1. Acute abdomen
Prof. M K Alam M S ; F R C S

2. Learning objectives Definition
Anatomy and physiology of abdominal pain.
Pathophysiology of common causes of acute abdomen.
Symptoms and signs of acute abdomen in relation to the underlying pathology
Laboratory and imaging investigations
Initial and definitive management

3. Definition
A clinical presentation of abdominal pain and tenderness, that often requires emergency surgical therapy.

4. Spectrum of surgical & gynaecological conditions.
Trivial to life-threatening conditions.
50% of general surgical emergencies.
Some non-surgical or non intra-abdominal diseases.
30 days mortality: 4% among patients with abdominal pain
Every attempt to make a correct diagnosis.
Appropriate therapy

5. The primary symptom: Abdominal pain
Types of abdominal pain:
Visceral
Parietal

6. Visceral pain Visceral peritoneum invests abdominal viscera
Shares its nerve supply (autonomic) with the viscera
Visceral pain mediated through sympathetic ANS
Visceral peritoneum insensitive to mechanical, thermal or chemical stimuli
Sensitive to distension, traction on mesentery ,visceral muscle spasm & ischemia
Visceral pain- dull & deep seated
Vague, poorly localized
Localized to the area of development
Foregut organs- pain localized to epigastrium
Midgut organs-, pain localized to periumbilical
Hindgut organs- pain localized to hypogastrium

7. Parietal pain Originate from the irritation of parietal peritoneum
Parietal peritoneum- somatic nerve
Sensitive to mechanical, thermal & chemical stimulation
When parietal peritoneum irritated- reflex contraction of corresponding muscle segment (guarding)
Pain sharp or knife like
Well localized to the affected area

8. Referred pain
Definition: Pain perceived at a site distant from the source of stimulus.
Common examples of referred pain:
Right shoulder- Gall bladder
Left shoulder- Heart, tail of pancreas, spleen (Kehr's sign)
Scrotum and testis- ureter

9. Pain locations (Great degree of overlap)
Right hypochondrium.- gallbladder
Left hypochondrium.- pancreas
Epigastrium.- Stomach and duodenum
Lumber- kidney
Umbilical- small bowel, caecum, retroperitoneal
Right iliac fossa- Appendix, caecum
Left iliac fossa- Sigmoid colon
Hypogastrium- Colon, urinary bladder, adenexae

11. Pathogenesis

12. Surgical Causes of Acute Abdominal
Inflammation: Appendicitis, cholecystitis, pancreatitis
Perforation- Perforated duodenal ulcer, perforated diverticulum, perforated appendix, perforated bowel
Obstruction- Small bowel adhesions, obstructed hernia, sigmoid volvulus, neoplasms
Ischemia- Mesenteric ischemia (thrombosis/ embolism) strangulated hernia
Hemorrhage- Ruptured ectopic pregnancy, ruptured aneurysms, solid organ trauma

13. Nonsurgical Causes of Acute Abdomen
Diabetic crisis
Uremia
Hereditary Mediterranean fever
Sickle cell crisis
Acute leukemia

14. Common causes of acute abdominal pain
Adults
Non specific -35%
Acute appendicitis- 30%
Ac. Chole./ biliary colic -10%
PUD- 5%
Small bowel obstruction - 5%
Gynaecological disorders -5%
Ac. Pancreatitis -2%
Renal/ ureteric colic- 2%
Malignant disease - 2%
Acute diverticulitis -2%
Misc. - 2%
Children
Acute appendicitis
UTI
Mesenteric adenitis
Gastroenteritis

15. Inflammation Types: Infective or Non-infective
Reactive hyperaemia- arteriolar/ capillary dilatation
Exudation of fluid- increased vessel permeability
Migration of leucocytes from vessels
Clinical effect: depends on severity, duration, organ involved
Abdominal pain, pyrexia, tachycardia, tenderness, guarding

16. Pathogenesis of Acute appendicitis
Most common general surgical emergency
Derived from the midgut
Obstruction of the lumen (fecalith, lymphoid hyperplasia, vegetable matter or seeds, parasites)
Obstruction contributes to bacterial overgrowth,

17. Pathogenesis of Acute appendicitis
Intraluminal distention.
Distention produces the visceral pain- periumbilical pain.
Promote a localized inflammatory process.
May progress to gangrene and perforation.
Inflammation of the adjacent peritoneum- localized pain RIF.
Perforation usually after 48 hours from the onset.

18. Peritonitis
Introduction of bacteria or irritating chemicals into the peritoneal cavity by extension of inflammation or perforation of viscus
Peritoneal inflammation
Localized inflammation (appendicitis)- sharply localized pain, normal bowel sounds
Generalized peritonitis (perforated viscus) -generalized abdominal pain, quiet abdomen

19. Types of peritonitis Primary peritonitis: Uncommon.
Children: Pneumococcus or hemolytic Streptococcus.
Adults: Peritoneal dialysis(gram +ve cocci).,
Ascites and cirrhosis(Escherichia coli and Klebsiella)
Secondary peritonitis: Common, secondary to inflammatory insult from within abdomen, most gram-negative infections (enteric organisms or anaerobes). Example- perf. appendicitis
Noninfectious : Pancreatitis (chemical peritonitis)

20. Obstruction
Impedance to normal flow through hollow viscus
Causes: 1. Lesion within lumen- stone, FB, worms, stool Lesion of the wall- neoplasms, stricture Extrinsic compression-adhesions, hernia
Viscus contracts to overcome obstruction (colicky pain)
Proximally- increased intraluminal pressure, dilatation, back pressure effect- hydronephrosis, bowel ischemia (infarction, perforation)

21. Aetiology of obstruction

22. Small bowel obstruction
Post-operative adhesion- most common
Hernia, tumour, Crohn’s disease- other causes
Early- the intestinal contraction increases to propel contents past the obstructing point (colicky pain)
Later- the intestine becomes fatigued and dilates, contractions becoming less intense.
Bowel dilates, water and electrolytes accumulate in lumen and in the bowel wall.
Massive third-space fluid loss: dehydration and hypovolemia.
Intraluminal pressure increases in the bowel, a decrease in mucosal blood flow occurs.

23. Ischemia Occlusion of arterial supply or venous drainage
Ischaemic coagulative necrosis (infarct)
Inflammatory response along the margin
Abdominal pain due to intestinal ischemia- common
Other causes of ischemic abdominal pain- spleen, kidney, liver, pancreas and ovaries

24. Mesenteric Ischemia Arterial: embolism, thrombosis Venous: thrombosis
Superior mesenteric vessel distribution- most common
Intestinal mucosal sloughing- within 3 hours of onset
Full-thickness intestinal infarction by 6 hours

25. Symptoms & Signs in Acute abdomen

26. Clinical assessment Good history Appropriate examination
Full history and thorough examination (not always possible)
Rapid evaluation
Resuscitation

27. Main symptom- Abdominal pain
Site: finger vs hand, most valuable indicator to underlying diagnosis (4 quadrants, 9 regions)
Onset: Sudden- perforation, ischemia, biliary colic. Gradual- inflammation
Severity: Visual analogue scale. Colicky pain- severe Inflammatory- initially mild, progress with time
Progress: worsens over several hours- inflammation or infection
Nature: Spasmodic: Biliary / ureteric colic. Constant- worse by movement- inflammatory
Radiation and shift: cholecystitis, appendicitis
Exacerbating factors: food worsen pain of bowel obstruction
Relieving factors: food relieves pain- non-perforated PUD, gastritis.

29. Associated symptoms
Vomiting: pain presents first in acute surgical abdomen. Vomiting precede significant abdominal pain in medical conditions. Constipation or obstipation can be a result of either mechanical obstruction or decreased peristalsis (ileus).
Diarrhea is associated with several medical causes of acute abdomen, including infectious enteritis, inflammatory bowel disease (IBD), and parasitic contamination
Bloody diarrhea- IBD, Colonic ischemia

30. EXAMINATION Inspection of the patient
Ischemic bowel and ureteral and biliary colic, typically cause patients to continually shift and fidget in bed while trying to find a position that lessens their discomfort.
Patients with peritonitis lie very still in the bed during the evaluation and often maintain flexion of their knees and hips to reduce tension on the anterior abdominal wall.

31. General Examination Vital signs- pulse, BP, temperature, RR Anemia
Jaundice
Sweating
Dehydration

32. Inspection of the abdomen
Distension: Obstruction
Restricted mobility- ?peritonitis
Scars of previous surgery- ?adhesion
Hernias- cough impulse, reducible/irreducible
Mass effect, distended veins
Visible peristalsis
Ecchymosis ? Acute pancreatitis (Cullen’s, Grey Turner’s sign)

33. Palpation of the abdomen
Gently / deep , away from the area of pain.
Severity/ location of tenderness- localized/ generalized
Involuntary guarding
Organomegaly, any mass
Murphy’s sign, Rovsing’s sign,
Rebound tenderness (Blumberg’s sign)

34. Percussion of the abdomen
Hyperresonance :distended bowel loops
Dullness due to organomegaly or mass
Liver dullness lost- free intra-abdominal air is suspected.
Shifting dullness- fluid
Tenderness (tap tenderness)

35. Auscultation of the abdomen
Quiet abdomen- ileus
Hyperactive bowel sounds- bowel obstruction, gastroenteritis
Mechanical bowel obstruction- high-pitched “tinkling” sounds that come in rushes and are associated with pain
Bruits- high-grade arterial stenosis

36. Digital rectal examination
Routine ? selective
Check for mass, tenderness, or intraluminal blood
Pelvic examination in female

37. Part 2

38. Investigations

39. Routine laboratory investigations
Hematology: WBC / differential count, hemoglobin, platelets, RBC, sickle test
Electrolytes, urea, creatinine, C-reactive protein, ca
Amylase, lipase
LFTs: Bilirubin (T & D), alkaline phosphatase, aminotransferase,
Serum lactate & arterial blood gas
Urine analysis
Urine human chorionic gonadotropin
Stool for parasites

40. Lactate levels and arterial blood gas: intestinal ischemia or infarction.
Urinalysis: bacterial cystitis, pyelonephritis, diabetes.
Urinary human chorionic gonadotropin: suggest pregnancy as a factor in the patient's presentation or aid in decision making regarding therapy.
Stool: occult blood, parasite, Cl. Difficile (toxin & culture).

41. Plain radiographs
Upright chest radiographs – free gas under the dome of diaphragm Perforated duodenal ulcer-75%
Lateral decubitus abdominal radiographs- pneumoperitoneum in patients who cannot stand

43. Plain x-ray abdomen Limited usefulness
Calcifications: renal stones 90%, chronic pancreatic, aortic aneurysms, fecalith
Supine and upright films: distension, fluid levels, gas distribution (small vs large bowel), volvulus of sigmoid colon/ cecum

47. Contrast X-ray Water soluble contrast
Oral/ nasogastric- small bowel follow through
Less specific
Obstruction/ perforation (rarely used)
Contrast not reached caecum in 4 hours- complete obstruction, needs surgery

49. Abdominal ultrasonography
Gallbladder: stone, wall thickness, fluid around gallbladder, diameter of bile ducts
Liver: abscess, other masses
Pelvis: Ovarian, adnexal & uterine pathologies
Free fluid in peritoneum
Limited evaluation of pancreas
Limitations: bowel gas, person dependent, difficult to interpret for most surgeons

51. Liver abscess (US)

52. CT abdomen Widely available Easier to interpret by surgeons
Imaging modality of choice in acute abdomen, following plain abdominal radiographs.
Accuracy and utility of CT abdomen and pelvis in acute abdominal pain is well established.
Most common causes of acute abdomen are readily identified by CT
Highly accurate in acute appendicitis, mechanical bowel obstruction, intestinal ischemia

53. Liver abscess Paracolic abscess

54. SMA Thrombosis

55. DIAGNOSTIC LAPAROSCOPY
Ability to diagnose and treat a number of the conditions causing an acute abdomen
High sensitivity and specificity
Decreased morbidity and mortality, decreased length of stay, and decreased overall hospital costs
Advances in equipment and greater availability

56. DIFFERENTIAL DIAGNOSIS
Differential diagnosis of acute abdominal pain is extensive.
Comprehensive knowledge of the medical and surgical conditions that create acute abdominal pain
Mild, self-limited illness to the rapidly progressive and fatal
Evaluated immediately upon presentation and reassessed at frequent intervals.
Many acute abdomen require surgical intervention but some abdominal pain are medical in aetiology.

58. Management

59. Preoperative preparation
Fluid and electrolyte abnormalities corrected
Antibiotic infusions for the bacteria common in acute abdominal emergencies (gram-negative enteric organisms and anaerobes)
Nasogastric tube to decrease the likelihood of vomiting and aspiration
Foley catheter- to assess urine output -0.5 mL/kg/hour
Blood typed and cross matched for operation

60. Preoperative preparation
Frequent evaluation of the patient
Stabilization of co-morbid conditions
Surgical vs non- surgical management
Consent for surgery

61. Surgical intervention
Excision: Appendectomy, cholecystectomy, tumors.
Resection and anastomosis: Bowel tumors, gangrenous bowel,
Relieve obstruction: Hernia, division of adhesion.
Repair of perforation: Perforated DU, stomach, ileum
Drainage: Appendicular abscess.
Bowel diversion: Colostomy.

62. Non-surgical intervention
Conservative management: NPO, IV fluid, antibiotics Example: Appendicular mass
Radiological intervention: PCD (liver abscess, appendicular abscess), placing stents in obstructed bowel ( carcinoma colon).
Endoscopic intervention: Bile duct decompression. Example : ERCP in cholangitis

63. Common Causes of Acute Abdomen

64. Acute appendicitis Most common general surgical emergency
Derived from the midgut
Obstruction of the lumen (fecalith, lymphoid hyperplasia, vegetable matter or seeds, parasites) is the major cause of acute appendicitis.
Obstruction contributes to bacterial overgrowth,

65. Acute appendicitis
Continued secretion of mucus leads to intraluminal distention.
Distention produces the visceral pain sensation as periumbilical pain.
Promote a localized inflammatory process
May progress to gangrene and perforation.
Inflammation of the adjacent peritoneum- localized pain in the right lower quadrant.
Perforation usually occurs after 48 hours from the onset of symptoms

66. Acute appendicitis- symptoms
Typical periumbilical pain (activation of visceral afferent neurons) followed by anorexia and nausea.
Pain localizes to the right lower quadrant (inflammatory process progresses to involve the adjacent parietal peritoneum)
Migratory pain is the most reliable symptom.

67. Acute appendicitis- signs
Ill looking patient, low grade fever
Coughing (Dunphy's sign), may cause increased pain
Tenderness at McBurney’s point, involuntary guarding
Site of tenderness may vary depending on the position of the appendix.
Pain in the right lower quadrant during palpation of the left lower quadrant (Rovsing's sign)
Perforated appendicitis: more severe and diffuse abdominal pain, tenderness and abdominal wall rigidity

68. Acute appendicitis- investigations
Elevated WBC and neutrophil
Normal WBC in 10%
Very high WBC (>20,000/ml)- complicated appendicitis
Urine analysis- exclude urinary system disease
Abdominal x-ray- generally not indicated, ? ureteric calculi, small bowel obstruction, perforated ulcer
Ultrasonography: Appendix of 7 mm or more in anteroposterior diameter, thick-walled, noncompressible luminal structure in cross section (target lesion), the presence of an appendicolith
CT abdomen: appendix > 7mm in diameter, wall thickening, periappendiceal edema or fluid

70. Surgical treatment (Acute appendicitis)
Uncomplicated:
Appendectomy - Laparoscopic vs open surgery
Complicated:
Localized perforation (abscess): percutaneous drainage under CT or ultrasound guidance
Free perforation (peritonitis): laparotomy vs laparoscopic appendectomy

72. Perforated peptic ulcer
5% of peptic ulcers penetrate through the duodenal wall into the peritoneal cavity
Produce chemical peritonitis

73. Clinical features of perforated peptic ulcer
Sudden onset epigastric pain
Fever and tachycardia
Abdominal tenderness, rigidity, rebound tenderness
Absent bowel sound
Free air underneath the diaphragm on an upright chest radiograph.

75. Perforated peptic ulcer- treatment
Fluid resuscitation
Early surgery to close the perforation by laparoscopy or open surgery

76. Small bowel obstruction
Post-operative adhesion- most common
Hernia, tumour, Crohn’s disease- other causes
Early- the intestinal contraction increases to propel contents past the obstructing point (colicky pain)
Later- the intestine becomes fatigued and dilates, contractions becoming less intense.
Bowel dilates, water and electrolytes accumulate in lumen and in the bowel wall.
Massive third-space fluid loss: dehydration and hypovolemia.
Intraluminal pressure increases in the bowel, a decrease in mucosal blood flow occurs.

77. Clinical features
Colicky abdominal pain, nausea, vomiting, abdominal distention, and a failure to pass flatus and feces-obstipation
Examination:
Distended abdomen
Surgical scars/ hernia
Hyperactive bowel sounds
Mild abdominal tenderness

78. Investigations Tests for fluid & electrolytes abnormality
Leukocytosis may be found in patients with strangulation
Plain x-ray abdomen: dilated bowel loops (supine) & multiple air-fluid levels (upright)
Patient in whom the diagnosis is not readily apparent- CT abdomen

79. Treatment Isotonic saline solution such as lactated Ringer's
Antibiotics-prophylactically
Nasogastric suction
Partial intestinal obstruction may be treated conservatively with resuscitation and tube decompression
Operative Management:
Adhesive obstruction- laparotomy & release of adhesions.
Hernia- operative reduction and repair

80. Mesenteric Ischemia
Arterial: embolism, thrombosis
Venous: thrombosis
Superior mesenteric vessel distribution
Intestinal mucosal sloughing within 3 hours
Full-thickness intestinal infarction by 6 hours

81. Symptoms & signs Abdominal pain- sudden onset
Severity- out of proportion to the degree of tenderness
The pain is colicky, most severe in the mid-abdomen.
Associated symptoms- nausea, vomiting, and diarrhea
Physical findings- absent early in the course.
Later- abdominal distention, tenderness, guarding and passage of bloody stools.

82. Investigations Leukocytosis, Acidosis, and
Elevated amylase and creatine kinase- late
CT scanning:
Acute arterial mesenteric ischemia-64 to 82%.
Acute mesenteric venous thrombosis- 90%

84. Mesenteric ischemia- treatment
Fluid resuscitation
Laparotomy
Test for viability of bowel
Resection of infarcted segment
Anticoagulation for SMV thrombosis

86. Conclusion A challenging part of a surgeon's practice.
Careful history and physical examination remain the most important part of the evaluation.
Laboratory investigations and imaging techniques have improved the diagnostic accuracy
Surgeon often make the decision to perform surgery with a good deal of uncertainty
Morbidity and mortality associated with a delay in the treatment demand an expeditious approach

87. Thank you!