When blockage prevents the normal flow of intestinal contents through the intestinal tract, intestinal obstruction exists. Obstruction of the GI tract is the condition when the normal flow of intestinal content is impeded by a constricted or occluded lumen or when there is impaired motility (paralytic ileus). The obstruction may be in small or large intestine, complete or partial obstruction and may be due to mechanical or paralytic ileus.
Intestinal obstruction occurs both in the small or large intestine but common in the small intestine. It is one of the most common surgical emergency during childhood period need prompt intervention.
Types of Intestinal Obstruction
- Mechanical Obstruction
- Non-Mechanical Obstruction
1. Mechanical obstruction: Bowel is physically blocked and its content cannot get a move in normal way causes vary the form of obstruction. An intraluminal obstruction or a mural obstruction from pressure on intestinal wall occurs. It may be acute or chronic. Common causes of mechanical obstruction are:
- A hernia
2. Non- Mechanical Obstruction: Also called paralytic ileus because of impairment of intestinal paralysis activity and common after surgery. The intestinal musculature cannot propel the contents along the bowel.
- Muscular dystrophy
- Endocrine disorders such as
– Diabetes mellitus
- Neurological disorder
– Parkinson’s Disease
The obstruction can be partial or complete. Its severity depends on the region of bowel affected, the degree to which the lumen is occluded, and especially the degree to which the vascular supply to the bowel is disturbed. Most bowel obstructions occur in the small intestine. Adhesion is the most common cause of small bowel obstruction, followed by hernias and neoplasms.
Causes of Intestinal Obstruction
- Volvulus: twisting of bowel upon itself usually at least full 180 degree
- Intussusception: prolapse of one part of intestine into lumen
- Other causes: fecal impaction, gallstones, inflammatory bowel disease
Non- Mechanical Obstruction
The causes of non-mechanical obstruction may result from a neuromuscular or vascular disorder.
- Paralytic ileus
- Vascular distinction
Pathophysiology of intestinal obstruction
- Obstruction of bowel lumen, accumulation of intestinal content and secretion above the blockage. The abdominal distension and retention of fluid reduce the absorption of fluids and stimulate more gastric secretion. With increasing distention, the pressure within the intestinal lumen increases, causing a decrease in venous and arteriolar capillary pressure. This causes edema, congestion, necrosis, and eventual rupture or perforation of the intestinal wall, with resultant peritonitis.
- Reflux vomiting may be caused by abdominal distension. Vomiting results in loss of hydrogen ions and potassium from the stomach, leading to a reduction of chlorides and potassium in the blood and to metabolic alkalosis. Dehydration and acidosis develop from loss of water and sodium. With acute fluid losses, hypovolemic shock may occur.
Clinical manifestations of intestinal obstruction
Clinical manifestations of intestinal obstruction depend on the level and length of bowel involved, the extent to which the obstruction interferes with the blood supply, the completeness of the obstruction and the type of lesion. The general clinical features of a patient with intestinal obstruction are as follows:
- Nausea/vomiting: occur due to accumulated abdominal contents. It is usually the first sign and characteristic of vomiting may be different according to the location of obstruction proximal to the small intestine. Form distal obstruction of the intestine is more gradual in onset; obstruction located in high intestine produces rapid onset, sometimes projectile vomiting with bile which may be orange-brown in color and foul smelling because of bacterial growth.
- Abdominal distension: related to an accumulation of gas and fluid above the level of obstruction. Abdominal distension progresses, and the abdomen may become extremely tender, rigid and firm.
- Cramping pain is related to vigorous contraction proximal to the obstruction as bowel attempts to move luminal content
- Colicky abdominal pain
- Inability to pass flatulence and constipation
- Tachycardia, hypotension or shocks
- Hypokalemia, hypernatremia
- Change in stooling pattern may range from constipation (prolong or absence of defecation) are early sign of low obstruction and later sign of higher obstruction
- Respiratory distress, due to upward pushing of diaphragm related to abdominal distension
- Fever may be present or absent
- X-rays: plain abdominal X-ray shows abnormal quantities of fluid and gases in bowel
- Barium mean/ enema x-ray shows abnormalities like stricture, tumor etc.
- Blood biochemistry: PH, bum, electrolytes
- Blood count- increased WBC count
- Ultrasonic evaluation of abdomen
- Computed Tomography scan and magnetic resonance imagining study
- Treatment is directed towards decompression of intestine by removal of gas and fluid, correction, and maintenance of fluid and electrolyte balance.
- NG- tube insertion for drawing fluid from abdomen
- Keep patient nil per orally
- Analgesic and antispasmodic drugs used to relieve pain and to provide comfort
- Antibiotic drugs to treat and prevent infection
- Administration of fluid and electrolytes by IV infusion
- A rectal tube may be used to decompress an area that is lower in bowel
Management focus is to detect cause and complication early and manage them properly.
Surgery will be performed to relieve the mechanical obstruction and if conservative efforts are failed.The operative procedure will be varied with the condition of the patient. It depends on an underlying condition such as:
- Resection of bowel is done for obstructing lesion or strangulated bowel; along with end to end anastomosis
- Cutting of Ladd’s band and lengthening of roots of the mesentery if malrotation of gut
- Enterotomy is performed to remove foreign body from the intestine