Diagnosis and pathologic characteristics of medullary thyroid carcinoma-review of current guidelines

Background

Medullary thyroid carcinoma (mtc) is a rare malignancy of the thyroid gland, and raising awareness of the recommended diagnostic workup and pathologic characteristics of this malignancy is therefore important.

Methods

We reviewed the current clinical practice guidelines and recent literature on mtc, and here, we summarize the recommendations for its diagnosis and workup. We also provide an overview of the pathology of mtc.

Results

A neuroendocrine tumour, mtc arises from parafollicular cells ("C cells"), which secrete calcitonin. As part of the multiple endocrine neoplasia (men) type 2 syndromes, mtc can occur sporadically or in a hereditary form. This usually poorly delineated and infiltrative tumour is composed of solid nests of discohesive cells within a fibrous stroma that might also contain amyloid. Suspicious nodules on thyroid ultrasonography should be assessed with fine-needle aspiration (fna). If a diagnosis of mtc is made on fna, patients require baseline measurements of serum calcitonin and carcinoembryonic antigen. Calcitonin levels greater than 500 pg/mL or clinical suspicion for metastatic disease dictate the need for further imaging studies. All patients should undergo dna analysis for RET mutations to diagnose men type 2 syndromes, and if positive, they should be assessed for possible pheochromocytoma and hyperparathyroidism.

Summary

Although the initial diagnosis of a suspicious thyroid nodule is the same for differentiated thyroid carcinoma and mtc, the remainder of the workup and diagnosis for mtc is distinct.

How can we meet the information needs of patients with early stage papillary thyroid cancer considering radioactive iodine remnant ablation?

In patients with early stage papillary thyroid carcinoma (PTC) who have had a thyroidectomy, the decision must be made to accept or reject radioactive iodine remnant ablation (RRA). Counselling patients about this decision can be challenging, given the medical evidence uncertainties and the complexity of related information. Although physicians are the primary source of medical information for patients considering RRA, some patients have a desire for supplemental information from sources such as the internet. Yet, thyroid cancer resources on the internet are of variable quality, and some may not be applicable to the individual case. We have developed a computerized educational tool [called a decision aid (DA)], directed to patients with early stage papillary thyroid cancer, and intended as an adjunct to physician counselling, to relay evidence-based medical information on disease prognosis and the choice to accept or reject RRA. DAs are tools used to inform patients about available treatment options and have been utilized in oncologic decision-making. We tested our web-based DA in fifty patients with early stage PTC and found that it improved medical knowledge. Furthermore, participants found the technical usability of the tool acceptable. We are currently conducting a randomized controlled trial comparing the use of the DA plus usual care to usual care alone to confirm the educational benefit of the website and examine its impact on the decision-making process. In the future, DAs may play an expanded role as an adjunct to physician counselling in the care of patients with thyroid cancer.

Risk factors for low BMD in healthy men age 50 years or older: a systematic review

SUMMARY

In this systematic review, we summarize risk factors for low bone mineral density and bone loss in healthy men age 50 years or older. Consistent risk factors were: age, smoking, low weight, physical/functional limitations, and previous fracture. Data specific to men has clinical and policy implications.

INTRODUCTION

Osteoporosis is a significant health care problem in men as well as women, yet the majority of evidence on diagnosis and management of osteoporosis is focused on postmenopausal women. The objective of this systematic review is to examine risk factors for low bone mineral density (BMD) and bone loss in healthy men age 50 years or older.

MATERIALS AND METHODS

A systematic search for observational studies was conducted in MEDLINE, Cochrane Database of Systematic Reviews, DARE, CENTRAL, CINAHL and Embase, Health STAR. The three main search concepts were bone density, densitometry, and risk factors. Trained reviewers assessed articles using a priori criteria.

RESULTS

Of 642 screened abstracts, 299 articles required a full review, and 25 remained in the final assessment. Consistent risk factors for low BMD/bone loss were: advancing age, smoking, and low weight/weight loss. Although less evidence was available, physical/functional limitations and prevalent fracture (after age 50) were also associated with low BMD/bone loss. The evidence was inconsistent or weak for physical activity, alcohol consumption, calcium intake, muscle strength, family history of fracture/osteoporosis, and height/height loss.

CONCLUSION

In this systematic review, we identified several risk factors for low BMD/bone loss in men that are measurable in primary practice.

The osteoporosis care gap in men with fragility fractures: the Canadian Multicentre Osteoporosis Study

We examined osteoporosis diagnosis/treatment in 2,187 community dwelling men age 50+. After five years in the study, 90% of men with fragility fractures remained undiagnosed and untreated for osteoporosis. The need to treat fragility fractures is well established in guidelines, and these numbers represent an important care gap.

INTRODUCTION

Whether physicians in the community are recognizing and appropriately treating osteoporosis and fragility fractures in men remains unknown. We examined the rate of diagnosis and treatment in community dwelling men participating in the Canadian Multicentre Osteoporosis Study (CaMos).

METHODS

Between February 1996 and September 2002, 2,187 participants were recruited from nine sites across Canada and prospectively followed. Information on osteoporosis diagnosis, fractures, medications were collected annually by a detailed questionnaire. DXA examination of lumbar spine (L1-4) and hip were conducted at baseline and year five.

RESULTS

Diagnosis and treatment in men with clinical fragility fractures was low: at baseline and year five only 2.3% and 10.3% of men with a clinical fracture reported an osteoporosis diagnosis, respectively. At year five, 90% of men with a clinical fragility fracture were untreated. Hip fractures were the most commonly treated (37.5% by year five). A diagnosis of osteoporosis resulted in greater treatment: 67% of participants with diagnosed osteoporosis were treated with a bisphosphonate and 87% were taking calcium and/or vitamin D (year five).

CONCLUSIONS

In this population-based study, both a diagnostic and therapeutic gap existed between knowledge and practice related to fragility fractures and osteoporosis in men aged >or=50 years.

Could a policy of provision of hip protectors to elderly nursing home residents result in cost savings in acute hip fracture care? The case of Ontario, Canada

Hip fractures are an important problem in nursing homes. Hip protectors are external devices that decrease the risk of hip fracture in elderly nursing home residents. We estimated the overall healthcare cost savings from a hypothetical strategy of provision of hip protectors to elderly nursing home residents in Ontario, Canada. In a recent meta-analysis, we determined that a strategy of provision of hip protectors decreases the risk of hip fracture in nursing home residents.

INTRODUCTION

Our objective was to determine whether the provision of hip protectors to all Ontario nursing home residents aged > or =65 years could result in cost savings, stemming from reductions in initial hospitalizations for hip fracture.

METHODS

We conducted a cost analysis from a Ministry of Health perspective (one year cycle length). The efficacy of the intervention was estimated from a meta-analysis of randomized controlled trials.

RESULTS

A strategy of provision of hip protectors to all 60,775 elderly Ontario nursing home residents could result in an overall mean cost savings of 6.0 million Canadian dollars in one year (95% credibility interval, -26.4 million, 39.7 million), with a probability of cost savings of 0.63 (assuming no additional labor costs). In sensitivity analyses, decreasing hip protector price increased cost savings, whereas additional labor expenditures for application for hip protectors decreased cost savings.

CONCLUSION

In conclusion, if hip protectors can be provided to elderly Ontario nursing home residents without additional labor expenditures, there is a reasonable probability that such a strategy may result in healthcare cost savings.

The diagnostic efficacy of urinary fractionated metanephrines measured by tandem mass spectrometry in detection of pheochromocytoma

BACKGROUND

There are limitations to currently available biochemical tests for pheochromocytoma. Our objective was to evaluate the diagnostic efficacy of a novel tandem mass spectrometry assay for the measurement of fractionated urinary metanephrines in patients suspected to have a pheochromocytoma. We also developed clinically based cut-offs for positivity of this measurement.

METHODS

We examined the medical records of 506 patients (including 102 patients with a catecholamine-producing tumour) who underwent measurement of 24-h urinary fractionated metanephrines using tandem mass spectrometry as well as adrenal imaging at Mayo Clinic, Rochester. The cut-offs for positivity were defined as follows: total metanephrines (sum of the metanephrine fractions) 5163 nmol/day, normetanephrine fraction 4001 nmol/day, metanephrine fraction 1531 nmol/day. Receiver operating characteristic (ROC) curves were constructed.

RESULTS

The diagnostic efficacy was as follows: normetanephrine fraction sensitivity 87.3% [(95% confidence interval (CI) 79.4-92.4%], specificity 95.0% (92.5-96.8); metanephrine fraction sensitivity 56.9% (47.2-66.1), specificity 95.0% (92.5-96.8); elevation of either normetanephrine or metanephrine fraction sensitivity 97.1% (91.7-99.0) and specificity 91.1% (87.9-93.5). Areas under the ROC curves (AUCs) were 0.972 (95% CI 0.955-0.990) for the normetanephrine fraction, 0.800 (0.741-0.858) for the metanephrine fraction, 0.991 (0.985-0.996) for total metanephrines, and 0.991 (0.985-0.996) for a regression-derived ROC curve incorporating both the metanephrine and normetanephrine fractions.

CONCLUSION

Measurement of 24-h urinary fractionated metanephrines by a tandem mass spectrometry assay appears to be an effective biochemical technique in the investigation of pheochromocytoma.

Health-related quality of life measurements in elderly Canadians with osteoporosis compared to other chronic medical conditions: a population-based study from the Canadian Multicentre Osteoporosis Study (CaMos)

The objective of this research was to determine the relative decrement in health-related quality of life, as measured by the health utilities index mark 3 (HUI3), in osteoporosis compared to other chronic medical conditions. The impact of chronic medical conditions other than osteoporosis on HUI3 measurements had been previously established in the 1996/1997 Canadian National Population Health Survey (NPHS). The Canadian Multicentre Osteoporosis Study (CaMos) is a national population-based study in which regional participants were randomly recruited, regardless of presence of osteoporosis. We analyzed data from participants aged > or = 65 years who completed a baseline HUI3 questionnaire and provided information on their medical history (n=3,750). We determined the age- and gender-adjusted mean decrement in HUI3 for several chronic medical conditions, including osteoporosis. The mean changes in HUI3 adjusted for age and gender (with 95% confidence intervals) were as follows: arthritis -0.10 (-0.11, -0.09), chronic obstructive pulmonary disease (COPD) -0.07 (-0.09, -0.05), diabetes mellitus -0.05 (-0.08, -0.03), heart disease -0.06 (-0.08, -0.04), hypertension -0.02 (-0.03, -0.01), and osteoporosis -0.08 (-0.11, -0.06), respectively (model r2=0.17; P<0.0001). These findings were comparable to those observed in the NPHS, with the exception of osteoporosis, which had not been previously studied in this fashion. The decrement in HUI3 score seen in participants with osteoporosis was comparable to that observed in other chronic medical conditions, such as arthritis, COPD, diabetes mellitus or heart disease.

Does a combination regimen of thyroxine (T4) and 3,5,3'-triiodothyronine improve depressive symptoms better than T4 alone in patients with hypothyroidism? Results of a double-blind, randomized, controlled trial

Some hypothyroid patients receiving levothyroxine replacement therapy complain of depressive symptoms despite normal TSH measurements. It is not known whether adding T(3) can reverse such symptoms. We randomized 40 individuals with depressive symptoms who were taking a stable dose of levothyroxine for treatment of hypothyroidism (excluding those who underwent thyroidectomy or radioactive iodine ablation of the thyroid) to receive T(4) plus placebo or the combination of T(4) plus T(3) in a double-blind manner for 15 wk. Participants receiving combination therapy had their prestudy dose of T(4) dropped by 50%, and T(3) was started at a dose of 12.5 micro g, twice daily. T(4) and T(3) doses were adjusted to keep goal TSH concentrations within the normal range. Compared with the group taking T(4) alone, the group taking both T(4) plus T(3) did not report any improvement in self-rated mood and well-being scores that included all subscales of the Symptom Check-List-90, the Comprehensive Epidemiological Screen for Depression, and the Multiple Outcome Study (P > 0.05 for all indexes). In conclusion, the current data do not support the routine use of combined T(3) and T(4) therapy in hypothyroid patients with depressive symptoms.

Primary aldosteronism: factors associated with normalization of blood pressure after surgery

BACKGROUND

Hypertension often persists after adrenalectomy for primary aldosteronism.

OBJECTIVE

To determine factors associated with resolution of hypertension after adrenalectomy for primary aldosteronism.

DESIGN

Retrospective cohort study.

SETTING

Tertiary care referral center in Rochester, Minnesota.

PATIENTS

All patients who underwent adrenalectomy for primary aldosteronism between 1 January 1993 and 31 December 1999.

MEASUREMENTS

Preoperative plasma renin activity, plasma and urinary aldosterone concentrations, and adrenal imaging. Follow-up blood pressure, measured at a clinic visit or at home, was reviewed.

RESULTS

97 adrenalectomies were performed, and follow-up was available in 93 patients. Hypertension was resolved at follow-up (blood pressure < 140/90 mm Hg) without use of antihypertensive agents in 31 of 93 patients (33%). According to a stepwise multivariable logistic regression analysis adjusted for duration of follow-up, resolution of hypertension was independently associated with family history of hypertension in no more than 1 first-degree relative (odds ratio [OR], 10.9; P < 0.001) and preoperative use of two or fewer antihypertensive agents (OR, 4.7; P = 0.005). Additional factors associated with resolution of hypertension based on univariate analysis included younger age, shorter duration of hypertension, higher preoperative ratio of plasma aldosterone concentration to plasma renin activity, and higher urine aldosterone level (P < 0.05).

CONCLUSIONS

Resolution of hypertension after adrenalectomy for primary aldosteronism is independently associated with a lack of family history of hypertension and preoperative use of two or fewer antihypertensive agents.

Remnant lipoproteins induce endothelial plasminogen activator inhibitor-1

Remnant lipoproteins (RLPs) accumulate in type III hyperlipoproteinemia, a condition associated with significant cardiovascular morbidity. The effect of RLPs on fibrinolysis is unknown. Our aim was to study the effect of RLPs on endothelial expression of plasminogen activator inhibitor-1 (PAI-1). After 24-h culture of human aortic endothelial cells with RLPs at concentrations of 0 (control), 0.038, or 0.076 mg triglyceride/mL, postculture PAI-1 antigen concentrations were: 870 +/- 80, 1963 +/- 183 (P = 0.005), and 3551 +/- 177 ng/mL (P < 0.001), respectively. Furthermore, after 24-h incubation of endothelial cells with RLPs (0 or 0.076 mg triglyceride/mL), PAI-1 activity increased from 0.667 +/- 0.144 to 1.268 +/- 0.198 U/mL, respectively (P = 0.008) and endothelial PAI-1 mRNA increased to 2.7 +/- 0.66 that of control (P = 0.048). In conclusion, RLPs from patients with type III hyperlipoproteinemia induce endothelial cell PAI-1 expression, which may contribute to a prothrombotic state.

Cardiac phaeochromocytoma presenting with severe hypertension and chest pain

Cardiac phaeochromocytoma is a rare cause of endocrine hypertension. We report a case of a 25-year-old woman, who presented with severe hypertension and intermittent chest pain. The patient denied typical phaeochromocytoma spells of palpitation, headache, and diaphoresis. The 24-hr urinary excretion of norepinephrine was increased sevenfold above the upper limit of normal; however, the excretion of total metanephrines, epinephrine, and dopamine were normal. Computed tomography (CT) scan of the abdomen was normal. An 131I-labelled metaiodobenzylguanidine (MIBG) scan was falsely negative while the patient was taking labetalol. The cardiac phaeochromocytoma was localized with indium-111-pentetreotide scintigraphy and chest magnetic resonance imaging scan. Repeat 123I-MIBG scintigraphy was positive after discontinuing labetalol. The cardiac phaeochromocytoma was located in the right atrial groove, adjacent to the tricuspid valve, and contained multiple feeder arteries from the right coronary artery. After treatment with volume expansion, alpha-methyl-p-tyrosine, and alpha- and beta-adrenergic blockade, surgical resection was performed. While under cardiopulmonary bypass, coronary bypass grafting and tricuspid annuloplasty were performed to facilitate the complete surgical resection of the 4.5-cm tumour. The surgical course was uncomplicated, with complete cure of hypertension and normalization of catecholamine excretion. Post-operative cardiac function, as measured by echocardiogram, was normal. Although cardiac phaeochromocytoma may be highly vascular, invasive and difficult to resect, it can be cured.

Loss of hypoglycemia awareness in an adolescent with type 1 diabetes mellitus during treatment with fluoxetine hydrochloride

A 17-year-old boy with type 1 diabetes mellitus developed new loss of hypoglycemia awareness while being treated with fluoxetine hydrochloride for depression. Hypoglycemia unawareness resolved after this medication was discontinued.

Tension pneumocranium, a rare complication of transsphenoidal pituitary surgery: Mayo Clinic experience 1976-1998

We describe four cases of symptomatic pneumocranium, a rare, potentially life-threatening complication of transsphenoidal pituitary surgery. Symptomatic pneumocranium manifested as impaired mental status, headaches, and grand mal seizures, early in the postoperative course after transsphenoidal pituitary surgery. Furthermore, a Cushing response, including systemic hypertension and bradycardia (secondary to intracranial hypertension) was seen, which has not been previously described in association with symptomatic pneumocranium. We describe a previously unreported risk factor for tension pneumocranium, untreated obstructive sleep apnea. Other factors predisposing to tension pneumocranium in our patients included: cerebrospinal fluid leaks, postoperative positive-pressure mask ventilation, large pituitary tumors, and intraoperative lumbar drainage catheters. Surgical drainage of the pneumocranium and repair of any coexistent cerebrospinal fluid leak markedly improved neurologic status. Symptomatic pneumocranium occurring early in the postoperative course after transsphenoidal pituitary surgery is rare, but prompt recognition and treatment of this condition can be life-saving.

Effect of temperature on digital systolic pressures in lower limb in arterial disease

BACKGROUND

Toe pressures correlate with the chances of healing of skin lesions and with the risk of amputation and mortality. They are not affected by incompressibility of the tibial vessels, which may render ankle pressures inaccurate and reflect the overall arterial obstruction down to the digits. Digital pressures, however, may be affected by temperature.

METHODS AND RESULTS

Measurements under routine laboratory conditions were compared with those at controlled temperatures in 77 limbs with arteriosclerosis obliterans. The desired local temperatures were attained by perfusing water through the cuffs for 7 minutes before the measurements while the flow was interrupted by a tourniquet to allow equilibration of the toe and water temperatures. Mean toe pressure of 34 +/- 4 mm Hg at 10 degrees C was significantly lower (p less than 0.001) than the values during routine measurements (57 +/- 4 mm Hg) and at 30 degrees C (69 +/- 4 mm Hg). The pressure at 30 degrees C was 10 +/- 3 mm Hg higher than during routine measurements when initial digit temperature was below 30 degrees C (p less than 0.01) but not when it was higher. Measurements at 3 degrees C increments from 27 degrees C to 39 degrees C showed progressive increase in pressure (p less than 0.01).

CONCLUSIONS

Pressures at 36 degrees C and 39 degrees C were the highest but were not significantly different from each other. When toe temperature is low under routine conditions, the measured pressure may be falsely low, probably because of an effect on the main digital arteries that leads to delayed opening during deflation of the cuffs. Measurements at warm local temperature will increase the accuracy of the assessment of the severity of the arterial obstruction and may improve prediction of spontaneous healing of skin lesions.