𝑰𝒏𝒕𝒆𝒔𝒕𝒊𝒏𝒂𝒍 𝑶𝒃𝒔𝒕𝒓𝒖𝒄𝒕𝒊𝒐𝒏 Flashcards
What is intestinal obstruction?
Blockage in the onward flow of intestinal contents.
How is intestinal obstruction classified?
Dynamic/ Mechanical:
- COMPLETENESS; 1)acute
2) chronic
3) acute on chronic
- SITE; 1) single
2) close loop obstruction
- BLOOD SUPPLY; 1) simple
2) strangulation
Adynamic: Paralytic ( pseudo obstruction )
What is dynamic (mechanical) obstruction?
When peristalsis works against a mechanical obstruction.
What are the types of dynamic obstruction?
Acute (sudden onset) and Chronic (slow progression).
What is acute-on-chronic intestinal obstruction?
A previously chronic case becoming acute.
What is adynamic (functional) obstruction?
No mechanical obstruction; peristalsis is absent or inadequate.
How long does it take for peristalsis to return after surgery?
Small intestine: 12–24 hours, Stomach: 24–48 hours, Large intestine: 48–72 hours.
What are the main etiological categories of intestinal obstruction?
Intraluminal, Intramural, Extramural.
Give examples of intraluminal causes of obstruction.
Fecal impaction, Foreign body, Gallstones, Parasites (Ascaris).
Mnemonic: Forget failing good people
Give examples of intramural causes of obstruction.
Malignancy, Atresia, Polyps, Stricture (TB, Crohn’s).
Mnemonic: MAPS
Give examples of extramural causes of obstruction.
Hernia, adhesions, volvulus.
Mnemonic: HAV
What is the most common cause of intestinal obstruction in Nigeria?
Hernia followed by Adhesions.
What percentage of patients have strangulated obstruction?
40%
What happens to the bowel proximal to the obstruction?
It dilates, increasing peristalsis.
What does dilation stimulate secretory cells to do?
Produce more fluid, which can lead to hypovolemia.
How does gas production increase in obstruction?
Growth of microorganisms.
What does increased bowel distension cause?
Increased pressure → backflow vomiting.
What happens when obstruction reaches the ampulla of Vater?
Bilious vomiting.
What is a severe consequence of continued increased bowel pressure?
Venous congestion → arterial occlusion → ischemia (strangulated obstruction).
What happens to the bowel below the obstruction?
Normal peristalsis and absorption continue until it becomes empty and collapses.
How is intestinal obstruction divided based on location?
High intestinal obstruction (duodenum, jejunum, ileum) and Low intestinal obstruction (terminal ileum, colon).
What are the main clinical symptoms of acute intestinal obstruction?
Vomiting, abdominal pain, abdominal distension, constipation.
What is usually the first symptom of intestinal obstruction?
Pain (sudden, colicky, and severe).
How does vomiting differ in small vs. large intestinal obstruction?
Small: Early onset, Large (colonic): Late onset.
Describe the vomitus in intestinal obstruction.
Bilious, profuse, persistent, and increases in frequency.
What types of constipation occur in intestinal obstruction?
Absolute and relative.
What is absolute constipation a sign of?
Complete intestinal obstruction.
What are some clinical signs of intestinal obstruction?
Rebound tenderness, abdominal distension, peristaltic rushes, dehydration, shock (in severe cases).
What are the key percussion findings in intestinal obstruction?
Tympanic (due to gas accumulation).
What is a late sign of obstruction that suggests strangulation?
Constant severe pain with peritoneal signs.
What is the gold standard imaging modality for intestinal obstruction?
CT scan with contrast.
What sign on X-ray suggests small bowel obstruction?
Dilated loops of small bowel with air-fluid levels.
What sign on X-ray suggests large bowel obstruction?
Dilated colon with haustra visible.
What is the initial management of suspected intestinal obstruction?
1) Correction of fluid and electrolyte
2) Transfuse blood if patient is pale.
3) Nasogastric fluid decompression.
4) Catheterise patient and measure hourly urinary output.
5) Intravenous antibiotics.
When is emergency surgery required in intestinal obstruction?
If strangulation or perforation is suspected.
What is the definitive treatment for mechanical obstruction?
Surgical intervention (e.g., bowel resection, adhesiolysis, hernia repair).
How is paralytic ileus managed?
Supportive care: IV fluids, electrolyte correction, prokinetics.
Which electrolyte imbalance can worsen paralytic ileus?
Hypokalemia.
When is early surgical intervention required?
Early surgical intervention is required in cases of suspicion of internal strangulation and obstructed hernia.
What factors influence the need for surgical intervention in intestinal obstruction?
Surgical intervention depends on the cause of the intestinal obstruction and associated complications.
What are some complications associated with intestinal obstruction?
Complications include shock, bowel gangrene, electrolyte derangement, strangulation, peritonitis, and perforation.
What is the prognosis for intestinal obstruction?
The prognosis is 10% mortality.
What factors are associated with postoperative complications?
Factors include age, co-morbidity, and treatment delay.
What are some complications of surgery?
Complications include short bowel syndrome, wound dehiscence, and intra-abdominal abscess.
What are the features of small bowel obstruction?
Features include early profuse vomiting with rapid dehydration and abdominal pain.
What characterizes pain in small bowel obstruction?
Pain is predominant with central distension and vomiting is delayed.
What characterizes large bowel obstruction?
Distension is early and pronounced, pain is mild, and vomiting is delayed.
What is the onset of constipation in large bowel obstruction?
Constipation is early in onset.
What are the intra-abdominal causes of Intestinal obstruction?
- Intra-peritoneal irritations.
a. trauma- accidental or operational
b. infective peritonitis
c. chemical peritonitis due to:
-blood
-bile
-urine
-pancreatic ferments - Extra-peritoneal irritations.
a. haemorrhage- retroperitoneal haematomas
i. soft tissue injury.
ii. Fracture spine or following lumbar surgery
b. inflammations e.g. pancreatitis.
c. renal failure e.g. renal calculi.
d. urinary retention. - Vascular insufficiency.
a. strangulated loop of bowel
b. mesenteric thrombosis. - Extreme bowel dissention.
What are the extra-abdominal causes of Intestinal obstruction?
- Toxic.
a. severe infections e.g pneumonia
b. uraemia
c. cholaemia.
d. toxaemia of pregnancy (eclampsia). - Neurogenic.
a. reflex from injury elsewhere, meteorism
e.g. fracture ribs.
b. oligaemia. ( hypovolaemia) - Biochemical.
a. electrolyte depletion.
i. sodium
ii. Potassium
iii. Magnesium
b. Hypoproteinemia.
c. Vitamin B depletion.
d. Diabetic coma
e. Porphyria ( abnormal metab. Haemoglobin.)
What is seen on palpation of the abdomen?
• Abdominal mass may suggest carcinoma or strangulated bowel.
• Rigidity and rebound tenderness, indicates ischemia
& peritoneal irritation.
What is seen on percussion of the abdomen?
• Resonance because of gas filled bowel
• Tenderness on percussion indicates the presence of peritonitis.
What is seen on auscultation of the abdomen?
• Bowel sounds
• Tympani
• Metallic clicks as pressure is raised if much gas is present in the bowel.
• Gurgling borborygmi if gas and fluid are present in
the bowel.
• Silence if generalized peritonitis or paralytic ileus is
present.
N/b: Gurgling borborygmi refers to the bubbling or gurgling sounds produced by the movement of gas and fluids through the intestines.
Borborygmi itself is the medical term for stomach or bowel sounds.
What is seen on digital rectal examination?
Impacted Faeces
Rectal cancer
Blood on finger which may present with mesenteric artery occlusions, intussusceptions & volvulus
What is the pathophysiology of intestinal obstruction?
- Dilation proximal to obstruction (gas, fluid and toxin)
- Hyper-peristalsis
- Flaccidity & paralysis
- Dehydration due to:
a)Reduced oral intake
b)Defective intestinal absorption
c)Vomiting
d)Sequestration in bowel lumen
What is a simple obstruction?
- The bowel is usually occluded at one site.
- Below the site of obstruction normal peristalsis and absorption continue for 2 to 3 hours until the contents are empty
What is a simple obstruction?
- The bowel is usually occluded at one site.
- Below the site of obstruction normal peristalsis and absorption continue for 2 to 3 hours until the contents are empty
What is a closed-loop intestinal obstruction?
Here, the bowel is obstructed at both proximal & distal points
