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

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

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

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

Types of abdominal pain Visceral Parietal

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

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

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

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

Pathophysiology

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

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

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,

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

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

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)

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.

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

Symptoms & Signs in Acute abdomen

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.

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

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.

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

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)

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

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

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

Investigations

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

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.

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).

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

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

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

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

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

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.

Management

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

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

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.

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

Thank you!