Phaeochromocytoma and paraganglioma.

Phaeochromocytomas and paragangliomas are rare catecholamine-producing neuroendocrine tumours which can potentially cause catastrophic crises with high morbidity and mortality. This best practice article considers the causes and presentation of such tumours, screening and diagnostic tests, management of these patients and consideration of family members at risk.

Adrenal insufficiency.

Adrenal insufficiency (AI), first described by Thomas Addison in 1855, is characterised by inadequate hormonal production by the adrenal gland, which could either be primary, due to destruction of the adrenal cortex, or secondary/tertiary, due to lack of adrenocorticotropic hormone or its stimulation by corticotropin-releasing hormone. This was an invariably fatal condition in Addison's days with most patients dying within a few years of diagnosis. However, discovery of cortisone in the 1940s not only improved the life expectancy of these patients but also had a dramatic effect on their overall quality of life. The diagnosis, easily confirmed by demonstrating inappropriately low cortisol secretion, is often delayed by months, and many patients present with acute adrenal crisis. Sudden withdrawal from chronic glucocorticoid therapy is the most common cause of AI. Currently, there remains a wide variation in the management of this condition across Europe. As primary AI is a relatively rare condition, most medical specialists will only manage a handful of these patients in their career. Despite many advances in recent years, there is currently no curative option, and modern cortisol replacement regimens fail to adequately mimic physiological cortisol rhythm. A number of new approaches including allograft of adrenocortical tissue and stem cell therapy are being tried but remain largely experimental.

Do we need 30 min cortisol measurement in the short synacthen test: a retrospective study.

OBJECTIVE: The short synacthen test (SST) is widely used across the UK to assess adrenal reserve but there remains no consensus on the timing of cortisol sampling to help diagnose adrenal insufficiency. The main objective of our study was to see if both 30 and 60 min sample are required following administration of synacthen to investigate suspected adrenal insufficiency (AI). DESIGN: This was a single-centre retrospective study of 393 SSTs measuring 0, 30 and 60 min cortisol levels after administration of 250 µg of synacthen. PATIENTS AND METHODS: All the SSTs for patients suspected of primary or secondary AI between April 2016 and October 2018 were included in this study. The tests were performed as per our hospital protocol. A post-adrenocorticotropic hormone (ACTH) cortisol response of 420 nmol/L at any time point was considered adequate to rule out AI. The data were analysed to ascertain the proportion of patients who achieved this level at 30 and/or 60 min. RESULTS: A total of 393 SST results were included in this study. Patients were divided into two groups depending on whether (group A) or not (group B) they were on steroids. Overall, a total of 313 (79.6%) subjects achieved cortisol level of ≥420 nmol/L at 30 and 60 min while 19 (4.8%) had late response (ie, insufficient 30 min cortisol levels, rising to ≥420 nmol/L at 60 min). Another 61 subjects (15.5%) showed insufficient response at both 30 and 60 min (ie, failed to achieved level of ≥420 nmol/L). Importantly, there was no patient in either group who had adequate response at 30 min and then failed at 60 min. Patients in group A were more likely to have inadequate response at both 30 and 60 min while patients in group B were more likely to have normal response at both time points. CONCLUSIONS: Our results suggest that about 5% of people undergoing SST may be inappropriately diagnosed as having AI (and subjected to long-term unnecessary steroid treatment) if the 60 min sample is not maintained. We suggest that 30 min sample does not add any additional diagnostic utility and can be omitted thus simplifying SST even further and saving on cost and resources. We propose that single measurement after 60 min of administration of synthetic ACTH is a sufficient screening test for AI.

A novel method for the analysis of clinical biomarkers to investigate the effect of diet on health in a rat model.

Experiments into the relationship between diet and health have been an area of high interest for a long time. In this study, we investigate the application of multivariate data analysis to differentiate between rat populations fed on two different diets: normal rat diet (control) and Western affluent diet (WAD). Two sets of data were acquired and analysed: one from a biochemical clinical analyser, taking measurements of blood-based biochemical markers; the other from the analysis of the volatile organic compounds (VOCs) emitted from faecal samples from the same animals using selected ion flow tube mass spectrometry (SIFT-MS). Five classes were considered: weanlings, 12 month controls, 12 month WADs, 18 month controls, and 18 month WADs. Data from the biochemical analyser, weanlings and 18 month WAD fed rats showed significant differences from the other measurement classes. This was shown in both the exploratory analysis and through multivariate classification. Classification of control diet versus WAD diets suggested there are differences between classes with 92% accuracy for the 12 month classes and 91% for the 18 month classes. Cholesterol markers, especially as low density lipoprotein-cholesterol (LDL), were the main factor in influencing WAD samples. The data from the SIFT-MS analysis also produced very good classification accuracies. Classification of control diet versus WAD diets using the H3O(+) precursor ion data suggested there are differences between classes with 71% accuracy for the 12 month classes and 100% for the 18 month classes. These findings confirm that total cholesterol and LDL-cholesterol are elevated in the 18 month WAD-fed rats. We therefore suggest that the analysis of VOCs from faecal samples in conjunction with multivariate data analysis may be a useful alternative to blood analysis for the detection of parameters of health.

Intraoperative PTH Assay during Minimally Invasive Parathyroidectomy May Be Helpful in the Detection of Double Adenomas and May Minimise the Risk of Recurrent Surgery.

Background. Minimally invasive parathyroidectomy (MIP) is increasingly replacing the traditional bilateral neck exploration in the treatment of primary hyperparathyroidism (PHP). Intraoperative PTH (IOPTH) measurement has recently been introduced as a useful adjunct in confirming successful excision of abnormal parathyroid gland. Aims. We evaluate the safety, efficacy, and clinical usefulness of IOPTH measurement during MIP in a district general hospital. Methods. Retrospective review of eleven consecutive patients with PHP who underwent MIP with IOPTH, following preoperative assessment with ultrasound and sestamibi scans. Results. All patients had successful removal of the abnormal parathyroid gland. The concordance rate between ultrasound and sestamibi scan in localising the parathyroid adenoma was 82%. IOPTH measurement confirmed the removal of adenoma in all cases and, in one case, led to identification of a second adenoma, not localised preoperatively. The median hospital stay was 2 days (range 1-7 days). All patients remained normocalcaemic after a median of 6 months (range 1-10 months). Conclusions. Minimally invasive parathyroidectomy is a feasible, safe, and effective method for treatment of PHP. The use of IOPTH monitoring potentially offers increased sensitivity in detecting multiglandular disease, can minimise the need and risk associated with recurrent operations, and may facilitate cost-effective minimally invasive surgery.

Urinary levels of creatine and other metabolites in the assessment of polymyositis and dermatomyositis.

BACKGROUND: A simple and reliable method is needed to assess disease activity and monitor the efficacy of therapy in polymyositis (PM) and dermatomyositis (DM). This study used in vitro proton ((1)H) magnetic resonance spectroscopy (MRS) to explore whether excretion of urinary metabolites can be used as a reliable marker of disease in PM and DM patients. METHODS: Urine samples were obtained from PM/DM patients (n=34), healthy controls (50) and subjects with known muscle-wasting conditions including adult-onset muscular dystrophy (8), stroke patients (10), rheumatoid arthritis (RA) patients on steroids (13) and not on steroids (16) and patients with alcoholic myopathy (12). Levels of urinary metabolites were then correlated with creatine kinase (CK) activities and quadriceps muscle strength. RESULTS: Creatine was detected in the urine in 26 of 35 patients with PM/DM, four of 60 cases with other medical disorders (including one with adult-onset dystrophy, one with a stroke and two with RA who were not on steroids) and 10 of 50 healthy controls. The urinary creatine/creatinine ratio exceeded 0.4 in 20 patients with PM/DM but no patients with other medical disorders and no healthy controls. These differences were highly significant (P<0.001) by Kruskal-Wallis test (comparing all groups) and by Mann-Whitney U-tests (comparing individual groups with PM/DM cases). Citrate, glycine, choline-containing compounds and taurine levels were significantly increased in PM/DM when compared with controls. There were positive correlations between CK activities and choline-containing compounds (r=0.78, P=0.0006) and also between CK activities and betaine (r=0.57, P=0.026). CONCLUSIONS: This study shows significant differences in the urinary levels of creatine, choline-containing metabolites, betaine and citrate in PM/DM subjects compared with controls, although further work is required to elucidate the underlying metabolic processes.

HRPT2, encoding parafibromin, is mutated in hyperparathyroidism-jaw tumor syndrome.

We report here the identification of a gene associated with the hyperparathyroidism-jaw tumor (HPT-JT) syndrome. A single locus associated with HPT-JT (HRPT2) was previously mapped to chromosomal region 1q25-q32. We refined this region to a critical interval of 12 cM by genotyping in 26 affected kindreds. Using a positional candidate approach, we identified thirteen different heterozygous, germline, inactivating mutations in a single gene in fourteen families with HPT-JT. The proposed role of HRPT2 as a tumor suppressor was supported by mutation screening in 48 parathyroid adenomas with cystic features, which identified three somatic inactivating mutations, all located in exon 1. None of these mutations were detected in normal controls, and all were predicted to cause deficient or impaired protein function. HRPT2 is a ubiquitously expressed, evolutionarily conserved gene encoding a predicted protein of 531 amino acids, for which we propose the name parafibromin. Our findings suggest that HRPT2 is a tumor-suppressor gene, the inactivation of which is directly involved in predisposition to HPT-JT and in development of some sporadic parathyroid tumors.

Skeletal muscle protein loss due to D-penicillamine results from reduced protein synthesis.

Reports in the literature indicate that the trifunctional amino acid D-penicillamine (D-P) induces a variety of muscle abnormalities, although the mechanisms are unknown. We hypothesised that defects may also arise due to the effects of D-P on rates of protein synthesis, possibly via changes in muscle metal composition. Male Wistar rats were injected with D-P at doses of 50 and 500 mg/kg body weight, i.p. Rats designated as controls were injected with 0.15 mol/l NaCl. After 24 h, there were reductions in muscle protein contents, protein synthetic capacities (RNA:protein ratio), fractional rates of protein synthesis, synthesis rates per unit RNA and synthesis rates per unit DNA in skeletal muscles of D-P treated rats. There were no statistically significant differences between the responses of the muscles containing a predominance of either Type I (represented by the soleus) or Type II (represented by the plantaris) fibres. In general, intracellular amino acids were not significantly affected by D-P treatment. Changes in muscle metals included significant reductions in copper, iron and manganese, without alterations in zinc or magnesium. In liver D-P reduced copper and iron though zinc, manganese and magnesium were unaffected. These effects of D-P on muscle may have been direct, as plasma indices of liver (activities of alkaline phosphatase and alanine aminotransferase) and kidney (urea, creatinine and electrolytes) damage were not significantly altered by D-P treatment. Plasma levels of corticosterone, insulin and free T3 were also not significantly affected by D-P treatment. Muscle protein carbonyl concentrations, an index of free radical activity, were similarly unaffected. This is the first report of reduced rates of muscle protein synthesis in D-P treatment. Our data suggests that the reduced rates of muscle protein synthesis may contribute to, or reflect, the muscle abnormalities observed in patients undergoing D-P treatment.

Poor regression of myocardial hypertrophy following concomitant chronic alcohol ingestion and angiotensin converting enzyme (ACE) inhibition.

In the following study we examined the combined effect of chronic alcohol administration and anti-hypertensive drug treatment in spontaneously hypertensive rats (SHR). SHR were fed alcohol for six weeks while taking the angiotensin converting enzyme (ACE) inhibitor lisinopril. After six weeks, protein synthesis rates, contractile protein levels and protease activities were examined in control; alcohol; control+lisinopril; alcohol+lisinopril groups. Lisinopril treatment significantly reduced left ventricular mass, protein content and contractile proteins in control rats, but these effects were not as pronounced in alcohol+lisinopril rats. Protein synthesis rates in both mixed and myofibrillar fractions were not significantly different in any of the 4 groups. The enzyme activities of the proteases cathepsin D and dipeptidyl aminopepetidase I increased in control+lisinopril rats, however, this effect was not evident in alcohol+lisinopril rats. Contractile proteins identified by one-dimensional electrophoresis showed that lisinopril treatment reduced all contractile proteins in control rats. However, in alcohol+ lisinopril rats, myosin heavy chain was higher than in control+lisinopril rats. In summary, alcohol ingestion impairs the regression of the hypertrophic myocardium in SHR on ACE-inhibitor treatment, which was reflected by altered protein metabolism. This study suggests that successful anti-hypertensive treatment may not be achieved if alcohol misuse is evident.

A comparative investigation into the effect of chronic alcohol feeding on the myocardium of normotensive and hypertensive rats: an electrophoretic and biochemical study.

We investigated whether the imposition of chronic alcohol in hypertension leads to greater biochemical and cellular abnormalities of the myocardium than those arising in normotension. Fifteen-week-old spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats were fed ethanol-containing diets for six weeks. Particular attention was focused on the composition of contractile proteins identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), fractional rate of protein synthesis, and synthesis rates relative to RNA (RNA activity) or DNA (cellular efficiency). In addition, myocardial enzymes and adenine nucleotides were measured. In both SHR and WKY rats chronic ethanol caused a general decrease in the contents of all nine contractile proteins with myosin heavy chain predominantly affected. Fractional rates of mixed (i.e., total) and myofibrillary proteins remained unaltered in both WKY rats and SHR, as were cellular efficiencies. The RNA activity was significantly reduced in ethanol-treated SHR but not in WKY rats. In ethanol-treated SHR, cardiac creatine kinase (CK) and malate dehydrogenase (MDH) activities were increased, AMP levels were elevated, whilst ATP levels and the energy charge were reduced. In WKY rats, the only significant change related to increased aspartate aminotransferase activities in response to alcohol feeding. Although there were only subtle differences between the response of the normotensive and hypertensive rats due to ethanol dosage, the reduced ATP levels and increased CK and MDH activities in SHR may reflect a greater susceptibility to ischaemic damage. Reduced contractile protein content, particularly myosin heavy chain, may contribute to contractile defects, a common feature of subclinical and clinical alcoholic cardiomyopathy.

Effects of lisinopril and amlodipine on antioxidant status in experimental hypertension.

The objective of this investigation was to compare changes in antioxidant status (together with other metabolites relevant to hypertension) in plasma and cardiac tissue from spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY), following 8 weeks of treatment with lisinopril (angiotensin converting enzyme inhibitor) or amlodipine (Ca(2+) channel antagonist) respectively. There was no significant difference in the levels of total antioxidant capacity, retinol, urea, albumin or triglyceride in plasma from SHR or WKY rats, with or without lisinopril or amlodipine treatment. However in SHR rats, levels of alpha-tocopherol were substantially reduced in both plasma (-54% WKY, P<0.01) and cardiac tissue (-43% WKY, P<0.05). Treatment with lisinopril ameliorated reduced levels of plasma alpha-tocopherol in SHR rats, but not in cardiac tissue. Amlodipine treatment had no effect on alpha-tocopherol levels in plasma or cardiac tissue in SHR rats. In SHR rats total cholesterol levels were significantly lower thanWKY controls (-36%, P<0.001). This effect was reversed in lisinopril treated SHR rats (+27%, P<0.01). Plasma high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol were reduced in untreated SHR rats (P<0.025) when compared to WKY controls; neither lisinopril nor amlodipine treatment significantly altered these parameters. These findings suggest possible alternative mechanisms of action for lisinopril, and reinforce its use in hypertensive patients or patients with left ventricular hypertrophy.

Metabolic abnormalities associated with skeletal myopathy in severe anorexia nervosa.

The aim of this study was to characterize the metabolic disturbance associated with the skeletal myopathy resulting from extreme weight loss in anorexia nervosa. Muscle function was examined in eight female patients with severe (40%) weight loss due to anorexia nervosa and histologically confirmed myopathy. A wide range of biochemical and hematologic investigations were carried out, including serum enzymes and the response of plasma lactate to ischemic exercise of forearm muscles. All patients showed proximal muscular weakness. A diminished lactate response to ischemic exercise was a consistent finding, and a reduction of serum carnosinase activity was also found. There were no other consistent biochemical or hematologic abnormalities apart from lymphopenia of no clinical consequence. These findings contribute to our understanding of severe protein-energy malnutrition on the musculoskeletal system. The resulting disorder is a metabolic myopathy from which the patients recover rapidly as their nutrition improves. Although the patients admitted to a variety of abnormal eating behaviors, no correlation was found between a specific type of abnormal eating behavior and subsequent biochemical abnormalities. Reinstating appropriate eating behavior will treat the myopathy.

Alternative genetic pathways in parathyroid tumorigenesis.

In this study 44 parathyroid tumors from 26 sporadic cases, 10 cases previously given irradiation to the neck, and 8 familial cases were screened for sequence copy number alterations by comparative genomic hybridization. In the sporadic adenomas, commonly occurring minimal regions of loss could be defined to chromosome 11 (38%), 15q15-qter (27%), and 1p34-pter (19%), whereas gains preferentially involved 19p13.2-pter (15%) and 7pter-qter (12%). Multiple aberrations were found in sporadic tumors with a somatic mutation and/or loss of heterozygosity of the MEN1 gene. The irradiation-associated tumors also showed multiple comparative genomic hybridization alterations and frequent losses of 11q (50%), and subsequent analysis of the MEN1 gene demonstrated mutations in 4 of 8 cases (50%). The adenomas from familial cases showed few alterations, and in 3 of these tumors a gain of 19p13.2-pter was seen as the only aberration. In this study numerical copy number alterations were frequently detected in sporadic and irradiation-associated parathyroid adenomas, although these tumors are benign. The majority of these alterations were found in tumors with confirmed involvement of the MEN1 gene locus in agreement with a role of the MEN1 gene in genomic stability. Furthermore, the frequent occurrence of MEN1 mutations (50%) in irradiation-associated parathyroid tumors suggests that inactivation of the MEN1 gene is an important genetic alteration involved in the development of parathyroid tumors in postirradiation patients.

Genetic studies of a family with hereditary hyperparathyroidism-jaw tumour syndrome.

BACKGROUND AND OBJECTIVES: Familial hyperparathyroidism may occur as familial isolated hyperparathyroidism (FIHP) or as part of an inherited syndrome, in particular multiple endocrine neoplasia types 1 and 2A (MEN1, MEN2A) and hyperparathyroidism-jaw tumour (HPT-JT) syndrome. The localization of the genes responsible for these syndromes has enabled genetic screening of families with primary hyperparathyroidism (PHPT) to be carried out. This has important clinical implications in terms of individual follow-up and management. We previously reported a large FIHP family with an increased risk of parathyroid cancer and excluded its linkage to MEN1, MEN2 and PTH genes. Here we re-analysed this family and performed genetic linkage to the HPT-JT locus in chromosome 1q21-q32. Loss of heterozygosity studies of 1q21-q32, 11q13 and X chromosome were also performed. PATIENTS AND DESIGN: We studied 19 family members, aged 6-63 years. High molecular weight DNA was isolated from peripheral blood samples from 17 family members. For the two deceased individuals, DNA was extracted from normal paraffin embedded tissues. MEASUREMENTS: All individuals (except two deceased patients) had serum corrected calcium, inorganic phosphate, intact PTH, prolactin and various pancreatic hormones, measured on fasting blood samples. Twenty microsatellite markers were examined for the 1q21-q32 region, the locus for the HPT-JT gene. Genetic polymorphisms were determined by polymerase chain reaction amplification of genomic DNA and genetic linkage analysis was performed. Loss of heterozygosity studies were performed using paraffin-embedded parathyroid tissues from four affected members. RESULTS: Seven of the eight affected family members included in this study had biochemical evidence of PHPT and surgically proven parathyroid tumours. Indication of linkage of the disease to the HPT-JT locus was demonstrated with a maximum lod score of 2.32 by two-points linkage analysis. Linkage data were supported by multi-point analysis which gave a maximum lod score of 2.7. Meiotic recombinations detected in one affected individual narrowed the region to 26 cM. As a result of the genetic findings, we re-screened the living family members by orthopantomograph and renal ultrasound, and identified two jaw lesions in two gene carriers. One affected family member demonstrated polycystic kidney disease, thus establishing the association between the two conditions. A reduced penetrance of HPT in females was evident, in agreement with our previous study. No allelic deletion was detected in any tumour at 1q21-q32, 11q13 or X chromosome. CONCLUSIONS: This study illustrates the usefulness and importance of genetic studies in familial isolated hyperparathyroidism families. Our clinical and genetic findings indicate that this previously reported familial isolated hyperparathyroidism family has hyperparathyroidism-jaw tumour syndrome.

Structural and functional changes in skeletal muscle in anorexia nervosa.

Protein-energy malnutrition in anorexia nervosa is an under-recognised cause of muscle dysfunction. To characterise the skeletal myopathy that occurs in patients with severe anorexia nervosa, muscle function and structure were comprehensively examined in eight young adult female patients with severe (40%) self-induced weight loss. All of the patients showed impaired muscle function on strength and exercise measurement. The maximum voluntary contraction force for the patient group was significantly less than predicted values. Electromyography revealed myopathy in five of the patients, four of whom also had electro-physiological evidence of neuropathy. However, muscle biopsy specimens consistently showed myopathic changes with severe type 2 fibre atrophy but with no evidence of neuropathic changes. Ultrastructurally, there was separation and segmental loss of myofibrils and most biopsy samples contained abundant glycogen granules; we have previously reported that one of the most consistent biochemical abnormalities in these patients is impaired ischaemic lactate responses to forearm exercise. The result of severe protein-energy malnutrition on the musculo-skeletal system is a metabolic myopathy. Although the patients admitted to a variety of abnormal dieting behaviours, such as over-exercising and self-induced vomiting, no association was found between any of these and quantitative histological changes in the muscle biopsy samples. It is recommended that myopathy in anorexia nervosa be treated by instituting an appropriate refeeding programme.

Severe hyponatraemia secondary to beer potomania complicated by central pontine myelinolysis.

A case of severe hyponatraemia in a 56-year-old male alcohol misuser secondary to beer potomania is presented. In view of severe volume depletion and the patient's inability to drink, normal saline was cautiously infused. Despite initial improvement, he subsequently deteriorated neurologically. Magnetic resonance imaging demonstrated the classical lesion of central pontine myelinolysis (CPM). The rate of correction of plasma sodium was within limits normally considered safe. Beer potomania should be considered as a cause of hyponatraemia in alcohol misusers. Recognition is important as the electrolyte imbalance repairs simply with cessation of alcohol intake and institution of normal diet. Correction of chronic hyponatraemia by infusion of normal or hypertonic saline should not be attempted unless life-threatening neurological complications supervene. When the balance of risks favours correction, caution should be exercised, as CPM may occur. Although a rate of correction of plasma sodium of up to 10 mM per 24-hour period has been associated with a low risk of precipitating CPM, this case illustrates that a completely safe rate of correction probably cannot be defined.