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