Summary

Pheochromocytoma (PHEO) in multiple endocrine neoplasia type 1 (MEN1) is extremely rare. The incidence is reported as less than 2%. We report a case of a 76-year-old male with familial MEN1 who was found to have unilateral PHEO. Although the patient was normotensive and asymptomatic, routine screening imaging with CT demonstrated bilateral adrenal masses. The left adrenal mass grew from 2.5 to 3.9 cm over 4 years with attenuation values of 9 Hounsfield units (HU) pre-contrast and 15 HU post-contrast washout. Laboratory evaluation demonstrated an adrenergic biochemical phenotype. Both ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT and ¹²³I-metaiodobenzylguanidine (¹²³I-mIBG) scintigraphy demonstrated bilateral adrenal uptake. In contrast, ¹⁸F-fluorodihydroxyphenylalanine (¹⁸F-FDOPA) PET/CT demonstrated unilateral left adrenal uptake (28.7 standardized uptake value (SUV)) and physiologic right adrenal uptake. The patient underwent an uneventful left adrenalectomy with pathology consistent for PHEO. Post-operatively, he had biochemical normalization. A review of the literature suggests that adrenal tumors >2 cm may be at higher risk for pheochromocytoma in patients with MEN1. Despite a lack of symptoms related to catecholamine excess, enlarging adrenal nodules should be biochemically screened for PHEO. ¹⁸F-FDOPA PET/CT may be beneficial for localization in these patients.

Learning points:

• ¹⁸F-FDOPA PET/CT is a beneficial imaging modality for identifying pheochromocytoma in MEN1 patients.

• Adrenal adenomas should undergo routine biochemical workup for PHEO in MEN1 and can have serious peri-operative complications if not recognized, given that MEN1 patients undergo frequent surgical interventions.

• MEN1 is implicated in the tumorigenesis of PHEO in this patient.

Summary

Familial dysalbuminemic hyperthyroxinemia (FDH) is a cause of discordant thyroid function tests (TFTs), due to interference in free T4 assays, caused by the mutant albumin. The coexistence of thyroid disease and FDH can further complicate diagnosis and potentially result in inappropriate management. We describe a case of both Hashimoto’s thyroiditis and Graves’ disease occurring on a background of FDH. A 42-year-old lady with longstanding autoimmune hypothyroidism was treated with thyroxine but in varying dosage, because TFTs, showing high Free T4 (FT4) and normal TSH levels, were discordant. Discontinuation of thyroxine led to marked TSH rise but with normal FT4 levels. She then developed Graves’ disease and thyroid ophthalmopathy, with markedly elevated FT4 (62.7 pmol/L), suppressed TSH (<0.03 mU/L) and positive anti-TSH receptor antibody levels. However, propylthiouracil treatment even in low dosage (100 mg daily) resulted in profound hypothyroidism (TSH: 138 mU/L; FT4: 4.8 pmol/L), prompting its discontinuation and recommencement of thyroxine. The presence of discordant thyroid hormone measurements from two different methods suggested analytical interference. Elevated circulating total T4 (TT4), (227 nmol/L; NR: 69–141) but normal thyroxine binding globulin (TBG) (19.2 µg/mL; NR: 14.0–31.0) levels, together with increased binding of patient’s serum to radiolabelled T4, suggested FDH, and ALB sequencing confirmed a causal albumin variant (R218H). This case highlights difficulty ascertaining true thyroid status in patients with autoimmune thyroid disease and coexisting FDH. Early recognition of FDH as a cause for discordant TFTs may improve patient management.

Learning points:

• The typical biochemical features of familial dysalbuminemic hyperthyroxinemia (FDH) are (genuinely) raised total and (spuriously) raised free T4 concentrations due to enhanced binding of the mutant albumin to thyroid hormones, with normal TBG and TSH concentrations.

• Given the high prevalence of autoimmune thyroid disease, it is not surprising that assay interference from coexisting FDH may lead to discordant thyroid function tests confounding diagnosis and resulting in inappropriate therapy.

• Discrepant thyroid hormone measurements using two different immunoassay methods should alert to the possibility of laboratory analytical interference. The diagnosis of FDH is suspected if there is a similar abnormal familial pattern of TFTs and increased binding of radiolabelled 125I-T4 to the patient’s serum, and can be confirmed by ALB gene sequencing.

• When autoimmune thyroid disease coexists with FDH, TSH levels are the most reliable biochemical marker of thyroid status. Measurement of FT4 using equilibrium dialysis or ultrafiltration are more reliable but less readily available.

Summary

This case report describes a family pedigree of a mother and her children with an E227K mutation in the KCNJ11 gene. People with this particular gene mutation typically present with transient neonatal diabetes; with more than half the cohort relapsing into permanent diabetes in adolescence or early adulthood. However, the mother developed diabetes as an adolescent and thus was initially diagnosed as having Type 1 Diabetes. All her children have inherited the same genetic mutation but with differing presentations. Her second, third and fourth child presented with transient neonatal diabetes which remitted at varying times. Her first child is 16 years old but had not developed diabetes at the time of writing. The KCNJ11 gene codes for the KIR6.2 subunit of the K_ATP channels of the pancreatic beta cells. Mutations in this gene limit insulin release from beta cells despite high blood glucose concentrations. Most people with diabetes caused by this genetic mutation can be successfully managed with glibenclamide. Learning of the genetic mutation changed the therapeutic approach to the mother’s diabetes and enabled rapid diagnosis for her children. Through this family, we identified that an identical genetic mutation does not necessarily lead to the same diabetic phenotype. We recommend clinicians to consider screening for this gene in their patients whom MODY is suspected; especially in those presenting before the age of 25 who remain C-peptide positive.

Learning points:

• K_ATP channel closure in pancreatic beta cells is a critical step in stimulating insulin release. Mutations in the KIR6.2 subunit can result in the K_ATP channels remaining open, limiting insulin release.

• People with KCNJ11 mutations may not present with neonatal diabetes as the age of presentation of diabetes can be highly variable.

• Most affected individuals can be treated successfully with glibenclamide, which closes the K_ATP channels via an independent mechanism.

• All first degree relatives of the index case should be offered genetic testing, including asymptomatic individuals. Offspring of affected individuals should be monitored for neonatal diabetes from birth.

• Affected individuals will require long-term follow-up as there is a high risk of recurrence in later life.

Summary

Graves’ disease is associated with tachydysrythmia, cardiac ischaemia and cardiomyopathy – all uncommon in young adults without previous cardiac disease. We present three young individuals who developed cardiac complications after periods of uncontrolled Graves’ disease. Subject 1: A 34-year-old female had severe thyrotoxic symptoms for weeks. Investigations showed fT4: 98.4 (11–25 pmol/L), fT3: 46.9 (3.1–6.8 pmol/L), TSH <0.01 (0.27–4.2 mU/L) and thyrotrophin receptor antibody (TRAb): 34.8 (<0.9 U//l). She had appropriate treatment but several weeks later she became breathless despite improving thyroid function. Echocardiography showed a pericardial effusion of 2.9 cm. She responded well to steroids and NSAIDs but developed active severe Graves’ orbitopathy after early total thyroidectomy. Subject 2: A 28-year-old male developed thyrotoxic symptoms (fT4: 38 pmol/L, fT3: 13.9 pmol/L, TSH <0.01 (for over 6 months) and TRAb: 9.3 U/L). One month after starting carbimazole, he developed acute heart failure (HF) due to severe dilated cardiomyopathy – EF 10–15%. He partially recovered after treatment – EF 28% and had early radioiodine treatment. Subject 3: A 42-year-old woman who had been thyrotoxic for several months (fT4: 54.3; fT3 >46.1; TSH <0.01; TRAb: 4.5) developed atrial fibrillation (AF) and heart failure. Echocardiography showed cardiomegaly – EF 29%. She maintains sinus rhythm following early total thyroidectomy (EF 50%). Significant cardiac complications may occur in previously fit young adults, who have had uncontrolled Graves’ disease for weeks to months. Cardiac function recovers in the majority, but early definitive treatment should be discussed to avoid Graves’ disease relapse and further cardiac decompensation.

Learning points:

• Cardiac complications of Graves’ disease are uncommon in young adults without previous cardiac disease.

• These complications may however occur if Graves’ disease had been poorly controlled for several weeks or months prior to presentation.

• Persistent symptoms after adequate control should alert clinicians to the possibility of cardiac disease.

• Specific treatment of Graves’ disease and appropriate cardiac intervention results in complete recovery in the majority and carries a good prognosis.

• Early definitive treatment should be offered to them to prevent cardiac decompensation at times of further relapse.

Summary

A 40-year-old woman was hospitalised at 25-week gestation following a diagnosis of severe symptomatic hypercalcaemia (adjusted serum calcium 3.02 mmol/L). A diagnosis of primary hyperparathyroidism (PHP) was made on the basis of elevated parathyroid hormone (PTH) 11.2 pmol/L (reference range 1.5–6.9) and exclusion of familial hypocalciuric hypercalcaemia. Ultrasound examination of the neck did not convincingly demonstrate an abnormal or enlarged parathyroid gland and parathyroid scintigraphy was not performed due to maternal choice relating to perceived radiation risk to the foetus. At neck exploration during the 28th week of pregnancy a right lower pole parathyroid lesion was excised together with two abnormal lymph nodes (largest 1.6 cm). Histology confirmed a parathyroid adenoma and also papillary thyroid carcinoma deposits in the two resected lymph nodes. Post-operatively, levels of adjusted serum calcium normalised and pregnancy progressed uneventfully to term. Total thyroidectomy was performed 2 weeks after delivery revealing two small foci of papillary micro-carcinoma (largest 2.3 mm, one in each thyroid lobe) with no evidence of further metastatic tumour in lymph nodes removed during functional neck dissection. Radioiodine remnant ablation (RRA) was performed 2 months post thyroidectomy to allow for breast involution. The patient remains in full clinical and biochemical remission 9 years later. We present and review the difficult management decisions faced in relation to the investigation and treatment of PHP in pregnancy, further complicated by incidentally discovered locally metastatic pT1aN1aM0 papillary thyroid carcinoma.

Learning points:

• PHP may have serious consequences during pregnancy and usually requires surgical management during pregnancy to reduce the risk of maternal and foetal complications. The indications for and optimal timing of surgical management are discussed.

• Localisation by parathyroid scintigraphy is controversial during pregnancy: modified dose regimes may be considered in preference as an alternative to unguided neck exploration.

• Breastfeeding is contraindicated for 6–8 weeks before radioactive-iodine remnant ablation (RRA) to prevent increased breast uptake. Breastfeeding is further contra-indicated until after a subsequent pregnancy.

• Incidentally discovered differentiated thyroid carcinoma (DTC) in cervical lymph nodes in some cases may be managed expectantly because in one quarter of thyroidectomies the primary tumour remains occult.

Summary

Although pheochromocytoma classically presents with headaches, palpitations and paroxysmal hypertension, atypical presentations such as cardiomyopathy, stroke and subarachnoid haemorrhage have been infrequently documented. We present in this case report, an uncommon presentation of pheochromocytoma with myocardial infarction with normal coronary arteries (MINOCA). A 79-year-old woman presented with central crushing chest pain radiating to left arm associated with headache, palpitations, sweating and difficulty in breathing. For 2 years, she experienced brief episodes of headache, tinnitus, dizziness, palpitations, and sweating that spontaneously resolved. Clinical examination was unremarkable except for high blood pressure (210/105 mmHg). Her electrocardiogram showed T wave inversions from V1 to V6 and elevated troponins (774 ng/L at baseline and 932 ng/L 3 h from baseline (normal <16 ng/L) in keeping with a diagnosis of non-ST elevated myocardial infarction. Coronary angiography showed normal coronary arteries. Patient was hence treated as myocardial infarction with normal coronaries (MINOCA). Despite appropriate treatment for MINOCA, she continued to experience episodic headaches, palpitations, dizziness and erratic blood pressures (particularly severe hypertension shortly after beta-blocker administration). Further investigations revealed raised urine noradrenaline of 4724 nmol/24 h (<554 nmol/24 h) and urine adrenaline of 92863 nmol/24 h (<77 nmol/24 h). Computerised tomography demonstrated a well-defined rounded mass in right adrenal gland morphological of pheochromocytoma. She underwent laparoscopic right adrenalectomy with histology confirming pheochromocytoma. This case highlights the importance of thorough investigation for the underlying cause for MINOCA. In patients with unexplained erratic blood pressure control, pheochromocytoma should be considered as a differential diagnosis.

Learning points:

• Pheochromocytoma is rare tumour that often presents with non-specific symptoms.

• It is important to investigate underlying cause of MINOCA.

• Thorough history is the key to diagnosis.

Summary

Diabetic myonecrosis, also known as diabetic muscle infarction is a rare complication of diabetes mellitus usually associated with longstanding suboptimal glycaemic control. Although theories of atherosclerosis, diabetic microangiopathy, vasculitis, ischaemia-reperfusion injury and hypercoagulable state have been proposed to explain the pathophysiology, none of these have been able to individually explain the pathophysiology in entirety. Diabetic renal disease is the most common risk factor for developing DMN and its recurrence. The diagnosis is often missed due to lack of awareness and the presentation mimicking other conditions associated with DM. The routine laboratory investigations are often non-specific and do not provide much value in the diagnosis as well. Muscle biopsy can provide a definite diagnosis but is not currently recommended due to its invasiveness and association with prolonged time to symptoms resolution. Magnetic resonance imaging, in combination with classic history and risk factors can clinch the diagnosis. Treatment is generally analgesia and rest, although the former’s use may be limited in the presence of renal disease.

Learning points:

• Diabetic myonecrosis is a rare complication of diabetes mellitus associated with longstanding suboptimal glycaemic control.

• Diabetic renal disease is a known risk factor, although the evidence is merely observational.

• Although muscle biopsy could provide a definite diagnosis, it is not recommended as it can prolong the disease process and should be reserved only for cases not responding to conventional treatment.

• Typical MRI findings in combination with classic symptoms and risk factors can clinch the diagnosis

• Current treatment recommendations include NSAIDs and/or aspirin (if not contraindicated) alongside bed rest. Physiotherapy is not recommended in the acute phase but should be started as soon as patient is discharged from hospital.

• Optimal glycaemic control is key to prevent recurrence.

Summary

We report our experience on managing a case of florid Cushing’s disease with Methicillin-resistant Staphylococcus aureus (MRSA) sepsis using intravenous etomidate in the intensive care unit of a UK district general hospital.

Learning points:

• Severe Cushing’s syndrome is associated with high morbidity and mortality.

• Etomidate is a safe and effective medical therapy to rapidly lower cortisol levels even in the context of severe sepsis and immunosuppression.

• Etomidate should ideally be administered in an intensive care unit but is still feasible in a district general hospital.

• During treatment with etomidate, accumulation of serum 11β-deoxycortisol (11DOC) levels can cross-react with laboratory cortisol measurement leading to falsely elevated serum cortisol levels. For this reason, serum cortisol measurement using a mass spectrometry assay should ideally be used to guide etomidate prescription.

Learning points:

• Sclerochoroidal calcifications (SCs), though rare and harmless, could be associated with an underlying systemic disease, such as primary hyperparathyroidism (PHPT).

• Biochemical screening for hypercalcaemia is a simple, cheap and widely available tool that could facilitate an identification of undiagnosed PHPT in patients with SC.

• A joint care by endocrinologists and ophthalmologists is warranted for those patients, as thorough investigations and long-term follow-up plans are crucial.

Learning points:

• Clinicians prescribing ferric carboxymaltose (Ferinject^®) should be aware of the common side effect of hypophosphataemia, which could be mild, moderate or severe.

• Patients receiving iron infusion should be educated concerning this potential side effect.

• Pre-existing vitamin D deficiency, low calcium levels, low phosphate levels or raised parathyroid hormone levels may be risk factors, and these should be evaluated and corrected before administering intravenous iron.

• Patients may require phosphate and vitamin D replacement along with monitoring for a long period after iron infusion-induced hypophosphataemia.

• Every incident should be reported to the designated body so that the true prevalence and management thereof can be ascertained.