Mecontium ileus and Distal ileal obstructive syndrome (DIOS) (also known as meconium ileus equivalent) are bowel blockages due to abnormal, thick, tenacious stool. These obstructions are seen an a subset of patients with cystic fibrosis.
Meconium Ileus
- • Present in 20% of newborns with cystic fibrosis and may be the first clinical manifestation.
- • Abdominal distention at birth, multiple doughy loops of dilated bowel on palpation, bilious emesis, and failure to pass meconium in the first 24-48 hours of life.
- • Neuhauser’s sign
2 Types: complicated and uncomplicated
- • Uncomplicated: simple obstruction of terminal ileum
- • Complicated: volvulus, gangrene, atresia, or perforation (meconium peritonitis).
In uncomplicated meconium ileus, contrast enema can be both diagnostic and therapeutic. (Adding an emulsifying agent (Tween 80) may enhance effectiveness). Therapeutic enemas are 40-60% effective in patients with simple meconium ileus. The risk of perforation is approximately 3%. Perforation requires operative intervention. Simple end-to-end anastomosis is preferred because the long term surgical morbidity is lower than with enterostomy. Enterostomy or T-tube enterostomy is still acceptable and preferred in some centers.
- • Survival rates 80-90%.
- • 20 % develope meconium ileus equivalent later in life
- • 7% developed fibrosing colonopathy (may be lower now)
- • Small risk of mechanical small bowel obstructions later in life which may be difficult to distinguish from DIOS.
Surgery for uncomplicated meconium ileus
- • After 2 failed attempts of nonoperative hypertonic washout, operative intervention is may be indicated.
- • Enterotomy and intraoperative saline irrigation for mechanical seperation of the pellets from the bowel wall and evacuation of the meconium.
Complicated meconium ileus may be due to volvulus (twisting of the bowel), gangrene (strangulation leading to dead bowel), atresia (congenital blockage due to reabsorption of a section of bowel prior to birth), or perforation (meconium peritonitis). Most complicated cases require surgical exploration.
Distal Ileal Obstructive Syndrome
Distal Ileal Obstructive Syndrome (DIOS) was previously called Meconium Ileus Equivalent. Essentially, this is an obstruction within the lumen of the bowel by thick, tenacious stool which leads to a blockage. DIOS is in contrast to typical small bowel obstructions which occur due to kinking of the bowel or scar tissue on the outside of the bowel. Treatment often involves use of PEG solution at a low rate given under close medical supervision. There is a risk of perforation or other complications in this setting, and inpatient treatment is typical. Prevention by controlling stool consistency is key. Patients with this condition should have a close relationship with their cystic fibrosis center or gastroenterologist.
- • In one study, 12 % of patients with CF were affected. The majority had meconium ileus as an infant.
- • Frequently brought on by cessation of pancreatic enzyme replacement, dietary indiscretions, dehydration, or colds.
- • Conservative therapy preferred, but 26% of patients in one study required operation.
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Cystic Fibrosis
- • Autosomal recessive
- • Usually presents clinically as pancreatic insufficiency or chronic pulmonary disease
- • Advances in neonatal critical care, antibiotics, and anesthesia have allowed CF patients to survive longer.
Meconium Ileus
- • Genetic studies – Delta F508 mutation associated with abdominal complaints rather than pulmonary complaints.
Meconium Ileus
- • 25% of patients with meconium plug syndrome had CF
Other Surgical Considerations in Cystic Fibrosis patients:
Appendix
- • Chronic antibiotic use for assoc. pulmonary infections may mask the classic signs and symptoms of appendicitis.
- • Incidence of perforated appendix at time of diagnosis higher than for general population.
Fibrosing colonopathy
- • Result of colonic strictures and classically associated with high strength pancreatic enzyme replacement.
- • Gross appearance of the affected colon: The lumen is thickened and narrow. The mucosa has an erythematous cobblestone appearance.
- • 89% required operation.
Rectal Prolapse
- • 6% incidence in one series, but reported to occur in up to 23% of the CF population.
- • Occurs most commonly between the ages of 6 months to 3 years.
- • Most managed conservatively by manual reduction.
- • Surgical repair indicated for significant bleeding, incarcerated prolapse, severe pain, or failure of medical management.
Hernia
- High incidence of inguinal hernia in the CF population.
- Chronic cough and poor nutrition may contribute
- Recurrence
Thoracic procedures
- • Tube thoracostomy or pleurodesis for pneumothorax, lobar or wedge resection for bronchiectasis, and lung transplantation.
- • High mortality rate in CF patients with PTX, and high prevalence of history of PTX in those patients who died.
- • Lung transplant only therapy available for those with end stage lung disease.
- • The donor lung does not carry the CFTR gene.
- • Mortality rate was 27%
GERD with aspiration
- • May aggravate FTT, adversely affect pulmonary function, and may account for the high incidence of CF lung disease in RLL
- • Theophylline
- • Incidence aprox. 81% in patients younger than 5 years old.
- • Children unresponsive to conservative therapy should have Nissen.
- • Gastrostomy tube
- • Pyloroplasty
Intussusception
- • Aprox. 1% of patients with CF.
- • Average age 9.5 years old
- • General pediatric population is 6-18 months
- • Abnormally thick stools adhere to the bowel wall and may act as a lead point.
General considerations: Multi-disciplinary approach
- • Pediatric Surgeons
- • PulmonarySpecialists at a CF Center
- • Critical care specialists
- • Respiratory care specialists
- • Nutrition support specialists
- • Improved antibiotic and pancreatic enzyme therapy.
