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

2. Learning objectives Definition of acute abdomen
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
Acute abdomen: a clinical presentation of abdominal pain and tenderness, that often requires emergency surgical therapy.

4. Some non-surgical or non intra-abdominal diseases, can present with acute abdominal pain.
Every attempt should be made to make a correct diagnosis so that an appropriate therapy is given

5. Types of abdominal pain
Visceral
Parietal

6. Visceral pain Vague, poorly localized Splanchnic nerves
Usually the result of distention of a hollow viscus
Depending on the origin of the affected organ from the primitive foregut, midgut, or hindgut, the pain is localized to epigastrium, periumbilical , or hypogastrium respectively

7. Parietal pain
-Corresponds to the segmental nerve roots (somatic nervous system) innervating the peritoneum.
-Sharper and better localized.

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. Pathophysiology

12. Surgical Acute Abdominal Conditions
Infection- Appendicitis, cholecystitis
Perforation- Perforated duodenal ulcer
Obstruction- Small bowel adhesions, obstructed hernia, sigmoid volvulus
Ischemia- Mesenteric ischemia (thrombosis/ embolism) strangulated hernia
Hemorrhage- Ruptured ectopic pregnancy, ruptured aneurysm, solid organ trauma

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

14. Pathophysiology: 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,

15. Pathophysiology: 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

16. Pathophysiology- peritonitis
Introduction of bacteria or irritating chemicals into the peritoneal cavity cause peritoneal inflammation
A localized inflammation (appendicitis) produce sharply localized pain and normal bowel sounds
A diffuse process (perforated viscus) produces generalized peritonitis causing generalized abdominal pain with a quiet abdomen

17. Types of peritonitis
Secondary peritonitis: more common, secondary to an inflammatory insult from within abdomen, most often gram-negative infections with enteric organisms or anaerobes. Example- appendicitis
Primary peritonitis: uncommon.
Children: Pneumococcus or hemolytic Streptococcus.
Adults: peritoneal dialysis for end-stage renal dis.(gram+ve cocci),
ascites and cirrhosis(Escherichia coli and Klebsiella)
Noninfectious inflammation- pancreatitis (chemical peritonitis)

18. Pathophysiology: 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.

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

20. Symptoms & Signs in Acute abdomen

21. Main symptom- Abdominal pain
Location: finger vs hand
Severity:
Onset: sudden in perforation, ischemia, biliary colic
Progress: develops and worsens over several hours is typical of progressive inflammation or infection such as appendicitis, cholecystitis
Spasmodic: Biliary colic, or genitourinary obstruction
Radiation and shift: cholecystitis, appendicitis
Exacerbating factors: food worsen pain of bowel obstruction
Relieving factors: food relieves pain of non-perforated peptic ulcer disease or gastritis.

22. Associated symptoms
Vomiting likely to precede significant abdominal pain in medical conditions whereas pain presents first in acute surgical abdomen.
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

23. PHYSICAL EXAMINATION (Inspection)
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.

24. Inspection of the abdomen
Distension
Restricted mobility- ?peritonitis
Scars of previous surgery
Hernias
Mass effect
Ecchymosis ? Acute pancreatitis (Cullen’s, Grey Turner’s sign)

25. Palpation of the abdomen
Start gently, away from the area of pain.
Severity and exact location of tenderness- localized/ generalized
Involuntary guarding
Organomegaly, mass
Murphy’s sign, Rovsing’s sign,
Rebound tenderness (Blumberg’s sign)

26. 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
Tenderness

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

28. Digital rectal examination
Performed in all patients with acute abdominal pain
Checking for mass, pelvic pain, or intraluminal blood
Pelvic examination in female

29. Investigations

30. Routine laboratory investigations
Hematology: WBC count, differential count, hemoglobin, platelets, red blood cells
Electrolytes, urea, creatinine
Amylase, lipase
LFTs: Bilirubin (T & D), alkaline phosphatase, aminotransferase,
Serum lactate & arterial blood gas
Urine analysis
Urine human chorionic gonadotropin
Stool for parasites

31. WBC count: confirm infection
Electrolytes, blood urea nitrogen, and creatinine: the effect of vomiting or third-space fluid losses
Serum amylase and lipase- acute pancreatitis, small bowel infarction or duodenal ulcer perforation
Liver function tests: biliary tract disease.

32. 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).

33. 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

35. Plain x-ray abdomen
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

39. 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

41. 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

43. 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

44. 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.

46. Management

47. 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

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

49. 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.

50. Non-surgical intervention
Conservative management: NPO, IV fluid, antibiotics
Radiological intervention: PCD, placing stents in obstructed bowel.
Endoscopic intervention: Bile duct decompression.

51. Thank you!