Drug-Induced Thyrotoxic Periodic Paralysis

Intravenous Iodinated Contrast Induced Thyrotoxic Periodic Paralysis: A Case Report

Thyrotoxic periodic paralysis (TPP) is an entity that has been described in the literature as a transient, symmetrical, flaccid paralysis, mainly affecting the lower limbs of patients with a current or previous history of hyperthyroidism. In most cases, Graves' disease is the cause of hyperthyroidism. Contrast and iodine-induced TPP have been described in the literature, but only one case of intravenous contrast induced TPP has been reported. We report a case of TPP following administration of intravenous contrast for a computed tomography scan of the neck prior to lymph node excision. A 35-year-old Kuwaiti male with known Graves' disease in remission until two months of his presentation, reported to the emergency room one early morning in December 2020. He sustained a fall from the stairs due to bilateral lower limb weakness, mostly proximal. The upper limbs were spared, and the patient did not experience any numbness or headache. His potassium was found to be 2.1 mmol/L and an electrocardiogram showed U waves and ST segment changes. He was initiated on 20 mEq of intravenous potassium chloride in 500 mL sodium chloride over one hour, following which his potassium approached normal and his weakness resolved. He was last known to be euthyroid in November 2019 but noted in October 2020 to be in the hyperthyroid state when thyroid function testing showed a thyroid-stimulating hormone of <0.005 (0.27-4.2 uIu/mL) and free thyroxine (T4) of 27.6 (7.8- pmol/L). In patients with known hyperthyroidism, more caution is required when iodine-containing substances are administered without proper evaluation of thyroid function.

Periodic paralysis: An unusual presentation of drug-induced hyperkalemia

Hyperkalemia is a life-threatening electrolyte abnormality. The most common cause of hyperkalemia includes renal disease and ingestion of medications. Drug-induced hyperkalemia may develop in patients with underlying renal impairment, disturbed cellular uptake of potassium load, excessive ingestion or infusion of potassium-containing substances. We report a case of “drug-induced severe hyperkalemia” presenting as periodic paralysis. A 67-year-old diabetic and hypertensive woman presented to emergency department with the complaint of intermittent episode of inability to walk for the past 5 days. Each episode lasted for 15-20 minutes and was associated with breathlessness and restlessness. There was no family history of periodic paralysis and drug history revealed that the patient was onolmesartan 20 mg per day (for past 2 years), perindopril 4 mg per day (for past 16 months), and torsemide 10 mg/day. On examination patient was found to be conscious, alert, and afebrile. Vitals were normal. Examination of cardiovascular and respiratory system did not reveal any significant finding. Blood report of the patient showed serum K+ level 8.6 mmol/l. All other investigations were within normal limits. A diagnosis of drug-induced hyperkalemia was made. Patient responded well to the symptomatic treatment. To the best of the author's knowledge, this is the first case report of drug-induced hyperkalemia presenting as periodic paralysis.

Thyroid disease and the nervous system

Thyroid disorders are common in the general population and in hospitalized patients. Thyroid disease may present first with neurological complications or else may occur concurrently in patients suffering other neurological disorders, particularly those with an autoimmune etiology. For this reason neurologists will commonly encounter patients with thyroid disease. This chapter provides an overview of the neurological complications and associations of disorders of the thyroid gland. Particular emphasis is placed on conditions such as thyrotoxic periodic paralysis and myxedema coma in which the underlying thyroid disorder may be occult leading to a first, often emergency, presentation to a neurologist. Information about clinical features, diagnosis, pathogenesis, therapy, and prognosis is provided. Emphasis is placed on those aspects most likely to be relevant to the practicing neurologist and the interested reader is directed to references to good, recent review articles for further information.

Iodine-induced thyrotoxic hypokalemic paralysis after ingestion of Salicornia herbace

A 56-year-old Korean man visited to emergency room due to paroxysmal flaccid paralysis in his lower extremities. There was no family or personal history of periodic paralysis. His initial potassium levels were 1.8 mmol/L. The patient had been taking Salicornia herbacea for the treatment of diabetes and hypertension. Results of a thyroid function test were as follows: T3 = 130.40 ng/dL, TSH = 0.06 mIU/L, and free T4 = 1.73 ng/dL. A thyroid scan exhibited a decreased uptake (0.6%). His symptoms clearly improved and serum potassium levels increased to 4.4 mmol/L by intravenous infusion of only 40 mmol of potassium chloride. Eight months after the discontinuation of only Salicornia herbacea, the patient's thyroid function tests were normalized. Large amounts of iodine can induce hypokalemic thyrotoxic paralysis and it may be necessary to inquire about the ingestion of iatrogenic iodine compounds, such as Salicornia herbacea.

Severe Hypokalemia Probably Associated With Sertraline Use

Objective: To report a case of ventricular fibrillation caused by severe hypokalemia probably associated with sertraline use. Case Summary: A 48-year-old male patient experienced ventricular fibrillation and cardiac arrest 2 hours after an uneventful coronary angiography procedure, which revealed normal, unobstructed coronary arteries. Blood chemistry was immediately obtained, revealing a very low potassium (K+) level of 2.44 mEq/L. Other blood electrolytes, including magnesium, ECG, and corrected QT intervals, were all within normal limits. A thorough search for an etiology of hypokalemia, including adrenal gland causes, herbal product consumption, and toxic exposure, did not reveal any identifiable cause. This led us to consider the only drug he was on—sertraline 50 mg per day—as the possible culprit. Discussion: There has been no clear identification of severe hypokalemia associated with sertraline use in the literature. However, there have been a considerable number of self-reported cases of hypokalemia in patients on sertraline therapy. Scoring according to the Naranjo adverse drug reaction scale revealed a probable relationship between severe hypokalemia and sertraline use in our patient. No clear pathogenic mechanism for the effect of sertraline on serum K equilibrium is known. However, considering the number of self-reported incidences and this case report, the effect of sertraline on serum K levels warrants consideration. Conclusions: This is the first documented case report of severe hypokalemia probably associated with sertraline use.

Thyrotoxic periodic paralysis: clinical and molecular aspects

Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism that most often affects young East Asian males but increasingly also in other ethnic groups. The typical presentation is acute attacks varying from mild weakness to total paralysis starting at night or in the early morning a few hours after a heavy meal, alcohol abuse or strenuous exercise with complete recovery within 72 h. Signs and symptoms of hyperthyroidism may not be obvious. The hallmark is hypokalemia from increased cellular sodium/potassium-ATPase pump activity with transport of potassium from the extracellular to the intracellular space in combination with reduced potassium output. Recently, KCNJ18 gene mutations which alter the function of an inwardly rectifying potassium channel named Kir2.6 have been detected in 0-33 % of cases. Hence, the pathophysiology in TPP includes a genetic predisposition, thyrotoxicosis and environmental influences and the relative impact from each of these factors may vary. The initial treatment, which is potassium supplementation, should be given with caution due to a high risk of hyperkalemia. Propranolol is an alternative first-line therapeutic option based on the assumption that hyperadrenergic activity is involved in the pathogenesis. If thyroid function tests are unobtainable in the acute situation the diagnosis is supported by the findings of hypokalemia, low spot urine potassium excretion, hypophosphatemia with hypophosphaturia, high spot urine calcium/phosphate ratio, and electrocardiographic abnormalities as tachycardia, atrial fibrillation, high QRS voltage, and atrioventricular block. Definitive treatment is cure of the hyperthyroidism. The underlying mechanisms of TPP remain, however, incompletely understood awaiting further studies.

Hypokalemic periodic paralysis as first sign of thyrotoxicosis

Background: periodic paralysis related to hypokalemia is seldom reported in thyrotoxicosis, and it usually occurs in Asian males.

Patients and methods: Two Romanian (Caucasian) young patients presented with hypokalemic paralysis. TSH, FT4, TT3 was measured by immunochemiluminescence.

Case report 1. Patient O.R, aged 19, presented marked asthenia and lower limbs paralysis, following high carbohydrate meal. He declared 10 kg weight loss on hypocaloric diet and mild sweating. Biochemical data revealed moderate hypokalemia (K+=2.6 mmol/L) and thyrotoxicosis (TSH<0.03 mIU/L, FT4=30 pmol/L, TT3=315 ng/dL).

Case report 2. Patient T.A., aged 18, presented 2 episodes of weakness and flaccid paralysis, with hypokalemia, precipitated by effort, without any sign of thyrotoxicosis. Biochemical data revealed severe hypokalemia (K+=1.8 mmol/L) and thyrotoxicosis (TSH<0.03 mIU/L, FT4=24 pmol/L, TT3=190 ng/dL). Treatment with intravenous potassium, thereafter methimazole and propranolol were administered in both cases, with the maintenance of normal kalemia and thyrotoxicosis’ control.

Conclusion: these 2 cases of hypokalemic periodic paralysis occurring in young Caucasian teenagers with mild thyrotoxicosis underlined the importance of thyroid screening in patients with symptomatic hypokalemia, even in the absence of symptoms and signs of thyrotoxicosis.

Abbreviations: THPP=Thyrotoxic periodic paralysis, BMI=body mass index, TRAb=TSH receptor antibody, ECG=electrocardiogram.

Paradoxical and bidirectional drug effects

A paradoxical drug reaction constitutes an outcome that is opposite from the outcome that would be expected from the drug's known actions. There are three types: 1. A paradoxical response in a condition for which the drug is being explicitly prescribed. 2. Paradoxical precipitation of a condition for which the drug is indicated, when the drug is being used for an alternative indication. 3. Effects that are paradoxical in relation to an aspect of the pharmacology of the drug but unrelated to the usual indication. In bidirectional drug reactions, a drug may produce opposite effects, either in the same or different individuals, the effects usually being different from the expected beneficial effect. Paradoxical and bidirectional drug effects can sometimes be harnessed for benefit; some may be adverse. Such reactions arise in a wide variety of drug classes. Some are common; others are reported in single case reports. Paradoxical effects are often adverse, since they are opposite the direction of the expected effect. They may complicate the assessment of adverse drug reactions, pharmacovigilance, and clinical management. Bidirectional effects may be clinically useful or adverse. From a clinical toxicological perspective, altered pharmacokinetics or pharmacodynamics in overdose may exacerbate paradoxical and bidirectional effects. Certain antidotes have paradoxical attributes, complicating management. Apparent clinical paradoxical or bidirectional effects and reactions ensue when conflicts arise at different levels in self-regulating biological systems, as complexity increases from subcellular components, such as receptors, to cells, tissues, organs, and the whole individual. These may be incompletely understood. Mechanisms of such effects include different actions at the same receptor, owing to changes with time and downstream effects; stereochemical effects; multiple receptor targets with or without associated temporal effects; antibody-mediated reactions; three-dimensional architectural constraints; pharmacokinetic competing compartment effects; disruption and non-linear effects in oscillating systems, systemic overcompensation, and other higher-level feedback mechanisms and feedback response loops at multiple levels. Here we review and provide a compendium of multiple class effects and individual reactions, relevant mechanisms, and specific clinical toxicological considerations of antibiotics, immune modulators, antineoplastic drugs, and cardiovascular, CNS, dermal, endocrine, musculoskeletal, gastrointestinal, haematological, respiratory, and psychotropic agents.

Novel etiopathophysiological aspects of thyrotoxic periodic paralysis

Thyrotoxicosis can lead to thyrotoxic periodic paralysis (TPP), an endocrine channelopathy, and is the most common cause of acquired periodic paralysis. Typically, paralytic attacks cease when hyperthyroidism is abolished, and recur if hyperthyroidism returns. TPP is often underdiagnosed, as it has diverse periodicity, duration and intensity. The age at which patients develop TPP closely follows the age at which thyrotoxicosis occurs. All ethnicities can be affected, but TPP is most prevalent in people of Asian and, secondly, Latin American descent. TPP is characterized by hypokalemia, suppressed TSH levels and increased levels of thyroid hormones. Nonselective β adrenergic blockers, such as propranolol, are an efficient adjuvant to antithyroid drugs to prevent paralysis; however, an early and definitive treatment should always be pursued. Evidence indicates that TPP results from the combination of genetic susceptibility, thyrotoxicosis and environmental factors (such as a high-carbohydrate diet). We believe that excess T(3) modifies the insulin sensitivity of skeletal muscle and pancreatic β cells and thus alters potassium homeostasis, but only leads to a depolarization-induced acute loss of muscle excitability in patients with inherited ion channel mutations. An integrated etiopathophysiological model is proposed based on molecular findings and knowledge gained from long-term follow-up of patients with TPP.

Effects of sex steroid hormones, thyroid hormone levels, and insulin regulation on thyrotoxic periodic paralysis in Chinese men

Our study is to determine the expression of thyroid hormone, sex hormone, insulin, and C-peptide in Chinese male patients with thyrotoxic periodic paralysis (TPP). This study covered 102 patients with hyperthyroidism from Xijing Hospital. According to whether occurrence of TPP or not, patients were divided into two groups (those that were hyperthyroid with and without TPP) that were, matched with age, blood pressure, urea, and creatinine. We found the body mass index (BMI) in patients with TPP was higher than that in pure hyperthyroidism patients. The levels of the total thyroxine (T4), free triiodothyronine (FT3), and free thyroxine (FT4) were significantly lower in patients with TPP compared with pure hyperthyroidism patients, while serum testosterone levels were higher compared with pure hyperthyroidism patients. Moreover, after glucose administration, the concentration of insulin at 60, 120, and 180 min were significantly higher in patients with TPP than those in pure hyperthyroidism patients. The insulin area under the curve (AUC) was significantly increased in patients with TPP compared with pure hyperthyroidism patients. The levels of thyroid hormone, sex hormone, and insulin were different in Chinese male patients with TPP compared to those with only hyperthyroidism.

Thyrotoxic hypokalaemic periodic paralysis in a Turkish population: three new case reports and analysis of the case series

OBJECTIVE

Thyrotoxic hypokalaemic periodic paralysis (THPP) is an uncommon condition with intermittent episodes of muscle weakness and occasionally severe paralysis. THPP is a common complication of hyperthyroidism in Asian populations, and has also been reported in other ethnic groups including Caucasians. This study aimed to conduct an analysis of THPP in a Turkish population, and is to our knowledge the first analysis of a homogeneous Caucasian group.

SUBJECTS

Forty cases with THPP were identified in the Turkish population. Three out of the 40 were new cases and were assigned as index cases. Two cases were not included in the analysis because of lack of data.

RESULTS

THPP was diagnosed in 10 cases during the first attack and was observed to have a significant shorter complete recovery time statistically in this group (P < 0.01). The majority of cases were hypokalaemic, while there were two normokalaemic cases. Classification of the cases according to their potassium (K) levels revealed that the group with K levels < 2.5 mEq/l had a statistically longer amelioration time than the group with K levels > or = 2.5 mEq/l. When the cases were classified according to intravenous or oral application of K, the mean amelioration time was 6.8 +/- 3.6 h for the intravenous group and 13.1 +/- 7.6 for the oral group. Mean complete recovery times of the groups were 29.4 +/- 16.2 h and 52.8 +/- 18.0 h, respectively. The intravenous group had a shorter amelioration time and complete recovery time, and both were statistically significant (P < 0.05 for each).

CONCLUSIONS

THPP may be seen among Caucasians. Diagnosing THPP during the first attack might decrease the recovery time. The level of hypokalaemia seems to affect the recovery time and initial low K levels may lead to more deterioration in a patient's health compared with mild or near-normal levels. Intravenous, rather than oral, application of K may be advantageous for shortening both the amelioration and complete recovery times.