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 as an acute abdomen. A correct diagnosis so important for an appropriate therapy.

Anatomy and Physiology of Abdominal pain

Types of abdominal pain Visceral Parietal

Visceral pain Vague, poorly localized ( patient directs with full hand) 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 location according to organs (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

Pain location in common acute abdominal conditions Right hypochondrium: Acute cholecystitis, Hepatitis Epigastrium: Acute pancreatitis, Perforated duodenal ulcer Left hypochondrium: Splenic infarction, acute pancreatitis Right lower quadrant: Ac. Appendicitis, Crohn’s disease Ectopic pregnancy, mid-cycle pain- female Left lower quadrant: Diverticulitis Periumbilical: appendicitis (initial), small bowel obstruction Lumber (flank): pyelonephritis, renal colic Hypogastrium: Colonic obstruction

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

Bacterial flora in appendicitis Polymicrobial nature of perforated appendicitis. Escherichia coli, Streptococcus viridans, and Bacteroides and Pseudomonas

Part II

Pathophysiology: Perforated peptic ulcer 5% of peptic ulcers penetrate through the duodenal wall into the peritoneal cavity Most common site: anterior wall of 1st part of the duodenum Produce chemical peritonitis

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

Peritonitis is peritoneal inflammation from any cause. Recognized by severe tenderness , with or without rebound tenderness, and guarding.

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 Full-thickness intestinal infarction by 6 hours

Symptoms & Signs in Acute abdomen

Main symptom- Abdominal pain Location: finger vs hand (visceral) 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

Past medical history: passage of stone(ureteric colic) previous surgery (intestinal obstruction) Gynecologic history: LMP (ectopic pregnancy), mid cycle pain (mittelschmerz) Medications: create acute abdominal conditions or mask their symptoms. NSAID (bleeding, perforation), narcotics (constipation), steroids (mask inflammation)

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

Part III

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 (high level), small bowel infarction or duodenal ulcer perforation (mild to moderate rise) 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).

Imaging studies None of the imaging techniques take the place of a careful history and physical examination.

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.

Part IV

Initial 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

Common Causes of Acute Abdomen

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,

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

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 parietal peritoneum) Migratory pain is the most reliable symptom.

Acute appendicitis- signs Ill looking patient, low grade fever Coughing may cause increased pain (Dunphy's sign) Tenderness at McBurney’s point, involuntary guarding Site of tenderness may vary depending on the position of the appendix. Pain felt 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

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

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

Part V

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

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.

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

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.

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

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

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 obst.-laparotomy & release of adhesions. Hernia- operative reduction and repair

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 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.

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

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

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

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Part VI

Case presentation

Case No. 1 A 19-year old male presents with abdominal pain since last night. He has vomited once early this morning. History Examination Differential diagnosis Investigations Pathophysiology Complications of delayed presentation/ treatment Treatment

History Location: Initially periumbilical, now RIF Severity: started mild, now severe Onset: gradual Progress: worsening Radiation and shift: Initially periumbilical, now RIF Exacerbating factors: none Relieving factors: none Associated symptoms: vomiting once, no anorexia Systemic inquiry, family, social, drug, past history- none

Examination Appearance: Looking ill Temperature: 38.5°C Abdomen: Inspection- flat, moving with respiration, no cough tenderness Palpation- guarding & tenderness in RIF and at McBurney’s point, Rovsing’s sign –ve Percussion- tender RIF Auscultation- diminished bowel sounds Rectal examination not done

Differential diagnosis Children: Meckel’s diverticulitis, intussusception, gastroenteritis, mesenteric lymphadenitis Adults: Crohn’s disease, pyelonephritis, ileo-cecal neoplasm, bowel obstruction Female: Ectopic pregnancy, mid cycle pain, tubo-ovarian pathology, PID

Acute appendicitis

Investigations Leucocytosis with high neutrophil Very high WBC > 20,000 in complicated app. Urinalysis to rule out urinary infection Ultrasonography: Not done. Indicated in children and pregnant. Thick wall, non-compressible, edema and fluid CT: Not done. Distended, thick wall periappendiceal edema and fluid

Pathophysiology Obstruction of the lumen Fecalith, lymphoid hyperplasia, vegetable, seeds, parasites, neoplasm Small lumen, obstruction lead to closed loop Bacterial overgrowth Continued mucous secretion lead to distension and typical visceral pain in periumbilical area Inflammation of adjacent parietal peritoneum gives rise to localized RIF (parietal) pain

Delayed presentation Inflammatory progress to gangrene Localized perforation- abscess formation Free perforation- peritonitis (secondary)

Treatment Nil orally IV fluid Pre-op. antibiotics: cefuroxime+ metronidazole Non-perforated: single pre-op. dose Perforated: continue post-op. until afebrile Consent for surgery Appendectomy- laparoscopic or open surgery Appendicular abscess- image guided drainage Free perforation- Open/ laparoscopic appendectomy

Case No. 2 A 30-year old female presents with right hypochondrial pain for 2 days associated with fever. History Examination Differential diagnosis Investigations Pathophysiology Management

History Location: right hypochondrium Severity: started mild, now severe Onset: gradual Progress: worsening Radiation: back and right shoulder Exacerbating factors: fatty food Relieving factors: analgesics Associated symptoms: fever, no vomiting , no anorexia Systemic inquiry, family, social, drug history- none Past medical history- similar pain of shorter duration 2 months back

Examination Appearance: In pain Temp. 38.6°C No jaundice Abdomen: Inspection- normal, few striae gravidarum Palpation- tenderness & guarding in RH, Murphy’s sign +ve ( tenderness & arrest of inspiration while palpating at costal margin) Percussion, auscultation- none

Differential diagnosis Chronic cholecystitis Biliary colic Obstructive jaundice Liver abscess Viral hepatitis

Acute cholecystitis

Investigations Leucocytosis LFT: very slight elevation of bilirubin, normal alkaline phosphatase and transaminase Abdominal ultrasonography: gall stones, gall bladder wall thickening, edema, pericholecystic fluid

Pathophysiology Obstruction of the cystic duct Bacterial inflammation If obstruction persists- ischemia and gangrene of the gall bladder Eventually perforation

Management Nil by mouth IV fluid Parenteral antibiotics- (gram –ve and gram +ve organisms)- cephalosporin Consent for surgery Early laparoscopic cholecystectomy

Thank you!