[Review of clinical practice guidelines for hypoparathyroidism]

[First experience of applying domestic video fluorescent equipment for visualization and blood flow evaluation of the parathyroid glands]

In recent years, predictive methods for assessing the preservation of the parathyroid glands have been actively implemented. The article describes the first experience of evaluating the blood supply of the parathyroid glands by quantitative determination of the indocyanine green (ICG) accumulation index in real time in 6 patients before and after a thyroidectomy with central neck lymph node dissection for papillary thyroid cancer. Intraoperative fluorescent angiography was performed by using domestic equipment with a fluorescent module, as well as by using a domestic medication of ICG. Intraoperative values of the ICG accumulation index were compared with the levels of ionized calcium and parathyroid hormone perioperatively. No clinical manifestations of hypocalcemia were detected in the postoperative period. The obtained results showed the informativeness of the numerical assessment of the intensity of ICG fluorescence. The evaluation of the distribution (accumulation) of ICG has prospects for practical application in thyroid surgery in the formation of tactics for preserving the parathyroid glands and predicting postoperative hypoparathyreosis.

[Neurological manifestations of hypoparathyroidism: diagnostic difficulties. Case report]

Hypoparathyroidism is a rare condition characterized by reduced production of parathyroid hormone or tissue resistance which leads to hypocalcemia and hyperphosphatemia. Neurological manifestations often occur as the first symptoms of hypoparathyroidism and are characterized by a wide variety of symptoms of both the central and peripheral nervous systems dysfunction, which requires a differential diagnosis with a wide range of neurological diseases. Two clinical cases illustrating the features of subacute and chronic hypoparathyroidism are presented. In the case of subacute hypoparathyroidism, a young woman presented with severe tetany involving the oculomotor muscles (paroxysmal strabismus), laryngeal muscles (respiratory stridor), body muscles (opisthotonus, «obstetrician's hand») and the development of secondary myopathy. In another case with a long-term chronic course of postoperative hypoparathyroidism, the patient's adaptation to severe hypocalcemia was noted; the clinical features were dominated by cerebral syndromes due to brain structures calcification (Fahr's syndrome). Possible reasons for late diagnosis of hypoparathyroidism, the importance of active detection of symptoms of neuromuscular hyperexcitability and laboratory testing of phosphorus and calcium metabolism are discussed.

Parameters of Vitamin D Metabolism in Patients with Hypoparathyroidism

Only a few studies evaluating the metabolism of vitamin D in patients with hypoparathyroidism (HypoPT) have been performed thus far, and, in particular, they mainly investigated the process of vitamin D activation (specifically, 1α-hydroxylation). This study, therefore, aimed to evaluate the extended spectrum of vitamin D metabolites in patients with HypoPT compared to healthy individuals. We examined 38 adult patients with chronic HypoPT in comparison to 38 healthy adults. The assessment included biochemical parameters (total calcium, albumin, phosphorus, creatinine, and magnesium), parathyroid hormone (PTH), and vitamin D metabolites (25(OH)D3, 25(OH)D2, 1,25(OH)2D3, 3-epi-25(OH)D3, and 24,25(OH)2D3) in serum. Our data show that an adequate level of 25(OH)D3 (median 35.3 (29.6; 42.0) ng/mL) is achieved with standard doses of cholecalciferol (median 2000 (2000; 2500) IU per day) in HypoPT patients. They also presented with supraphysiological levels of 1,25(OH)2D3 (median 71 (47; 96) vs. 40 (34; 59) pg/mL, p < 0.001) and the increased production of inactive metabolite (median 24,25(OH)2D3 3.8 (3.0; 5.1) vs. 1.9 (1.3; 2.7) ng/mL, p < 0.001; median 25(OH)D3/24,25(OH)2D3 ratio 8.9 (7.6; 11.1) vs. 13.5 (11.1; 17.0), p < 0.001) as compared to the control group. This might be a consequence of the therapy received (treatment with activated vitamin D) and the pathophysiology of the disease (lack of PTH). The abnormality of vitamin D metabolism does not seem to interfere with the achievement of hypoparathyroidism compensation.