Diseases of the small intestine – diseases of the small intestine are divided into primary and secondary diseases.
Primary small intestinediseases arise from the small intestine's own tissue. They include congenital enzyme deficiencies (lactase deficiency, abetalipoproteinaemia, amino acid transport disorders), infections (viral, bacterial, protozoal, worm and fungal infections), bacterial overgrowth syndrome, gluten sensitivity (coeliac disease), Crohn's disease (which can affect any part of the digestive tract), Whipple's disease (a rare infection), tropical sprue, collagenous sprue, amyloidosis, eosinophilic inflammation of the small intestine, sarcoidosis, and primary tumours arising in the small intestinewall itself.
Secondary diseases are conditions that do not originate directly in the small intestine but also affect the small intestinetissue. These include changes caused by certain medicines (mucosal damage caused by non-steroidal anti-inflammatory drugs, harmful effects of laxatives or chemotherapy drugs), the effects of hormonal disorders (thyroid dysfunction, overactive parathyroid glands), disorders of the blood supply of the small intestinewall, motility disorders caused by diabetes, harmful effects of neuroendocrine tumours, the harmful effects of AIDS, and the damaging effects of autoimmune diseases affecting the whole body (e.g. progressive systemic sclerosis).
The small intestinediseases may include diarrhoea, digestive disorders, bloating, foul-smelling fatty stools, weight loss, protein, vitamin and trace element deficiencies, fatigue, abdominal pain, nausea, vomiting, oedema, fever, skin symptoms, neurological symptoms, and diseases of the heart, heart muscle and skeletal muscles.
