Intestinal disorders in hypothyroidism. Clinical and manometric study

From hormone replacement therapy to regenerative scaffolds: A review of current and novel primary hypothyroidism therapeutics

Primary hypothyroidism severely impacts the quality of life of patients through a decrease in the production of the thyroid hormones T3 and T4, leading to symptoms affecting cardiovascular, neurological, cognitive, and metabolic function. The incidence rate of primary hypothyroidism is expected to increase in the near future, partially due to increasing survival of patients that have undergone radiotherapy for head and neck cancer, which induces this disease in over half of those treated. The current standard of care encompasses thyroid hormone replacement therapy, traditionally in the form of synthetic T4. However, there is mounting evidence that this is unable to restore thyroid hormone signaling in all tissues due to often persistent symptoms. Additional complications are also present in the form of dosage difficulties, extensive drug interactions and poor patience compliance. The alternative therapeutic approach employed in the past is combination therapy, which consists of administration of both T3 and T4, either synthetic or in the form of desiccated thyroid extract. Here, issues are present regarding the lack of regulation concerning formulation and lack of data regarding safety and efficacy of these treatment methods. Tissue engineering and regenerative medicine have been applied in conjunction with each other to restore function of various tissues. Recently, these techniques have been adapted for thyroid tissue, primarily through the fabrication of regenerative scaffolds. Those currently under investigation are composed of either biopolymers or native decellularized extracellular matrix (dECM) in conjunction with either primary thyrocytes or stem cells which have undergone directed thyroid differentiation. Multiple of these scaffolds have successfully restored an athyroid phenotype in vivo. However, further work is needed until clinical translation can be achieved. This is proposed in the form of exploration and combination of materials used to fabricate these scaffolds, the addition of peptides which can aid restoration of tissue homeostasis and additional in vivo experimentation providing data on safety and efficacy of these implants.

The underlying mechanisms: how hypothyroidism affects the formation of common bile duct stones-a review

For decades, one well-known risk factor for the development of gallbladder stones has been hypothyroidism. Recent studies have interestingly reported that the risk in particular for common bile duct (CBD) stones increases in clinical and subclinical hypothyroidism. There are multiple factors that may contribute to the formation and/or accumulation of CBD stones in hypothyroid patients, including decreased liver cholesterol metabolism, diminished bile secretion, and reduced sphincter of Oddi relaxation. This paper focuses on the mechanisms possibly underlying the association between hypothyroidism and CBD stones. The authors conclude that when treating patients with CBD stones or microlithiasis, clinicians should be aware of the possible hypothyroid background.

Ogilvie's syndrome in a case of myxedema coma

Ogilvie's syndrome [acute colonic pseudo-obstruction (ACPO)] presents as massive colonic dilatation without a mechanical cause, usually in critically ill patients due to imbalanced sympathetic and parasympathetic activity. The initial therapy remains conservative with supportive measures (correction of metabolic, infectious or pharmacologic factors) followed by neostigmine and decompressive colonoscopy. Surgery is reserved for patients with clinical deterioration or with evidence of colonic ischemia or perforation. A 60-year-old lady presented with fever, altered sensorium, obstipation, bradycardia and abdominal distension. Investigation revealed hyponatremia and acute colonic pseudo-obstruction. Supportive measures and decompressive colonoscopy were not of great benefit. Thyroid profile was suggestive of primary hypothyroidism. Colonic motility was restored only on starting thyroxin. The case is illustrative of the need to consider hypothyroidism, a common endocrine disorder, in the differential diagnosis of Ogilvie's.

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.

Diagnosis and management of adult patients with chronic intestinal pseudoobstruction

Chronic intestinal pseudoobstruction (CIP) is a motility syndrome that presents with symptoms and signs of intestinal obstruction and radiographic evidence of dilated bowels, but no anatomic obstruction can be found. It primarily is a disorder of small bowel motility, but it can occur anywhere in the gastrointestinal tract. This review will focus on the diagnosis and treatment of adult patients with CIP. The clinical presentation of CIP is variable, and its incidence is rare. It is a disorder with a multitude of etiologies, many of which are poorly understood. To properly manage the patient, clinicians should be aware of the various symptoms, signs, and systemic diseases that are associated with CIP. Diagnostic studies are needed to confirm the diagnosis, identify the etiology, and search for coexisting motility dysfunction. The management goals of CIP are to restore proper nutrition and fluid balance, relieve symptoms, improve intestinal motility, and treat complications.

Gastric emptying function changes in patients with thyroid cancer after withdrawal of thyroid hormone therapy

BACKGROUND

Hypothyroidism is commonly thought to cause decreased gastric emptying but is mostly associated with autoimmune disease. In the present study the gastric emptying function of thyroid cancer patients with severe hypothyroidism of short duration was evaluated with a radionuclide solid meal gastric emptying study.

METHODS

Twenty-two patients who had undergone surgical operation and (131)I ablation for thyroid cancer participated in solid meal gastric emptying studies before the withdrawal of thyroxine and then again 4 weeks after the withdrawal of thyroxine. Eleven patients had an additional gastric emptying study at 6 weeks after withdrawal of thyroxine. Gastric emptying curves and emptying parameters were calculated. Student's paired t-test was used for statistical analysis of data for all cases between the baseline and at 4 weeks after withdrawal. An additional repeated measure anova with multiple comparisons was performed on data between baseline, 4 weeks and 6 weeks after withdrawal for the other 11 patients. All P values presented are two-tailed and the significance level is 0.05.

RESULTS

Hypothyroidism status was confirmed by the marked change of the serum thyroxine and thyroid-stimulating hormone 4 weeks and 6 weeks after withdrawal of the thyroxine replacement (P < 0.001). The gastric half-emptying time and emptying rate changed significantly after short-term severe thyroid hormone deficiency (P < 0.005). However, the length of the lag phase did not have a statistically significant change at 4 weeks or 6 weeks after withdrawal of the thyroxin replacement (P = 0.219 and 0.142).

CONCLUSIONS

Hypothyroidism following the withdrawal of the thyroxine replacement in thyroid cancer patients preparing for (131)I cancer work-up can significantly prolong gastric half-emptying time and emptying rate.

Noninvasive detection of ischemic bowel

PURPOSE

Acute mesenteric arterial occlusion is an abdominal catastrophe that carries high morbidity and mortality rates. Current diagnostic methods, however, lack sensitivity and specificity and do not provide information about the viability of the affected bowel. Early diagnosis and intervention would improve patient outcomes and survival rates. The basic electrical rhythm (BER) is the omnipresent electrical slow wave of the gastrointestinal tract that characterizes the underlying electrical activity of the bowel. BER frequency is known to fall with ischemia. Superconducting quantum interference devices (SQUIDs) can detect BER by measuring the magnetic fields generated by the electrical activity of the smooth muscle of the small bowel. The purpose of this study was to determine the ability of a SQUID to detect mesenteric ischemia in a free-lying section of small bowel in an animal model of acute superior mesenteric artery occlusion.

METHODS

Seven adult male rabbits (six experimental and one control) were studied with transabdominal SQUID and electrode recordings during baseline and after the induction of mesenteric ischemia with balloon occlusion of the superior mesenteric artery. Continuous recordings were taken for 120 minutes of ischemia and analyzed with autoregressive spectral analysis to determine the BER frequency during specific time points of the study. Two independent investigators blinded to the experimental preparation examined the results to determine whether there was decreased BER frequency and thus ischemia. The results are expressed as mean +/- SEM, and paired t tests were used to determine statistical significance.

RESULTS

BER was detected in all seven animals and fell from 10.7 +/- 0.5 cpm to 7.0 +/- 1.8 cpm after 30 minutes of ischemia in the magnetic channels (P <.05, with t test). The fall in BER was detected by the SQUID in all six experimental animals. The blinded observers correctly identified healthy and ischemic magnetic data recording, with a sensitivity of 94% and specificity of 100%.

CONCLUSION

SQUIDs can noninvasively detect bowel ischemia early in a free-lying segment of small bowel in this animal model with a high degree of sensitivity and specificity.

Unusual presentations of hypothyroidism

Hypothyroidism is a commonly diagnosed endocrine disorder. Typical signs and symptoms of hypothyroidism include lethargy, cold intolerance, hoarseness, dry skin, constipation, delayed relaxation phase of deep tendon reflexes, and bradycardia. Hypothyroidism, presenting with such classic manifestations, usually is readily recognized and, therefore, easy to diagnose. Occasionally patients have less commonly emphasized symptoms, making the diagnosis less apparent. Such atypical presentations may suggest other diseases as the primary problem and, therefore, the initial focus of attention is on a diagnosis other than hypothyroidism. We have observed patients with hypothyroidism with rare manifestations. The diagnosis of primary hypothyroidism was established in all patients by thyroid function tests, and initiation of thyroid hormone therapy resulted in significant improvement of the presenting symptom. We considered it instructive to report about these patients because it shows the need to be aware of the unusual presentations of hypothyroidism and to consider hypothyroidism when confronted with atypical clinical manifestations.

Acute colonic surgery and unrecognized hypothyroidism: a warning. Report of six cases

PURPOSE

This study was designed to highlight the significant morbidity related to undetected hypothyroidism in the elderly who are undergoing emergency surgery.

METHOD

Case reports of six patients who presented with acute colonic surgical conditions are reviewed.

RESULTS

Six cases of undetected hypothyroidism in a group of elderly patients was unmasked at the time of surgery for acute colonic conditions or in the perioperative period. These patients experienced increased morbidity, but once detected and treated, all but one had an uneventful recovery.

CONCLUSION

Unrecognized hypothyroidism may lead to unnecessary surgery or even a potentially fatal outcome. A heightened awareness of this not so uncommon entity is mandatory.

Case report: reversible gastroparesis in patients with hypopituitary disease

A 72-year-old woman with chronic fatigue, malaise, weight loss, nausea, and vomiting was treated unsuccessfully for gastroparesis for more than 2 years. Clinical and biochemical features of hypopituitary disease and symptoms of a nonsecreting pituitary tumor had been overlooked and became apparent only after the differential diagnosis of hyponatremia was considered. Transsphenoidal resection of the pituitary tumor and appropriate 1-thyroxine and hydrocortisone replacement returned her gastric emptying time to normal and relieved her symptoms. Primary and secondary deficits of l-thyroxine and cortisol should be considered when making a possible diagnosis of gastroparesis.

Noninvasive diagnosis of mesenteric ischemia using a SQUID magnetometer

OBJECTIVE

The authors assessed the ability of a Superconducting Quantum Interference Device (SQUID) magnetometer to noninvasively detect mesenteric ischemia in a rabbit model.

SUMMARY BACKGROUND DATA

Superconducting Quantum Interference Device magnetometers have been used to detect magnetic fields created by the basic electrical rhythm (BER) and to detect changes in BER of exteriorized bowel of anesthetized rabbits during mesenteric ischemia.

METHODS

The BER of rabbit ileum was noninvasively measured transabdominally using a SQUID magnetometer and compared with the electrical activity recorded with surgically implanted serosal electrodes before, during, and after snare occlusion of the superior mesenteric artery.

RESULTS

Transabdominal SQUID recording of BER frequency was highly correlated to the measurements obtained with electrodes (R = 0.91). Basic electrical rhythm frequency decreased from 16.4 +/- 0.8 to 8.3 +/- 0.3 cpm (p < 0.001) after 25 minutes of ischemia. Reperfusion of ischemic bowel resulted in recovery of BER frequency to 14.3 +/- 0.4 cpm 10 minutes after blood flow was restored.

CONCLUSIONS

A SQUID magnetometer is capable of noninvasively detecting mesenteric ischemia reliably and at an early stage by detecting a significant drop in BER frequency. These positive findings have encouraged the authors to continue development of clinically useful, noninvasive, detection of intestinal magnetic fields using SQUID magnetometers.

Colorectal manifestations of endocrine disease

PURPOSE

The aim of this review is to alert the colon and rectal surgeon to the colorectal manifestations of endocrine disease.

METHODS

This report was obtained by a review of the medical literature. Endocrine disease may initially present as a symptom felt to be referable to colorectal disease. Furthermore symptoms of well-established endocrine disorders may have refractory colorectal symptoms.

RESULTS

Constipation is the most common gastrointestinal symptom of diabetics; however, in patients with brittle diabetes, diarrhea may be chronic and intermittent. Unexplained diarrhea, despite an exhaustive work-up for an etiology, should alert the clinician to the possibility of a pancreatic endocrine tumor. Thyroid disorders, depending on activity of the gland, may have refractory constipation, diarrhea, or steatorrhea as the only presenting symptoms. Constipation is a common symptom of hypercalcemia, secondary to hyperparathyroidism. Primary hyperparathyroidism has been associated with increased incidence of malignancies, specifically of colonic origin. In patients with acromegaly a threefold to eightfold increased risk of colon carcinoma or adenomatous polyps is seen. Chronic adrenal insufficiency may present initially as diarrhea and malabsorption. The adrenal gland is a frequent site of metastases from colorectal cancer. Pheochromocytomas may be a cause of occult gastrointestinal bleeding or ischemic colitis.

CONCLUSION

Unexplained symptoms referable to the colon and rectum should alert the clinician to the possibility of an underlying endocrine disorder.

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

Myxedema megacolon is rare; usually, it manifests with abdominal distention, flatulence, and constipation. Herein we describe a 72-year-old man who had intermittent diarrhea, bloating, and abdominal pain for more than a year. Cultures of stool specimens for Clostridium difficile enterotoxin were variably positive and negative. Colonoscopic biopsy specimens were thought to be consistent with chronic ischemia. Thyroid function tests showed severe hypothyroidism; the patient's symptoms resolved with thyroid hormone replacement. We hypothesize that gross dilatation of the colon, attributed to myxedema, was followed by intestinal ischemia and complicated by recurrent episodes of pseudomembranous colitis. A review of the relevant literature is provided. This unusual manifestation of myxedema should be considered in the differential diagnosis when a patient has diarrhea, bloating, and abdominal pain.

Circulating somatostatin after oral glucose in hypothyroidism

The response of circulating somatostatin-like immunoactivity (SLI) to oral glucose and its relation to other pancreatic islet cell hormones were studied in 10 hypothyroid subjects before and after treatment. None of the patients suffered from diabetes mellitus or obesity. Compared with normal controls, the hypothyroid subjects had higher fasting and stimulated SLI levels but lower fasting pancreatic glucagon levels. Integrated glucose and insulin responses following glucose ingestion were normal, but the peak insulin response was delayed to 120 min suggesting impaired pancreatic beta-cell response to oral glucose. On the other hand, the peak response of plasma C-peptide was higher probably because of a reduction in metabolic clearance. In both hypothyroid subjects and controls, a significant correlation was found between the maximal increment of SLI and the maximal decrement of glucagon following oral glucose. In conclusion, plasma SLI is increased in hypothyroidism. The changes in SLI may be due to either an increased hormonal secretion or a reduced metabolic clearance in hypothyroidism. This elevated SLI might contribute to the slower gastrointestinal motility observed in hypothyroidism. Our data also suggest that the reduction in glucagon secretion may be secondary to the increase in circulating SLI.

Orocaecal transit time in health and in thyroid disease

Altered bowel habit commonly occurs in thyroid disease. We measured orocaecal transit in healthy volunteers and in hyperthyroid and hypothyroid patients before and after treatment, using the lactulose hydrogen breath test incorporating a standard liquid meal to obtain a more physiological assessment. Mean transit time in 12 control subjects was 85 (8) minutes (mean (SE)) (mean coefficient of variation between replicate studies, 8.6% (3%)). In eighteen hyperthyroid patients transit was more rapid at 49 (4) minutes (p less than 0.01). Ten hypothyroid patients had a transit time similar to controls at 91 (9) minutes. Transit time returned to normal in thyrotoxic patients after treatment but in eight hypothyroid patients retested, it remained unchanged. Our findings suggest that (a) the inclusion of a liquid meal provides a reproducible method of measuring orocaecal transit using the lactulose hydrogen breath test, (b) rapid small bowel transit in thyrotoxicosis may be one factor in the diarrhoea which is a feature of the disease and (c) if altered gut transit is the cause of sluggish bowel habit in hypothyroidism, delay in the colon, and not small bowel, is likely to be responsible.

A role for colonic stasis in the pathogenesis of disease related to Clostridium difficile

The records of 133 consecutive patients (65 men, 68 women; age range, 15 months to 88 years; median, 57 years) with either a positive Clostridium difficile stool culture or toxin assay from 1982 to 1984 were reviewed in order to assess the pattern of this disease in a large hospital and to examine the type of patient at risk. All patients had diarrhea and/or bloody stools (121 and 36, respectively). Less specific symptoms were common. Most patients had been exposed to multiple antibiotics, but of those who had received only one agent, cephalosporins were most common (21/43). Nineteen patients had cancer chemotherapy. C. difficile toxin assay was positive in 106, culture was positive in 74, and pseudomembranes were seen in six of the 39 patients who underwent endoscopy. Treatment consisted of stopping antibiotic therapy alone (86 percent response), oral vancomycin (88 percent response) or metronidazole (82 percent response). The overall mortality rate was 23 percent, due to C. difficile colitis in three of 31 cases. Many patients were receiving medications or had other diseases associated with fecal stasis. There is much circumstantial evidence to support a role for fecal stasis in the pathogenesis of C. difficile disease. Patients predisposed to colonic stasis who are receiving antibiotics should be considered at risk for this disease, and preventative measures should be taken to decrease stool transit times.

Gastrointestinal motility disorders

A classification of gastrointestinal motility disorders is offered based upon the type of disorder in transit (delay or acceleration), and the region of the gastrointestinal tract affected. Specific abnormalities of myoelectrical patterns are identified when possible and related to disturbances in transit in the stomach and small bowel.

Myxedema megacolon after external neck irradiation

Myxedema megacolon is a rare manifestation of hypothyroidism. It may respond to appropriate treatment but is sometimes irreversible, resulting in fatal complications. Two possible mechanisms to explain the colonic atony include (1) myxomatous infiltration of the submucosa with separation of the muscular fibers from the ganglia of Auerbach's plexus, and (2) severe autonomic neuropathy affecting the extrinsic nerves to the colon and the myenteric plexus. Histology from our case supports the first proposed mechanism. Urecholine challenge and manometric measure response may help predict reversibility of colonic atony. Treatment should be individualized and should include factors such as age, duration of symptoms, and other medical illness. Low-dose oral or intravenous triiodothyronine is effective. Hypothyroidism following external radiation of the neck for lymphoma is not uncommon, and the risk increases following one or more lymphangiograms. Such patients should be followed up with regular TSH estimations for at least three years.

Myxedema megacolon

The radiological findings on barium enema examination of 239 patients with thyroid deficiency (192 hypothyroid and 47 myxedematous) were reviewed. A new radiologic finding of transverse ridging superimposed on megacolon is described in myxedema and an explanation for this finding is postulated. The colonic findings associated with thyroid deficiency are presented.

Myoelectrical and mechanical activity of stomach and intestine in hypothyroid dogs

Myoelectrical activity was studied in normothyroid and hypothyroid Labrador dogs in the resting state, following injection of pentagastrin, bethanechol chloride, and after feeding. Hypothyroidism was produced by total thyroidectomy and chronic treatment with thiouracil. Electrodes were surgically implanted over the serosa of the stomach, duodenum, jejunum, and ileum and used for repeated recording of myoelectrical activity of gastrointestinal muscles. A strain gauge was implanted over the gastric antrum and served to record mechanical activity of the stomach. As compared with control dogs, hypothyroid animals showed (a) decreased frequency of electrical control activity of the stomach and jejunum, (b) decreased occurrence of electrical response activity (spike potentials) following stimulation, and (c) decreased mechanical response to the same stimulants, ie, pentagastrin, bethanechol chloride, and food.