[Thyrotoxic hypokalemic periodic paralysis: report of one case]

Thyrotoxic hypokalemic periodic paralysis is characterized by attacks of generalized weakness associated to hypokalemia in patients with hyperthyroidism. We report a 25-year-old man with a history of spontaneously relapsing episodes of muscular weakness, who consulted for a rapidly evolving upper and lower limb paresis. Hypokalemia associated to a primary hyperthyroidism was detected. Treatment with antithyroid Drugs and potassium supplementation reverted symptoms and the episodes of acute muscular weakness did not reappear.

Hypokalemic periodic paralysis associated with thyrotoxicosis, renal tubular acidosis and nephrogenic diabetes insipidus

A 19-year-old girl presented at our emergency room with hypokalemic periodic paralysis. She had a thyrotoxic goiter and had experienced three paralytic attacks during the previous 2 years on occasions when she stopped taking antithyroid drugs. In addition to thyrotoxic periodic paralysis (TPP), she had metabolic acidosis, urinary potassium loss, polyuria and polydipsia. Her reduced ability to acidify urine during spontaneous metabolic acidosis was confirmed by detection of coexisting distal renal tubular acidosis (RTA). The polyuria and polydipsia were caused by nephrogenic diabetes insipidus, which was diagnosed using the water deprivation test and vasopressin administration. Her recurrent and frequent paralytic attacks may have been the combined effects of thyrotoxicosis and RTA. Although the paralytic attack did not recur after improving the thyroid function, mild acidosis and nephrogenic DI have been remained subsequently. Patients with TPP, especially females with atypical metabolic features, should be investigated for possible precipitating factors.

Thyrotoxic periodic paralysis as the first manifestation of a thyrotropin-secreting pituitary adenoma

Thyrotoxic Periodic Paralysis (TPP) is a rare manifestation of hyperthyroidism characterized by muscle weakness and hypokalemia. Thyroid-Stimulating Hormone (TSH)-secreting pituitary adenoma is a rare cause of hyperthyroidism. Even more rare is the occurrence of TPP as the first manifestation of a TSH-secreting pituitary adenoma. We report a 31-year-old Asian male patient suffering from TPP caused by a TSH-secreting adenoma, who was evaluated for persistent episodes of muscle paralysis. Laboratory investigation revealed hypokalemia as well as elevated levels of both thyroid hormones and TSH. The Magnetic Resonance Imaging (MRI) of the pituitary gland revealed a microadenoma, thus suggesting the presence of a TSH-secreting adenoma. The patient underwent transphenoidal resection and the pathological investigation confirmed the diagnosis of TSH-secreting pituitary adenoma. After the adenomectomy and the restoration of euthyroidism, the patient did not experience any episode of hypokalemic paralysis or weakness. Despite its rarity, TSH-secreting pituitary adenoma should be included in the differential diagnosis of TPP.

[Clinical features of hypokalemic periodic paralysis]

OBJECTIVE

To explore the clinical features of hypokalemic periodic paralysis, and compare clinical features of primary group with those of thyrotoxicosis secondary group.

METHODS

Clinical data of 44 patients with hypokalemic periodic paralysis in Peking University First Hospital from 1996 December to 2008 December were retrospectively analyzed.

RESULTS

There were 22 patients in primary group, and 22 in thyrotoxicosis group. Identical clinical features of both the groups: (1)It had a predilection in young men. (2)Main symptoms were limb movement disorder and fatigue, and paralysis recurrent attacked in most patients. (3) 40.9% to 68.2% patients had obvious incentives, and the common ones were a heavy meal, sweet drinks, or strenuous exercise. (4) Serum potassium levels of the two groups were obviously lower than the normal range. (5)In 20% patients of primary group and 25% patients of thyrotoxicosis secondary group, CK levels were higher than normal, while LDH and HBDH levels were normal. (6)The doses of potassium replishment were not correlated to serum potassium levels at the onset. Different clinical features of the two groups: (1) Patients of thyrotoxicosis group had hypermetabolism symptoms and thyroid dysfunction. Patients of primary group had no hypermetabolism symptoms, and all of them were euthyroid. (2)Serum potassium levels of thyrotoxicosis secondary group were lower than those of primary group significantly [(2.25 +/- 0.67) vs (2.78 +/- 0.49) mmol/L, P=0.007]. (3) Hyperkalemia is easier than primary group to rebound in thyrotoxicosis secondary group, after replenishment of potassium.

CONCLUSION

Hypokalemic periodic paralysis has its clinical features, and patients with early diagnosis and replenishment of potassium in time have good prognosis. The doses of potassium replenishment are not determined by serum potassium levels at the onset. Hyperkalemia is easier to rebound in thyrotoxicosis secondary group after replenishment of potassium, serum potassium levels should be monitored closely, and hyperthyrosis radically cured.

[Hypokalemic paralysis during pregnancy: a report of two cases]

The hypokalemic paralysis is a disease characterized by the development of acute muscular weakness, associated to low levels of blood potassium (< 3.5 meq/L). Here we present two cases: in the first one, a 23 years old woman, with 15.5 weeks of gestation has a cuadriplegia associated to blood potassium level of 1.4 meq/L, diagnosed with distal tubular acidosis; she required mechanical ventilation for respiratory paralysis. The medical profile remits with potassium intravenous replacement and the pregnancy ends with a spontaneous abortion. The second case is a 15 years old woman with 26.5 weeks of pregnancy, who suffers a generalized paralysis with blood potassium of 2.7 meq/L, requiring also mechanical ventilation for respiratory paralysis; the final diagnosis was Barterr syndrome, and the medical profile remited after potassium supplement. Her pregnancy got complicated with a severe preeclampsia, enough reason for interrumpting the pregnancy at 29.1 weeks of gestation. In both cases Guilliain-Barre syndrome was ruled out.

[Hypoglycaemic periodic paralysis in hyperthyroidism patients]

Hypokalemic periodic paralysis (HPP) is a rare disorder characterised by acute, potentially fatal atacks of muscle weakness or paralysis. Massive shift of potassium into cells is caused by elevated levels of insulin and catecholamines in the blood. Hypophosphatemia and hypomagnesemia may be also present. Acidobasic status usually is not impaired. HPP occurs as familiar (caused by ion channels inherited defects) or acquired (in patients with hyperthyroidism). On the basis of two clinical cases we present a review of hypokalemic periodic paralysis in hyperthyroid patients. We discuss patogenesis, clinical and laboratory findings as well as the principles of prevention and treatment of this rare disorder.

[A new type of periodic paralysis: Andersen-Tawil syndrome]

Andersen-Tawil syndrome includes a clinical triad consisting of periodic paralysis, cardiac arrhythmia, and usually mild but diagnostically useful dysmorphic features. This potassium channelopathy is due to mutation of the KCNJ2 gene encoding the protein Kir 2.1. The main muscular manifestation is periodic paralysis, usually of the hypokalemic type. Muscle biopsy may reveal tubular aggregates or be normal, as in our patient. Cardiac manifestations are variable and may include a long QT syndrome, premature ventricular contractions, complex ventricular ectopy, and polymorphic or bidirectional ventricular tachycardia. Imipramine therapy had a positive effect on arrhythmia in our patient. Dysmorphic features provide a diagnostic clue but may be difficult to identify and should thus be methodically sought. Clinical expression is variable, even within the same family. Since the culprit gene KCNJ2 was identified, locus heterogeneity has been shown in Andersen-Tawil syndrome. Kindreds without KCNJ2 mutations are clinically indistinguishable from those with mutations. Kir2.1 is an inward rectifier K+ channel with important roles in maintaining membrane potential and during the terminal phase of cardiac action potential repolarization. Several studies show a dominant negative effect of KCNJ2 mutation on Kir 2.1 channel function.

[Hypokalemic thyrotoxic periodic paralysis--a rare differential diagnosis in patients presenting acute tetraparesis]

A 40-year-old Caucasian man was diagnosed hyperthyroid in 2001. In 2002 he suddenly developed a feeling of muscle weakness. Medical investigation showed decreased muscle strength of the legs and arms, reduced deep reflexes of the patella and low serum potassium. The neurological symptoms disappeared 10 hours later without potassium treatment. Similar diseases and symptoms appeared in 2006. This case demonstrates that it is important to keep HTTP in mind since it can be the clinical manifestation of hyperthyroidism.

Hypokalemic periodic paralysis as a manifestation of thyrotoxicosis

OBJECTIVE

To study the clinical characteristics of patients who suffer from hypokalemic periodic paralysis, as the presenting symptoms of thyrotoxicosis.

MATERIAL AND METHOD

A retrospective review of 29 patients who presented with the syndrome of hypokalemic periodic paralysis as the symptom of thyrotoxicosis at Ratchaburi Hospital between January 1,1995 and December 31, 2007. Patients'data, diagnosis, blood chemistry, and thyroid function test were collected from medical records.

RESULTS

All patients exhibited muscle weakness for a duration of one to two days, while all patients with hypokalemic periodic paralysis were determined to have high serum thyroid hormone and diagnosed with thyrotoxicosis. Patients with hypokalemic periodic paralysis were the first symptom leading to diagnosis of thyrotoxicosis. The attack of weakness occurred during the night in all patients. The patients, 96.6% being male, showed improvement of their symptoms through potassium replacement and thyrotoxicosis treatment using propylthiouracil and non selective beta adrenergic blocker All patients recovered and did not demonstrate reoccurring hypokalemic periodic paralysis. The degree of muscle weakness was found to correlate significantly (p < 0.05) with level of serum potassium, magnesium, and duration of weakness.

CONCLUSION

It is important to determine blood thyroid hormone in all patients with hypokalemic periodic paralysis.

Primary periodic paralyses

OBJECTIVE

To review the current knowledge about primary periodic paralyses (PPs).

RESULTS

Periodic paralyses are a heterogeneous group of disorders, clinically characterized by episodes of flaccid muscle weakness, occurring at irregular intervals. PPs are divided into primary (hereditary) and secondary (acquired) forms of which the secondary PPs are much more common than the primary PPs. Primary PPs are due to mutations in genes encoding for subunits of channel proteins of the skeletal muscle membrane, such as the muscular sodium, potassium or calcium channels, or the SCL4A1 protein. Primary PPs include entities such as hyperkalemic PP, hypokalemic PP, paramyotonia congenita von Eulenburg, Andersen's syndrome, thyrotoxic PP, distal renal tubular acidosis, X-linked episodic muscle weakness syndrome and congenital myasthenic syndromes. Attacks of weakness or myotonia may be triggered or enhanced by vigorous exercise, cold, potassium-rich food, emotional stress, drugs such as glucocorticosteroids, insulin or diuretics, or pregnancy. Depending on the pathomechanism, episodes of weakness may respond to mild exercise, ingestion of potassium, carbohydrates, salbutamol, calcium gluconate, thiazide diuretics, carboanhydrase inhibitors, such as acetazolamide or dichlorphenamine, and episodes may be prevented by avoidance of potassium-rich food, or drugs, which increase serum potassium.

CONCLUSION

This review presents and discusses current knowledge and recent advances in the etiology, molecular genetics, genotype-phenotype correlations, pathogenesis, diagnosis and treatment of primary PPs.

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.

Thyrotoxic periodic paralysis

A young man of 30 yrs got himself admitted in Bangabandhu Sheikh Mujib Medical University (BSMMU) Hospital, Dhaka, Bangladesh with the complaints of suddenly developed weakness in his all four limbs. He had features of hyperthyroidism and he gave the history of similar attacks of weakness in his all four limbs in the previous months. His potassium was in the lower part of the normal range and his T4 and T3 were elevated but TSH was markedly low. He was diagnosed as a case of thyrotoxic periodic paralysis on the basis of clinical and biochemical findings. After treatment with carbimazole, propranolol and potassium replacement, patient's condition improved dramatically.

Toxic thyroid adenoma presenting as hypokalemic periodic paralysis

Toxic thyroid adenoma presenting as hypokalemic periodic paralysis is extraordinarily rare. We describe a 26-year-old Japanese man who suffered from acute and painful muscle weakness of extremity in the morning. Physical examination showed a left anterior neck mass and laboratory tests revealed hypokalemia during his paralysis, and thyrotoxicosis. Neck sonogram showed a solitary nodule in the left lobe of the thyroid. Thyroid scintigraphy revealed a hot nodule of the tumor region with suppressed uptake in the other thyroid area. The tumor was surgically removed and his paralytic attack ceased. No somatic mutation of TSH receptor was found in his thyroid adenoma and no known genetic mutations of ionic channel genes, such as calcium (CACN1S), sodium (SCN4A) and potassium (KCNE3), were found. Although thyrotoxic periodic paralysis is usually accompanied with Graves' disease, thyrotoxicosis of other conditions including Plummer's disease should be considered.

A case report of familial periodic paralysis

A 20-year-old male was brought to the hospital with the complaints of severe weakness and inability to move the limbs of 12 hours duration. For the last 2 years he had the same episodes with spontaneous recovery. Family history strongly suggested involvement of other members of the family. Physical examination did not suggest any neurological deficit. All investigations were normal except serum potassium level being 2.2 meq/l during attack and 3.4 meq/l after the attack. He was treated with oral acetazolamide and potassium chloride. The case was diagnosed to be familial periodic paralysis belonged to the group 'episodic myasthenia'.

Thyrotoxic periodic paralysis in a Polynesian male following highly active antiretroviral therapy for HIV infection

Hyperthyroidism has been described after highly active antiretroviral therapy for AIDS and has been attributed to late onset immune reconstitution. The team reports a young Polynesian man with AIDS who responded to highly active antiretroviraltherapy. However, 15 months after initiation of antiretroviral therapy, he was hospitalized for hypokalemic thyrotoxic periodic paralysis, an unusual manifestation of hyperthyroidism which typically occurs in young Asian males.

Early diagnosis of thyrotoxic periodic paralysis: Spot urine calcium to phosphate ratio*

OBJECTIVES

To identify a clinically reliable index of thyrotoxic periodic paralysis (TPP), a life-threatening emergency with unique and effective therapies.

DESIGN

Diagnostic study.

SETTING

University teaching hospital.

PATIENTS

Fifty-three consecutive patients with hypokalemic paralysis during a 3-yr period and 30 thyrotoxic patients without paralysis as the thyrotoxic control group.

INTERVENTIONS

For patients with hypokalemic paralysis, blood and second-void spot urine samples were obtained and measured by routine laboratory prior to therapy. For the thyrotoxic control group, blood and spot urine were collected when they visited outpatient clinics.

MEASUREMENTS AND MAIN RESULTS

Twenty-nine patients fulfilled the criteria for TPP. Compared with the thyrotoxic control group, the TPP group had significant decreases in plasma potassium (K) and phosphate concentrations associated with very low urine K and phosphate excretion. Compared with the non-TPP group, the TPP group had significantly lower plasma creatinine and phosphate levels, a significantly higher urine calcium to creatinine ratio (0.25 +/- 0.12 vs. 0.08 +/- 0.07 mg/mg, p < .001), and a significantly lower urine phosphate to creatinine ratio (0.08 +/- 0.05 vs. 0.31 +/- 0.23 mg/mg, p < .001). The urine calcium to phosphate ratio had greater discriminatory power between TPP and non-TPP hypokalemic paralysis (4.1 +/- 2.3 vs. 0.5 +/- 0.6 mg/mg, p < .001). Using a urine calcium to phosphate ratio cutoff value of 1.7 mg/mg, sensitivity and specificity for TPP were 100% and 96%, respectively.

CONCLUSIONS

Hypercalciuria and hypophosphaturia are characteristic features of TPP.

Exercise test in the inter-attack period of thyrotoxic periodic paralysis: a useful diagnostic tool

Exercise test was reported to be useful for some patients with periodic paralysis. We report here the results of exercise test in three cases of thyrotoxic periodic paralysis, for whom the exercise test was all positive. Exercise test could be one of the diagnostic tools in the "inter-attack" state of the probable cases with thyrotoxic periodic paralysis. However, the case number of this study is small and larger-scale studies may be warranted in the future.

À propos de deux cas de paralysie périodique hypokaliémique

We report on two cases of hypokaliemic periodic paralysis due to a potassium shift from the extracellular to the intracellular compartment of skeletal muscle cells. The first case occurred in a 15-year-old boy who experienced rapid onset flaccid tetraplegia without neurological abnormalities. Physical exam revealed facial dysmorphy, and EKG a long QT. Biology evidenced shift hypokalemia that was quickly reversible after administration of intravenous potassium. After exclusion of Andersen-Tawil syndrom, hypokalemic familial paralysis (Westphall disease) was diagnosed by molecular genetic testing (disease-causing mutation in CACNA1S) in the proband and in three other family members. The second case occurred in a 24-year-old male who experienced rapid onset flaccid tetraplegia due to intracellular potassium shift that was quickly reversible after administration of intravenous potassium. Biology revealed thyrotoxicosis due to Grave's disease. To the best of our knowledge, this is the first case described in a people from pacific origin. The clinical, biological, and electromyographic findings of the most frequent causes of periodic paralysis are underlined as well as the molecular genetic diagnosis in familial forms.

Gene analysis of the calcium channel 1 subunit and clinical studies for two patients with hypokalemic periodic paralysis

Hypokalemic periodic paralysis (HypoPP) is a skeletal muscle disorder in which episodic attacks of muscle weakness occur; they are associated with decreased serum potassium (K+) levels. Recent molecular approaches have clarified that the condition is caused by mutations in the skeletal muscle voltage-gated calcium channel 1 subunit (CACNA1S). We describe two unrelated patients with HypoPP, followed by their relevant clinical studies and gene analysis. Clinical studies included an oral glucose tolerance test (OGTT), food-loading and insulin tolerance tests (ITT). For Case 1, serum K+ levels were extremely decreased following insulin tolerance testing compared with levels for controls. These results support the hypothesis that no efflux of K+ ion occurs in patients because of low activity of adenosine triphosphate (ATP)-sensitive K+ channel (KATP) channels. Mutational analysis of the CACNA1S gene showed a duplicate insertion of 14 base pairs (bp) from 52 to 65 in intron 26, present in the heterozygous state in both patients. No other mutations were detected in the CACNA1S gene, the muscle sodium channel gene (SCN4A) or the voltage-gated K+ channel gene (KCN3) of either patient. Further analysis showed that this duplicate insertion of 14 bp in intron 26 of the CACNA1S gene was found in 23.7% of healthy subjects. K+ dynamics studies are useful for confirming this syndrome, while further gene analysis for various ion channels using amplification and direct sequencing are required to evaluate the molecular basis of the disorder in the individual patient.

Hypokalemic paralysis due to Gitelman syndrome: a family study

Hypokalemic paralysis is rarely seen as the presenting feature in patients with Gitelman syndrome. We report a Chinese man who presented with periodic paralysis, in whom molecular analysis revealed compound heterozygous inheritance of three mutations of the thiazide-sensitive sodium chloride cotransporter. Family history revealed intrafamilial variation in phenotypes. Gitelman syndrome should be considered as a cause of hypokalemic paralysis, and molecular analysis may help establish the diagnosis.

An Unusual Cause of Muscle Weakness: A Case Report

Thyrotoxic hypokalemic periodic paralysis (THPP) has been reported earlier in the Asian population. However, it is now becoming increasingly common in the Western countries as well. Thus, its in-depth knowledge is a must for every physician so that this diagnosis is not overlooked in any case presenting with extremity weakness and paralysis, especially considering its reversible nature. We present an interesting case of THPP in a Vietnamese patient presenting with bilateral lower extremity weakness and extremely low serum potassium levels. We also present a comprehensive discussion and review of literature related to THPP, which would be helpful for the internists to diagnose and appropriately manage this disease.