Hypokalemia and metabolic alkalosis: algorithms for combined clinical problem solving

This article reviews an approach to patients with hypokalemia and metabolic alkalosis using the information obtained from spot urine chloride values, blood pressure determinations, and renin and aldosterone measurements in order to simplify clinical problem solving.

Successful management of hypokalaemia related conduction disturbances in acute aluminium phosphide poisoning

A case of acute aluminium phosphide poisoning is described, who presented in shock secondary to electrolyte related cardiac rhythm disturbance and the judicious correction of the same could save his life without any consequence.

Prolonged QT interval in acute psychotic patients

Some recent clinical studies indicate that hypokalemia is characteristic for acute psychotic patients at the time of emergency admission. As hypokalemia is one of the major causes for prolonged QT interval, it was hypothesized that acute psychotic patients could show prolonged QT interval. Sixty-seven drug-free, acute psychotic patients were evaluated for corrected QT (QTc) interval, as well as demographic and clinical characteristics at the time of emergency admission. The mean QTc interval of psychiatric emergency patients was prolonged, and the mean QTc interval of psychiatric emergency patients was longer than that of psychiatric outpatients (t=5.20, P<0.0001). Age- or gender-related difference, circadian fluctuation of QT interval, medication, concomitant disease, obesity, and serum electrolytes except potassium were not major causes. There was a significant negative correlation as evidenced by a coefficient of correlation of -0.28 (P<0.05). As psychiatric emergency patients often receive parenteral antipsychotics, which may have adverse effects on prolonged QT interval, paying attention to QT interval might have some clinical significance on emergency admission.

[Thyrotoxic periodic paralysis: two new cases in Blacks]

INTRODUCTION

Thyreotoxic hypokalemic periodic paralysis (THPP) has mainly been described in Asian people. It is rare in Caucasians, and only 12 cases were reported in Blacks.

EXEGESIS

We report two cases of THPP in black patients. Hypokalemia was important in case number 1, leading to severe flaccid tetraplegia with respiratory and cardiac complications, but was only mild in case number 2. Complete relief of paralysis was observed under potassic treatment in the first case and spontaneously in the second one. Hyperthyroidism was established only on the basis of biological tests in case number 1, and had been previously diagnosed but undertreated in case number 2.

CONCLUSION

Whatever the patient's race, acute paralysis with hypokalemia requires testing for hyperthyroidism, even in the absence of suggestive clinical signs.

Thyrotoxic hypokalemic periodic paralysis case report and review of the literature

A rare complication of hyperthyroidism consists of sudden diffuse muscle weakness associated with severe hypokalemia. The clinical presentation is similar in most respects to familial periodic paralysis; however, the therapies proven to be effective differ in the two syndromes. A case of thyrotoxic hypokalemic periodic paralysis is presented and the literature is reviewed.

Transtubular potassium concentration gradient (TTKG) and urine ammonium in differential diagnosis of hypokalemia

BACKGROUND

Hypokalemia is a common and sometimes serious clinical problem, whose etiological diagnosis can frequently be based on the patient's history and the clinical setting. Measurement of urinary indices such as excretory rate of K+, random urine K+ concentrations and blood acid-base parameters have been employed in the pathophysiological diagnosis, though with some pitfalls.

METHODS

To investigate the diagnostic usefulness of the transtubular potassium concentration gradient (TTKG) and urine ammonium in the differentiation of hypokalemia, we measured serum K+ and osmolality, random urine electrolytes, osmolality and ammonium, the urinary [Na]/[K] ratio (U(Na)/K), plasma aldosterone and TTKG in 7 patients with diarrhea, 6 with vomiting, 7 with mineralocorticoid excess, 6 with diuretic usage, and compared them with those of 7 overnight fasted and acid-loaded healthy volunteers.

RESULTS

The urine K+ concentrations did not reflect urinary loss of potassium according to the subjects' hydration status. U(Na)/k in the hypokalemic patients with mineralocorticoid excess (1.4 +/- 0.5) was lower than in normal subjects (2.3 +/- 0.4) (p<0.05). TTKG was higher in hypokalemic patients with mineralocorticoid excess (13.3 +/- 4.4) and diuretic usage (8.6 +/- 1.3) and lower in those with diarrhea (1.6 +/- 0.3) than in the normal controls (5.0 +/- 0.7) (p<0.5). TTKG in the patients with vomiting (3.5 +/- 0.6) was the same as in normal controls. TTKG was stronger correlated with the plasma aldosterone levels in the hypokalemic patients due to renal potassium loss. Urine ammonium concentrations of the acid-loaded normal subjects (73.3 +/- 5.0 mEq/L), patients with diarrhea (74.4 +/- 2.0 mEq/L) and patients with mineralocorticoid excess (68.7 +/- 6.9 mEq/L) were higher than in overnight-fasted normal subjects (31.3 +/- 4.9 mEq/L).

CONCLUSION

TTKG and random urine ammonium were useful in the pathophysiological differential diagnosis of hypokalemia.

Thyrotoxic periodic paralysis and intravenous propranolol in the emergency setting

A 27-year-old male of Malaysian descent presented to the Emergency Department (ED) with rapidly progressive flaccid paralysis that quickly compromised his respiratory effort. The patient was found to have a serum potassium of 1.9 meq/L, and was diagnosed as having an acute paralytic episode secondary to thyrotoxic periodic paralysis. The paralytic attack was aborted with a combination of potassium replacement and parenteral propranolol in large doses. We report the use of a rarely described, yet possibly more effective, therapy for an acute attack of thyrotoxic periodic paralysis.

[Lymphocytic colitis: hypopotassemia as a complication and an association with toxic multinodular goiter]

Lymphocytic colitis is a rare clinicopathologic syndrome, characterized by chronic watery diarrhea, diffuse inflammatory changes in the colonic mucous in spite of normal findings on colonoscopy and marked intraepithelial lymphocytic infiltration on biopsy. Although the physiological mechanism of diarrhea is not clear, patients do not usually present hydroelectrolytic alterations and the results of routine laboratory investigations are usually normal. The association between lymphocytic colitis and thyroid disease, possibly autoimmune, in the form of hypo- or hyperthyroidism is relatively common. We report a 61-year-old woman with a history of multinodular toxic goiter, whose previously uninvestigated chronic diarrhea became more acute and led to the diagnosis of lymphocytic colitis. Results of laboratory investigations revealed only a significant hypokalemia with an associated nonfunctioning bilateral adrenal incidentaloma. The patient evolved well when treated with sulfasalazine. Hypokalemia as a complication of lymphocytic colitis and an association between lymphocytic colitis and toxic multinodular goiter does not seem to have been previously described.

[How I investigate ... dyskalemia]

Potassium is the most important intracellular cation, playing a role in neuromuscular excitability. Dyskalemia is common. The consequence of this ionic perturbation could be serious related to its magnitude. Thus a quick etiological approach and a medical intervention are needed to rapidly correct this potentially lethal ionic disturbance and prevent its recurrence.

Treatment of potassium balance disorders

Potassium is the predominant intracellular cation and is critical for the maintenance of resting cellular membrane potential. Abnormalities of potassium balance can manifest as skeletal and cardiac muscle dysfunction. Abnormalities of potassium concentration in plasma can result from changes in external potassium balance (intake vs. excretion) or internal balance (intracellular to extracellular). Hyperkalemia can result from renal failure, uroperitoneum, or severe dehydration and acidosis in calves with diarrhea. Hypokalemia occurs due to reduced forage intake, when increased gastrointestinal losses occur as with diarrhea, due to increased renal losses as with metabolic alkalosis or exogenous corticosteroid administration which promote kaliuresis, or with redistribution of potassium into the intracellular compartment with alkalosis or in association with insulin-mediated glucose uptake. Aggressive intravenous and oral therapy are often necessary to correct potassium balance disorders, in addition to therapy aimed at correcting any underlying disorder contributing to the potassium imbalance.

Gitelman's syndrome: report of a 19-year old woman with intractable hypomagnesemia and hypokalemia, and a review of the syndrome

A case of refractory hypomagnesemia associated with hypokalemic alkalosis and hypocalciuria (Gitelman's syndrome) is described. The genetic mutations discovered to cause the hypokalemic alkalotic syndromes are described (the thiazide-sensitive sodium chloride co-transporter gene or TSC mutations in Gitelman's syndrome, and the sodium-potassium-chloride co-transporter gene or NKCC2 mutations in Bartter's syndrome). The molecular, electrolyte, and volume abnormalities are described, and the implications for diagnosis, therapy, and future research discussed.

[Thyrotoxic periodic paralysis. A report of 2 cases]

INTRODUCTION

Thyrotoxic hypokalemic periodic paralysis is characterized by recurrent episodes of motor weakness of variable intensity associated with thyroid overactivity. It is usually associated with low plasma potassium levels and is often precipitated by physical activity or ingestion of carbohydrates.

CLINICAL CASES

We describe two men, aged 33 and 50, who complained of several episodes of muscular paralysis in the context of previously undiagnozed hyperthyroidism and associated with low plasma potassium levels. There were clearly raised levels of T3, T4 and free T4 and TSH was depressed due to hyperactive diffuse goitre. In one patient the precipitating factor was known to have been a large intake of carbohydrates and intense physical exercise. Antithyroid treatment, and the resulting correction of hyperthyroid function, prevented any further episodes of muscular weakness in both patients.

CONCLUSIONS

Thyrotoxic periodic paralysis should be considered in the differential diagnosis of all acute episodes of motor paralysis in young patients. Determination of the plasma levels of potassium and thyroid hormones helps diagnosis. Early diagnosis is important so as to be able to establish antithyroid treatment and avoid further episodes of weakness.

[A rare case of hypokalemic thyrotoxic periodic paralysis in a Caucasian patient with Basedow's disease]

Thyrotoxicosis periodic paralysis is a very rare complication of thyrotoxicosis in whites, but is more frequently reported in oriental and latin american populations and associates the clinical picture of hyperthyroidism with bouts of paralysis due to hypokalemia. The hypokalemia is due to a massive shift of potassium from the extra- to the intracellular compartment. In this paper the authors report a case of 34-years old white male with an history of hypokalemic periodic paralysis and hyperthyroidism, studied with potassium, thyroid hormone, TSH and thyroid antibodies sampling and thyroid ultrasonography with color-Doppler. The restoration of a euthyroid state with methimazole and propranolol was effective in preventing further episodes of paralysis. It is suggested that the mechanism for the development of the hypokalemic periodic paralysis is the intracellular blockade of potassium by the surplus of thyroid hormones.

Preponderance of hypokalaemia as a cause of acute onset quadriparesis in northern India/southern Nepal

Of 68 patients who were admitted with acute quadriparesis to a hospital in northern India, over 70% were found to be hypokalaemic. The most common cause of hypokalaemia was that associated with gastroenteritis (54%). These patients had all received intravenous fluids previously. It is likely that their hypokalaemia was caused by gastrointestinal loss compounded by parenteral fluid replacement. The next most common group of hypokalaemia-associated quadriparesis had no obvious cause for hypokalaemia (38%). Hypokalaemia-induced quadriparesis is a potentially life-threatening illness which can be readily treated with potassium supplements. The physician should consider hypokalaemia in patients who present with acute onset quadriparesis, and even if diagnostic tests for hypokalaemia are not available, should consider a judicious trial of potassium supplementation empirically, provided that there are no contraindications.