Intestinal obstruction and ileus Flashcards
What is intestinal obstruction?
Obstruction of the normal movement of bowel contents – mechanical blockage of the bowel due to structural pathology
In what ways can an intestinal obstruction be classified?
Classification:
o Small or Large bowel
o Partial or Complete obstruction
o Simple or Strangulated
What are some causes for intestinal obstruction?
- Extramural
- Hernia
- Adhesions
- Bands
- Volvulus - Intramural
- Tumours
- Inflammatory strictures (e.g. Crohn’s strictures, diverticulitis) - Intraluminal
- Pedunculated tumours
- Foreign body (e.g. bezoars, gallstones)
- Faecal impaction
What are the presenting symptoms of an intestinal obstruction?
- Severe gripping colicky pain with periods of ease
- Abdominal distension – more marked as obstruction progresses
- Frequent vomiting (it may be bile-stained or faeculent)
- Absolute constipation
- Anorexia
- Previous episode of bowel obstruction
- Previous surgery and conditions e.g., PID, diverticulitis, appendicitis.
What signs of an intestinal obstruction can be found on physical examination?
- Abdominal distension with generalised tenderness
- May see visible peristalsis
- Tinkling bowel sounds
- Peritonitis - absent bowel sounds, guarding and rebound tenderness
- Inspect for hernias
- Look for abdominal scars - previous abdominal surgery increases the risk of adhesions
- Inspect for abdominal mass (e.g. intussusception, carcinoma)
- Fever, leukocytosis, tachycardia, metabolic acidosis.
- Assess hydration - check for signs of dehydration:
- Tachycardia
- Dry mucous membranes (check tongue + mouth)
- Hypotension
- Altered mental state (drowsiness)
What investigations are used to diagnose/ monitor an intestinal obstruction?
- AXR
- Small bowel: dilated bowel >3cm, central gas shadows with valvulae conniventes that completely cross the lumen and no gas in large bowel
- Large bowel: dilated bowel >6cm or >9cm if at caecum, peripheral gas shadows proximal to the blockage with haustra which do not cross whole lumen width - Water-Soluble Contrast Enema
- Barium follow through
- CT scan – more sensitive
- Blood tests: amylase, FBC, U+Es, CRP
How is an intestinal obstruction managed?
- General – drip and suck management
- NBM, insert NG tube
- Gastric aspiration via NG tube if the patient is vomiting
- IV fluids to rehydrate
- Electrolyte replacement
- Analgesia
- Urinary catheter and fluid balance
- Monitor vital signs, fluid balance and urine output - Surgical
- Strangulation and large bowel obstruction require surgery. Ileus and incomplete small bowel obstruction can be managed conservatively, at least initially.
- Emergency laparotomy in acute obstruction
What complications may arise from an intestinal obstruction?
- Dehydration
- Bowel perforation
- Peritonitis
- Toxaemia
- Gangrene of ischaemic bowel wall
Describe the prognosis of an intestinal obstruction
Variable - dependent on the general state of patients and prevalence of complications
Describe the epidemiology of an intestinal obstruction
- Common
- More common in elderly due to increasing incidence of adhesions, hernias and malignancy
What is ileus?
Ileus is a slowing of gastrointestinal motility that is not associated with mechanical obstruction. Disrupt peristalsis. Diagnosis of exclusion after bowel obstruction has been ruled out.
What are some causes of ileus?
- Abdominal surgery
- Current medication, e.g., opioid based analgesics.
- Inflammation (peritonitis, appendicitis)
- Acute systemic illness (e.g., MI, pneumonia, acute cholecystitis, pancreatitis, sepsis.)
- Electrolyte imbalance
What are the presenting symptoms of ileus?
- Nausea and vomiting
- Abdominal pain
- Abdominal distention, tenderness
- Constipation
- Failure to pass flatus
- Discomfort from gaseous distension, usually with pain
What signs of ileus can be found on physical examination?
- Abdominal distension
- Tachycardia
- Hypotension
- Hypovolaemic/haemodynamically unstable
- Pain
- Mechanical obstruction e.g., mass
- Decreased bowel sounds
- In a post-operative patient with absent bowel sounds and a distended abdomen, ileus is most likely.
What investigations are used to diagnose/ monitor ileus?
- CTAP using oral contrast/IV contrast.
- FBC (elevated WBC)
- Electrolytes (hypokalaemia, hypo-chloremia, hypermagnesemia)
- Urea + creatinine
- ABG (metabolic alkalosis if dehydrated)
- LFTs, lipase, amylase
