Grand Rounds Contributor: Case Report/Focused ReviewHypokalemic Thyrotoxic Periodic Paralysis With Thyrotoxic Psychosis and Hypercapnic Respiratory Failure
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CASE REPORT
A 27-year-old Korean man with no medical or surgical history was brought to the hospital with vague complains of anorexia, insomnia, muteness, and disinterest. All of his symptoms had begun since his wife left him and went back to Korea. According to the family, during the past 3 to 4 days, the patient had been behaving unlike his usual self and had been in a labile mood. In the emergency room, he was agitated, screaming loudly and incoherently. He was pulling out intravenous (IV) lines and was
DISCUSSION
Hyperthyroidism refers to a disorder of accelerated synthesis and secretion of thyroid hormones from the thyroid gland. Thyrotoxicosis is a hypermetabolic clinical syndrome resulting from any cause of excessive serum thyroid hormone concentration. The thyroid storm is an extreme manifestation of thyrotoxicosis involving a severe systemic dysfunction of the thermoregulatory, central nervous, cardiovascular, and gastrointestinal systems. TPP is a rare thyroid disorder associated with
TYPES
TPP is a well-established phenomenon.2 In general, hypokalemic paralysis can be divided into 2 main groups: hypokalemic periodic paralysis (HPP) and the non-HPP. The HPP occurs due to an acute and massive shift of potassium into the cells, whereas the non-HPP occurs due to a large total body deficit.3 According to cause, the HPP can be further grouped into the TPP and the familial periodic paralysis. Similarly, the non-HPP can be grouped into Bartter syndrome/Gitelman syndrome, renal tubular
EPIDEMIOLOGY
TPP is most widely known and studied in the Asian population, including Chinese, Japanese, Vietnamese, Filipino, and Koreans. Its incidence is 10-fold higher in this population compared with the whites.4., 7. Sporadic cases have been reported in the non-Asian populations, including the whites, Afro-Americans, and Hispanic.8
Despite the higher incidence of thyroid disease in women, this entity is far more common in men with a preponderance ratio of 17:1 to 70:1.7., 9., 10. Approximately 80% of
CLINICAL PRESENTATION
TPP is a rare neurologic manifestation of thyrotoxicosis. The neurologic manifestations of thyrotoxicosis are limited and rare. In many cases, they present in conjunction with the systemic features of the disease but may be the presenting symptoms in some patients.
The neurologic manifestations of thyrotoxicosis are as follows:
- 1.
Cognitive impairment and seizures: cognitive impairment with behavioral and personality changes are common in hyperthyroidism. It is usually subacute but may progress to
DIAGNOSIS
The diagnosis of TPP must be suspected on clinical grounds. A recurrent clinical pattern of flaccid paralysis with evidence of hyperthyroidism supports the diagnosis. The presence of hypokalemia and absence of an acid-base disorder also strengthen the diagnostic likelihood.6
PATHOPHYSIOLOGY
The exact pathophysiology of TPP is unknown; however, various theories have been suggested. The hypokalemia seen in TPP is the result of the increased Na K ATPase activity, which results in massive shift of potassium from the extracellular to the intracellular compartment and causes hypokalemia without causing urinary losses.34., 35., 36. Both catecholamines and insulin are well-known hormones involved in increased intracellular shift of potassium and phosphate.37., 38. Hyperinsulinemia, which
Correction of K+
Prompt correction of potassium with immediate IV/oral supplementation can prevent serious cardiopulmonary complications. Patient may require anywhere between 40 and 200 mEq of KCl.37., 50. Lu et al50 reported that 40% of patients who received >40% of IV KCl at a rate of 10 mEq/hr developed rebound hyperkalemia to levels >5.5 mEq/L. It is thus recommended that KCl be replaced at a slow rate unless cardiopulmonary complications warrant otherwise.
Nonselective beta blockers have also been shown to
DIFFERENTIAL DIAGNOSES
All periodic paralyses are characterized by episodic weakness. Motor strength remains normal between attacks. The following diagnoses must be considered and ruled out before committing to the diagnosis of thyrotoxic HPP.
SUMMARY
TPP is a disorder characterized by concurrent thyrotoxicosis, hypokalemia, and progressive symmetrical weakness leading to paralysis. It is rare in non-Asians and therefore a high clinical suspicion is required for early diagnosis and prompt initiation of management, which can prevent potentially serious and life-threatening consequences. Although the exact mechanism of TPP is unknown, it is attributed to the enhanced activity of the Na-K ATPase leading to increased influx of potassium and
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Cited by (24)
Types of neuromuscular disease
2023, Pulmonary Assessment and Management of Patients with Pediatric Neuromuscular DiseaseManagement of hypokalemia in patients with thyrotoxicosis periodic paralysis in Soetomo general hospital: A case report
2022, Annals of Medicine and SurgeryCitation Excerpt :In a retrospective study of 45 patients with periodic paralysis thyrotoxicosis, the rate of recurrent attacks was still high at 62.2% and most of them occurred in the first 3 months after being diagnosed with periodic paralysis thyrotoxicosis. Although most patients improve within hours of receiving therapy, respiratory collapse and death have been reported [16,17]. Early diagnosis and management of the underlying cause of thyrotoxicosis is the most important procedure in patients with periodic paralytic thyrotoxicosis.
Thyrotoxic Periodic Paralysis: A Review and Suggestions for Treatment
2021, Endocrine EmergenciesThyrotoxic periodic paralysis complicated by life-threatening acute hypercapnic respiratory failure in a Chinese male with painless thyroiditis
2019, American Journal of Emergency MedicineCitation Excerpt :Given the similarities between the characteristics of TPP due to painless thyroiditis and TPP caused by hyperthyroidism, we argue that the mechanism that causes TPP with painless thyroiditis and TPP due to hyperthyroidism may share something in common. A few cases have reported TPP patients associated with acute paralysis of the respiratory muscles (Table 2) [1-3,14]. All of the patients were of male Asian origin and their ages varied from 27 to 36 years.
Changing Management Guidelines in Thyrotoxic Hypokalemic Periodic Paralysis
2018, Journal of Emergency MedicineCitation Excerpt :It also starts to treat the underlying hyperthyroidism by reducing T4 to T3 conversion, helping to mitigate many of the uncomfortable symptoms. If thyroid storm is present, methimazole or propylthiouracil should also be administered along with steroids, with at least 1 h given prior to administration of iodine (5). Admission is recommended for continued monitoring and further endocrine work-up to evaluate the underlying etiology for the hyperthyroidism–be it Grave's disease (most common), thyroid nodule, or thyroiditis–and the precipitants of the thyrotoxicosis.
Unilateral gynecomastia and hypokalemic periodic paralysis as first manifestations of Graves' disease
2013, American Journal of the Medical SciencesCitation Excerpt :Rare symptoms and signs of Graves’ disease include gynecomastia, erectile dysfunction, pretibial myxedema and thyroid acropachy.1 HPP is comparatively a more common manifestation.2 The only case of hyperthyroidism with manifestations of both gynecomastia and HPP was reported >20 years ago.