5 Flashcards
Bowel obstruction
most common site for obstruction?
Clinical Findings?
Small bowel (SB) is the most common site for obstruction.
Due to the small lumen when compared to the large bowel
Clinical Findings:
- Colicky & intermittent abdominal pain: Severe pain alternating with pain-free intervals
- Abdominal distention
- Nausea & Vomiting, In a proximal obstruction, nausea and vomiting are more prevalent
- inability to pass flatus:
- No rebound tenderness
Bowel obstruction
Causes of Mechanical Intestinal Obstruction
Causes of Functional Intestinal Obstruction
Major Causes
1- Hernias, internal or external
2- Intestinal Adhesions
3- Volvulus
4- Intussusception
5- Crohn’s disease
Less Frequent Conditions
1- Tumors
2- Obstructive gallstones
3- Foreign body
Causes of Functional Intestinal Obstruction
1- Paralytic ileus:
which is seen in the postoperative stage of
- Major abdominal surgery
- Peritonitis
2- If the ganglia or nerves of the intestine are damaged: e.g.
- Hirschsprung disease
Bowel obstruction Radiographic Findings:
Radiographic Findings:
1- Bowel distention
2- Multiple Air-fluid levels with a step-ladder appearance
3- Absence of air distal to obstruction
Twisting of a segment of bowel around its vascular mesentery,
resulting in intestinal obstruction → and strangulation called
Volvulus
Volvulus Sites, Risk factors, Complication
Sites: sigmoid colon (is most common site in elderly),
cecum (is the most common site in young adults), small bowel
Risk factors: chronic constipation (most common), laxative abuse
Complication: infarction and peritonitis
denotes telescoping (invagination) of a proximal segment of bowel into the immediately distal segment.
Intussusception
Intussusception
Peak incidence?
Complication?
Complication:Infarction of the intussuscepted (trapped) segment
Peak incidence: ages 1–5
In infants and children:
- intussusception perhaps related to excessive peristaltic activity
- The terminal ileum invaginates into the cecum due to hyperplastic lymphoid tissue in Peyer’s patches → obstruction and ischemia
C/P: colicky pain with bloody diarrhea;
adults: - It may be associated with an intraluminal mass (e.g., a tumor or polyp is the nidus for intussusception)
Adhesions Etiology
from previous surgery (most common)
- from endometriosis,
- from healing of localized or general peritoneal inflammation (peritonitis).
Incarcerated Hernia
Mechanisms predisposing to acquired hernias?
Sites?
Mechanisms predisposing to acquired hernias:
- Increased intra-abdominal pressure (e.g., coughing, heavy weight lifting)
- Weakness in the abdominal wall
Sites: The usual sites of weakness (or defect) are:
- at the inguinal and femoral canals,
- at the umbilicus, and
- in previous surgical incision (scars) → Incisional hernia
Complication of Hernias
- permanent trapping (incarceration)
- intestinal obstruction and
- infarction of the trapped segment (strangulation).
Ischemic Bowel Disease: Types of infarctions:
Transmural Infarction: of the gut Involving all layers of intestinal wall → full-thickness dark red hemorrhagic
- Usually due to acute occlusion of a major mesenteric artery e.g. superior mesenteric artery (SMA)
2- Mural Infarction:
- Infarction of the mucosa and submucosa, sparing the muscular wall,
- Usually occur in hypoperfusion states (e.g. shock)
3- Mucosal Infarction:
- If the infarction extends no deeper than the muscularis mucosae.
- Usually occur in hypoperfusion states
Causes of acute ischemia involving small bowel:
1- Thrombosis of the mesenteric artery: (usually SMA):
- usually due to severe atherosclerosis,
2- Embolism to the mesenteric artery: (usually SMA)
- usually from the left side of the heart (as endocarditis with vegetations, myocardial infarction with mural thrombosis or Atrial fibrillation (AF)
3- Nonocclusive ischemia:
- Hypotension secondary to heart failure (most common),
- Hypovolemic shock
4- Mesenteric vein thrombosis:
- Hypercoagulable states e.g. by oral contraceptives, postoperative state,
5- Miscellaneous:
- e.g. volvulus, stricture, and internal or & Vascular Disorders
Clinical Features: Ischemic Bowel Disease
With the transmural lesions:
-sudden onset of diffuse abdominal pain, bowel distention , may be associated with bloody diarrhea. Absent bowel sounds (ileus)
- may progress to shock and vascular collapse
Prognosis: Poor; → 90% mortality rate ???
- Within 24 hours intestinal bacteria invade the wall → gangrene → perforation
With the mural and mucosal ischemia: - gradual onset of abdominal distention , discomfort or pain.
Prognosis: -Not fatal, if the cause of hypoperfusion is corrected, the lesions may heal.
tortuous dilated anal and perianal submucosal venous plexuses
Called
Hemorrhoids
Hemorrhoids Etiology, Predisposing Risk factors:
Persistently elevated venous pressure within the hemorrhoidal plexus
1- Chronic constipation and prolonged straining during
2- Pregnancy due to the venous stasis. .
3- Less commonly, due to portal hypertension, usually resulting from cirrhosis of the liver
