Acute abdomen

• Acute abdomen


  Sudden onset of severe abdominal pain developing over a short period of time
• Common causes of acute abdomen

  • Acute appendicitis
  • Acute peptic ulcer and its complications
  • Acute cholecystitis
  • Acute pancreatitis
  • Acute intestinal ischemia
  • Acute diverticulitis
  • Ectopic pregnancy
  • Ovarian torsion
  • Acute peritonitis (including hollow viscus perforation)
  • Acute ureteric colic
  • Bowel volvulus
  • Intestinal obstruction
  • Acute pyelonephritis
  • Biliary colic
  • Abdominal aortic aneurysm dissection
  • Hemoperitoneum
  • Rupture spleen
  • Meckel's diverticulitis
• Acute appendicitis


  Appendix is blind ended tubular structure that arises from cecum
• Positions of the appendix

  • Retrocecal 64-74%
  • Pelvic position 21-32%
  • Paracecal 2%
  • Subcecal 2%
  • Preileal 1%
  • Postileal 0.5%

  
• Blood supply of the appendix

  • Supplied by one or two appendicular arteries arising from ileacolic artery
  • Venous drainage by tributaries of the ileocolic vein to SMV then to portal vein
• Incidence of acute appendicitis

  • It is the commonest cause of acute abdomen and the commonest surgical emergency and more in males
  • It usually occurs between 15-30 years
  • Rare in old age due to atrophy of the lymphoid tissue and fibrosis of the appendix with complete obliteration of the lumen
  • Rare in children below 5 years due to short wide lumen of the appendix obstruction and stasis does not occur
  • Appendicitis is more common in citizens than in the farmers due to high protein and low fibers diet

  
• Predisposing factors for acute appendicitis

  • Obstruction (most important predisposing factor)
  • Anatomical factors (narrow lumen & wall rich in lymphoid follicles)
  • Septic focus from which organisms are carried to the lymphoid follicles of the appendix
  • Diet (high protein and low fibers diet predisposes to constipation, stasis all over the colon & liability of faecolith formation)

  
• Acute obstructive appendicitis


  • Obstruction of the lumen of the appendix → stasis → overgrowth of normal bacterial flora → spread of bacteria to mucosa
  • Rapidly progressive severe inflammation, gangrene & perforation are rapid & common
• Progression of acute obstructive appendicitis

  1. Catarrhal inflammation affect mucosa only → mucocele of the appendix

  2. Suppurative inflammation → formation of multiple abscesses in the wall of the appendix and pus in the lumen → pyocele or empyaema of the appendix

  3. Gangrenous inflammation: Gangrene usually occurs at the tip of the appendix or the site of obstruction
• Acute non-obstructive appendicitis


  • Produce mild slowly progressive inflammation
  • Usually catarrhal inflammation rarely progress to suppuration or gangrene
• Fate and complications of acute appendicitis

  • In non-obstructive type, acute inflammation may resolve spontaneously and becomes recurrent subacute appendicitis
  • Appendicular mass: Greater omentum, caecum, loops of intestine and adhesions surround the inflamed appendix
  • Perforation: More common in young below 5 years and elderly
  • Local spread of infection with irritation of nearby organs
  • Rarely Pylephlebitis: Septic thrombophlebitis of portal vein or one of its tributaries
• Clinical features of acute appendicitis

  Symptoms: Periumbilical pain shifting to the right iliac fossa, Anorexia and nausea, Constipation is usual

  Signs: Tenderness and cough tenderness, Rebound tenderness at McBurney's point, Rovsing sign, Psoas sign, Obturator sign, Rigidity indicates perforation, Tender appendicular mass

  
• Appendicitis in pregnancy


  Pain is displaced upwards as pregnancy progress, Localization by the omentum is less efficient, The condition is usually misdiagnosed as pyelitis, If perforation occurs, there is a high chance of abortion or premature labour
• Appendicitis in infants & young children

  More serious as perforation occurs in 80% of cases because difficult examination of children, thin wall, greater omentum is not well developed & the case may be misdiagnosed as gastroenteritis
• Appendicitis in elderly


  Perforation is common due to weak immunity & atherosclerosis → early thrombosis & gangrene
• Investigations for acute appendicitis

  • CBC (leukocytosis), Urine analysis, Pregnancy test to rule out ectopic pregnancy, Abdominal US, CT scan, Diagnostic laparoscopy

  
• Ultrasound findings in acute appendicitis

  Blind ended loop, Non compressible, Edematous wall, Increased diameter 7mm or more, Reactive regional lymph nodes, Inflamed mesenteric fat and omentum and adjacent bowel loops, Free fluid collection, Appendicolith leading to obstruction, Complications including appendicular mass, perforated appendix or appendicular abscess
• Treatment options for acute appendicitis

  • Uncomplicated acute appendicitis, Appendicular mass, Appendicular abscess, Perforated appendicitis with generalized peritonitis, Chronic appendicitis
• Intestinal obstruction


  Arrest of downward propulsion of intestinal content
• Classifications of intestinal obstruction

  • According to the pathological nature of cause: Simple mechanical, Strangulation, Closed loop obstruction, Paralytic ileus

  Depending on Aetiopathology: Dynamic (Outside the wall, In the wall, In the lumen), Adynamic

  According to the level of obstruction: High small bowel obstruction, Low small bowel obstruction, Large bowel obstruction

  According to the onset of the course of obstruction: Acute obstruction, Chronic obstruction, Acute on top of chronic obstruction

  Congenital, Acquired

  
• Causes of acute mechanical obstruction

  • In the lumen (e.g. faecal impaction, gallstone, parasitic infestation)

  In the wall (e.g. congenital atresia, tumors, stricture)

  Outside the lumen (e.g. adhesions, strangulated hernia, volvulus)
• Common causes of intestinal obstruction according to age

  • Neonates: Congenital atresia, volvulus neonatrum, anorectal malformation, Hirschsprung's disease

  Infants: Ileocecal intussusception, Hirschsprung's disease, strangulated hernia

  Adult: Adhesions, strangulated hernia

  Elderly: Colon cancer, strangulated hernia
• Pathology of simple obstruction

  Distal to obstruction the intestine empties and become collapsed, Proximally the intestine becomes distended by gas and fluid, Stretched smooth muscles undergo hyperperistalsis to overcome the obstruction, Distension impairs blood supply and may end in ulceration and perforation
• Pathology of strangulated obstruction

  In addition to simple obstruction, bacteria and toxins in the lumen can transgress ischemic bowel to the peritoneal cavity and unrelieved strangulation can lead to septicaemic shock, The mucosa is the first layer to suffer from ischemia producing acute ulceration and intraluminal bleeding, Unrelieved strangulation is followed by gangrene of the ischemic bowel with perforation and peritonitis

  
• General lethal effects of intestinal obstruction

  Fluid and electrolyte loss from vomiting and from accumulation in the proximal bowel, Septicemia from peritonitis
• Clinical features of intestinal obstruction

  Pain, Distension, Absolute constipation, Vomiting
• Examination findings in intestinal obstruction


  General examination (evidence of dehydration), Abdominal inspection (distension and visible peristalsis, hernias, scars), Abdominal palpation (mass), Auscultation (exaggerated bowel sounds), Rectal examination (empty rectum or impacted stool)

  
• Assessment of intestinal obstruction

  Is there intestinal obstruction?

  What is the pathological type of obstruction (paralytic ileus, strangulation, impacted stool)?

  What is the cause of obstruction?

  What is the level of obstruction?

  
• Features of high small bowel obstruction

  Vomiting and dehydration are early, Slight abdominal distension

  
• Features of low small bowel obstruction

  Vomiting is delayed for about 12 hours, Central abdominal distension
• Features of colonic obstruction

  Constipation is early while vomiting may be absent or occurs after few days, Marked distension especially in the flank
• General examination


  • Evidence of dehydration as tachycardia, oligouria, dry tongue or even hypotension may be present
• Abdominal inspection


  Distension and visible peristalsis, hernias, scars
• Abdominal palpation


  Mass
• Auscultation


  Exaggerated bowel sounds
• Rectal examination


  Empty rectum or impacted stool
• Assessment should answer the following questions

  • Is there intestinal obstruction?
  • What is the pathological type of obstruction - paralytic ileus, strangulation, impacted stool?
  • What is the cause of obstruction?
  • What is the level of obstruction?

  
• High small bowel obstruction

  • Vomiting and dehydration are early, slight abdominal distension

  
• Low small bowel obstruction

  • Vomiting is delayed for about 12 hours and there is central abdominal distension

  
• Colonic obstruction


  • Constipation is early while vomiting may be absent or occurs after few days. Distension is marked especially in the flanks