Juvenile Intestinal Polyposis

Familial premalignant polyposis of the colon characterized by abdominal pain, rectal bleeding, and diarrhea.

Juvenile Polyposis Syndrome.

Solitary juvenile polyps occur in 1% of children, but juvenile polyposis is much rarer.

There are both familial and nonfamilial polyposis. A family history of juvenile polyposis is present in 20 to 50% of patients. Autosomal dominant inheritance. There is evidence that mutations in the SMAD4/DPC4 gene located on 18q21.1 result in juvenile polyposis. Juvenile polyposis has been suggested to be caused by mutations in the PTEN gene (possible gene map location 10q23.3).

Patients have a variable number of polyps, usually between 50 and 200, distributed throughout the gastrointestinal tract, most commonly in the colon.

Juvenile polyps are distinctive both macroscopically and histologically. They are usually pedunculated and spherical with a smooth surface within which are numerous large cystic spaces of variable size, filled with grayish or yellowish mucus surrounded by copious reddish stroma. In contrast to the hamartomatous polyps of Peutz-Jeghers syndrome, muscle fibers are not present in the stroma.

Usually present in childhood; less than 15% present in adulthood. Classified into three groups:

• Juvenile polyposis of infancy (presents with diarrhea, hemorrhage, intussusception, rectal prolapse and protein-losing enteropathy; entire gastrointestinal tract is affected, prognosis related to severity and extent of gastrointestinal involvement); usually fatal before 2 years of age.
• Generalized juvenile polyposis
• Juvenile polyposis of the colon

The latter two groups commonly present with abdominal pain, weakness, rectal bleeding, diarrhea, or rectal prolapse. Laboratory findings include anemia, hypoalbuminemia, hypokalemia, and skin test anergy. Juvenile polyposis is a premalignant condition with changes seen in children as young as 3 years of age. Patients with generalized involvement require surgical intervention. Subtotal colectomy and ileoproctostomy are the procedures of choice. Patients with a small number of polyps may choose instead to undergo periodic colonoscopy with colonoscopic polypectomy. Approximately 10 to 20% of affected patients have extracolonic abnormalities. These include finger clubbing and hypertrophic pulmonary osteoarthropathy related to pulmonary arteriovenous fistulas. Congenital cardiac defects, macrocephaly, cleft lip/palate, extra teeth, arteriovenous malformations of the skin, gut malrotation, psoriasis, and genitourinary abnormalities have been described.

Correct anemia, electrolytes, and any intravascular volume deficit. Nutritional status should be assessed and metabolic deficiencies corrected prior to elective surgery. Investigations: complete blood count, serum electrolytes, creatinine, urea, albumin, and liver function tests. Parenteral nutrition should not be stopped suddenly, as rebound hyperglycemia may occur. Assess for any extracolonic abnormalities that may be relevant to anesthesia. Check for congenital cardiac defects. An electrocardiogram (ECG) and echocardiography may be indicated.

The major increase in intraoperative and postoperative complications result from the malabsorption state. Monitoring of blood sugar and electrolyte levels is mandatory. Regional anesthesia minimizes impairment of the cardiorespiratory system by general anesthetic agents. Epidural anesthesia as a perioperative adjunct provides superior pain control and has been implicated in more rapid ileus resolution after major abdominal surgery, possibly through a sympatholytic mechanism. Postoperative mechanical ventilation will be required for those with severely reduced cardiorespiratory reserves. Anemia may be significant and requires correction before surgery. Rectal bleeding may cause severe hypovolemia and must be corrected before induction of anesthesia. Diarrhea may result in electrolyte disturbances, especially hypokalemia. Cardiac defects may require specific anesthetic management or antibiotic prophylaxis.

In severe malnutrition, there is an increased sensitivity to intravenous induction agents, succinylcholine (as pseudocholinesterase deficiency may exist), nondepolarizing neuromuscular blockers (in the presence of hypocalcemia, hypophosphatemia, and hypomagnesemia), and drugs bound to albumin (e.g., diazepam).

Gardner Syndrome: Autosomal dominant variant of familial adenomatous polyposis characterized by intestinal polyposis, multiple osteomas, skin and soft tissue tumors. Untreated polyps spontaneously undergo malignant degeneration in 100% of cases.

Bannayan-Zonana Syndrome: Polymalformative syndrome characterized by macrocephaly, lipomas, hemangiomas, thyroid disorders, and multiple hamartomatous polyps of the small and large intestine.

Cowden Syndrome: Autosomal dominant disorder characterized by gastrointestinal polyps with a tendency to become malignant, mucocutaneous pigmentation, thyroiditis, and breast cysts.

Gorlin-Goltz Syndrome: Autosomal dominant cancer syndrome, basal cell carcinomas and medulloblastoma with sensitivity to ionizing radiation, multiple abnormalities of the skin, skeleton, and nervous system (“the fifth phakomatosis”). Gene map locus is 9q22.3-q31.

Peutz-Jeghers Syndrome: Autosomal recessive or sporadic syndrome characterized by the association of gastrointestinal polyposis with mucocutaneous pigmentation. Mutation in the STK11 gene (at locus 19p13.3) is present in approximately 70% of familial cases and 30 to 70% of sporadic cases.

Turcot Syndrome: Autosomal recessive syndrome characterized by the association of a primary brain tumor and multiple colorectal adenomas. This condition could be a variant of Gardner syndrome. It has been suggested that it could result from two distinct germline defects: mutation of the APC gene or mutation of a mismatch-repair gene; candidate gene map locus 5q21-q22.