Summary

Functioning gonadotroph adenomas with clinical manifestations are extremely rare and the majority of these are FSH-secreting macroadenomas. Clinical symptoms are due to excess gonadotrophins and sex hormones, and these may be present for a long time before the diagnosis of pituitary adenoma is made. We present the case of a 37-year-old Caucasian male with clinical manifestations of an FSH-secreting pituitary macroadenoma. He had sexual dysfunction for a year followed by bilateral testicular pain and enlargement which was initially treated as suspected recurrent epididymitis, but his symptoms did not resolve. He presented a year later with headaches and bilateral superior temporal visual field defects. Brain imaging confirmed a pituitary macroadenoma with optic chiasm compression. Pituitary profile demonstrated an unusually high FSH with high normal LH and normal testosterone level. The patient successfully underwent transsphenoidal hypophysectomy and histology confirmed gonadotroph differentiation and immunoreactivity predominantly with FSH. Gonadotrophin levels and testosterone dropped significantly after surgery, and he was started on testosterone replacement. MR imaging, 2 years post surgery, showed no recurrence of pituitary adenoma. In conclusion, testicular enlargement and hypogonadal symptoms associated with low testosterone levels are recognised features in FSH-secreting pituitary adenomas. Our patient had hypogonadal symptoms but consistently high normal testosterone levels prior to surgery. The reason for low libido despite high testosterone is unclear. Our case highlights the need to suspect such rare underlying pituitary pathology when dealing with unusual combinations of hypogonadal symptoms, testicular enlargement with low or normal testosterone levels.

Learning points

• Functioning pituitary adenomas that secrete excess follicle-stimulating hormone (FSH) are very rare and often present with symptoms related to pituitary mass effect.

• Testicular enlargement alongside sexual dysfunction are commonly reported symptoms amongst male patients.

• Pituitary profile results demonstrate a raised FSH level with either a low, normal, or even high testosterone level which may not always correlate to clinical symptoms.

• Pituitary pathology should be considered in males presenting with unusual combinations of testicular enlargement and hypogonadal symptoms even with normal testosterone levels.

Summary

The use of a low-carbohydrate diet (LCD) reduces insulin requirements in insulinopenic states such as type 1 diabetes mellitus (T1DM). However, the use of potentially ketogenic diets in this clinical setting is contentious and the mechanisms underlying their impact on glycaemic control are poorly understood. We report a case of a patient with a late-onset classic presentation of T1DM who adopted a very low-carbohydrate diet and completely avoided insulin therapy for 18 months, followed by tight glycaemic control on minimal insulin doses. The observations suggest that adherence to an LCD in T1DM, implemented soon after diagnosis, can facilitate an improved and less variable glycaemic profile in conjunction with temporary remission in some individuals. Importantly, these changes occurred in a manner that did not lead to a significant increase in blood ketone (beta-hydroxybutyrate) concentrations. This case highlights the need for further research in the form of randomised controlled trials to assess the long-term safety and sustainability of carbohydrate-reduced diets in T1DM.

Learning points

• This case highlights the potential of low-carbohydrate diets (LCDs) in type 1 diabetes mellitus (T1DM) to mediate improved diabetes control and possible remission soon after diagnosis.

• Could carbohydrate-reduced diets implemented early in the course of T1DM delay the decline in endogenous insulin production?

• Adherence to an LCD in T1DM can facilitate an improved and less variable glycaemic profile.

• This case suggests that LCDs in T1DM may not be associated with a concerning supraphysiological ketonaemia.

Summary

Calciphylaxis is a rare disorder characterised by the development of painful necrotic skin lesions. Occlusion of cutaneous arterioles due to ectopic calcification leads to potentially life-threatening widespread skin loss. Most cases occur in patients with chronic renal disease, which leads to dysregulation of calcium and phosphate homeostasis. Only a handful of case reports exist describing calciphylaxis occurring in patients without chronic renal disease but with hypoparathyroidism. We report on a unique case of a 53-year-old man with multiple endocrine neoplasia type 1 syndrome and acquired hypoparathyroidism due to total parathyroidectomy who went on to develop calciphylaxis following cardiac surgery.

Learning points

• Calciphylaxis most commonly occurs in the context of chronic renal disease but can rarely occur in its absence as a consequence of calcium and phosphate dysregulation.

• Patients who develop necrotic skin lesions in the presence of hypoparathyroidism require an urgent dermatological opinion.

• Mortality from calciphylaxis is high, with the majority of deaths occurring secondary to sepsis.

• Management of calciphylaxis requires a multidisciplinary team approach to manage wound healing, infections and pain.

• Recovery with full rehabilitation from calciphylaxis can take months to years.

Summary

A 20-year-old South Asian male presented with polyuria, polydipsia, HbA1c 81 mmol/mol, BMI 28.8 and family history of both type 1 and type 2 diabetes mellitus. As autoantibody testing was negative and c-peptide level demonstrated significant endogenous insulin secretion, type 1 diabetes was excluded. Given his age and family history, the differential diagnosis included maturity-onset diabetes of the young (MODY), a rare form of diabetes caused by a single-gene variant. A high probability of MODY was calculated and he was subsequently referred for genetic testing. Although a useful tool, the pre-test probability calculator for MODY is only validated in White Europeans. A heterogenous variant of unknown clinical significance of the NEUROD1 gene was detected, leading to gliclazide use with poor response. The patient responded well to metformin. Type 2 diabetes was considered the most likely diagnosis. This case highlights the diagnostic challenges in young patients of Asian ethnicity and the importance of interpreting genetic results of unknown significance within the clinical context. Ethnicity-specific BMI thresholds should be used when classifying patients as overweight or obese.

Learning points

• Variants of unknown significance detected by genetic sequencing should be interpreted within the context of the patient’s other clinical parameters.

• It is important to use ethnicity-specific BMI thresholds for obesity.

• Diagnosis of type 2 diabetes mellitus at younger ages is becoming increasingly common.

• The pre-test probability calculator for MODY is only validated in White Europeans; although a useful guide, results should be interpreted with caution in patients of other ethnicities.

Summary

Type 1 diabetes mellitus (T1DM) is an autoimmune disorder caused by the destruction of the pancreatic beta cells, which produce insulin. Individuals with T1DM usually require at least 3-5 years to develop microvascular complications in comparison to people with type 2 diabetes (T2DM), who may develop complications even before the diagnosis of diabetes. We discuss a patient who presented with proliferative diabetic retinopathy subsequently diagnosed with T1DM and diabetic neuropathy following investigations. Diabetic retinopathy or other microvascular complications as the presenting feature of T1DM is rarely known or reported in the literature. A 33-year-old healthcare worker had been seen by the opticians due to 1-week history of blurred vision. The ophthalmology assessment had confirmed proliferative retinopathy in the right eye and severe non-proliferative retinopathy in the left eye with bilateral clinically significant macular oedema. His BMI was 24.9 kg/m². The nervous system examination revealed bilateral stocking type peripheral neuropathy. The random venous glucose was 24.9 mmol/L. Plasma ketones were 0.7 mmol/L and HbA1c was 137 mmol/mol. On further evaluation, the anti-glutamic acid decarboxylase (GAD) antibody was positive, confirming the diagnosis of T1DM. He was started on aflibercept injections in both eyes, followed by panretinal photocoagulation. Subsequent nerve conduction studies confirmed the presence of symmetrical polyneuropathy. The pathogenesis of the development of microvascular complications in T1DM is multifactorial. Usually, the development of complications is seen at least a few years following the diagnosis. The occurrence of microvascular complications at presentation is rare. This makes the management challenging and extremely important in preventing the progression of the disease.

Learning points

• The pathogenesis of the development of microvascular complications in type 1 diabetes mellitus is multifactorial.

• The development of complications is seen at least a few years following the diagnosis.

• Occurrence of microvascular complications at presentation is rare.

• This makes the management challenging and extremely important to prevent the progression of the disease.

Summary

A Caucasian man in his 60s with recent diagnosis of metastatic renal cell carcinoma presented to the emergency department with a 5-day history of severe polyuria, polydipsia and fatigue and 1-day history of confusion, abdominal pain, nausea and vomiting. Investigations revealed an overlap of diabetic ketoacidosis (DKA) and hyperosmolar hyperglycaemic state (HHS). He had received the first dose of immunotherapy with nivolumab and ipilimumab 3 weeks prior to this attendance. New-onset type 1 diabetes (T1DM) was confirmed based on the clinical features at presentation, seropositivity for glutamic acid decarboxylase antibodies and significant insulin deficiency. He is currently on a multiple daily injections of insulin and uses intermittent-scanned glucose monitoring. Given the irreversible impact on beta-cell function and clinical response with insulin resulting in improved diabetes control, immunotherapy was resumed for his metastatic cancer with good radiological response. Although rare, new-onset T1DM can present with DKA and HSS overlap after a single dose of nivolumab/ipilimumab in individuals without pre-existing history of diabetes.

Learning points

• Although rare, new onset of T1DM after immunotherapy can present with DKA and HSS overlap after a single dose of nivolumab/ipilimumab in individuals without pre-existing history of diabetes and normal glycaemic parameters.

• Due to the irreversible destruction of beta-cells, treatment with steroids is not indicated in contrast to other settings such as immunotherapy-induced hypophysitis.

• Presence of low c-peptide levels post-acute presentation is indicative of an irreversible impact on beta-cell function and supports resuming immunotherapy given the significant benefits on cancer prognosis.

• Clinicians must maintain a high index of suspicion in regards to diagnosis and management of new-onset type 1 diabetes and advice patients on reporting symptoms suggestive of diabetes and/or diabetes-related hyperglycaemic emergencies.

Summary

Mpox (MPX) formerly known as monkeypox was declared a public health emergency of international concern, following an outbreak that commenced in May 2022. We report a case of subacute thyroiditis following MPX infection. To our knowledge, it is the first documented incidence of this complication in humans. A 51-year-old male, with a well-controlled human immunodeficiency virus (HIV) infection on antiretroviral therapy, was reviewed 3 weeks after a positive test for MPX. The acute skin lesions and initial systemic symptoms had resolved, but he described significant neck discomfort, fatigue, weight loss and night sweats. Blood tests showed a raised C-reactive protein, free T4 and suppressed thyroid-stimulating hormone. His thyroid antibodies were negative. He was treated initially with carbimazole and propranolol, pending exclusion of any other intercurrent infection. A chest radiograph was normal; blood cultures and a combined nose and throat swab for respiratory virus PCR testing were negative. Following this, he commenced a 2-week course of prednisolone; his symptoms resolved completely within 24 h of starting. He subsequently developed hypothyroidism, which was treated with levothyroxine. The clinical features, abnormal thyroid function, raised CRP and negative thyroid antibodies 3 weeks post-MPX positive test was consistent with viral subacute thyroiditis. This case demonstrates that, as described following other viral infections, MPX can cause subacute thyroiditis, which follows a similar course to the classic form of subacute thyroiditis. Clinicians should be aware of this potential endocrine complication when attending to patients with MPX.

Learning points

• Subacute thyroiditis can present following mpox virus infection.

• Its course is similar to the classic form of subacute thyroiditis and steroids are effective.

• It is important to exclude other concurrent infections prior to starting steroids, especially for patients who are immunosuppressed or in other high-risk groups.

Summary

Pituitary adenomas are intracranial neoplasms, usually demonstrating a benign phenotype. We present the case of 21-year-old male with an 18-month history of reduced visual function (acuity and field) in the left eye. Based on neuroimaging and endocrine profile, a giant prolactinoma causing hypogonadotropic hypogonadism was diagnosed and cabergoline was commenced. After a month of treatment, the tumour size reduced, and visual function improved to normal; however, he developed Foster Kennedy syndrome with a swollen right optic disc. After almost 1 year of follow-up, he regained full visual functioning. Two years since his diagnosis, his prolactin remains normal with no adverse effects or further visual complications.

Learning points

• Foster Kennedy syndrome is a rare entity but can be a feature of pituitary adenomas.

• Visual deterioration secondary to a compressive optic neuropathy can be reversible, provided that diagnosis and treatment are prompt.

• This case highlights the importance of frequent monitoring of visual function during follow-up of these lesions, particularly when there are deficits at diagnosis.

Summary

A 49-year-old teacher presented to his general physician with lethargy and lower limb weakness. He had noticed polydipsia, polyuria, and had experienced weight loss, albeit with an increase in central adiposity. He had no concomitant illnesses and took no regular medications. He had hypercalcaemia (adjusted calcium: 3.34 mmol/L) with hyperparathyroidism (parathyroid hormone: 356 ng/L) and hypokalaemia (K: 2.7 mmol/L) and was admitted for i.v. potassium replacement. A contrast-enhanced CT chest/abdomen/pelvis scan revealed a well-encapsulated anterior mediastinal mass measuring 17 × 11 cm with central necrosis, compressing rather than invading adjacent structures. A neck ultrasound revealed a 2 cm right inferior parathyroid lesion. On review of CT imaging, the adrenals appeared normal, but a pancreatic lesion was noted adjacent to the uncinate process. His serum cortisol was 2612 nmol/L, and adrenocorticotrophic hormone was elevated at 67 ng/L, followed by inadequate cortisol suppression to 575 nmol/L from an overnight dexamethasone suppression test. His pituitary MRI was normal, with unremarkable remaining anterior pituitary biochemistry. His admission was further complicated by increased urine output to 10 L/24 h and despite three precipitating factors for the development of diabetes insipidus including hypercalcaemia, hypokalaemia, and hypercortisolaemia, due to academic interest, a water deprivation test was conducted. An ¹⁸flurodeoxyglucose-PET (FDG-PET) scan demonstrated high avidity of the mediastinal mass with additionally active bilateral superior mediastinal nodes. The pancreatic lesion was not FDG avid. On 68Ga DOTATE-PET scan, the mediastinal mass was moderately avid, and the 32 mm pancreatic uncinate process mass showed significant uptake. Genetic testing confirmed multiple endocrine neoplasia type 1.

Learning points

• In young patients presenting with primary hyperparathyroidism, clinicians should be alerted to the possibility of other underlying endocrinopathies.

  In patients with multiple endocrine neoplasia type 1 (MEN-1) and ectopic adrenocorticotrophic hormone syndrome (EAS), clinicians should be alerted to the possibility of this originating from a neoplasm above or below the diaphragm.

• Although relatively rare compared with sporadic cases, thymic carcinoids secondary to MEN-1 may also be associated with EAS.

• Electrolyte derangement, in particular hypokalaemia and hypercalcaemia, can precipitate mild nephrogenic diabetes insipidus.

Summary

A 33-year-old gentleman of Egyptian heritage presented with a 21 years history of unexplained and recurrent hypercalcaemia, nephrolithiasis, nephrocalcinosis, and myocarditis. A similar history was also found in two first-degree relatives. Further investigation into the vitamin D metabolism pathway identified the biochemical hallmarks of infantile hypercalcaemia type 1 (IIH). A homozygous, likely pathogenic, variant in CYP24A1 was found on molecular genetic analysis confirming the diagnosis. Management now focuses on removing excess vitamin D from the metabolic pathway as well as reducing calcium intake to achieve serum-adjusted calcium to the middle of the reference range. If undiagnosed, IIH can cause serious renal complications and metabolic bone disease.

Learning points

• Infantile hypercalcaemia type 1 (IIH) is an autosomal recessive disorder characterised by homozygous mutations in the CYP24A1 gene that encodes the 24-hydroxylase enzyme used to convert active vitamin D metabolites such as 1,25-(OH)₂-vitamin D into their inactive form.

• IIH should be questioned in individuals presenting with a history of unexplained hypercalcaemia, especially if presenting from childhood and/or where there is an accompanying family history of the same in first and/or second degree relatives, causing complications such as nephrocalcinosis, pericarditis, and calcium-based nephrolithiasis.

• Associated biochemistry of IIH is persistent mild to moderate hypercalcaemia, normal or raised 25-(OH)-vitamin D and elevated 1,25-(OH)₂-vitamin D. An elevated ratio of 25-(OH)-vitamin D to 24,25-(OH)₂-vitamin D can be a useful marker of defects in the 24-hydroxylase enzyme, whose measurement can be facilitated through the supra-regional assay service.

• Management should focus on limiting the amount of vitamin D introduced into the body either via sunlight exposure or supplementation in addition to calcium dietary restriction to try and maintain appropriate calcium homeostasis