Cardiac dysfunction in a patient with familial hypokalemic periodic paralysis

Familial Hypokalemic Periodic Paralysis: Case Report

Hypokalemic periodic paralysis is a congenital disorder which is characterized by intermittent episodes of muscle weakness or paralysis. The attacks can occur everyday or once a year, may last for a few hours or for several days. Serum potassium level is low during the attack. But serum potassium levels are normal between two attacks. There is no potassium deficiency in the whole body. In this report, a 16 years old boy, whose grandfather, father and uncle had the same semptoms, and had his first attack of familial hypokalemic periodic paralysis following a grand exercise were presented according to the clinical and laboratory features.

Re-feeding syndrome and alcoholic cardiomyopathy: A case of interacting diagnoses

Re-feeding syndrome is an uncommon clinical entity of fluid and electrolyte disorders that typically occurs after re-initiation of enteral nutrition following prolonged fasting. This disorder can be complicated by left ventricular (LV) dysfunction, arrhythmias, and death. Alcohol abuse and anorexia nervosa are independently associated with similar complications. The interaction between these diagnoses can result in significant, but reversible, LV dysfunction. We present the case of a 69-year-old woman with a history of significant alcohol abuse and anorexia nervosa. The patient was admitted to hospital for the management of re-feeding syndrome, which was complicated by significant LV dysfunction. Her LV function normalized following a combination of electrolyte replacement, re-institution of feeding, and abstinence from alcohol. Re-feeding syndrome, anorexia nervosa, and alcohol abuse are conditions that commonly co-exist. These conditions may have a synergistic relationship, potentially resulting in a profound cardiomyopathy. Careful monitoring and aggressive electrolyte replacement may be helpful in identifying this complication and minimizing its potential harm. <Learning objective: Re-feeding syndrome can be complicated by significant myocardial dysfunction, particularly in patients with a history of alcohol abuse or anorexia nervosa, which independently cause cardiac dysfunction. Physicians should be aware of the risk of new cardiomyopathy in patients with these overlapping diagnoses. We review the case of a patient with these conditions who developed a significant reversible cardiomyopathy managed with re-institution of feeding and electrolyte replacement.>.

Cardiac arrhythmias in hypokalemic periodic paralysis: Hypokalemia as only cause?

It is unknown how often cardiac arrhythmias occur in hypokalemic periodic paralysis (HypoPP) and if they are caused by hypokalemia alone or other factors. This systematic review shows that cardiac arrhythmias were reported in 27 HypoPP patients. Cases were confirmed genetically (13 with an R528H mutation in CACNA1S, 1 an R669H mutation in SCN4A) or had a convincing clinical diagnosis of HypoPP (13 genetically undetermined) if reported prior to the availability of genetic testing. Arrhythmias occurred during severe hypokalemia (11 patients), between attacks at normokalemia (4 patients), were treatment-dependent (2 patients), or unspecified (10 patients). Nine patients died from arrhythmia. Convincing evidence for a pro-arrhythmogenic factor other than hypokalemia is still lacking. The role of cardiac expression of defective skeletal muscle channels in the heart of HypoPP patients remains unclear. Clinicians should be aware of and prevent treatment-induced cardiac arrhythmia in HypoPP.

First case study of periodic hypokalemic thyreotoxic paresis with partial respiratory insufficiency and concomitant sinus bradycardia

This report describes the case of a 29-year-old Chechen refugee with periodic hypokalemic thyreotoxic tetraparesis (PHTP). Besides a partial respiratory insufficiency, the patient was also presented with sinus bradycardia. Medical literature describes several cases of thyreotoxicosis in combination with bradycardia. For the first time, we were able to observe a case of PHTP in combination with sinus bradycardia. PHTP is rarely seen in central Europe. In this case establishing a final diagnosis was difficult because of the concomitant presence of bradycardia and Graves' disease.

Severe prognosis in a large family with hypokalemic periodic paralysis

Hypokalemic periodic paralysis (HypoPP) is a channel disorder caused primarily by mutations in the human skeletal muscle alpha1 subunit (CACNA1S) of the dihydropyridine-sensitive calcium channel. Molecular, clinical, and biochemical studies were aimed at establishing genotype/phenotype correlations in a large Italian family affected by a severe form of HypoPP. Whereas patients with HypoPP usually show a normal life span, in this family three male patients died young, one of them from anesthetic complications resembling malignant hyperthermia. Our patients carried the c1583G>A genetic lesion (R528H), which has been associated with a mild phenotype and with incomplete penetrance in women. Surprisingly, the R528H amino acid substitution in the family presented here correlated with an unfavorable prognosis in both male and female patients. We conclude that genetic characterization is an important requirement to alert physicians about the management of similar patients, especially when anesthesia is considered.

Andersen's syndrome: a distinct periodic paralysis

A previous study of 4 patients defined Andersen's syndrome (AS) as a triad of potassium-sensitive periodic paralysis, ventricular dysrhythmias, and dysmorphic features. AS appears to be distinct in terms of its genetic defect from the alpha-subunit of skeletal muscle sodium channel and the cardiac potassium channel responsible for most long QT syndromes (LQT1). We studied 11 additional patients with AS from 5 kindreds. Spontaneous attacks of paralysis were associated with hypokalemia, normokalemia, or hyperkalemia. All 11 patients had similar dysmorphic features. The QT interval was prolonged in all patients although only 4 were symptomatic. Genetic linkage studies excluded linkage to the alpha-subunit of the skeletal muscle sodium channel and to four distinct LQT loci. In addition, none of the common dihydropyridine receptor mutations responsible for hypokalemic periodic paralysis were present. We conclude that (1) AS is a genetically unique channelopathy affecting both cardiac and skeletal membrane excitability, (2) attacks of paralysis may be either hypokalemic or hyperkalemic, (3) a prolonged QT interval is an integral feature of this syndrome, and (4) a prolonged QT interval may be the only sign in an individual from an otherwise typical AS kindred. This may be confused with more common, potentially lethal LQT syndromes.

Andersen's syndrome: potassium-sensitive periodic paralysis, ventricular ectopy, and dysmorphic features

Andersen's syndrome is a clinically distinct form of potassium-sensitive periodic paralysis associated with cardiac dysrhythmias. The subtle nature of the cardiac and dysmorphic features may delay the recognition of this syndrome and its potentially lethal cardiac dysrhythmias. The genetic defect in Andersen's syndrome is not genetically linked to other forms of potassium-sensitive periodic paralysis and is probably distinct from the long QT syndrome locus.

Familial hypokalemic periodic paralysis. Clinical, diagnostic and therapeutic aspects

Five generations of a family with hypokalemic periodic paralysis (HOPP) were studied. Of the 120 screened family members, 64 were found to have HOPP of which 38 were suffering from attacks. In the other 26 the diagnosis was made on account of vacuolar myopathy, a reduced muscle fiber conduction velocity or the signs of permanent muscle weakness (PMW) in combination with (grand)children with attacks. Applying these criteria skipping of generations did not occur in this family. When defined properly, PMW was found in all patients at older age, independent of the previous occurrence of paralytic attacks. Dynamometry and muscle CT-scanning appeared valuable in the diagnosis and the progression of PMW. In 2 patients autopsy was performed. Characteristics vacuolization was found in the striated muscle tissue in various degrees. Heart and smooth muscle tissue were not involved. Therapy is limited. Potassium salts shortening and preventing the paralytic attacks are tolerated well. Acetazolamide is more effective in the prevention of the paralytic attacks, but is not tolerated very well. HOPP can be considered as a myopathy characterized by PMW at older age in all patients, combined with paralytic attacks in more than half the patients.

Familial hypokalaemic periodic paralysis in Finland

Seven families with familial hypokalaemic periodic paralysis were found in Finland. Nine of the 103 asymptomatic family members studied had abnormal results on a potassium exercise test. The overall prevalence of familial hypokalaemic periodic paralysis in Finland was 0.4/100,000. Carbohydrate intake and hard exercise were the most important triggers of paralytic attacks. Half of the patients reported having attacks at least once a month. Seven patients reported cardiac symptoms (especially bradycardia) during attacks. Permanent muscular weakness was not prominent.

Myoglobin, creatine kinase and creatine kinase subunit-beta in serum from patients and relatives with hypokaliaemic familial periodic paralysis

Increased levels of serum myoglobin (S-myoglobin) were found in 6 investigated patients with hypokaliaemic familial periodic paralysis (hypoKPP) in their habitual condition. Furthermore, in 3 of the 6, increased levels of serum creatine kinase (S-CK) were found. These findings support the hypothesis that hypoKPP is a permanent myopathy, which is aggravated during attacks. It was found that 1 definite carrier had elevated S-myoglobin and among healthy relatives 6/11 had elevated S-myoglobin and 3/11 elevated S-CK. The use of S-myoglobin and S-CK for carrier detection is discussed.

Potentiation by hypokalemia of the effects of acetylcholine on the canine heart in situ

In the heart in situ of vagotomized dogs, atrioventricular conduction was studied by the His bundle potential recording, sinus rate continuously registered and the effective refractory period (ERP) of the atrial muscle measured by the extrastimulus method. The modifications induced by the acute lowering of plasma potassium concentration from 3.5 to 2.0 mmol/l obtained by hemodialysis appeared to be similar to those due to parasympathetic stimulation and the effects of hypokalemia and acetylcholine (ACh) on the atrioventricular (A-V) and sinoatrial nodes as well as on the atrial contractile tissue gave rise to potentiation. Intraaortically injected near coronary ostia in a dose lower than liminal dose, ACh enhanced to a large extent all the phenomena elicited by hypokalemia, since the variations respectively observed under the influence of hypokalemia alone and the combination of hypokalemia and ACh were as follows: lengthening of conduction time in the A-V node by 100 and 180%, reduction of sinus rate by 10 and 20%, shortening of the atrial ERP by 20 and 40%.

Effects of hypokalemia on the various parts of the conduction system of the dog heart in situ

The effects of hypokalemia were studied on the various parts of the conduction system by means of His bundle potential recording in the heart of vagotomized dogs. Plasma potassium concentration was lowered by extracorporeal dialysis, precautions being taken against the simultaneous impairment of other parameters, especially humoral. In order to make sure that the changes in atrioventricular conduction observed were due to hypokalemia, a control series of experiments was carried out, under strictly identical conditions except that the dialysis fluid was not devoid of potassium. The following alterations were observed during the lowering of potassium concentration from 3.2 to 1.6 mmol/l: atrioventricular node conduction time (AH interval) increased steadily up to 250% of control values; conduction time in atrial contractile tissue (SA interval) and His Purkinje system (HV interval) exhibited variations much later and much smaller; conduction time in ventricular contractile tissue was not significantly affected; effective refractory period (ERP) of atrial muscle, initially the longest in ERPs of conduction system in vagotomized animals, was shortened by about 20%. The mechanism of all these alterations is discussed.

Heart muscle disease in familial hypokalaemic periodic paralysis

The case history, skeletal muscle and heart muscle biopsy findings from an affected member of a family suffering from hypokalaemic periodic paralysis associated with permanent muscular weakness are reported. The patient, a female aged 35 years, while treated with 750 mg and later 1000 mg of acetazolamide daily, developed typical exercise angina pectoris. The ECG during exercise showed ST-segment depression. A coronary angiography was performed because coronary artery disease was suspected. To exclude cardiac muscle disease a biopsy of the left ventricular wall was taken. The angiography was normal. Ultrastructural analysis of the biopsy specimen showed an unusual amount of intermyofibrillary glycogen resembling, although far less abundant, the increase of glycogen found in the skeletal muscle biopsy specimen obtained from the same patient. The possible implications of these findings are discussed with reference to the normal echocardiographic findings in the family.