requires urgent surgery.
• Septic patients need immediate management, even without a specific diagnosis.

Findings Suggesting Surgery is Needed (Box 46.5)

Physical Exam Findings

• Involuntary guarding
• Rebound tenderness
• Pain out of proportion to exam
• Unexplained systemic sepsis
• Penetrating abdominal trauma
• Intraabdominal pressure >25 mm Hg

Laboratory Findings

• Anemia requiring >4 units of blood transfusion.
• Evidence of hypoperfusion:
  • Acidosis
  • Rising creatinine
  • Elevated liver function tests

Diagnostic Imaging Findings

• Pneumoperitoneum (free air)
• Progressive dilation of a stationary loop of intestine.
• Evidence of bowel perforation.
• Fat stranding or thickened bowel wall with sepsis.
• Bowel wall pneumatosis

Diagnostic Peritoneal Lavage Findings

• Presence of feculent or particulate matter.
• >250 WBCs/mL.
• >300,000 RBCs/mL.
• Peritoneal bilirubin > serum bilirubin.
• Peritoneal creatinine > serum creatinine.

Management

• Avoid delays in surgical intervention.
• Once diagnosed, proceed without unnecessary tests.
• Continue resuscitation en route to the OR.
• Laparoscopy can guide incision placement if diagnosis is unclear.

Medical Causes

• Require close observation and serial examinations.
• Monitor for any deterioration or new symptoms.
• Examinations should be consistent, preferably by the same clinician.

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Special Patient Populations

Pregnancy

Considerations

• Physiological changes can mask or mimic symptoms.
• Nausea and vomiting may be attributed to pregnancy.
• Radiation exposure concerns limit imaging options.

Common Surgical Conditions

• Appendicitis
  • Most common non-obstetric surgical emergency.
  • Presentation may shift due to uterine enlargement.
  • MRI is recommended when ultrasound is inconclusive.
• Biliary Disease
  • Increased risk due to bile stasis.
  • Ultrasound is diagnostic.
  • Surgery preferred in the second trimester.

• Bowel Obstruction

  • May be confused with pregnancy symptoms.
  • Peritoneal signs are not normal and warrant evaluation.

  

Surgical Considerations

• Anesthesia
  • Treat all pregnant patients as having a full stomach.
  • Use rapid sequence induction.
• Fetal Monitoring
  • Monitor fetal heart tones before and after surgery.
  • Continuous monitoring if fetus is viable.
• Laparoscopy
  • Safe during pregnancy.
  • Use open (Hasson) technique to avoid uterine injury.

Pediatrics

Considerations

• Children may be poor historians; observation is key.
• Assess for reluctance to move, which may indicate peritonitis.

Common Causes

• Appendicitis
  • Most common surgical cause.
  • Similar presentation to adults in older children.
  • Younger children may present with vague symptoms.
• Intussusception
  • Consider in children <3 years old.
  • Symptoms: Abdominal pain, currant jelly stools, vomiting.

• Other Causes

  • Gastroenteritis
  • Meckel diverticulitis
  • C. difficile colitis

  

Diagnostic Approach

• Imaging is crucial due to examination challenges.
• Ultrasound preferred, especially in experienced centers.
• Limit radiation exposure; minimize CT use.

Critical Illness

Challenges

• Diagnosis is complicated by sedation, organ failure, and subtle signs.
• Blunted inflammatory responses due to medications.

Approach

• Use imaging judiciously; balance risks of transport vs. benefits.
• Consider bedside diagnostic laparoscopy if feasible.
• Be prepared for nontherapeutic laparotomy risks.

Immunocompromised Patients

Considerations

• Transplant patients may not show typical inflammatory signs.
• Presentations may be minimal or delayed.

Common Causes

• Biliary disease
• Gastrointestinal perforation
• Complicated diverticulitis
• Small bowel obstruction
• Appendicitis

Diagnostic Approach

• Check immunosuppressive drug levels.
• Be vigilant for atypical infections like Cytomegalovirus, fungal infections, TB.
• Maintain a high index of suspicion; low threshold for surgery.

Cardiac Patients

Considerations

• Abdominal issues may be masked by cardiac symptoms.
• Risk factors include:
  • Lengthy cardiopulmonary bypass.
  • Valve surgery.
  • Need for intraaortic balloon pump.

Common Complications

• Ileus
• Pancreatitis
• Mesenteric ischemia
• Bowel obstruction
• Cholecystitis
• Perforation

Risk Factors (Box 46.6)

• Age >70
• Low cardiac output
• Peripheral vascular disease
• Reoperation for bleeding
• Renal failure
• Prolonged ventilation
• Sepsis
• Liver failure

Morbidly Obese

Considerations

• Classic signs may be masked.
• Physical exam findings are challenging to interpret.
• Symptoms may be vague.

Diagnostic Approach

• Rely on labs, vital signs, imaging, and subtle symptoms.
• Imaging may be limited by equipment constraints.
• Early laparoscopy is often necessary.

Concerning CT Findings (Box 46.7)

• Dilated alimentary limb
• Dilated excluded stomach
• Mesenteric swirl sign
• Transition points between dilated and non-dilated bowel

Elderly

Considerations

• Often experience delays due to biases.
• Age should not deter appropriate surgical intervention.
• Aggressive resuscitation improves outcomes.

Common Indications for Surgery

• Cholecystitis
• Bowel obstruction
• Perforated viscus
• Diverticulitis
• Appendicitis
• Mesenteric ischemia

Advanced Disease

Considerations

• Surgery in advanced cancer patients carries high risks.
• High mortality and low chance of prolonging survival.

Management

• Engage in frank discussions about goals of care.
• Consider quality of life and patient wishes.
• Recognize that emergency surgery often indicates a turning point.

Common Causes in Oncologic Patients

• Bowel obstruction
• Perforation
• Infection or abscess
• Ischemia
• Complications from cancer treatment

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Summary

• Evaluation of an acute abdomen requires a thorough physical exam, appropriate laboratory tests, and judicious use of imaging.
• Intraabdominal pressure monitoring is critical in patients at risk for abdominal compartment syndrome.
• Formulating a continuous and refined differential diagnosis is essential.
• Special considerations are necessary for specific patient populations.
• Early recognition and prompt intervention improve patient outcomes.