The where, who and how of adrenal vein sampling in Australia and New Zealand

INTRODUCTION

Primary aldosteronism (PA) causes 10-15% of cases of hypertension, and it is increasingly recognised as being under-diagnosed. An interventional radiology procedure, adrenal vein sampling (AVS), is a necessary and important diagnostic procedure for complete workup of PA. There is an anticipated increase in demand for AVS as detection of PA improves. This study aims to describe the current landscape of AVS in Australia and New Zealand (NZ).

METHODS

Two surveys exploring AVS methodology and performance were conducted of (i) Endocrinology Unit Heads and (ii) interventional radiologists who perform AVS, at public hospitals with Endocrinology Units across Australia and NZ.

RESULTS

Responses were received from 48/53 Endocrinology Unit Heads (91%) and 35 radiologists from 26 sites (87% of AVS sites). AVS was provided at 28/48 Endocrinology sites (58%) across Australia and NZ. In Australia, sites were concentrated in Victoria, New South Wales and Queensland with none in the Northern Territory; in NZ, sites were more evenly distributed across the North and South Islands. AVS was performed by 1-2 dedicated radiologists at 24 sites, 2-3 radiologists at two sites and a rotating roster of radiologists at two sites. Responses to both surveys revealed significant variation in AVS methodology and interpretation of AVS results.

CONCLUSION

There is significant heterogeneity in the availability of AVS, the procedural details and the interpretation of results across Australia and NZ, which potentially impacts the quality of patient care and ability to scale up AVS capacity to meet increasing demand.

Vitamin D in newborns. A randomised controlled trial comparing daily and single oral bolus vitamin D in infants

AIM

There are no published data to demonstrate the efficacy of bolus dose vitamin D in newborn infants. The study sought to evaluate this alternative approach of supplementation.

METHODS

This single centre, open randomised controlled trial was conducted from August 2013 to May 2014. It compared the efficacy and safety of daily (400 IU) versus a bolus dose (50 000 IU) of cholecalciferol in newborn infants of vitamin D deficient mothers. The primary outcome measure was the rate of 25 hydroxyvitamin D (25OHD) repletion-defined as 25OHD greater than 50 nmol/L. The secondary objective was determining safety using adjusted total serum calcium.

RESULTS

Of 70 eligible infants, 36 received a daily dose and 34 received a single high-dose cholecalciferol. Mean 25OHD in the bolus group (154 nmol/L, 95% confidence interval (CI) 131-177) was higher than the daily group (48 nmol/L, 95% CI 42-54) at 1-2 weeks of age. This was reversed at 3-4 months, (65 nmol/L, 95% CI 59-71) compared with the daily group (81 nmol/L, 95% CI 77-85). More infants in the single bolus group achieved vitamin D repletion (100 vs. 31%) at 1-2 weeks. By 3-4 months, both groups achieved similar vitamin D repletion rates (91 vs. 89%). Mean adjusted total serum calcium in the bolus group were normal at 1-2 weeks (2.73 mmol/L) and 3-4 months (2.55 mmol/L).

CONCLUSION

Single bolus dosing of 50 000 IU cholecalciferol achieves higher 25OHD repletion rates at 1-2 weeks of age compared with daily dosing, but repletion rates were similar by 3-4 months. There was no hypercalcaemia documented with single bolus dosing in this study.

Thalassemia bone disease: a 19-year longitudinal analysis

Thalassemia is an inherited disorder of alpha or beta globin chain synthesis leading to ineffective erythropoiesis requiring chronic transfusion therapy in its most severe form. This leads to iron overload, marrow expansion, and hormonal complications, which are implicated in bone deformity and loss of bone mineral density (BMD). In this 19-year retrospective longitudinal study, the relationships between BMD (determined by dual-energy X-ray absorptiometry) and risk factors for osteoporosis in 277 subjects with transfusion-dependent thalassemia were examined. The mean age at first review was 23.2 ± 11.9 years and 43.7% were male. Hypogonadism was present in 28.9%. Fractures were confirmed in 11.6% of subjects and were more frequent in males (16.5%) compared with females (7.7%). Lumbar spine (LS), femoral neck (FN), and total body (TB) Z-scores were derived. Patients with transfusion-dependent thalassemia had a significant longitudinal decline in BMD at the FN and TB. In the linear mixed-model analysis of BMD and risk factors for bone loss, FN Z-score was more significantly associated with risk factors compared with the LS and TB. The rate of decline at the FN was 0.02 Z-score per year and was 3.85-fold greater in males. The decline in FN Z-score over the last 5 years (years 15 to 19) was 2.5-fold that of the previous 7 years (years 8 to 14) and coincided with a change in iron chelator therapy from desferrioxamine to deferasirox. Hemoglobin (Hb) levels positively correlated with higher TB and LS Z-scores. In conclusion, the FN is the preferred site for follow-up of BMD. Male patients with β-thalassemia experienced a greater loss of BMD and had a higher prevalence of fractures compared with females. Transfusing patients (particularly males) to a higher Hb target may reduce the decline in BMD. Whether deferasirox is implicated in bone loss warrants further study.

Effect of exercise on albuminuria in people with diabetes

AIM

Spot urine measurement of albumin is now the most commonly accepted approach to screening for proteinuria. Exertion prior to the collection may potentially influence the result of spot urine albumin estimation. We aim to evaluate the effect of exercise on albuminuria in subjects at various stages of diabetic nephropathy in comparison with healthy control volunteers.

METHODS

Thirty-five people with diabetes (19 with normoalbuminuria (NA), nine with microalbuminuria (MA) and seven with overt proteinuria (OP)) and nine control subjects were assessed. A 1 km treadmill walk was performed. Four spot urine specimens were collected: first morning void, immediately prior to exercise, and 1 h and 2 h after exercise. A random effects linear regression mixed model was used to assess the effect of exercise on albumin/creatinine ratio (uACR). Results are presented separately for male and female subjects with diabetes due to a significant exercise/gender interaction (P < 0.05).

RESULTS

No significant effect of exercise on uACR was seen in control subjects. In NA males with diabetes no effect of exercise was seen, while in females uACR 1 h after exercise was significantly higher than the early morning sample (3.55 mg/mmol (96% confidence interval 0.27-6.83). Both female and male diabetes subjects with MA have increase in uACR 1 h after exercise (87.8, -24.3-199.4 and 6.7, 2.1-11.3). For both males and females with OP, uACR was significantly increased 1 h post exercise (67.5, 22-113 and 21.6, 8.4-34.8, respectively). In all groups uACR at 2 h after exercise was not significantly different to the early morning sample.

CONCLUSIONS

Exercise increased uACR estimation in normoalbuminuric subjects with diabetes with a larger effect in females. Whether exercise unmasks early diabetic nephropathy in NA subjects requires further study.

Clinical associations and characterisation of antineutrophil cytoplasmic antibodies directed against bactericidal/permeability-increasing protein and azurocidin

Bactericidal/permeability-increasing protein (BPI) and azurocidin (AZ) are recently described target antigens of antineutrophil cytoplasmic antibodies (ANCA). In this study, BPI-ANCA were demonstrated most often in patients with ulcerative colitis (36/92, 39%), Crohn's disease (17/66, 26%) and cystic fibrosis (11/14, 79%), but also in patients with rheumatoid arthritis (8/40, 20%), systemic lupus erythematosus (SLE) (111/65, 17%) and mixed connective tissue disease (4/18, 22%). BPI-ANCA were also common in sera containing antinuclear (ANA) (9/43, 21%) or antidouble-stranded (ds) DNA (7/28, 25%) antibodies. There was no increased frequency of abnormal alpha1-antitrypsin (alphal1AT) phenotypes in patients with BPI-ANCA, and BPI-ANCA were not more common in individuals with an abnormal phenotype. The predominant IgG subclasses were IgG1 and IgG3; IgA but not IgM was present. Both IgG and IgA BPI-ANCA were high affinity antibodies, and the affinity of IgG antibodies did not change with time in the sera tested. Four of the five sera (80%) containing BPI-ANCA did not bind to denatured, reduced BPI, suggesting that most BPI-ANCA recognised conformational epitopes. AZ-ANCA were demonstrated in 2/11 patients (18%) with Wegener's granulomatosis, 3/12 (25%) with cystic fibrosis and 3/14 (21%) with chronic active hepatitis. AZ-ANCA were present in 5/25 sera (25%) with ANA, but the levels were only marginally elevated. AZ-ANCA were uncommon in patients with inflammatory bowel and rheumatological diseases, and in sera containing other autoantibodies. Again, there was no association with abnormal alpha1-AT phenotypes. BPI represents a major ANCA target antigen in patients with rheumatological as well as inflammatory bowel disease and cystic fibrosis, but AZ-ANCA are uncommon.

Parathyroid-hormone-related protein in sarcoidosis

Parathyroid-hormone-related protein (PTHrP) is the main mediator of the humoral hypercalcemia of malignancy. It is also detected in many normal adult and fetal tissues. Altered calcium metabolism occurs in sarcoidosis, and two cases of sarcoidosis with hypercalcemia and elevated plasma PTHrP are described. An archival study of 20 lymph node biopsies with the pathological diagnosis of sarcoidosis was performed. Immunohistochemistry using a polyclonal antiserum to human PTHrP and in situ hybridization using a riboprobe to human PTHrP were performed on the lymph node biopsies. Immunohistochemistry for PTHrP was also performed on the biopsies from the two cases with elevated plasma levels. Immunohistochemical analysis detected PTHrP in macrophages within granulomata in 17 of the 20 (85%) biopsies. In situ hybridization detected a positive signal for messenger RNA in the granulomata of 11 of 19 (58%) biopsies. PTHrP immunoreactivity and PTHrP gene expression are present in sarcoid granulomata. PTHrP may contribute to the hypercalcemia of sarcoidosis.

The value of C-reactive protein measurement in the diagnosis of neonatal infection

We examined whether serum C-reactive protein (CRP) measurements used in conjunction with leucocyte counts help in the diagnosis of perinatally acquired and nosocomial infections in very preterm newborn infants. One hundred and twenty-five infants born at a gestational age between 23 and 31 weeks with respiratory distress were studied at birth. A similar group of 85 infants beyond 3 days of age were also studied on 100 occasions for suspected infection. The diagnosis of proven or probable infection was correlated with abnormal haematology (leucopenia less than 5000/mm3, leucocytosis greater than 20,000/mm3 or ratio of immature forms to total neutrophils of greater than 0.2) and an elevated CRP (greater than 10 mg/L) singly or in combination. The sensitivity of an elevated CRP was relatively higher than abnormal haematology in both early and late infections and the sensitivity was highest when either test was abnormal. Similarly, the specificity, positive and negative predictive values and efficiency of an elevated CRP was relatively higher than abnormal haematology. The performance of the tests in 45 infants born at 23-28 weeks gestation was similar to that in 80 infants born at 29-31 weeks gestation. It was concluded that both CRP and leucocyte counts should be determined as they provide valuable information in the diagnosis of neonatal bacterial infection.

Diagnosis of gestational diabetes in Australia: a national survey of current practice

A national survey of pathology laboratories revealed a great diversity in the use of screening tests, and in the performance and interpretation of oral glucose tolerance tests for the detection of gestational diabetes. This situation is unsatisfactory and highlights the need for rationally established procedures and diagnostic criteria.

Pseudothrombocytopenia due to platelet aggregation and degranulation in blood collected in EDTA

Three patients are described in whom platelet aggregation and/or degranulation occurred in blood collected into EDTA. These changes resulted in spurious thrombocytopenia and morphological changes similar to those observed in some thrombocytopathies. The abnormalities were dependent on the presence of EDTA and did not occur in citrate, oxalate or heparin anticoagulants. In two patients the abnormality was shown to be due to a plasma factor which was not IgG, IgM, fibrinogen or albumin. The most likely explanation is that these patients have an unidentified abnormal plasma component which, on exposure to EDTA, develops 'anti-platelet activity'. Althought relatively uncommon a prospective study of the incidence of these phenomena indicates that they are probably more common than either platelet cold agglutinins or platelet satellitism. They have practical significance with respect to the diagnosis of thrombocytopenia and also to the interpretation of abnormal platelet morphology.

Ultraviolet light: a new stimulus for the induction of platelet aggregation

Exposure to ultraviolet light (253.7 nanometers) causes mammalian blood platelets to aggregate. Aggregation is markedly enhanced in the presence of extracellular fibrinogen and is followed by the grodual of relatively small amounts of nucleotide and serotonin. Aggregation is inhibited by ethylenediamine tetraacetic acid or a combination of 2-deoxy-D-glucose and antimycin A. Adenosine, apyrase, and prostaglandin E(1) produced slight inhibition. The effect of exposure to ultraviolet light is cumulative and lasting. This agent may be used to study the process of platelet aggregation after the removal of the stimulus, by delaying the addition of fibrinogen until after cessation of irradiation. Thus ultraviolet light is the first agent known which may be used to study platelet aggregation in a period following its removal.

Aspirin: Its Effect on Platelet Glycolysis and Release of Adenosine Diphosphate

Incubation of human platelets with aspirin inhibited glycolysis and produced a fall in the concentration of adenosine triphosphate. When platelets were exposed to collagen there was an increase in glycolysis and release of adenosine diphosphate. Prior incubation of the platelets with aspirin for 5 minutes did not totally suppress the increase in glycolysis after exposure to collagen but completely inhibited the collagen-induced reaction of the release of adenosine diphosphate. It is suggested that aspirin acts on human platelets by inhibiting both release of adenosine diphosphate and the transport of glucose across the platelet membrane.