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 ...