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, orhindgut, 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
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+vecocci), 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.
MesentericIschemia • Arterial: embolism, thrombosis • Venous: thrombosis • Superior mesenteric vessel distribution • Intestinal mucosal sloughing- 3 hours of onset. • Full-thickness intestinal infarction- 6 hours
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 inacute surgical abdomen. • Constipationor 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 :distendedbowel 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
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.