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Open access

Keerthana Haridas

Summary

Human T-cell lymphotropic virus-1 (HTLV-1) causes adult T-cell leukemia and lymphoma (ATLL) and is a rare but important cause of hypercalcemia. A 53-year-old male with HTLV-1-associated myelopathy presented with acute on chronic bilateral lower extremity weakness and numbness. Initial blood work revealed hypercalcemia with corrected calcium of 16.2 mg/dL (8.5–11.5) with normal levels of phosphorus and alkaline phosphatase. Workup for hypercalcemia revealed parathyroid hormone (PTH) of 14 pg/mL (10–65), 25 hydroxy vitamin D at 19.6 ng/mL (30–100), 1,25 dihydroxy vitamin D at 6.7 pg/mL (19.9–79.3), thyroid-stimulating hormone of 1.265 μIU/mL (0.5–5), undetectable PTH-related protein (PTHrP) and lactate dehydrogenase of 433 U/L (100–220). The urine calcium creatinine ratio was 0.388. Reverse transcriptase PCR was positive for HTLV-1 and negative for HTLV-2. Peripheral blood flow cytometry and lymph node biopsy confirmed ATLL. He received treatment with fluids, calcitonin and denosumab after which serum calcium levels fell (nadir: 7.7 mg/dL) and then normalized. Humoral hypercalcemia in this setting is mediated by receptor activator of nuclear factor-kappa B ligand (RANKL), PTHrP and other cytokines. PTHrP levels depend on levels of the TAX gene product, cell type and lymphocyte-specific factors. Thus, a low level, like in our patient, does not rule out HTLV-1 infection/ATLL as the cause of hypercalcemia. Hypercalcemia is known to be responsive to monoclonal antibodies against RANKL given the compound’s role in mediating hypercalcemia in these cases.

Learning points

  • Human T-cell lymphotropic virus-1 infection and adult T-cell leukemia and lymphoma are associated with high rates of hypercalcemia and hypercalcemic crises.

  • Hypercalcemia in these cases is mediated by osteoclastic bone resorption carried out by several agents including receptor activator of nuclear factor-kappa B ligand, parathyroid hormone-related protein (PTHrP), macrophage inflammatory protein 1 alpha, interleukins, etc. A normal PTHRrP does not rule out humoral hypercalcemia of malignancy in this setting, as indicated by this case.

  • Hypercalcemia in such settings is highly responsive to monoclonal antibodies against RANKL given the role the ligand plays in resorptive hypercalcemia.

Open access

Adele J Beck, Venkat M Reddy, Tom Sulkin, and Duncan Browne

Summary

Primary hyperparathyroidism (PHP) is the most common aetiology for hypercalcaemia. The incidence of PHP in pregnant women is reported to be 8/100 000 population/year. It presents a threat to the health of both mother (hyperemesis, nephrolithiasis) and fetus (fetal death, congenital malformations, and neonatal severe hypocalcaemia-induced tetany). However, there is a lack of clear guidance on the management of primary hyperparathyroidism in pregnancy. In this study, we describe the case of a 26-year-old female patient who presented with severe hypercalcaemia secondary to PHP and underwent successful parathyroid adenectomy under local anaesthesia.

Learning points

  • Primary hyperparathyroidism is a rare complication in pregnancy, but the consequences for mother and fetus can be severe.

  • A perceived risk of general anaesthesia to the fetus in the first trimester has resulted in a general consensus to delay parathyroid surgery to the second trimester when possible – although the increased risk of fetal loss may occur before planned surgery.

  • If the patient presents with severe or symptomatic hypercalcaemia, minimally invasive surgery under local anaesthetic should be considered regardless of the gestational age of the pregnancy.

Open access

Saki Nakashima, Masahiro Kawada, Akinari Sekine, Masayuki Yamanouchi, Daisuke Ikuma, Hiroki Mizuno, Yuki Oba, Eiko Hasegawa, Tatsuya Suwabe, Kei Kono, Keiichi Kinowaki, Kenichi Ohashi, Naoki Sawa, Junichi Hoshino, and Yoshifumi Ubara

A 63-year-old Japanese woman was admitted to our institute for the evaluation of proteinuria. The patient was diagnosed with medullary sponge kidney, distal type renal tubular acidosis, and renal infection at the age of 37. Thereafter, the patient had repeated renal infections. Urinary proteinuria appeared at around the age of 61 and gradually increased up to 1.0 g daily. In the same period, glycated hemoglobin (HbA1c) increased to 7.0%. On kidney biopsy, light microscopy showed a nodular glomerular lesion and capsular drop. Linear staining for immunoglobulin G along the glomerular basement membrane was observed by immunofluorescence. Electron microscopy showed thickening of the glomerular basement membrane to a width of 800–900 nm. A class III glomerular lesion was diagnosed according to the Tervaert classification. This case indicates that mild but prolonged hyperglycemia for more than 10 years may also contribute to the formation of nodular lesions, although long-standing repeated chronic renal infection and chronic acidosis may have been a precipitating factor in the formation of diabetic nephropathy, including nodular glomerular lesions. This hypothesis is of interest because nodular lesions specific to diabetes are currently considered to be associated with long-term severe hyperglycemia.

Learning points

  • Nodular glomerular lesions in diabetes mellitus are thought to be associated with long-term severe hyperglycemia.

  • This case shows that although mild, long-term hyperglycemia for more than 10 years may also contribute to the formation of nodular lesions and that repeated chronic kidney infections over the years and chronic acidosis may be facilitating factors in the formation of diabetic nephropathy, including nodular glomerular lesions.

  • This case appears to be idiopathic nodular glomerulosclerosis of the medullary sponge kidney associated with chronic urinary tract infection.

Open access

Livia Lugarinho Correa, Priscila Alves Medeiros de Sousa, Leticia Dinis, Luana Barboza Carloto, Maitane Nuñez-Garcia, Ignacio Sajoux, and Sidney Senhorini

Summary

There is a close association between obesity and type 2 diabetes (T2D). The value of weight loss in the management of patients with T2D has long been known. Loss of 15% or more of body weight can have a disease-modifying effect in people with diabetes inducing remission in a large proportion of patients. Very low-carbohydrate ketogenic diets (VLCKDs) have been proposed as an appealing nutritional strategy for obesity management. The diet was shown to result in significant weight loss in the short, intermediate, and long terms and improvement in body composition parameters as well as glycemic and lipid profiles. The reported case is a 35-year-old man with obesity, dyslipidemia, and T2D for 5 years. Despite the use of five antidiabetic medications, including insulin, HbA1c was 10.1%. A VLCKD through a commercial multidisciplinary weight loss program (PnK method) was prescribed and all medications were discontinued. The method is based on high-biological-value protein preparations and has 5 steps, the first 3 steps (active stage) consist of a VLCKD (600–800 kcal/d) that is low in carbohydrates (<50 g daily from vegetables) and lipids. The amount of proteins ranged between 0.8 and 1.2 g/kg of ideal body weight. After only 3 months, the patient lost 20 kg with weight normalization and diabetes remission, and after 2 years of follow-up, the patient remained without the pathologies. Due to the rapid and significant weight loss, VLCKD emerges as a useful tool in T2D remission in patients with obesity.

Learning points

  • Obesity and type 2 diabetes (T2D) are conditions that share key pathophysiological mechanisms.

  • Loss of 15% or more of body weight can have a disease-modifying effect in people with T2D inducing remission in a large proportion of patients.

  • Diabetes remission should be defined as a return of HbA1c to <6.5% and which persists for at least 3 months in the absence of usual glucose-lowering pharmacotherapy.

  • The very low-carbohydrate ketogenic diet (VLCKD) is a nutritional approach that has significant beneficial effects on anthropometric and metabolic parameters.

  • Due to the rapid and significant weight loss, VLCKD emerges as a useful tool in T2D remission in patients with obesity.

Open access

Motohiro Sekiya, Mikiko Yuhara, Yuki Murayama, Mariko Ohyama Osawa, Rikako Nakajima, Nami Ohuchi, Nako Matsumoto, Daichi Yamazaki, Sayuri Mori, Takaaki Matsuda, Yoko Sugano, Yoshinori Osaki, Hitoshi Iwasaki, Hiroaki Suzuki, and Hitoshi Shimano

Summary

A paired homeodomain transcription factor, PAX6 (paired-box 6), is essential for the development and differentiation of pancreatic endocrine cells as well as ocular cells. Despite the impairment of insulin secretion observed in PAX6-deficient mice, evidence implicating causal association between PAX6 gene mutations and monogenic forms of human diabetes is limited. We herein describe a 33-year-old Japanese woman with congenital aniridia who was referred to our hospital because of her uncontrolled diabetes with elevated hemoglobin A1c (13.1%) and blood glucose (32.5 mmol/L) levels. Our biochemical analysis revealed that her insulin secretory capacity was modestly impaired as represented by decreased 24-h urinary C-peptide levels (38.0 μg/day), primarily explaining her diabetes. Intriguingly, there was a trend toward a reduction in her serum glucagon levels as well. Based on the well-recognized association of PAX6 gene mutations with congenital aniridia, we screened the whole PAX6 coding sequence, leading to an identification of a heterozygous Gln135* mutation. We tested our idea that this mutation may at least in part explain the impaired insulin secretion observed in this patient. In cultured pancreatic β-cells, exogenous expression of the PAX6 Gln135* mutant produced a truncated protein that lacked the transcriptional activity to induce insulin gene expression. Our observation together with preceding reports support the recent attempt to include PAX6 in the growing list of genes causally responsible for monogenic diabetes. In addition, since most cases of congenital aniridia carry PAX6 mutations, we may need to pay more attention to blood glucose levels in these patients.

Learning points

  • PAX6 Gln135* mutation may be causally associated not only with congenital aniridia but also with diabetes.

  • Blood glucose levels may deserve more attention in cases of congenital aniridia with PAX6 mutations.

  • Our case supports the recent attempt to include PAX6 in the list of MODY genes, and Gln135* may be pathogenic.

Open access

Adam I Kaplan, Catherine Luxford, and Roderick J Clifton-Bligh

Summary

Biallelic pathological variants in the thyroid stimulating hormone (TSH) subunit β gene (TSHB) result in isolated TSH deficiency and secondary hypothyroidism, a rare form of central congenital hypothyroidism (CCH), with an estimated incidence of 1 in 65 000 births. It is characterised by low levels of free thyroxine and inappropriately low serum TSH and may therefore be missed on routine neonatal screening for hypothyroidism, which relies on elevated TSH. We describe a patient with CCH who developed recurrence of pituitary hyperplasia and symptomatic hypothyroidism due to poor compliance with thyroxine replacement. She was diagnosed with CCH as a neonate and had previously required trans-sphenoidal hypophysectomy surgery for pituitary hyperplasia associated with threatened chiasmal compression at 17 years of age due to variable adherence to thyroxine replacement. Genetic testing of TSHB identified compound heterozygosity with novel variant c.217A>C, p.(Thr73Pro), and a previously reported variant c.373delT, p.(Cys125Valfs*10). Continued variable adherence to treatment as an adult resulted in recurrence of significant pituitary hyperplasia, which subsequently resolved with improved compliance without the need for additional medications or repeat surgery. This case describes a novel TSHB variant associated with CCH and demonstrates the importance of consistent compliance with thyroxine replacement to treat hypothyroidism and prevent pituitary hyperplasia in central hypothyroidism.

Learning points

  • Pathogenic variants in the TSH subunit β gene (TSHB) are rare causes of central congenital hypothyroidism (CCH).

  • c.217A>C, p.(Thr73Pro), is a novel TSHB variant, presented in association with CCH in this case report.

  • Thyroxine replacement is critical to prevent clinical hypothyroidism and pituitary hyperplasia.

  • Pituitary hyperplasia can recur post-surgery if adherence to thyroxine replacement is not maintained.

  • Pituitary hyperplasia can dramatically reverse if compliance with thyroxine replacement is improved to maintain free thyroxine (FT4) levels in the middle-to-upper normal range, without the need for additional medications or surgeries.

Open access

Eimear Mary O’Donovan, Begona Sanchez-Lechuga, Emma Prehn, and Maria Michelle Byrne

Summary

The coexistence of autoimmune diabetes and maturity-onset diabetes (MODY) is rare. The absence of pancreatic autoantibodies is a key factor prompting MODY genetic testing. In this study, we report three cases of young-onset diabetes with progressive beta-cell dysfunction, strongly positive glutamic acid decarboxylase (GAD) antibodies, and genetic confirmation of pathogenic gene variants of HNF-1A, HNF-4A, and ABCC8-MODY. The first case is a woman diagnosed with HNF-1A-MODY diabetes more than 30 years after her diagnosis of adult-onset diabetes at 25 years. She required insulin after her fourth pregnancy. She became ketotic on oral hypoglycaemic agents (OHAs) and subsequently, her GAD antibodies tested positive. The second case is a woman diagnosed with diabetes at 17 years who was subsequently diagnosed with HNF-4A-MODY after many hypoglycaemic episodes on low-dose insulin. GAD antibodies were strongly positive. The last case is a man diagnosed with diabetes at 26 years who was well controlled on OHAs and required insulin years later due to sudden deterioration in glycaemic control. His ABCC8-MODY was diagnosed upon realisation of strong family history and his GAD antibodies tested positive. All subjects are now treated with insulin. Less than 1% of subjects with MODY have positive autoantibodies. These cases highlight individuals who may have two different types of diabetes simultaneously or consecutively. Deterioration of glycaemic control in subjects with MODY diabetes should highlight the need to look for the emergence of autoantibodies. At each clinic visit, one should update the family history as MODY was diagnosed in each case after the development of diabetes in their offspring.

Learning points

  • These cases highlight the rare coexistence of autoimmune diabetes and MODY.

  • Deterioration of glycaemic control in subjects with MODY diabetes should highlight the emergence of autoantibodies.

  • One should revise and update the family history as the diagnosis of MODY was made after the development of diabetes in offspring.

  • Understanding the spectrum of diabetes allows for precision medicine.

Open access