SMALL BOWEL MANIFESTATIONS OF
SYSTEMIC DISEASES
CONNECTIVE TISSUE DISORDER AND DERMATOLOGIC DISEASES
Scleroderma frequently involves the small bowel, primarily causing dysmotility. It is characterized by a dilated bowel, associated with scattered wide-mouthed diverticula and even intestinal pseudoobstruction, and small intestinal bacterial overgrowth.
Ehlers-Danlos syndrome is a collection of inherited diseases affecting collagen
synthesis that can involve the intestine, causing bleeding from mucosal lesions
or intraabdominal bleeding of ruptured aneurysms of splanchnic arteries.
Dermatomyositis and polymyositis can affect the entire gastrointestinal but
commonly involve the proximal esophagus.
Systemic lupus enteritis with or without
terminal ileitis is not uncommon and can be
confused with Crohn disease. Rarely, malabsorption and protein-losing
enteropathy with lymphangiectasia can be seen.
In rheumatoid arthritis, the small intestine may
rarely manifest with intestinal ischemia, bleeding, or infarction as a result
of vasculitis of the mesenteric vessels or with chronic diarrhea from secondary
amyloidosis. More commonly, chronic use of medications in rheumatoid arthritis,
such as nonsteroidal antiinflammatory agents, causes erosions and ulcers.
In Behçet disease, there is gastrointestinal
involvement in up to 50% of patients with ulcerative lesions through-out the
gastrointestinal tract, in particular the ileocecal region, which can mimic
Crohn disease. Similarly, patients with reactive arthritides may have
endoscopic or histologic evidence of ileocolonic inflammation that sometimes
resembles Crohn disease.
Diarrhea affects up to a quarter of diabetics. Visceral
autonomic neuropathy plays an important role in association with segmental
small intestinal dilatation often seen in long-standing diabetes. Additionally,
certain drugs used for diabetes, such as metformin, or the presence of
concomitant pancreatic insufficiency, small bowel
bacterial overgrowth, or celiac disease may be causing the diarrhea.
Hyperthyroidism, which causes rapid intestinal transit, may lead to diarrhea or
hyper-defecation, whereas intestinal motility is slowed in hypothyroidism.
Likewise, hypoparathyroidism can lead to neuromuscular irritability, which
manifests with abdominal pain, intestinal tetany, diarrhea, steatorrhea, and
intestinal pseudoobstruction.
Dermatologic Diseases
Blue rubber bleb nevus syndrome is characterized by blue nevi on the skin and
gastrointestinal hemangiomas and can present with iron deficiency anemia or
overt gastrointestinal bleeding or as the lead point of intestinal
intussusceptions. Neurofibromatosis (von Recklinghausen disease) is
associated with polypoid neurofibromas that can be present throughout the
gastrointestinal tract and can cause gastrointestinal bleeding or obstruction,
or both.
Acrodermatitis enteropathica is a rare autosomal recessive disorder thought to be due
to an inability to absorb sufficient intestinal zinc, or it can result from
zinc deficiency secondary to Crohn disease. It usually presents at the time of
weaning, with eczematous pink scaly plaques on the hands and feet and around
the mouth and anus, in addition to paronychia and nail dystrophy.
Gastrointestinal symptoms are often intermittent and consist of diarrhea and
malabsorption. The small bowel shows patchy villous lesions of variable
severity, with abnormal inclusions in Paneth cells. It can be reversed by
giving zinc orally.
MISCELLANEOUS DISORDERS
Aortic stenosis has long been associated with angiodysplasia (Heyde syndrome) resulting
from an acquired deficiency of von Willebrand factor. Congestive heart
failure can lead to congestion of the splanchnic venous bed, causing
anorexia, nausea, bloating, and abdominal pain. Rarely, it can lead to mesenteric
ischemia of the bowel and weight loss, diarrhea, malabsorption, and
proteinlosing enteropathy.
Solitary plasmacytomas most frequently occur in
bone (plasmacytoma of bone) but can also be found outside bone in the
gastrointestinal tract. Waldenström macroglobulinemia can involve the
gastrointestinal tract where monoclonal IgM protein may be deposited as
extracellular amorphous material in the lamina propria, producing severe
malabsorption with diarrhea and steatorrhea. Similarly, heavy-chain disease commonly
leads to infiltration of the jejunal mucosa with plasmacytoid cells, resulting
in abdominal pain, malabsorption with chronic diarrhea, steatorrhea, and loss
of weight.
Endometriosis is characterized by the presence of endometrial glands or stroma, or both,
in abnormal sites. Intestinal endometriosis commonly takes the form of plaques
of tissues on the serosal surface of the bowel lying in the pelvis, but the
plaques can rarely infiltrate the deeper layers of the bowel, causing
intestinal obstruction and gastrointestinal bleeding even lower in the tract.
Sarcoidosis is a systemic disorder that is characterized by noncaseating granulomas.
Involvement of the small bowel is extremely rare, and the presence of typical
granulomatous ileocolitis even in a patient known to have sarcoidosis should
prompt a search for Crohn disease.
Graft-versus-host disease can be acute or chronic and commonly involves the gastrointestinal
tract. Small bowel involvement causes diarrhea that can often be severe.
Cystic fibrosis is associated with unique intestinal disorders that arise as a result of inspissation of thick and viscous mucus secretions. Meconium ileus occurs exclusively in newborns and is often the first manifestation of cystic fibrosis. Distal intestinal obstructive syndrome is t e adult equivalent and can cause intestinal obstruction.
