A retrospective review of the short Synacthen test in Queensland hospitals

BACKGROUND

The short Synacthen test (SST) is widely used to investigate adrenal insufficiency, but it can be time-consuming, costly and labour-intensive to perform and is not without risk of adverse events.

AIM

To review SST requesting patterns and practices across public hospitals in Queensland.

METHODS

The electronic medical records of patients who underwent a SST with Pathology Queensland between January 2020 and December 2020 were reviewed to collect data regarding the indication for the test, the requesting speciality, SST results and any adverse events.

RESULTS

Six hundred and fifty-two SSTs were identified, of which 363 individual patients were included in the analysis. The majority of the tests (n = 198, 54.5%) were performed in the inpatient setting. Endocrinology most commonly ordered SSTs (n = 188, 51.8%). The suspected aetiology of adrenal insufficiency was unclear in a large proportion of requests (n = 167, 46.0%). Static testing of morning cortisol prior to SST was performed in only 249 (68.6%) patients. Of 140 inpatients data, 17.9% (n = 25) showed a robust static cortisol of ≥400 nmol/L and were treated as having normal adrenal function, suggesting SST was unnecessary in these patients. Twenty-two (6.1%) patients had a documented adverse event occurring during or after the SST.

CONCLUSIONS

There was wide variability in requesting patterns and practices for SSTs across Queensland. More than one in six SSTs could have been avoided if a static morning cortisol had been performed prior. Clinician education and the adoption of a structured referral form may improve testing practices.

Tumor-Induced Osteomalacia in a Patient with Crohn's Disease: A Case Report and Approach to Investigating Hypophosphatemia

Introduction

Hypophosphatemia occurs commonly in inflammatory bowel disease (IBD) patients and can cause considerable morbidity. The differential diagnoses in IBD include nutritional causes and hypophosphatemia induced by some formulations of intravenous iron infusions.

Case Presentation

We present the case of a 37-year-old man with active Crohn's disease, presenting with difficulty walking and fractures of the vertebrae and calcaneus. He had long-standing hypophosphatemia. Nutritional causes for hypophosphatemia were considered in the first instance given the presence of chronic diarrhea and vitamin D deficiency; however, there was minimal response to appropriate supplementation with oral phosphorous and vitamin D. Iron infusion-induced hypophosphatemia was then considered, but the nadir phosphate level preceded any iron infusion. Therefore, work-up was undertaken for less common causes. He was ultimately diagnosed with tumor-induced osteomalacia, caused by excess fibroblast growth factor 23 (FGF23) secretion from a phosphaturic mesenchymal tumor about the knee. He had complete resolution of symptoms and biochemical abnormalities following successful resection of the tumor.

Conclusion

This case illustrates the approach to investigation of hypophosphatemia in IBD patients. If the time course and response to phosphate supplementation are not as expected for nutritional or iron infusion-induced hypophosphatemia, less common causes should be considered.

Voriconazole‐Associated Periostitis: New Insights into Pathophysiology and Management

Voriconazole‐associated periostitis (VAP) is an underrecognized and unpredictable side effect of long‐term voriconazole therapy. We report two cases of VAP occurring in the post‐transplant setting: a 68‐year‐old lung transplant recipient who required ongoing voriconazole therapy, in whom urinary alkalinization was used to promote fluoride excretion and minimize voriconazole‐related skeletal toxicity, and a 68‐year‐old stem‐cell transplant recipient with a high voriconazole dose requirement, identified on pharmacogenomic testing to be a CYP2C19 ultrarapid metabolizer, the dominant enzyme in voriconazole metabolism. This is the first reported case of pharmacogenomic profiling in VAP and may explain the variability in individual susceptibility to this uncommon adverse effect. Our findings provide new insights into both the management and underlying pathophysiology of VAP. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

A family with partially penetrant multicentric carpotarsal osteolysis due to gonadal mosaicism: First reported case

Multicentric carpotarsal osteolysis (MCTO) is an autosomal dominant condition characterized by carpal-tarsal abnormalities; over half of affected individuals also develop renal disease. MCTO is caused by mutations of MAFB; however, there is no clear phenotype-genotype correlation. We describe the first reported family of variable MCTO phenotype due to mosaicism: the proband had classical skeletal features and renal involvement due to focal segmental glomerulosclerosis (FSGS), and the father had profound renal impairment due to FSGS, necessitating kidney transplantation. Mosaicism was first suspected in this family due to unequal allele ratios in the sequencing chromatograph of the initial blood sample of proband's father and confirmed by sequencing DNA extracted from the father's hair, collected from different bodily parts. This case highlights the need for a high index of clinical suspicion to detect low-level parental mosaicism, as well as a potential role for MAFB mutation screening in individuals with isolated FSGS.

Post-Traumatic Heterotopic Ossification With Incidental Hyperparathyroidism

Background: Heterotopic ossification (HO) is a rare disease characterised by abnormal bone growth in non-osseous tissues, causing pain, immobility and impaired quality of life. Although still being elucidated, the underlying pathophysiology may relate to local macrophage-driven inflammation in response to trauma¹.

Case: A 35-year-old man involved in a motor vehicle accident (MVA) fractured over twenty bones (multiple vertebrae, ribs and complex open book pelvic fracture with shattered left acetabulum) with extensive soft tissue injuries requiring multiple surgeries. Past medical history included a renal calculus three years earlier. His serum corrected calcium on admission was elevated at 2.87mmol/L (2.10-2.60mmol/L). Peri-operative fluid over-resuscitation necessitated boluses of intravenous furosemide, and serum calcium transiently normalised before rapidly incrementing and peaking at 3.04 mmol/L. Serum parathyroid hormone post-operatively was inappropriately high at 9.4pmol/L (1.0–7.0pmol/L) and 25-hydroxyvitamin D low at 24nmol/L (50-150nmol/L). Oral vitamin D replacement was commenced and he received intravenous pamidronate (3x60mg infusions) which briefly restored normocalcaemia. Neck ultrasound and sestamibi scintigraphy demonstrated a left parathyroid adenoma, and he underwent parathyroidectomy. Histology revealed a single parathyroid adenoma. He has been normocalcaemic since surgery. Despite excellent overall recovery, mobility at the left hip remained restricted in all planes of movement. He could not perform simple activities such as putting on his shoe. Plain radiographs showed HO lateral to the left acetabulum, femoral head and neck, with bony bridging to the left ilium on computed tomography. Bone turnover markers (BTMs) measured eleven months post-MVA (and pamidronate) were elevated, with CTX of 750ng/L (100-600ng/L) and P1NP of 207ug/L (15-80ug/L). BTMs gradually reduced over time, plateauing two years post-MVA (CTX 480ng/L and P1NP 103ug/L). Surgery with pre-operative radiotherapy to remove the left hip HO is now planned.

Discussion: This man had multiple recognised risk factors for HO, including male sex, trauma followed by immobilisation and pelvic fracture. His hyperparathyroidism may have predisposed HO development through excess calcium-phosphate product promoting soft tissue calcification. Bisphosphonates may also increase the risk². Elevated BTMs have been demonstrated in the early phase of HO; further research may elucidate whether BTMs can guide timing of surgical intervention relative to the pathophysiological processes driving HO.

References:

1 Meyers C et al. Heterotopic Ossification: A Comprehensive Review. JBMR Plus 2019, 3: e10172

2 Genêt F et al. Neurological heterotopic ossification following spinal cord injury is triggered by macrophage-mediated inflammation in muscle 2015. J Pathol. 236(2):229–40

A checklist of marine sponges (Porifera) of peninsula India

An inventory of sponges from the shallow subtidal reefs of the west and east coasts of southern India is presented. The specimens offered in this paper were based on in-situ collections unlike the previous records of dry and net-entangled collections. A total of 101 species belonging to 12 orders, 22 families, 5 subfamilies and 44 genera from 4 subclasses of Class Demospongiae and one species from Class Calcarea are recorded. We recorded 18 new records to India, six new species combinations, 37 potential new records, and 40 species for the first time from the southwest coast.

Characterization of Normal Murine Carpal Bone Development Prompts Re-Evaluation of Pathologic Osteolysis as the Cause of Human Carpal-Tarsal Osteolysis Disorders

Multicentric carpal-tarsal osteolysis; multicentric osteolysis, nodulosis, and arthropathy; and Winchester syndromes, skeletal dysplasias characterized by carpal/tarsal and epiphyseal abnormalities, are caused by mutations in v-maf musculoaponeurotic fibrosarcoma oncogene ortholog B (MAFB), matrix metalloproteinase (MMP) 2, and MMP14, respectively; however, the underlying pathophysiology is unclear. Osteoclast-mediated osteolysis has been regarded as the main mechanism, but does not explain the skeletal distribution. We hypothesized that MAFB, MMP-2, and MMP-14 have integral roles in carpal/tarsal and epiphyseal bone development. Normal neonatal mouse forepaws were imaged by micro-computed tomography and examined histologically. Murine forepaw ossification occurred sequentially. Subarticular regions of endochondral ossification showed morphologic and calcification patterns that were distinct from archetypical physeal endochondral ossification. This suggests that two different forms of endochondral ossification occur. The skeletal sites showing the greatest abnormality in the carpal-tarsal osteolysis syndromes are regions of subarticular ossification. Thus, abnormal bone formation in areas of subarticular ossification may explain the site-specific distribution of the carpal-tarsal osteolysis phenotype. MafB, Mmp-2, and Mmp-14 were expressed widely, and tartrate-resistant acid phosphatase staining notably was absent in the subarticular regions of the cartilage anlagen and entheses at a time point most relevant to the human osteolysis syndromes. Thus, abnormal peri-articular skeletal development and modeling, rather than excessive bone resorption, may be the underlying pathophysiology of these skeletal syndromes.

The IFITM5 mutation c.-14C > T results in an elongated transcript expressed in human bone; and causes varying phenotypic severity of osteogenesis imperfecta type V

Background

The genetic mutation resulting in osteogenesis imperfecta (OI) type V was recently characterised as a single point mutation (c.-14C > T) in the 5’ untranslated region (UTR) of IFITM5, a gene encoding a transmembrane protein with expression restricted to skeletal tissue. This mutation creates an alternative start codon and has been shown in a eukaryotic cell line to result in a longer variant of IFITM5, but its expression has not previously been demonstrated in bone from a patient with OI type V.

Methods

Sanger sequencing of the IFITM5 5’ UTR was performed in our cohort of subjects with a clinical diagnosis of OI type V. Clinical data was collated from referring clinicians. RNA was extracted from a bone sample from one patient and Sanger sequenced to determine expression of wild-type and mutant IFITM5.

Results

All nine subjects with OI type V were heterozygous for the c.-14C > T IFITM5 mutation. Clinically, there was heterogeneity in phenotype, particularly in the manifestation of bone fragility amongst subjects. Both wild-type and mutant IFITM5 mRNA transcripts were present in bone.

Conclusions

The c.-14C > T IFITM5 mutation does not result in an RNA-null allele but is expressed in bone. Individuals with identical mutations in IFITM5 have highly variable phenotypic expression, even within the same family.

A brilliant breakthrough in OI type V

Interferon-induced transmembrane protein 5 or bone-restricted ifitm-like gene (Bril) was first identified as a bone gene in 2008, although no in vivo role was identified at that time. A role in human bone has now been demonstrated with a number of recent studies identifying a single point mutation in Bril as the causative mutation in osteogenesis imperfecta type V (OI type V). Such a discovery suggests a key role for Bril in skeletal regulation, and the completely novel nature of the gene raises the possibility of a new regulatory pathway in bone. Furthermore, the phenotype of OI type V has unique and quite divergent features compared with other forms of OI involving defects in collagen biology. Currently it appears that the underlying genetic defect in OI type V may be unrelated to collagen regulation, which also raises interesting questions about the classification of this form of OI. This review will discuss current knowledge of OI type V, the function of Bril, and the implications of this recent discovery.

Next-generation sequencing: a frameshift in skeletal dysplasia gene discovery

In the last decade, huge breakthroughs in genetics-driven by new technology and different statistical approaches-have resulted in a plethora of new disease genes identified for both common and rare diseases. Massive parallel sequencing, commonly known as next-generation sequencing, is the latest advance in genetics, and has already facilitated the discovery of the molecular cause of many monogenic disorders. This article describes this new technology and reviews how this approach has been used successfully in patients with skeletal dysplasias. Moreover, this article illustrates how the study of rare diseases can inform understanding and therapeutic developments for common diseases such as osteoporosis.

A novel mutation of the primary protein kinase C phosphorylation site in the calcium-sensing receptor causes autosomal dominant hypocalcemia

OBJECTIVE

The calcium-sensing receptor (CASR) is a key controller of calcium homeostasis by regulating parathyroid hormone (PTH) secretion and renal calcium reabsorption. CASR(T888) is a protein kinase C (PKC) phosphorylation site in the receptor's intracellular domain that has previously been identified as a critical negative regulator of CASR downstream signaling in vitro, but whose importance in vivo is unknown.

CASE REPORT

The proband presented with mild symptomatic hypocalcemia following treatment for nephrotic syndrome due to minimal change glomerulonephropathy. Laboratory tests revealed inappropriately normal PTH concentrations and relative hypercalciuria typical of autosomal dominant hypocalcemia. His asymptomatic father had similar laboratory test results.

DESIGN AND METHODS

The CASR gene was sequenced. To investigate the molecular consequences of CASR(T888M) mutation, site-directed mutagenesis was used to modify the wild-type (wt)-CASR gene, with the resulting mutant being transfected transiently into HEK-293 cells.

RESULTS

A novel CASR missense mutation, T888M, was identified in both cases. The CASR(T888M) mutant exhibited enhanced sensitivity to extracellular calcium concentration, both for intracellular calcium (Ca(2+)(i)) mobilization and for ERK phosphorylation, despite having unaltered levels of cell surface expression. Furthermore, CASR(T888M) elicited sustained Ca(2+)(i) mobilization rather than high frequency Ca(2+)(i) oscillations, and, unlike the wt-CASR, the response was resistant to acute inhibition by the PKC activator, phorbol 12-myristate 13-acetate.

CONCLUSIONS

The clinical and functional data provide the first genotype-phenotype correlation for a mutation at T888, indicating its critical physiological importance in CASR signaling. Thus, CASR(T888) represents a functionally important, inhibitory phosphorylation site that contributes to the control of PTH secretion.

Chest and Abdominal Injuries Caused by Seat Belt Wearing

The authors report an original case of seat belt syndrome. Sternal fractures are common in patients with seat belt injuries. Its association with blunt bowel trauma is rarely related in the literature. Distracted injury has contributed to delay the diagnosis of intestine injury. The presence of a seat belt sign must lead to the consideration of occult injuries especially abdominal. Close observation and serial examination should be the rule.

Evaluation of magnetic foil and PPT Insoles in the treatment of heel pain

The effect of a magnetic foil placed in the PPT/Rx Firm Molded Insole on the relief of heel pain was determined using the foot function index. Nineteen patients wore the PPT/Rx Firm Molded Insoles with the magnetic foil for 4 weeks and 15 patients wore the same PPT/Rx Firm Molded Insole with no magnetic foil for the same time. Approximately 60% of patients in both groups reported improvement. There was also no significant difference in the improvement between the magnetic foil group and the PPT/Rx Firm Molded Insole group in their scores on the post-treatment foot function index. These results suggest that the PPT/Rx Firm Molded Insole alone was effective in treating heel pain after only 4 weeks. The magnetic foil offered no advantage over the plain insole.

Comparison of Viscoped and PORON for painful submetatarsal hyperkeratotic lesions

A clinical study was performed to evaluate the efficacy of the Viscoped Insole as compared with an 1/8-inch PORON medical materials insole in the treatment of lesser submetatarsal hyperkeratotic callosities. Thirty-five patients, ranging in age from 23 through 61 years (average 42 years) were randomly divided into three groups. All three groups initially had debridement of their submetatarsal callosities. In addition to the debridement, the first group (16 patients) wore a Viscoped Insole for 4 weeks. The patients in the second group wore a PORON insole for 4 weeks. The third group did not receive an insole after their debridement and served as the control. There was a significant improvement in the Viscoped group and the PORON group versus the control group (x2 = 40; p < 0.01) as measured by the foot function index. Insole therapy combined with debridement for submetatarsal hyperkeratoses is more effective than debridement alone.