A 10-year analysis of thyrotoxic periodic paralysis in 135 patients: focus on symptomatology and precipitants

Atypical Normokalemic Case of Thyrotoxic Periodic Paralysis in a Pediatric Patient

Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism characterized by typical muscular symptoms, ranging from paresis to complete paralysis, commonly associated with low potassium blood levels (<3 mmol/l). It is more commonly reported in adult Asian individuals and can lead to life-threatening situations. Therefore, early clinical diagnosis and targeted therapy are of crucial importance. In this article, we report the case of a 17-year-old adolescent with a Vietnamese background and known Graves' disease who was admitted with typical TPP-related symptoms but no hypokalemia. After treatment with an antithyroid medication and oral potassium supplementation, no new episode of TPP was observed. Using next-generation sequencing, a genetic analysis of TPP-related ion channel genes (KCNJ2, KCNJ18, KCNE3, SCN4A, and CACNA1S) found no known/likely pathogenic variants or variants of unknown significance. To the best of our knowledge, this is only the second reported case of quite normokalemic TPP in the pediatric population. Prompt diagnosis of TPP is essential to prevent harmful complications. Supplementation with potassium appears to be successful alongside non-selective beta-blockers. Normalization of thyroid function should be pursued to prevent new attacks, which is considered the best preventive measure.

Thyrotoxic periodic paralysis presenting with quadriparesis and hyperreflexia

Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism that manifests as painless flaccid paralysis. An East Asian man in his late 20s presented to the emergency department with an acute onset of quadriparesis associated with hypertonia and hyperreflexia. His initial symptoms and signs suggested involvement of the brain and spinal cord; however, MRI of the neuroaxis was normal. His serum potassium concentration was low, and thyroid test results were consistent with hyperthyroidism. The patient was diagnosed with TPP associated with Graves' disease and was treated with potassium supplementation, propranolol and methimazole. Motor strength improved to his baseline level of power; bulk was normal, and tone was increased. Although flaccid paralysis is a typical presentation of TPP, brisk reflexes and muscle spasticity cannot rule out this condition. This case highlights the importance of considering TPP as a possible diagnosis in patients presenting with acute quadriparesis.

Thyrotoxic Periodic Paralysis With Hypokalemia: A Case Study

Thyrotoxic periodic paralysis (TPP) is a rare life-threatening condition most commonly seen in individuals between the ages of 20-40 years. It is most prevalent in Hispanic and Asian populations. Here we present a case report of a young male patient admitted to our facility with an acute onset of paralysis. He was found to have new-onset hyperthyroidism and severe hypokalemia. TPP was exacerbated by the intake of a high-carbohydrate meal as well as a steroid injection within 24 hours of symptom onset.

Neurologic Complications of Endocrine Disorders

OBJECTIVE

This article provides an overview of the neurologic complications of the most prevalent endocrine disorders in adults with an emphasis on relevant neurologic symptoms, signs, and laboratory and neuroimaging findings.

LATEST DEVELOPMENTS

Although the mechanisms of many of the neurologic complications discussed here remain unclear, our understanding of the impacts of diabetes and hypothyroidism on the nervous system and muscle, including complications of rapid correction of chronic hyperglycemia, has advanced in recent years. Recent large studies have not demonstrated a convincing association between subclinical or overt hypothyroidism and cognitive decline.

ESSENTIAL POINTS

Neurologists must become familiar with the neurologic complications of endocrine disorders not only because they are common and treatable (and often reversible) but also because they may be iatrogenic, as is the case with adrenal insufficiency in the setting of long-term corticosteroid therapy.

Thyrotoxic periodic paralysis as the first presentation of Graves' disease: A case report

Thyrotoxic periodic paralysis (TPP) is a rare disease seen predominantly in men of Asian origin. It should be considered in the differential diagnosis of patients with acute onset of weakness, and it is reversible after the correction of serum potassium. TPP can rarely be the initial presentation of Graves' disease.

High-dose intravenous hydrocortisone for the treatment of hyperthyroidism: a rare precipitant of thyrotoxicosis periodic paralysis

Summary

Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism triggered by precipitants that increase the activity of the sodium-potassium pump in the skeletal muscle. In our case study, a previously healthy 34-year-old male presented to the emergency department with new onset thyrotoxicosis, secondary to Graves' disease. Given the severity of his triiodothyronine (T3) thyrotoxicosis, he was admitted and started on a high dose of beta-blocker, thioamides, and intravenous hydrocortisone. On the second day of his hospitalization, he developed acute flaccid paralysis of his lower extremities. Subsequent stroke workup was negative, and his electrolytes revealed severe hypokalemia and hyperglycemia consistent with TPP. He was treated with potassium and had a complete recovery of his paralysis and hypokalemia within hours. The patient has not had any recurrence since this singular episode in the hospital. This case highlights the scenario where the treatment of hyperthyroidism with high-dose corticosteroids to reduce the conversion of thyroxine to T3 inadvertently resulted in TPP. Clinicians should be aware of this potentially rare but serious consequence of using steroids to manage hyperthyroidism.

Learning points

High-dose steroids used to treat hyperthyroidism in hospitalized patients may rarely precipitate thyrotoxic periodic paralysis (TPP) by inducing hypokalemia and hyperglycemia. TPP should be included in the differential diagnosis for acute flaccid paralysis in hospitalized patients with hyperthyroidism. Since TPP is associated with trans-cellular shifts in potassium instead of total body potassium depletion, conservative repletion of potassium is recommended to avoid rebound hyperkalemia.

Thyrotoxic Periodic Paralysis: An Under-Recognized Cause of Paralysis in Young Hispanic Men

BACKGROUND

Patients presenting to the emergency department with paralysis can have a wide differential diagnosis. Thyrotoxic periodic paralysis (TPP) is a rare disorder causing transient flaccid paralysis in the setting of thyrotoxicosis and hypokalemia. It has been reported in Asian male populations predominantly, and the diagnosis is rarely considered in non-Asian populations. Recent research has identified cases in patients with diverse ethnic backgrounds, although epidemiologic data from the United States are very limited.

OBJECTIVE

Our aim was to report our experience with TPP at a tertiary care center in the United States.

METHODS

A retrospective chart review was conducted between January 2006 and February 2022 to identify cases of TPP and determine their demographic and clinical characteristics. Prevalence of TPP was estimated using the institutional hyperthyroidism registry.

RESULTS

Thirty-three patients with TPP were identified. All of the patients were male; median age was 28 years, and 85% were Hispanic. All patients had hypokalemia at presentation and 23% had rebound hyperkalemia after treatment. Prevalence of TPP in our population of patients with hyperthyroidism was approximately 0.5%.

CONCLUSIONS

Young Hispanic men presenting with paralysis should be evaluated for TPP, as the prevalence in this population may be higher than estimated previously. Management of TPP involves treatment of underlying hyperthyroidism and cautious potassium repletion, with an initial dose of no more than 60 mEq/L of potassium chloride to avoid rebound hyperkalemia.

A Case of Thyrotoxic Periodic Paralysis: "I Can't Move!"

Thyrotoxic periodic paralysis (TPP) is a form of hypokalemic periodic paralysis associated with hyperthyroidism. It is characterized by hypokalemia associated with acute proximal symmetrical lower limb weakness and can progress to involve all four limbs and the respiratory musculature. We present a case of a 27-year-old Asian male with recurrent attacks of weakness in all four extremities. A subsequent diagnosis of thyrotoxic periodic paralysis was made, which was secondary to a previously undiagnosed Grave's disease. TPP should be a differential in a young male of Asian ethnicity who presents to the hospital with acute onset of paralysis.

Management of hypokalemia in patients with thyrotoxicosis periodic paralysis in Soetomo general hospital: A case report

Introduction

The prevalence of Graves' disease varies widely between 21 and 80% of all cases of hyperthyroidism. Research conducted in 2018 at the Dr. Soetomo Regional General Hospital Surabaya found Graves' disease in as many as 66.7% of all cases of hyperthyroidism. Thyrotoxicosis Periodic Paralysis (TPP) is a disorder characterized by reversible muscle weakness and paralysis, accompanied by hypokalemia, which usually accompanies hyperthyroidism, mostly caused by Graves' disease. Management of severe hypokalemia in TPP is challenging.

Case illustration

male, 29 years patient complained that both lower legs felt weak in the last 6 hours before coming to the hospital emergency department. The patient was diagnosed with hyperthyroidism in 2018. A fine tremor was found, and the patient was admitted to the hospital for 4 days and routinely controlled at the endocrine polyclinic.

Clinical discussion

The underlying disease or causative etiology of thyrotoxicosis must be determined before treatment is conducted. The main concern when performing potassium replacement therapy is the occurrence of rebound hyperkalemia because this hypokalemia condition is caused not by total potassium depletion.

Conclusion

The principles of management for thyrotoxicosis periodic paralysis are proper diagnosis, exclusion of other causes of paralysis, and other causes of hypokalemia, slow and gradual correction of hypokalemia, and close and careful clinical monitoring, ECG, and laboratory.

Subacute thyroiditis associated with thyrotoxic periodic paralysis after COVID-19 vaccination: a case report

Summary

We report a 26-year-old Japanese man who visited our outpatient clinic presenting fever immediately after i.m. injection of the second dose of a coronavirus disease 2019 (COVID-19) vaccine (Moderna®). At the first visit, the patient had a fever of 37.7°C and a swollen thyroid gland with mild tenderness. He was diagnosed with subacute thyroiditis (SAT) based on the presence of thyrotoxicosis (free tri-iodothyronine, 32.3 pg/mL; free thyroxine, >7.77 ng/dL; and thyroid-stimulating hormone (TSH) < 0.01 μIU/mL), high C-reactive protein level (7.40 mg/dL), negative TSH receptor antibody, and characteristic ultrasound findings. His HLA types were A*02:01/24:02, B*15:11/35:01, Cw*03:03, DRB1*09:01/12:01, DQB1*03:03, and DPB1*05: 01/41:01. He was initially administered prednisolone 15 mg/day, following which the fever subsided. After 10 days, he developed limb weakness and could not walk. The serum potassium level decreased to 1.8 mEq/L, which confirmed the diagnosis of thyrotoxic periodic paralysis (TPP). Potassium supplementation was initiated. The muscle weakness gradually decreased. Prednisolone therapy was terminated 6 weeks after the first visit. His thyroid function returned to normal 5 months after the first visit, through a hypothyroid state. To our knowledge, this is the first reported case of TPP-associated SAT following COVID-19 vaccination. Persistent fever following vaccination should be suspected of SAT. Additionally, TPP may be associated with SAT in Asian male patients.

Learning points

Following coronavirus disease 2019 (COVID-19) vaccination, subacute thyroiditis may develop regardless of the vaccine type. If persistent fever, anterior neck pain, swelling and tenderness of thyroid gland, and symptoms of thyrotoxicosis are observed immediately after the COVID-19 vaccination, examination in consideration of the onset of subacute thyroiditis is recommended. HLA-B35 may be associated with the onset of subacute thyroiditis after the COVID-19 vaccination. Although rare, subacute thyroiditis can be associated with thyrotoxic periodic paralysis, especially in Asian men. Glucocorticoid therapy for subacute thyroiditis may induce thyrotoxic periodic paralysis through hypokalemia.

Thyrotoxic periodic paralysis in two sexagenarian men: A case report

RATIONALE

Thyrotoxic periodic paralysis (TPP) characterized by the triad of muscle paralysis, acute hypokalemia, and the presence of hyperthyroidism is often reported in young adults but rarely reported in age >60 year-old.

PATIENT CONCERNS

Two sexagenarian males (age 61 and 62) presenting to the emergency department with progressive muscle paralysis for hours. There was symmetrical flaccid paralysis with areflexia of lower extremities. Both of them did not have the obvious precipitating factors and take any drugs.

DIAGNOSIS

Their Wayne scores, as an objective index of symptoms and signs associated with thyrotoxicosis, were <19 (7 and 14, respectively). Their blood pressure stood 162/78 and 170/82 mm Hg, respectively. Their thyroid glands were slightly enlarged. Both of them had severe hypokalemia (1.8 and 2.0 mmol/L). Their presumptive diagnosis of mineralocorticoid excess disorders with severe potassium (K+) deficit were made. However, low urine K+ excretion and relatively normal blood acid-base status were suggestive of an intracellular shift of K+ rather than K+ deficit. Hormone studies confirmed hyperthyroidism due to Graves disease.

INTERVENTIONS

A smaller dose of K+ supplementation (only a total of 50 and 70 mmol K+, respectively) were prescribed for the patient.

OUTCOMES

After treatment, their serum K+ levels became normal with a full recovery of muscle strength.

LESSONS

Our 2 cases highlight the fact that thyrotoxic periodic paralysis must be still kept in mind as the underlying cause of hypokalemia with paralysis and hypertension in elderly patients to avoid missing curable disorders.

An Unusual Presentation of Thyrotoxicosis: Leg Weakness and Hypokalemia in a 21-Year-Old Male

Patients with hyperthyroidism or thyrotoxicosis present with an unspecific constellation of signs or symptoms such as palpitations, tremors, weight loss, or diarrhea. In some severe cases, hyperthyroidism can predispose patients to metabolic abnormalities and arrhythmias. Thyrotoxic periodic paralysis (TTP) is a rare, life-threatening complication or variant of hyperthyroidism associated with hypokalemia and muscle weakness that affects young Asian or Hispanic males between 20–40 years. TTP is reversible, and the management consists of beta-blockers, antithyroid therapy, and conservative potassium correction to prevent severe cardiovascular events such as ventricular arrhythmias with the improvement of transient muscle paralysis. We present a case of a 21-year-old Hispanic male complaining with symptoms of thyrotoxicosis, marked hypokalemia, and severe generalized muscle weakness. Physicians must be aware of this uncommon complication of thyrotoxicosis called thyrotoxic periodic paralysis (TTP) to avoid potassium overcorrection and all the endocrine associations with this pathology.

Making weight: acute muscle weakness and hypokalaemia exacerbated by thyrotoxicosis factitia in a bodybuilder

SUMMARY

A 32-year-old Caucasian male presented to the emergency department with a one-day history of acute severe bilateral lower limb weakness, three days after competing in a bodybuilding competition. He consumed large quantities of carbohydrate-rich foods following the competition. His past medical history was significant for anxiety, and family history was non-contributory. Examination was normal except for reduced power and hyporeflexia in both legs, despite his muscular physique. He was noted to have severe hypokalaemia (K+= 1.9 mmol/L). His thyroid function tests were consistent with thyrotoxicosis. He reported taking thyroxine and several other agents to facilitate muscle mass generation before the bodybuilding competition. His presentation was reminiscent of thyrotoxic periodic paralysis, albeit uncommon with Caucasian ethnicity. He also had transient hyperglycaemia at presentation with concomitant hyperinsulinaemia, which could be attributed to the carbohydrate load and may have exacerbated his hypokalaemia through a transcellular shift. Urine toxicology screen subsequently ruled out the use of diuretics but confirmed the presence of a long-acting beta agonist (clenbuterol) which, along with other substances, may have aggravated the hypokalaemia further. After 12 h of i.v. replacement, the potassium level normalised and leg weakness resolved. The patient agreed to stop taking thyroxine and beta agonists and was well during the clinic visit at one month follow-up. This case highlights the potential for thyrotoxicosis factitia to exacerbate hypokalaemia and muscle weakness from other causes in bodybuilders presenting with acute severe weakness, irrespective of ethnicity.

LEARNING POINTS

In patients presenting with muscle weakness and hypokalaemia, early consideration of thyrotoxicosis is essential, even in the absence of a past history of thyroid disease or specific symptoms of thyrotoxicosis, in order to allow prompt initiation of appropriate treatment and to prevent recurrence. Bodybuilders may constitute a uniquely 'at-risk' group for thyrotoxic periodic paralysis secondary to thyrotoxicosis factitia, especially where there is concomitant use of beta-adrenergic agonists, even in the absence of diuretic use. Although rare and usually described in patients of Asian or Polynesian ethnicity, this case highlights that thyrotoxic periodic paralysis secondary to thyrotoxicosis factitia can also occur in patients with Caucasian ethnicity. We speculate that consuming large quantities of carbohydrates may induce hyperinsulinaemia, which could theoretically contribute to worse hypokalaemia, though mechanistic studies would be needed to explore this further.

Thyrotoxic Periodic Paralysis: A Case Report and Literature Review

Thyrotoxic periodic paralysis (TPP) is a rare presentation of thyrotoxicosis most commonly associated with Graves' disease. It is rare in Caucasians, but it affects approximately 2% of Asians (occurring in those of Chinese, Japanese, Vietnamese, Filipino, and Korean descent) with thyrotoxicosis of any cause. Typical thyrotoxic features may be absent despite biochemical thyrotoxicosis. Hypokalemia and muscle paralysis are the result of an acute intracellular shift of potassium and not due to total body potassium deficiency. TPP is a self-limiting condition that is easily corrected by treatment of the thyrotoxicosis. We present a case of a Filipino man, aged 47 years, who presented to the emergency department with acute bilateral lower extremity weakness and hypokalemia who was subsequently diagnosed with TPP due to Graves' disease.

Artificial Intelligence-Assisted Electrocardiography for Early Diagnosis of Thyrotoxic Periodic Paralysis

Context

Thyrotoxic periodic paralysis (TPP) characterized by acute weakness, hypokalemia, and hyperthyroidism is a medical emergency with a great challenge in early diagnosis since most TPP patients do not have overt symptoms.

Objective

This work aims to assess artificial intelligence (AI)-assisted electrocardiography (ECG) combined with routine laboratory data in the early diagnosis of TPP.

Methods

A deep learning model (DLM) based on ECG12Net, an 82-layer convolutional neural network, was constructed to detect hypokalemia and hyperthyroidism. The development cohort consisted of 39 ECGs from patients with TPP and 502 ECGs of hypokalemic controls; the validation cohort consisted of 11 ECGs of TPP patients and 36 ECGs of non-TPP individuals with weakness. The AI-ECG–based TPP diagnostic process was then consecutively evaluated in 22 male patients with TTP-like features.

Results

In the validation cohort, the DLM-based ECG system detected all cases of hypokalemia in TPP patients with a mean absolute error of 0.26 mEq/L and diagnosed TPP with an area under curve (AUC) of approximately 80%, surpassing the best standard ECG parameter (AUC = 0.7285 for the QR interval). Combining the AI predictions with the estimated glomerular filtration rate and serum chloride boosted the diagnostic accuracy of the algorithm to AUC 0.986. In the prospective study, the integrated AI and routine laboratory diagnostic system had a PPV of 100% and F-measure of 87.5%.

Conclusion

An AI-ECG system reliably identifies hypokalemia in patients with paralysis, and integration with routine blood chemistries provides valuable decision support for the early diagnosis of TPP.

Ventricular tachycardia secondary to thyrotoxic periodic paralysis: A case report

Thyrotoxic periodic paralysis (TPP) is a rare but potentially life-threatening entity, which is characterized by sudden onset of muscle weakness and can in exceptional cases be associated with more severe symptoms, such as severe hypokalemia. We present the rare case of a young patient presenting with monomorphic ventricular tachycardia secondary to hypokalemia due to TPP. This case report highlights the importance of recognition of TPP as a rare cause of VT. A high index of suspicion is needed since signs of hyperthyroidism may be subtle. However, early diagnosis is crucial in order to avoid cardiovascular complications and improve outcomes.

Retracted: Thyrotoxic Periodic Paralysis: Clinical Challenges

[This retracts the article DOI: 10.1155/2014/649502.].

Thyrotoxic Periodic Paralysis with Thyroid Storm as the First Presentation of Graves' disease; a Case Report

Thyrotoxic periodic paralysis is a rare endocrine emergency that manifests as acute onset muscle weakness and hypokalaemia secondary to thyrotoxicosis. It mainly occurs due to rapid and dramatic intracellular shift of potassium resulting in hypokalaemia and acute flaccid paralysis. This condition predominantly affects males of Asian descent, and presentation can range from mild generalized weakness to complete quadriplegia, as seen in our case. We herein report a case of a 40-year-old female, who presented to us with acute onset flaccid quadriplegia and thyroid storm, which is the first ever manifestation of previously undiagnosed Grave's disease. Liver abscess was found to be the underlying trigger for thyrotoxic paralysis and thyroid storm.

Thyrotoxic Periodic Paralysis with Thyroid Storm as the First Presentation of Graves' disease; a Case Report

Thyrotoxic periodic paralysis is a rare endocrine emergency that manifests as acute onset muscle weakness and hypokalaemia secondary to thyrotoxicosis. It mainly occurs due to rapid and dramatic intracellular shift of potassium resulting in hypokalaemia and acute flaccid paralysis. This condition predominantly affects males of Asian descent, and presentation can range from mild generalized weakness to complete quadriplegia, as seen in our case. We herein report a case of a 40-year-old female, who presented to us with acute onset flaccid quadriplegia and thyroid storm, which is the first ever manifestation of previously undiagnosed Grave's disease. Liver abscess was found to be the underlying trigger for thyrotoxic paralysis and thyroid storm.

Noninvasive ventilator prevents intubation in thyrotoxic hypokalemic periodic paralysis-associated respiratory failure: A case report and literature review

Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism, often presents with limb muscle paralysis, hypokalemia with elevated-free T3, T4, and low thyroid-stimulating hormone (TSH). We herein reported an unusual presentation of TPP with acute hypercapnic respiratory failure. A 28-year-old female had complaints of nausea and vomiting. Laboratory investigations showed a serum potassium level of 1.2 mEq/L. Thyroid function test revealed the TSH level of 0.021 μlU/mL and free T4 at 2.01 ng/dL. She suddenly suffered from dyspnea and drowsiness. Acute hypercapnic respiratory failure with CO₂ retention was found. Noninvasive ventilation was used. Rapid correction of hypokalemia and administration of propylthiouracil, propranolol, and 5% Lugol's solution were performed. After the normalization of potassium levels, the patient's respiratory pattern stabilized and noninvasive ventilator (NIV) use was discontinued. Respiratory failure is an unusual but lethal complication of TPP. Rapid correction of hypokalemia and temporarily NIV can successfully avoid endotracheal intubation for respiratory failure.

Thyrotoxic periodic paralysis: A retrospective, observational study from India

Background & objectives:

Thyrotoxic periodic paralysis (TPP) is an endocrine emergency presenting with acute-onset flaccid paralysis in a patient having thyrotoxicosis accompanied by hypokalaemia. This study was conducted to evaluate the clinical profile of patients with TPP presenting to three centres in India.

Methods:

This retrospective, observational study was conducted at three tertiary care Armed Forces medical centres, located at Lucknow, Kolkata and Delhi. The history, clinical features, treatment details and outcomes were evaluated.

Results:

Of the 244 patients with thyrotoxicosis, 15 were diagnosed with TPP and included in the study. These 15 patients (14 male and 1 female) had 32 episodes of TPP which were analyzed. The mean age was 30.2±6.2 yr (range: 21-39), and overt thyrotoxicosis was seen in all patients except one who had subclinical hyperthyroidism. Graves’ disease was the most common cause of thyrotoxicosis (13/15) and the remaining two patients had subacute thyroiditis and gestational thyrotoxicosis. Hypokalaemia (serum potassium <3.5 mmol/l) was seen in 12 patients, and the mean serum potassium was 3.2±0.9 mmol/l (range: 2.1-4.9). All patients had flaccid weakness, predominantly involving the lower limb with no bulbar, respiratory or cranial nerve involvement. The average duration of paralysis was 10.6±5.7 h (range: 3-28 h).

Interpretation & conclusions:

Our study demonstrated an early age of presentation and presence of clinical and biochemical thyrotoxicosis in majority of patients with TPP. Hypokalaemia may not always be evident in patients with TPP.

Impact of first-line treatment choice on long-term outcomes of hyperthyroid Graves' disease patients with thyrotoxic periodic paralysis

Background

Thyrotoxic periodic paralysis (TPP) is a unique manifestation of Graves’ disease. While it is uncommon in Asian, it is extremely rare in Caucasian patients (0.1–0.2%). Previous studies suggested that TPP indicate more severity of Graves’ disease and definitive treatments should be used to prevent relapses.

Aim

To describe clinical features and impact of first-line treatment on long-term outcomes of TPP patients.

Method

A retrospective cohort study over 35 years (1985–2019) of TPP from Graves’ disease patients was conducted. All cases were analyzed and their clinical courses were compared between those who received anti-thyroid drugs (ATD) versus radioactive iodine (RAI) as a primary treatment. None of them underwent surgery.

Results

A total of 2964 hyperthyroid Graves’ disease patients were treated and followed-up at least 3 months over the study period. TPP was identified in 63 cases (2.1%) of all patients. There were 60 males and only 3 females with age at presentation of 35.0 ± 8.2 years. TPP was the first presentation of hyperthyroid Graves’ disease in 82.5% of them. During the acute attack of TPP, all patients presented with bilateral lower limb flaccid weaknesses with median serum potassium of 2.1 mmol/L. No fatal TPP cases were found. RAI was selected as primary treatment in 27 patients (42.9%). Nearly all RAI-treated patients rendered hypothyroidism with the median RAI dose at 15 mCi. No patients who were in remission after RAI treatment developed recurrent attack of TPP. In the remaining 36 ATD-treated patients with mean follow-up time at 9.1 years, relapse was found in 10 patients (27.8%) after the drug discontinuation and 6 patients suffered recurrent TPP. Only 8 ATD-treated TPP patients (22.2%) went into remission.

Conclusions

TPP is a rare complication of hyperthyroid Graves’ disease. Definitive treatment with RAI or thyroidectomy should be employed to prevent relapse and further attacks of TPP.

Thyrotoxic Hypokalemic Periodic Paralysis Triggered by Dexamethasone Administration

Thyrotoxic hypokalemic periodic paralysis (THPP) is a disease characterized by recurrent episodes of muscle weakness due to intracellular potassium shifting in the presence of high levels of thyroid hormone. It occurs more commonly amongst young Asian men with underlying Graves' disease. Attacks are commonly precipitated by ingestion of carbohydrate-rich meals or alcohols, stress or strenuous exercise. Herein, we describe an adult Thai man suffering from a hypokalemic periodic paralysis attack after receiving a dexamethasone injection. The diagnosis of Graves' disease was confirmed by his thyroid function test and a presence of thyrotropin-receptor antibody. His weakness and hypokalemia responded well to potassium supplement and a non-selective beta blocker, while his thyrotoxicosis was initially controlled by an anti-thyroid medication and subsequently with a subtotal thyroidectomy. Clinicians should beware of this manifestation when administering steroids in the thyrotoxic patients, especially of Asian male descent.

Thyrotoxic Periodic Paralysis-A Misleading Challenge in the Emergency Department

Despite its' life-threatening potential due to cardiac severe dysrhythmia in the context of severe hypokalemia, thyrotoxic periodic paralysis (TPP) often goes unrecognized. Although classically confined to young Asian men, it can occur irrespective of age, sex, and race. We report a short series of three cases of TPP as first presentation of Graves' disease in a young Caucasian male and in two Caucasian elderly and middle-aged women, respectively. The first patient developed malignant ventricular arrhythmias due to severe hypokalemia and was defibrillated, with recovery after prompt potassium correction and administration of antithyroid agents and propranolol. The other two cases developed persistent hypokalemia despite adequate potassium chloride (KCl) repletion, with slow recovery of motor deficit and serum potassium normalization up to day 5. In the first case, long-term euthyroid state was achieved via total thyroidectomy due to the presence of a suspicious nodule that proved to be malignant. In the other two cases, medical treatment was the choice of therapy for thyrotoxicosis. None experienced recurrent TPP. Thyroid hormone evaluation is mandatory in the presence of hypokalemic paralysis, even in the absence of clinical signs of thyrotoxicosis. If TPP is confirmed, initial therapy should comprise antithyroid drugs and propranolol, besides hypokalemia correction.

Thyrotoxic Periodic Paralysis: An Incidental Diagnosis!

Thyrotoxic periodic paralysis is a rare presentation of thyrotoxicosis where the patient develops a transient motor deficit secondary to acute hypokalemia. The thyroid hormone augments gene transcription and post-transcriptional modification of Na-K ATPase, a cell membrane protein that regulates the electrical potential of the cell. Na-K ATPase increases active transport of potassium (K+) ions into the intracellular compartment causing hypokalemia without total body potassium deficit. Severe hypokalemia affects depolarization of the muscle cell membrane, clinically evidenced as paralysis. Other factors that may trigger hypokalemia and paralysis in the setting of hyperthyroidism include diet intake high in carbohydrates and salt, alcohol ingestion, trauma, infections, certain medication, and strenuous exercise. This rare but possible clinical presentation of thyrotoxicosis is significantly more predominant in males of Asian descent. We are reporting a case of a 44-year-old Asian-American male who presented to the emergency department with complaints of acute onset of bilateral lower extremity weakness. He had severe hypokalemia and was diagnosed with primary hyperthyroidism due to Graves' disease.

Graves' disease: Clinical manifestations, immune pathogenesis (cytokines and chemokines) and therapy

Graves' disease (GD) is characterized by thyrotoxicosis, caused by the presence of circulating thyroid stimulating antibodies (TSAb), that are determinant also in the pathogenesis of its extrathyroidal manifestations [Graves' ophthalmopathy (GO), pretibial myxedema]. T helper (Th)1 immune response prevails in the immune-pathogenesis of GD and GO, during the active phase, when Th1 chemokines, and their (C-X-C)R3 receptor, play a key role. In GD, the existing treatments are not ideal for hyperthyroidism (long-term remission with anti-thyroid-drugs only in 50% of patients; while radioiodine and surgery cause hypothyroidism). In GD, antigen-specific therapy has been recently published, with the induction of T cell tolerance via an immunization by TSH-R peptides. In GO, rituximab and drugs targeting cytokines have been evaluated. Furthermore, teprotumumab (a human monoclonal anti-IGF-1R blocking antibody) showed to be very effective in GO patients. Further researches are necessary to identify novel effective therapies targeting GD, or GO.

Thyroxine-induced periodic paralysis: a rare complication of nutritional supplements

The consumption of daily nutritional supplements has risen dramatically all over the world. Many people believe that dietary supplements, if not useful, are at least safe to fulfil small dietary gaps. Many nutritional supplements have not been approved by Federal Drug Administration due to their unregulated active ingredients, but they are available as over the counter. One of the active ingredients, exogenous triiodothyronine (T3), has been reported in dietary supplements. We present a case of sudden onset of tetraparesis. Laboratory workup showed hypokalaemia, low thyroid-stimulating hormone and thyroxine (T4) but normal T3 and thyroglobulin levels. The radioiodine uptake scan also showed reduced uptake. After aggressive serum potassium correction and stopping supplements, his condition got improved. So the suspicion of exogenous T3-induced thyrotoxic periodic paralysis was confirmed.

A Rare Case of Thyrotoxic Periodic Paralysis After Epidural Steroid Injection: A Case Report and Literature Review

Patient: Male, 36

Final Diagnosis: Epidural steroid induced thyrotoxic periodic paralysis

Symptoms: Paralysis

Medication: —

Clinical Procedure: Epidural steroid injection

Specialty: Endorinology and Metabolic

Periodic paralysis with normokalemia in a patient with hyperthyroidism: A case report

RATIONALE

Thyrotoxic periodic paralysis is characterized by a sudden onset of hypokalemia and paralysis. This condition mainly affects the lower extremities and is secondary to thyrotoxicosis. The underlying hyperthyroidism is often subtle without typical symptoms such as palpitations, tremors, anxiety, and weight loss; this causes a difficulty in early diagnosis. Here, we reported a case of periodic paralysis in a patient with hyperthyroidism whose potassium level was within the normal range.

PATIENT CONCERNS

A 33-year-old Taiwanese man presented to the emergency department with bilateral limb weakness (more severe in the lower limbs than in the upper limbs). On arrival, the patient's vital status was stable with clear consciousness. He denied experiencing recent trauma, back pain, chest pain, abdominal pain, headache or dizziness, or a fever episode. Physical examination showed no specific findings. Neurological examination showed weakness in the muscles of the bilateral upper and lower limbs. Muscle weakness was more severe in the proximal site than in the distal site.

DIAGNOSIS

Blood examination showed normal complete blood count, normal renal and liver function, and normal potassium (3.5 mmol/L, normal range 3.5-5.1 mmol/L), sodium, and calcium levels; however, the examination showed impaired thyroid function (thyroid stimulating hormone: 0.04 uIU/mL, normal range 0.34-5.60 uIU/mL; free T4: 1.96 ng/dL, normal range 0.61-1.12 ng/dL). Brain computed tomography without contrast showed no obvious intra-cranial lesion.

INTERVENTIONS

Intravenous potassium infusion (20 mEq/L) with normal saline was prescribed for the patient.

OUTCOMES

After treatment, the patient felt a decrease in limb weakness. He was discharged from our emergency department with a scheduled follow-up in the endocrine outpatient department.

LESSONS

TPP should be considered as a differential diagnosis in young Asian men presenting with limb paralysis that is more severe in the proximal site and in the lower limbs than in the distal site and in the upper limbs, respectively. It is important for emergency department physicians to consider TPP as a differential diagnosis as it can occur even if the patient's potassium level is within the normal range.

Graves' Disease Presenting with Periodic Paralysis to the Emergency Department

Thyrotoxic periodic paralysis is an infrequent manifestation of hyperthyroidism and an uncommon cause of muscle weakness in western countries. The diagnosis should be considered in the differential when a patient presents with transient and recurrent weakness associated with hypokalaemia. We present a case of a 26-year-old Asian male presenting with sudden onset muscle weakness affecting predominantly his lower limbs on a background of weight loss. Physical examination demonstrated symmetrical proximal muscle weakness with normal sensation and reflexes. Initial biochemical investigations revealed hypokalaemia, hypomagnesaemia, and hyperthyroidism. Intravenous electrolyte replacement was administered in the emergency department. The patient's symptoms resolved during inpatient admission. Subsequent TSH receptor antibody testing and radionuclide thyroid scan confirmed a diagnosis of Graves' disease. The patient was discharged on antithyroid medication with no further episodes of weakness on follow-up. Therefore, thyrotoxic periodic paralysis can be the presenting feature of previously undiagnosed Graves' disease and should be considered in the differential diagnosis in patients presenting with weakness.

Steroids and Thyrotoxicosis Precipitate Periodic Paralysis

Thyrotoxic Periodic Paralysis (TPP) belongs to a group of muscle diseases called channelopathies, which present with painless generalized muscle weakness without exertion. TPP can be precipitated by a large carbohydrate meal, stress, strenuous exercise, alcohol, a high-salt diet, menstruation, and cold temperatures. Rarely, steroids such as dexamethasone can also precipitate a TPP attack.

A 29-year-old Hispanic male, with a history of hyperthyroidism, presented to the emergency department with progressive weakness, predominantly in the lower extremities since morning. Earlier that day, the patient was seen in the same emergency department for difficulty in swallowing. He was diagnosed with uvulitis and received intramuscular dexamethasone and was discharged with amoxicillin for ten days. At home, he started to develop cramps in his lower extremities associated with paresthesias, which progressed to severe weakness to the point where he could not get out of bed. He returned to the hospital and revealed that he had suffered a similar episode following a steroid injection five years ago. He had not sought medical attention as it resolved spontaneously. He denied strenuous exercise, carbohydrate-rich meal, or alcohol ingestion. The patient had been noncompliant with atenolol and methimazole for the past month after losing his medical insurance. On examination, the patient appeared alert and calm. His vitals were significant for tachycardia of 123 beats per minute. Thyromegaly and tenderness were absent on examination of the neck. Muscle strength was 5/5 in the ankle dorsiflexors and ankle plantar flexors bilaterally, but the strength of the iliopsoas, quadriceps, and hamstrings was only 2/5 bilaterally. Deep tendon reflexes were diminished throughout to 1+. Laboratory findings were significant for profound hypokalemia, hypophosphatemia, low thyroid stimulating hormone, and elevated free T3 and T4 levels suggestive of hyperthyroidism. His electrolytes were replaced aggressively and his home medications were restarted. His electrolyte imbalance corrected and his symptoms resolved within a day and he was discharged home.

The overwhelming majority of TPP cases reported are male patients, hence this case demonstrates the need to be aware of this complication while treating hyperthyroid male patients with steroids. Hyperthyroidism potentiates catecholamine-mediated Na/K ATPase transport of potassium into the cells. Glucocorticoids are used in the treatment of thyroid storm as it prevents the peripheral conversion of T4 to T3. Moreover, glucocorticoids increase glucose levels stimulating insulin release, which shifts potassium intracellularly accentuating muscle weakness. Although the incidence of glucocorticoids causing TPP is low and not many cases are documented, it is still an important condition to be aware of and can have major clinical implications. Clinicians should be aware of this small subset of hyperthyroidism patients where the use of glucocorticoids can precipitate paralysis.

Toxic and Endocrine Myopathies

PURPOSE OF REVIEW

This article discusses the clinical features, pathophysiology, and management of toxic and endocrine myopathies.

RECENT FINDINGS

Early detection and expeditious correction of metabolic disturbances in endocrinopathies such as Cushing syndrome, thyroid and parathyroid diseases, and acromegaly can minimize and prevent neurologic complications including myopathy. Recently proposed mechanisms of injury in patients with critical illness myopathy include inhibition of protein synthesis, mitochondrial dysfunction, disruption of the ubiquitin-proteasome system, oxidative stress, and disruption of intramuscular calcium homeostasis, which can cause a myosin-loss myopathy. Mechanisms underlying toxic myopathies include myosin loss; damage to cellular structures, including myofibrils and organelles such as lysosomes and mitochondria; inflammation; and necrosis. Presentations range anywhere from acute, painful, and necrotic myopathies, as can occur in statin myopathy, to more insidious presentations such as steroid myopathy.

SUMMARY

Endocrinopathies known to cause myopathy include thyroid and parathyroid diseases, disorders of the adrenal axis such as Cushing syndrome, and acromegaly. Patients in the intensive care unit are at risk for developing critical illness myopathy, also known as myosin-loss myopathy, which should be considered if intensive care unit acquired weakness develops. The most common toxic agents associated with myopathy include statins and other lipid-lowering medications, corticosteroids, colchicine, amiodarone, hydroxychloroquine, and chloroquine.

Long Exercise Test in the Interattack Period of Periodic Paralysis: A Useful and Sensitive Diagnostic Tool

PURPOSE

The reference values of long exercise test are inconsistent in previous studies. Our research aims to determine the reference values and improve diagnostic efficiency of long exercise test in periodic paralysis.

METHODS

In this study, 100 healthy controls, 35 non-periodic paralysis patients, and 47 patients with periodic paralysis were recruited. The procedures of long exercise test were conducted following McMannis(1986) method.

RESULTS

The decrease rate in compound muscle action potential amplitudes was correlated with gender, and it was not influenced by age, height, weight, and exercise. After analyzing receiver operating characteristic curves, the compound muscle action potential amplitude decrease rate was stratified by sex. The mean area under the curve, sensitivity, and specificity were higher in male and female than all pooled subjects. The reference values of compound muscle action potential amplitude decrease rate were 46.8% in male and 26.9% in female, respectively.

CONCLUSIONS

The long exercise test is a useful and sensitive diagnostic tool for primary periodic paralysis and thyrotoxic periodic paralysis. However, the reference values should be set by sex, which has better diagnostic performance, sensitivity, and specificity.

Thyrotoxic periodic paralysis as an initial presentation of Graves' disease in a Saudi patient

Thyrotoxic periodic paralysis (TPP) is a well-known complication of hyperthyroidism, characterised by recurrent flaccid paralysis with hypokalaemia. To date, only five cases of this rare disorder have been reported in Saudi Arabia. Here, we report an additional case involving a 25-year-old Saudi man who presented with lower limb paralysis and severe hypokalaemia. Clinically, he showed symptoms and signs suggestive of Graves' disease, which was confirmed by laboratory investigations. Carbimazole, a beta-blocker and potassium replacement were administered, resulting in dramatic improvement of the TTP. This case emphasises the importance of considering TPP in patients with acute muscle weakness and the importance of promptly initiating treatment and preventing relapse of TPP.

A Case of Nonfatal Ventricular Arrhythmia Due to Thyrotoxic Periodic Paralysis in a Saudi Patient as an Initial Presentation of Graves' Disease

Thyrotoxic periodic paralysis (TPP) is a potentially lethal complication of hyperthyroidism characterized by recurrent muscle weakness and hypokalemia. It has been commonly reported in non-Asian populations. Four cases were reported in Saudis so far, and one had a life-threatening arrhythmia. We describe an additional case of a 28-year-old apparently healthy Saudi male patient, who presented with acute paraparesis associated with hypokalemia (K: 2.0 mmol/L), complicated by ventricular tachycardia and cardiac arrest. He was successfully resuscitated and his hypokalemia was corrected. A diagnosis of Graves’ disease associated with TPP was made. He was initially treated with carbimazole and β-blockers and then given a definitive therapy with radioactive iodine, which showed a good response. This case highlights the importance of early recognition and prompt treatment of TPP as a differential diagnosis for muscle weakness. A brief review of TPP and associated arrhythmia is included.

The clinical and genetic features in a cohort of mainland Chinese patients with thyrotoxic periodic paralysis

BACKGROUND

Thyrotoxic periodic paralysis (TPP) is a life-threatening channelopathy manifesting as recurrent episodes of hypokalemia and muscle weakness in the presence of hyperthyroidism. Recent findings indicate defects of inward rectifying K+ (Kir) channels are associated with some TPP patients. The associations are not only found in Caucasian population (mainly Brazilian), but also in Singaporean population. However, potential genetic risk factors for mainland Chinese patients, the largest group of TPP cases in the world, have been largely unexplored.

METHODS

Samples of DNA from 127 individuals with TPP and 102 hyperthyroidism male controls self-reported as mainland Chinese were collected from 5 clinical centers from Jan 2011 to Jan 2014. The KCNJ2 gene, KCNJ18 gene, as well as loci polymorphisms (rs623011and rs312691) at 17q24.3 were directly sequenced in TPP patients and controls. Clinical data were summarized from TPP participants for genotype/phenotype correlations.

RESULTS

3.1% of TPP cases harbored KCNJ18 gene mutations in mainland Chinese patients. Patients with KCNJ18 mutation had shorter attack duration, higher prevalence of muscle soreness and weakness recurrence than patients without KCNJ18 mutation. The alleles at 17q24.3 (rs623011and rs312691) were more common in patients with TPP than in controls, and therefore were significant risk factors for TPP (odds ratio, 11.94 and 10.57; 95% CI, 5.93-24.05 and 5.48-20.40; P = 1.81 × 10(-14) and 1.07 × 10(-14) respectively).

CONCLUSIONS

This study demonstrates that the KCNJ18 variants are only responsible for a small proportion of TPP patients in mainland China. There are significant clinical differences between patients with KCNJ18 mutations and patients without KCNJ18 mutations. In addition, the rs623011and rs312691 loci are significantly associated with TPP patients in mainland China, and highlight the Kir2.1 channel as a causative target in TPP.

Etiologic and therapeutic analysis in patients with hypokalemic nonperiodic paralysis

BACKGROUND

Hypokalemic nonperiodic paralysis represents a group of heterogeneous disorders with a large potassium (K(+)) deficit. Rapid diagnosis of curable causes with appropriate treatment is challenging to avoid the sequelae of hypokalemia. We prospectively analyzed the etiologies and therapeutic characteristics of hypokalemic nonperiodic paralysis.

METHODS

Over an 8-year period, patients with hypokalemic nonperiodic paralysis were enrolled by excluding those with hypokalemic periodic paralysis due to acute shift of K(+) into cells. Blood and spot urine samples were collected for the measurements of electrolytes, pH, and biochemistries. Intravenous potassium chloride (KCl) at a rate of 10-20 mmol/h was administered until muscle strength recovered.

RESULTS

We had identified 58 patients with hypokalemic nonperiodic paralysis from 208 consecutive patients with hypokalemic paralysis, and their average K(+) concentration was 1.8 ± 0.2 mmol/L. Among patients with low urinary K(+) excretion (n = 17), chronic alcoholism, remote diuretic use, and anorexia/bulimia nervosa were the most common causes. Among patients with high urinary K(+) excretion (n = 41) and metabolic acidosis, renal tubular acidosis and chronic toluene abuse were the main causes, while primary aldosteronism, Gitelman syndrome, and diuretics were the leading diagnoses with metabolic alkalosis. The average KCl dose needed to restore muscle strength was 3.8 ± 0.8 mmol/kg. Initial lower plasma K(+), volume depletion, and high urinary K(+) excretion were associated with higher recovery KCl dosage. During therapy, patients with paradoxical hypokalemia (n = 32) who required more KCl supplementation than patients without (4.1 ± 0.7 vs 3.4 ± 0.7 mmol/kg, P < 0.001) often exhibited significantly higher plasma renin activity and received a higher volume of normal saline before its appearance.

CONCLUSIONS

Understanding the common etiologies of hypokalemic nonperiodic paralysis may aid in early diagnosis. Patients with initial lower plasma K(+), renal K(+) wasting, and hypovolemia required higher recovery K(+) dosage. Paradoxical hypokalemia is prone to develop in hypovolemic patients even during K(+) supplementation with volume repletion.

Thyrotoxic hypokalemic periodic paralysis in an African male: a case report

Thyrotoxic hypokalemic periodic paralysis is a rare manifestation of thyrotoxicosis and is rarely reported in non-Asian populations. A 26-year-old Ethiopian male who presented with recurrent flaccid tetraparesis, hypokalemia, and hyperthyroidism is reported here. Thyroid function should be routinely checked in patients with acute or recurrent hypokalemic paralysis.

The insulin-sensitivity sulphonylurea receptor variant is associated with thyrotoxic paralysis

Thyrotoxicosis is the most common cause of the acquired flaccid muscle paralysis in adults called thyrotoxic periodic paralysis (TPP) and is characterised by transient hypokalaemia and hypophosphataemia under high thyroid hormone levels that is frequently precipitated by carbohydrate load. The sulphonylurea receptor 1 (SUR1 (ABCC8)) is an essential regulatory subunit of the β-cell ATP-sensitive K(+) channel that controls insulin secretion after feeding. Additionally, the SUR1 Ala1369Ser variant appears to be associated with insulin sensitivity. We examined the ABCC8 gene at the single nucleotide level using PCR-restriction fragment length polymorphism (RFLP) analysis to determine its allelic variant frequency and calculated the frequency of the Ala1369Ser C-allele variant in a cohort of 36 Brazilian TPP patients in comparison with 32 controls presenting with thyrotoxicosis without paralysis (TWP). We verified that the frequency of the alanine 1369 C-allele was significantly higher in TPP patients than in TWP patients (61.1 vs 34.4%, odds ratio (OR)=3.42, P=0.039) and was significantly more common than the minor allele frequency observed in the general population from the 1000 Genomes database (61.1 vs 29.0%, OR=4.87, P<0.005). Additionally, the C-allele frequency was similar between TWP patients and the general population (34.4 vs 29%, OR=1.42, P=0.325). We have demonstrated that SUR1 alanine 1369 variant is associated with allelic susceptibility to TPP. We suggest that the hyperinsulinaemia that is observed in TPP may be linked to the ATP-sensitive K(+)/SUR1 alanine variant and, therefore, contribute to the major feedforward precipitating factors in the pathophysiology of TPP.

A case of thyrotoxic periodic paralysis as initial manifestation of Graves' disease in a 16-year-old Korean adolescent

Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism, with recurrent muscle paralysis and hypokalemia that are caused by an intracellular shift of potassium. TPP is relatively common in Asian males, but is extremely rare in children and adolescents, even for those of Asian descent. We describe a 16-year-old Korean adolescent presenting with a two-week history of episodic leg weakness in the morning. He showed sinus tachycardia, lower leg weakness, and hypokalemia. Thyroid function test showed hyperthyroidism, and thyroid ultrasonography revealed a diffuse enlarged thyroid with increased vascularity, consistent with Graves' disease. He was treated with β-adrenergic blocker and antithyroid drugs. He has been symptom free for one year, as his hyperthyroidism has been controlled well with antithyroid drugs. TPP should be considered in children and adolescents with acute paralysis of the lower extremities and hypokalemia.