ABSTRACT
Thyrotoxic periodic paralysis (TPP) is a complication of hyperthyroidism among Asians, characterised by sudden onset of hypokalaemia and muscle paralysis. Several factors may contribute to a delay in diagnosis, including the subtlety of hyperthyroidism, the transient nature of the events and the rarity of this disease in the West. As life-threatening arrhythmias may occur during an attack, awareness among physicians is necessary for early recognition and treatment. Advances have been made in understanding the pathophysiological mechanism leading to hypokalaemia, which include recently identified mutations of the inwardly rectifying potassium channel Kir2.6. Treatment includes the supplementation of potassium, a nonselective beta-blocker, and ultimately treatment of the underlying hyperthyroidism. Here we report three cases of TPP in the Netherlands, and review the literature on clinical features, pathophysiological hypothesis and treatment.
Subject(s)
Antithyroid Agents/therapeutic use , Hyperthyroidism/complications , Hypokalemia/etiology , Paralysis/etiology , Potassium/administration & dosage , Thyrotoxicosis , Adult , Female , Humans , Hyperthyroidism/drug therapy , Hyperthyroidism/physiopathology , Hypokalemia/drug therapy , Male , Potassium/blood , Thyrotoxicosis/diagnosis , Thyrotoxicosis/drug therapy , Thyrotoxicosis/etiology , Young AdultABSTRACT
BACKGROUND: Treatment of differentiated thyroid carcinoma (DTC) often involves administration of radioactive iodine (I-131) for remnant ablation or adjuvant therapy. As DTC has favorable outcome and the incidence is increasing, concerns have been raised about the possible adverse effects of I-131 therapy. We systematically reviewed the literature to examine the risk of intermediate and long-term adverse effects of I-131 therapy in DTC patients. METHODS: Multiple electronic databases were searched up to November 2014 for English-language, controlled studies that reported on the risk of salivary gland dysfunction, lacrimal gland dysfunction, gonadal dysfunction, female reproductive outcomes or second primary malignancies (SPM) after I-131 exposure. The certainty of the evidence found was assessed using GRADE. RESULTS: In total, 37 articles met all inclusion criteria, no studies reporting on adverse effects after I-131 treatment focused solely on children. After exposure to I-131 for DTC, patients experienced significantly more frequently salivary gland dysfunction (prevalence range: 16-54%, moderate-level evidence), lacrimal gland dysfunction (prevalence: 11%, low-level evidence), transient male gonadal dysfunction (prevalence: 35-100%, high-level evidence), transient female gonadal dysfunction (prevalence: 28%, low-level evidence) and SPM (prevalence: 2.7-8.7%, moderate-level evidence) compared to unexposed patients. I-131 therapy seems to have no deleterious effects on female reproductive outcomes (very-low level evidence). The prevalence and severity of adverse effects were correlated to increasing cumulative I-131 activity. CONCLUSION: Treatment with I-131 for DTC may have significant adverse effects, which seem to be dose dependent. These adverse effects of treatment must be balanced when choosing for I-131 therapy in patients with DTC.