Measurement of anti-TSH receptor antibodies: what is the correct cut-off value?

BACKGROUND: Autoantibodies against the thyroid stimulating hormone receptor, thyrotropin receptor autoantibodies (TRAb) are diagnostic for Graves' disease and can be measured by different methods. As antibody concentrations are not comparable between methods, appropriate cut-off values need to be established for every single method. For a third-generation TRAb assay (Phadia, Thermofisher), the manufacturer determined the cut-off value in a study population consisting of Graves' disease (both newly diagnosed and patients under treatment) and non-Graves' disease patients. The aim of this study was to verify whether this cut-off value holds true in our population. METHODS: Retrospective analysis was performed on TRAb measurements collected over a period of six months from all patients referred for TRAb testing. For our study, we included patients that were newly diagnosed with hyperthyroidism including Graves' disease, multinodular goitre, toxic adenoma, and thyroiditis. Furthermore, we included Graves' patients that were under treatment at the time of TRAb measurement. RESULTS: Whereas all patients with Graves' disease had positive TRAb, few patients with multinodular goitre, toxic adenoma, and thyroiditis scored positive for TRAb. ROC curve analysis revealed a cut-off value of 4.5 IU/l (compared to 3.3 IU/l established by the manufacturer). Newly diagnosed Graves' patients had higher TRAb concentrations compared to patients under treatment. CONCLUSION: The cut-off value of this immunoassay should probably be set higher in untreated Graves' patients than proposed by the manufacturer as the cut-off value should be determined in a study population excluding Graves' patients under treatment. The overall clinical picture remains crucial in the diagnosis of Graves' disease.

Thyrotoxic periodic paralysis: an unusual presentation of hyperthyroidism.

Thyrotoxic periodic paralysis (TPP) is a complication of hyperthyroidism among Asians, characterised by sudden onset of hypokalaemia and muscle paralysis. Several factors may contribute to a delay in diagnosis, including the subtlety of hyperthyroidism, the transient nature of the events and the rarity of this disease in the West. As life-threatening arrhythmias may occur during an attack, awareness among physicians is necessary for early recognition and treatment. Advances have been made in understanding the pathophysiological mechanism leading to hypokalaemia, which include recently identified mutations of the inwardly rectifying potassium channel Kir2.6. Treatment includes the supplementation of potassium, a nonselective beta-blocker, and ultimately treatment of the underlying hyperthyroidism. Here we report three cases of TPP in the Netherlands, and review the literature on clinical features, pathophysiological hypothesis and treatment.

ENDOCRINOLOGY IN PREGNANCY: Pheochromocytoma in pregnancy: case series and review of literature.

Pheochromocytoma in pregnancy is extremely rare. Early recognition is crucial as antepartum diagnosis can largely decrease maternal and fetal mortality rates. As symptoms of pheochromocytoma are rather similar to those of other far more common causes of hypertension during pregnancy, timely diagnosis is a challenge. In pregnant patients, similar to non-pregnant patients, increased plasma and/or 24-h urine (nor)metanephrine concentrations most reliably confirm the diagnosis of pheochromocytoma. MRI and ultrasound are the only imaging modalities that can be used safely during pregnancy to localize the tumor. During pregnancy, pretreatment consists of alpha blockade as usual. However, dosing of α-adrenergic receptor blockers during pregnancy is a challenge as hypertension must be treated while preserving adequate uteroplacental circulation. When the diagnosis is made within the first 24 weeks of pregnancy, it is generally recommended to remove the tumor in the second trimester, while resection is generally postponed till after delivery when the diagnosis is made in the third trimester and medical pretreatment is sufficient. Both during and after pregnancy, laparoscopic surgery is the preferred approach for resection of the tumor. There is no consensus in literature about the preferred route and timing of delivery. Therefore, in our opinion, decisions should be made on an individual basis by an experienced and dedicated multidisciplinary team. Over the last decades, maternal and fetal prognosis has improved considerably. Further increasing awareness of this rare diagnosis and treatment of these patients by a dedicated team in a tertiary referral hospital are critical factors for optimal maternal and fetal outcome.

Protocolised inpatient care of diabetes mellitus.

BACKGROUND: The prevalence of hyperglycaemia in patients with diabetes mellitus at admission is high. Prevention and treatment is important to prevent further clinical complications. We have conducted a study evaluating implementation of a new protocol to standardise inpatient care of patients with diabetes mellitus. METHODS: A retrospective study including all glucose measurements of adult patients with diabetes mellitus type 1 o r 2 , admitted to a surgery department, was performed before and after implementation of the new protocol. This protocol included direct consultation of an internist and diabetes specialist nurse at admission, who initiated a daily treatment program and adjustment scheme based on glucose measurements four times a day by the HemoCue201DM glucose point of care device. We compared the prevalence of hyperglycaemia and hypoglycaemia before and after implementation with logistic regression analyses adjusted for age and gender. RESULTS: Overall, 360 patients with diabetes mellitus type 1 or 2 with 5322 glucose measurements were included. The risk of developing hyperglycaemia was significantly reduced after implementation of the protocol (22 patients with 65 hyperglycaemias) compared with before the intervention (70 patients with 417 hyperglycaemias) (RR adjusted 0.24 (95% confidence interval 0.19; 0.32)). Overall, 45 patients experienced 95 episodes of hypoglycaemia, which did not differ significantly between the two groups. CONCLUSION: After implementation of a new protocol to standardise inpatient care of diabetes mellitus we established a decrease in the risk to develop hyperglycaemia of 76% without an increased risk of developing hypoglycaemia. Implementation of this protocol required frequent glucose measurements which are facilitated by point of care glucose measurements.

Tiotropium Handihaler and the risk of cardio- or cerebrovascular events and mortality in patients with COPD.

BACKGROUND: Tiotropium has been associated with an increased risk of mortality and/or cardiovascular events. Recent data from RCTs suggests tiotropium Handihaler to be safe, but its safety has not yet been fully investigated under real-life circumstances. METHODS: We conducted 2 nested case-control studies in a COPD cohort from the Dutch IPCI database. In the first case-control study, cases had a cardiovascular or cerebrovascular endpoint (CCVE): stroke and transient ischemic attack (TIA), myocardial infarction, heart failure and/or ventricular arrhythmia. In the second, cases were all patients who died. Cases were matched to controls on age, sex and index date. Conditional logistic regression analysis was used to calculate adjusted odds ratios (OR(adj)) with 95% confidence intervals (CI) for tiotropium vs. long-acting beta-agonists (LABA). RESULTS: Within a cohort of 6788 COPD patients, 784 CCVE's and 1032 deaths were reported. Compared to current LABA use, use of tiotropium Handihaler was neither associated with an increased risk of a CCVE (OR(adj) 0.89, 95% 0.55-1.44) nor with an increased risk of death (OR(adj) 0.79, 95% CI 0.49-1.28). CONCLUSIONS: In real life, use of tiotropium Handihaler in COPD patients is not associated with an increased risk of a CCVE or mortality compared to LABA.