An unusual case of myxedema megacolon with features of ischemic and pseudomembranous colitis

Thyroid disorders and gastrointestinal dysmotility: an old association

Gastrointestinal motility symptoms may be closely related to thyroid diseases. Sometimes, such symptoms are the only thyroid disease-related clue although the degree of the symptoms may vary. The exact mechanism of action of thyroid hormones on gastrointestinal motility is not completely understood, however, a clue lies in the fact that muscle cell receptors can be directly acted upon by thyroxines. Both hypo- and hyperthyroidism can cause impairment of gastrointestinal motility, modifying structure and function of pharynx and esophagus, and regulating esophageal peristalsis through neuro-humoral interaction. In hyperthyroid patients, alterations of postprandial and basic electric rhythms have been observed at gastro-duodenal level, often resulting in slower gastric emptying. Gastric emptying may also be delayed in hypothyroidism, but an unrelated gastric mucosa-affecting chronic modification may also cause such pattern. Hyperthyroidism commonly show malabsorption and diarrhoea, while hypothyroidism frequently show constipation. In summary, it can be stated that symptoms of gastrointestinal motility dysfunction can be related to thyroid diseases, affecting any of the gastrointestinal segment. Clinically, the typical thyroid disease manifestations may be missing, borderline, or concealed because of intercurrent sicknesses. Motility-linked gastrointestinal problems may easily conceal a misdetected, underlying dysthyroidism that should be carefully analyzed. Here, we aim to elaborate on the associations between thyroid disorders and GI dysmotility and the common clinical manifestations associated with GI dysmotility.

The thyroid and the gut

Thyroid disease is common, and its effects on the gastrointestinal system are protean, affecting most hollow organs. Hashimoto disease, the most common cause of hypothyroidism, may be associated with an esophageal motility disorder presenting as dysphagia or heartburn. Dyspepsia, nausea, or vomiting may be due to delayed gastric emptying. Abdominal discomfort, flatulence, and bloating occur in those with bacterial overgrowth and improve with antibiotics. Reduced acid production may be due to autoimmune gastritis or low gastrin levels. Constipation may result from diminished motility, leading to an ileus, megacolon, or rarely pseudoobstruction. Ascites in myxedema is characterized by a high protein concentration. Graves' disease accounts for 60% to 80% of thyrotoxicosis. Hyperthyroidism is accompanied by normal gastric emptying with low acid production, partly due to an autoimmune gastritis with hypergastrinemia. Transit time from mouth to cecum is accelerated, resulting in diarrhea. Steatorrhea is due to hyperphagia and stimulation of the adrenergic system. Diarrhea in medullary carcinoma of the thyroid (MCT) may be due to elevated calcitonin, prostaglandins, or 5-hydroxyindoleacetic acid. Ileal or colonic function may be abnormal. The esophagus may be compressed by benign processes, but more often by malignancies. MRI and CT scans are the best diagnostic modalities. The gastrointestinal manifestations of thyroid disease are generally due to reduced motility in hypothyroidism, increased motility in hyperthyroidism, autoimmune gastritis, or esophageal compression by a thyroid process. Symptoms usually resolve with treatment of the thyroid disease.

Refractory gastrointestinal bleeding treated with thyroid hormone replacement

Although bleeding diathesis has been associated with hypothyroidism, refractory gastrointestinal bleeding has not been previously described in association with hypothyroidism. We report a patient who presented with refractory gastrointestinal bleeding over an 8-week period. Extensive work-up demonstrated small intestinal vascular malformations as the source of bleeding. Despite endoscopic therapy and hormonal therapy, bleeding continued and required transfusion of 54 units of packed red blood cells. Surgical therapy was offered to the patient but was declined. Ultimately, correction of the patient's underlying hypothyroidism resulted in cessation of gastrointestinal bleeding, and no further blood transfusion was necessary. To date, the patient has remained euthyroid without further gastrointestinal bleeding for 30 months.

Surgical aspects of Clostridium difficile colitis

BACKGROUND

There has been a marked increase in the number of surgical patients developing Clostridium difficile colitis. The epidemiology, pathogenesis, diagnosis and management of C. difficile infection were reviewed from a surgical perspective.

METHODS

A literature review was carried out based primarily on a Medline search of all English language publications containing the term C. difficile.

RESULTS

The recent dramatic increase in diagnosis of C. difficile infection amongst surgical patients results from heightened awareness of the condition, better methods of diagnosis, more widespread use of antibiotics for treatment and prophylaxis, and the increasing numbers of elderly and immunocompromised patients with malignancy, sepsis, and (multiple) organ failure being cared for within intensive therapy and high-dependency units. In addition to morbidity and mortality, the economic burden of C. difficile infection in terms of delayed discharge and other hospital costs is considerable.

CONCLUSION

Appropriate use of antibiotics, isolation of affected patients and meticulous hygiene measures on the part of staff are vital if the morbidity, mortality and economic consequences of this nosocomial infection are to be minimized.