Thyrotoxic Periodic Paralysis: A Case Report and Literature Review

Thyrotoxic Periodic Paralysis in a Samoan Male With Metabolic Acidosis: A Case Report and Review of the Literature

Thyrotoxic periodic paralysis (TPP) is a rare disorder characterized by muscle paralysis, thyrotoxicosis, and hypokalemia. It commonly manifests as paralysis of both proximal and distal upper and lower limbs, and if left untreated, may progress to respiratory failure or cardiac arrhythmias. It is most common in Asian males and is frequently precipitated by strenuous exercise, high carbohydrate diet, stress, corticosteroid therapy, or alcohol. Early diagnosis of TPP is crucial as the condition may be reversible with oral or IV potassium replacement therapy, and management of the underlying hyperthyroidism. We describe a Samoan man in his 30s who presented with acute onset lower extremity paralysis. Laboratory investigations revealed low serum potassium of 2.2 mEq/L (reference range 3.5-5.0 mEq/L) and thyrotoxicosis with a low (thyroid stimulating hormone (TSH) of <0.07 uIU/mL (reference range 0.27-4.20 uIU/mL) and an elevated free T4 of 5.4 ng/dL (reference range 0.9-2.1 ng/dL). He was treated with both oral and IV potassium chloride as well as propranolol and regained full strength in his extremities. While rare, TPP is a reversible complication of thyrotoxicosis and a high index of suspicion in clinical practice is essential to prevent adverse outcomes.

Thyrotoxic Periodic Paralysis as an Ongoing Diagnostic Challenge: A Case Report and Literature Review

Thyrotoxic periodic paralysis (TPP) is a rare condition that presents with episodic periodic paralysis due to hypokalemia that develops from hyperthyroidism. Timely diagnosis is still an ongoing challenge due to lack of awareness, self-resolving episodes, and the fact that it clinically mimics familial hypokalemic periodic paralysis (FHPP), which is more common in the West. TPP is more commonly seen among Asians but has been emerging in Western countries due to globalization. We present a case of a 24-year-old Hispanic male who presented with bilateral lower extremity weakness. He had five such episodes in the past year, which resolved on their own. The current episode of weakness was worse, and he required a wheelchair to ambulate. Despite extensive work, it took over four months to make a definitive diagnosis and treat his hyperthyroidism. A literature review reported that most cases of TPP are usually diagnosed after multiple episodes, and the causes of diagnostic error were studied. Through this review, we present a case of TPP with diagnostic delay, a literature review discussing the etiology, pathogenesis, clinical manifestations, and management, with an emphasis on the diagnostic challenge of TPP. Awareness of this condition, timely evaluation for hyperthyroidism as a cause for hypokalemic periodic paralysis, and understanding the factors that contribute to its diagnostic challenge will aid in timely recognition and treatment.

Pathogenic SCN5A Mutation and Thyrotoxicosis-Related Neurological Syndrome: Casual or Causal Relationship?

BACKGROUND

Various neurologic complications of hyperthyroidism are reported, and most of these complications are reversible with the amelioration of thyrotoxicosis. We report a previously undescribed concurrence of hyperthyroid-associated exercise-induced myalgia and stiffness, pyramidal tract dysfunction, and myoclonic movements that make an initial clinical diagnosis difficult.

CASE PRESENTATION

A 17-year-old male was hospitalized in the department of neurology, presenting with a 4-year history of severe exercise-induced myalgia and stiffness, weakness of lower limbs, and myoclonic movements. Laboratory investigations unexpectedly revealed hyperthyroidism. MRI of the brain and spine, electrophysiology, and whole exome sequencing were also performed. Antithyroid therapy led to marked improvement of neurologic symptoms, accompanied by a significant improvement of the time-dependent decline in compound muscle action potentials (CMAP) amplitudes after exercise and normalization of the prolonged QTc interval. Genetic analysis identified a rare variant in SCN5A.

CONCLUSION

This case report provides important insights into the relationship between hyperthyroidism and neurologic/cardiac complications, particularly in those with a genetic predisposition. SCN5A mutation possibly plays a role in the complex neurological syndrome associated with hyperthyroidism. Further studies are warranted to better understand the underlying mechanisms and potential therapeutic options for these complex conditions.

Hypokalemic periodic paralysis as the first sign of thyrotoxicosis- a rare case report from Somalia

BACKGROUND

Thyrotoxic hypokalemic periodic paralysis (THPP) is a rare complication of hyperthyroidism characterized by thyrotoxicosis, hypokalemia, and paralysis. It is the most common form of acquired periodic paralysis. THPP is precipitated by strenuous exercise, a high carbohydrate diet, stress, infection, alcohol, albuterol, and corticosteroid therapy. It is most common in Asian men with hyperthyroidism and exceptionally rare in black people.

CASE PRESENTATION

A 29-year-old man was admitted to the emergency department in Somalia with a sudden onset of paralysis after a high carbohydrate meal. Laboratory investigations showed low serum potassium 1.8 mEq/l (3.5-4.5), and biochemical thyrotoxicosis with TSH 0.006 miu/l (0.35-5.1), total T3 3.2 ng/ml (0.9-2.8) and total T4 13.5 ng/ml (0.6-1.2). He was successfully treated with potassium chloride infusion and an antithyroid drug, methimazole.

CONCLUSION

To prevent life-threatening cardiac and respiratory complications, it is critical to consider and diagnose THPP early, even in populations where the condition is rare.

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.

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.

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.

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.