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

Anatomy and Physiology of Abdominal pain

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:

Gall bladder- right subscapular or shoulder

Heart, tail of pancreas, spleen- left shoulder (Kehr's sign)

Ureter- Scrotum and testis

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, ileum, colon

• Obstruction- Small bowel adhesions, obstructed hernia,

sigmoid volvulus, carcinoma colon

• Ischemia- Mesenteric ischemia (thrombosis/ embolism),

strangulated hernia

• Hemorrhage- Ruptured ectopic pregnancy, ruptured

aneurysm, solid organ-trauma, tumour

Common nonsurgical causes of Acute Abdomen

• Diabetic crisis

• Uremia

• Hereditary Mediterranean fever

• Sickle cell crisis

• Acute leukemia

• Myocardial ischemia

Pathophysiology: Acute appendicitis

• Most common general surgical emergency

• Derived from the midgut

• Obstruction of the lumen (fecalith, lymphoid hyperplasia,

vegetable matter or seeds, parasites) - 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 RLQ

• Perforation usually after 48 hours from the onset of symptoms

Bacterial flora in appendicitis

• Polymicrobial

• Escherichia coli, Streptococcus viridans, and

Bacteroides and Pseudomonas

Perforated peptic ulcer

• 5% of peptic ulcers penetrate through the

duodenal wall into the peritoneal cavity

• Most common site: 1st part of the duodenum, anteriorly

• Produce chemical peritonitis initially.

Bacterial peritonitis develops within few hours.

Peritonitis

• Peritonitis is peritoneal inflammation from any cause.

• 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 inflammation (perforated viscus) produces generalized

peritonitis causing generalized abdominal pain with a quiet abdomen (absent bowel sound).

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- perforated appendicitis

• Primary peritonitis: uncommon. No intra-abdominal cause.

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- chemical peritonitis –pancreatitis.

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.

Mesenteric Ischemia

• Arterial: embolism, thrombosis

• Venous: thrombosis

• Superior mesenteric vessel distribution

• Intestinal mucosal sloughing- 3 hours of onset.

• Full-thickness intestinal infarction- 6 hours

Symptoms & Signs in

Acute abdomen

Main symptom- Abdominal pain

• Location: finger vs hand• Severity: Colic, ischemia (severe), inflammation- milder• Onset: Sudden in perforation, ischemia, biliary colic• Progress: Inflammation- develops and worsens over

several hours - appendicitis, cholecystitis• Spasmodic: Biliary colic, or genitourinary obstruction• Radiation and shift: Cholecystitis, appendicitis• Exacerbating factors: Food worsen pain- bowel

obstruction, gastric ulcer• Relieving factors: Food relieves pain- duodenal peptic

ulcer disease or gastritis.

Associated symptoms • Vomiting likely to precede abdominal pain in medical conditions

whereas pain presents first in acute surgical abdomen.

• Constipation or obstipation - 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- patients 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, and often maintain

flexion of their knees and hips to reduce tension on the anterior

abdominal wall.

Inspection of the abdomen

• Distension- obstruction, ileus• 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- free fluid

• 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: Leukocytosis in infection, ischemia

• Electrolytes, blood urea nitrogen, and creatinine: Disturbed

due to 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, acute pancreatitis.

• Lactate levels and arterial blood gas: intestinal

ischemia or infarction.

• Urinalysis: Bacterial cystitis, pyelonephritis, diabetes.

• Urinary human chorionic gonadotropin: Pregnancy - a factor in the patient's presentation or aid in

decision making regarding therapy.

• Stool: Fresh blood , 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. • 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 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.

Initial management

Preoperative preparation• Fluid and electrolyte abnormalities corrected- IV crystalloid infusion

• Nasogastric tube to decrease the likelihood of vomiting and aspiration

• Antibiotic infusions for the bacteria common in acute abdominal emergencies (gram-negative enteric organisms and anaerobes)

• 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-

(diabetes, hypertension, coagulopathy)

• Decision: 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 adjacent parietal peritoneum)

• Migratory pain is the most reliable symptom.

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

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

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

Thank you!

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. 2A 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!