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Internal hemorrhoids are masses of vascular tissue covered by
rectal mucosa. They arise from the superior hemorrhoidal plexus
and lie above the pectinate line (eFigs. 416.1 and 416.2). External hemorrhoids arise from the
inferior hemorrhoidal veins lying below the pectinate line and are
covered by skin (eFig. 416.3).
Hemorrhoids are rare in children and are usually external, associated
with chronic constipation.1 When engorged by straining,
they appear as pearly gray or purple masses at the anal verge that
occasionally bleed a small amount. They may become firm and painful
when thrombosed or infected, conditions more common in adolescence
than infancy. Hemorrhoids may be a sign of childhood sexual abuse.
Symptoms from hemorrhoids usually improve with treatment of underlying
constipation. Incision and evacuation of thrombosed or infected
hemorrhoids may be necessary, but stool softeners, warm sitz baths,
and antibiotics are often sufficient therapy.
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Anorectal varices are found beneath the rectal mucosa or in the
anal canal. These high-pressure venous channels shunt blood from
the portal venous circulation (ie, superior hemorrhoidal vein) to
the systemic circulation (ie, external iliac vein) in response to
portal hypertension. One third of children with portal hypertension
have hemorrhoids, 35% have anorectal varices, and 15% have
isolated external anal varices. Occurrence is related to the duration
and severity of portal hypertension.2 Rectal varices
occasionally cause bleeding, but other symptoms are rare. Injection
sclerotherapy or banding of varices is occasionally required in
patients with severe portal hypertension and bleeding.
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Prolapse is the protrusion of one or all layers of the rectum
through the anus.3 Isolated mucosal prolapse is
common and appears as a red-purple, cylindrical protrusion from
the anus of variable length, with radial folds extending from a
central lumen at the leading point. Prolapsed mucosa may bleed and
may secrete copious mucus. Anal pain may result from anal sphincter
spasm. Children often complain of a mass in the anus after defecation
that they cannot expel. Transient minor prolapse of rectal mucosa
is common ...