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Open access

Elaine E Sanderson, Mark Shah, Amanda J Hooper, Damon A Bell, and Catherine S Choong

Summary

We report a case of an 11-year-old girl presenting with a new diagnosis of diabetes associated with a heterozygous missense mutation in the insulin receptor (INSR) gene. This case highlights that INSR gene variants can be a cause for monogenic diabetes in children and adolescents and the need for genetic evaluation in atypical presentations of diabetes. We also describe the possible role of metformin in treating individuals with type A insulin resistance syndrome due to INSR gene variants.

Learning points

  • Insulin receptor (INSR) gene variants can be a cause of monogenic diabetes in children and adolescents.

  • Genetic evaluation should be considered in children and adolescents with type 2 diabetes (T2D), particularly where there is an atypical presentation and/or positive family history.

  • Metformin may have a role in the treatment of type A insulin resistance syndrome due to heterozygous mutation of the INSR gene.

Open access

Ray Wang, Benjamin Solomon, Stephen J Luen, Owen W.J. Prall, Christine Khoo, Anthony J Gill, Jeremy Lewin, and Nirupa Sachithanandan

Summary

Adrenocortical carcinoma is a rare disease with poor prognosis whose clinical heterogeneity can at times present a challenge to accurate and timely diagnosis. We present the case of a patient who presented with extensive pulmonary lesions, mediastinal and hilar lymphadenopathy and an adrenal mass in whom the oncological diagnosis was initially uncertain. Through the use of immunohistochemistry, biochemistry and genomic testing, an accurate diagnosis of adrenocortical carcinoma was ultimately made which resulted in more directed treatment being administered. The use of multidisciplinary input and genomics to aid in diagnosis and prognosis of adrenocortical carcinoma is discussed.

Learning points

  • Adrenocortical carcinomas can present a diagnostic challenge to clinicians given it is a rare malignancy with significant clinical heterogeneity.

  • Specialist multidisciplinary team input is vital in the diagnosis and management of adrenocortical carcinomas.

  • Hormonal testing is recommended in the diagnostic workup of adrenal masses, even in the absence of overt clinical signs/symptoms of hormone excess.

  • Immunostaining for the highly sensitive and specific steroidogenic factor-1 is vital for accurate diagnosis.

  • Genomics can provide prognostic utility in management of adrenocortical carcinoma.

Open access

Arunan Sriravindrarajah, Amelia Fernandes, Ted Wu, and Samantha Hocking

Summary

Maturity-onset diabetes of the young type 3 (MODY3) accounts for approximately 50% of cases of MODY. First-line treatment with sulfonylureas has been well established for individuals with MODY3. In contrast, the use of sodium-glucose co-transporter 2 (SGLT2) inhibitors in the treatment of individuals with MODY3 remains unclear. This case illustrates the in vivo effect of an SGLT2 inhibitor in a 30-year-old woman with MODY3 with poor glycaemic control despite the treatment with supramaximal doses of sulfonylurea and metformin. The addition of a SGLT2 inhibitor resulted in a rapid improvement in glycaemic control without any hypoglycaemic episodes. This case suggests that SGLT2 inhibitors may be an effective and potent treatment option in addition to sulfonylureas for individuals with MODY3.

Learning points

  • Maturity-onset diabetes of the young type 3 (MODY3) arises from mutations in the hepatocyte nuclear factor-1alpha gene, which controls the expression of sodium-glucose co-transporter 2 (SGLT2) in the kidneys.

  • Paradoxically, despite individuals with MODY3 having reduced expression of SGLT2, SGLT2 inhibitors induce higher glycosuria in individuals with MODY3 compared to individuals with type 2 diabetes mellitus.

  • SGLT2 inhibitors may be an effective treatment for achieving glycaemic control in individuals with MODY3.

Open access

Vishal Navani, James F Lynam, Steven Smith, Christine J O’Neill, and Christopher W Rowe

Summary

We report concurrent metastatic prostatic adenocarcinoma (PC) and functioning androgen-secreting adrenocortical carcinoma (ACC) in a 77-year-old man. The failure to achieve adequate biochemical castration via androgen deprivation therapy (ADT) as treatment for PC metastases, together with elevated DHEA-S, androstenedione, and discordant adrenal tracer uptake on FDG-PET and PSMA-PET, suggested the presence of a concurrent functional primary adrenal malignancy. On histopathological analysis, scant foci of PC were present throughout the ACC specimen. Castration was achieved post adrenalectomy with concurrent drop in prostate-specific antigen. We outline the literature regarding failure of testosterone suppression on ADT and salient points regarding diagnostic workup of functioning adrenal malignancies.

Learning points

  • Failure to achieve castration with androgen deprivation therapy is rare and should prompt careful review to identify the underlying cause.

  • All adrenal lesions should be evaluated for hormone production, as well as assessed for risk of malignancy (either primary or secondary).

  • Adrenocortical carcinomas are commonly functional, and can secrete steroid hormones or their precursors (androgens, progestogens, glucocorticoids and mineralocorticoids).

  • In this case, a co-incident, androgen-producing adrenocortical carcinoma was the cause of failure of testosterone suppression from androgen deprivation therapy as treatment for metastatic prostate cancer. Pathological adrenal androgen production contributed to the progression of prostate cancer.

Open access

Lachlan M Angus, Jun Yang, and Ada S Cheung

Summary

Primary aldosteronism is one of the most common (affecting up to 10%) yet treatable causes of hypertension in our community, notable due to an associated elevated risk of atrial fibrillation, stroke and myocardial infarction compared to essential hypertension. Guidelines have focussed on improving case detection due to significant underdiagnosis in the community. While our case experienced significant delay in diagnosis, we highlight a state of protracted, persistent post-operative hypoaldosteronism which manifested with severe hyponatraemia and hyperkalaemia, necessitating long-term mineralocorticoid replacement. We discuss whether pre-operative mineralocorticoid receptor antagonists to stimulate aldosterone secretion from the contralateral gland may have prevented this complication.

Learning points

  • Hypoaldosteronism is an uncommon complication of adrenalectomy for primary aldosteronism, typically manifesting with hyperkalaemia and hyponatraemia. While most cases are transient, it may be persistent, necessitating ongoing mineralocorticoid replacement.

  • Routine electrolyte monitoring is recommended post-adrenalectomy.

  • Risk factors for hypoaldosteronism include age >50 years, duration of hypertension >10 years, pre-existing renal impairment and adrenal adenoma size >2 cm.

  • Mineralocorticoid receptor antagonists may assist in the management of hypokalaemia and hypertension pre-operatively. However, it is unclear whether this reduces the risk of post-operative hypoaldosteronism.

Open access

Annabelle M Warren, Peter R Ebeling, Vivian Grill, Ego Seeman, and Shoshana Sztal-Mazer

Summary

Hypophosphatasia (HPP) is a rare and under-recognised genetic defect in bone mineralisation. Patients presenting with fragility fractures may be mistakenly diagnosed as having osteoporosis and prescribed antiresorptive therapy, a treatment which may increase fracture risk. Adult-onset HPPhypophosphatasia was identified in a 40-year-old woman who presented with bilateral atypical femoral fractures after 4 years of denosumab therapy. A low serum alkaline phosphatase (ALP) and increased serum vitamin B6 level signalled the diagnosis, which was later confirmed by identification of two recessive mutations of the ALPL gene. The patient was treated with teriparatide given the unavailability of ALP enzyme-replacement therapy (asfotase alfa). Fracture healing occurred, but impaired mobility persisted. HPP predisposes to atypical femoral fracture (AFF) during antiresorptive therapy; hence, bisphosphonates and denosumab are contraindicated in this condition. Screening patients with fracture or ‘osteoporosis’ to identify a low ALP level is recommended.

Learning points

  • Hypophosphatasia (HPP) is a rare and under-recognised cause of bone fragility produced by impaired matrix mineralisation that can be misdiagnosed as a fragility fracture due to age-related bone loss.

  • Antiresorptive therapy is contraindicated in HPP.

  • Low serum alkaline phosphatase (ALP) provides a clue to the diagnosis.

  • Elevated serum vitamin B6 (an ALP substrate) is indicative of HPP, while identification of a mutation in the ALPL gene is confirmatory.

  • Enzyme therapy with recombinant ALP (asfotase alfa) is currently prohibitively costly.

  • Treatment with anabolic bone agents such as teriparatide has been reported, but whether normally mineralized bone is formed requires further study.

Open access

Niamh O’Donnell, Aisling McCarthy, and Ken Thong

Summary

Carbimazole is a commonly used antithyroid drug (ATD), which is associated with several well-established side effects. However, Carbimazole-induced rhabdomyolysis is rarely reported in the literature. We report a 27-year-old male who presented with upper limb myalgia and significantly raised creatine kinase elevation, 1-month post commencement of Carbimazole for Graves’ disease. Carbimazole was ceased with subsequent clinical and biochemical improvement. Though the pathophysiology remains unclear, we hope to raise awareness regarding this rare adverse effect with a view to promote early recognition and prompt discontinuation of the offending medication caused by a commonly used medication in endocrinology.

Learning points

  • Musculoskeletal complaints can relate to unidentified and untreated hyperthyroidism. However one must be mindful that the treatment for these disorders can too induce myopathies.

  • ATD-induced myopathy should be considered when there is a temporal relationship between introduction of ATDs and the onset of symptoms.

  • If ATD-induced myopathy is being considered, other causes of myopathy should still be outruled.

  • Prompt discontinuation of potentially offending medications may provide resolution of symptoms and avoid significant consequences.

Open access

R K Dharmaputra, K L Wan, N Samad, M Herath, J Wong, S Sarlos, S R Holdsworth, and N Naderpoor

Summary

Insulin autoimmune syndrome (IAS) is a rare cause of non-islet cell hypoglycaemia. Treatment of this condition is complex and typically involves long-term use of glucocorticoids. Immunotherapy may provide an alternative in the management of this autoimmune condition through the suppression of antibodies production by B-lymphocyte depletion. We present a case of a 62-year-old male, with refractory hypoglycaemia initially presenting with hypoglycaemic seizure during an admission for acute psychosis. Biochemical testing revealed hypoglycaemia with an inappropriately elevated insulin and C-peptide level and no evidence of exogenous use of insulin or sulphonylurea. Polyethylene glycol precipitation demonstrated persistently elevated free insulin levels. This was accompanied by markedly elevated anti-insulin antibody (IA) titres. Imaging included CT with contrast, MRI, pancreatic endoscopic ultrasound and Ga 68-DOTATATE position emission tomography (DOTATATE PET) scan did not reveal islet cell aetiology for hyperinsulinaemia. Maintenance of euglycaemia was dependent on oral steroids and dextrose infusion. Complete resolution of hypoglycaemia and dependence on glucose and steroids was only achieved following treatment with plasma exchange and rituximab.

Learning points

  • Insulin autoimmune syndrome (IAS) should be considered in patients with recurrent hyperinsulinaemic hypoglycaemia in whom exogenous insulin administration and islet cell pathologies have been excluded.

  • Biochemical techniques play an essential role in establishing high insulin concentration, insulin antibody titres, and eliminating biochemical interference. High insulin antibody concentration can lead to inappropriately elevated serum insulin levels leading to hypoglycaemia.

  • Plasma exchange and B-lymphocyte depletion with rituximab and immunosuppression with high dose glucocorticoids are effective in reducing serum insulin levels and hypoglycaemia in insulin autoimmune syndrome (IAS).

  • Based on our observation, the reduction in serum insulin level may be a better indicator of treatment efficacy compared to anti-insulin antibody (IA) titre as it demonstrated greater correlation to the frequency of hypoglycaemia and to hypoglycaemia resolution.

Open access

Simon Ryder, Jed Robusto, Thomas Robertson, Hamish Alexander, and Emma L Duncan

Summary

Although pituitary macroadenomas often cause mass effects on surrounding structures, it is extremely rare for pituitary lesions to disturb cerebrospinal fluid circulation. Sellar gangliocytoma-pituitary adenomas (SGPAs) are also extremely rare. Here we report the unique case of a man with the unusual combination of acromegaly from an SGPA, who presented with unilateral hydrocephalus. A 60-year-old man presented with rapid neurological deterioration, bitemporal hemianopia, and acromegalic features. Neuroimaging revealed a large sellar lesion extending superiorly into the left foramen of Monro, causing acute obstructive unilateral hydrocephalus. External ventricular drain placement improved consciousness immediately. Biochemical assessment confirmed acromegaly. Following trans-sphenoidal debulking, histology revealed a mixed gangliocytoma/sparsely-granulated somatotrophinoma. Despite the residual disease, his vision recovered remarkably, low-dose cabergoline controlled residual excess growth hormone (GH) secretion, and the residual tumour has remained extremely stable over 2 years. Hydrocephalus is an extremely rare complication of pituitary lesions, and unilateral hydrocephalus has never been reported previously. GH secretion in SGPAs is more common than for pituitary adenomas in general, raising questions regarding the aetiology and therapeutic approach to this rare combination tumour.

Learning points

  • Pituitary tumours most commonly present with symptoms related to endocrine disturbance or mass effects upon visual pathways (e.g. optic chiasm, nerves in the lateral cavernous sinus). However, extremely rarely, pituitary masses may disrupt cerebrospinal fluid (CSF) circulation resulting in hydrocephalus.

  • Sellar gangliocytomas are very rare tumours and most of them are hybrid tumours with pituitary adenomas (SGPAs).

  • SGPAs are typically indolent and may be functioning or non-functioning tumours.

  • Growth hormone (GH)-producing SGPAs are less likely to respond to somatostatin agonists than classic somatotrophinomas.

  • Primary surgical debulking via a trans-sphenoidal approach was effective in this individual, leading to the restoration of CSF circulation and improvement in visual disturbance, while also negating the need for permanent CSF diversion despite the residual tumour burden.

Open access

Jasmine Jiang Zhu, William J Naughton, Kim Hay Be, Nicholas Ensor, and Ada S Cheung

Summary

Hypercalcaemia is a very common endocrine condition, yet severe hypercalcaemia as a result of fungal infection is rarely described. There are have only been two reported cases in the literature of hypercalcaemia associated with Cryptococcus infection. Although the mechanism of hypercalcaemia in these infections is not clear, it has been suggested that it could be driven by the extra-renal production of 1-alpha-hydroxylase by macrophages in granulomas. We describe the case of a 55-year-old woman with a 1,25-OH D-mediated refractory hypercalcaemia in the context of a Cryptococcus neoformans infection. She required treatment with antifungals, pamidronate, calcitonin, denosumab and high-dose glucocorticoids. A disseminated fungal infection should be suspected in immunosuppressed individuals presenting with hypercalcaemia.

Learning point

  • In immunocompromised patients with unexplained hypercalcaemia, fungal infections should be considered as the differential diagnoses;

  • Glucocorticoids may be considered to treat 1,25-OH D-driven hypercalcaemia; however, the benefits of lowering the calcium need to be balanced against the risk of exacerbating an underlying infection;

  • Fluconazole might be an effective therapy for both treatment of the hypercalcaemia by lowering 1,25-OH D levels as well as of the fungal infection.