Hyporeninemic hypoaldosteronism. An overlooked cause of hyperkalemia

Managing hyperkalemia in patients with heart failure on guideline-directed medical therapy: challenges and opportunities

Heart failure is a chronic and invalidating syndrome that affects tens of millions of people worldwide with significant socio-economic ramifications for the health care systems. Significant progress in the understanding of the pathophysiology of heart failure has allowed the gradual introduction of several drug classes for the management of such patients. Beta-blockers, mineralocorticoid receptor antagonists, angiotensin receptor neprilysin inhibitors, and sodium-glucose-cotransporter 2 inhibitors are all considered pillars of the guideline-directed medical therapy for heart failure. Despite remarkable improvements in the morbidity and mortality of heart failure, however, many patients still develop clinically significant hyperkalemia during combined treatment with those four pharmacological pillars. The consequence is often a down-titration or discontinuation of one or more crucial drugs, which in turns leads to a considerable increase in the risk of cardiovascular events, dialysis, and all-cause mortality. This paper will explore novel approaches for the management of hyperkalemia in heart failure, including closer monitoring of potassium levels, early review of drugs that might increase the risk of hyperkalemia, and pharmacological treatment of hyperkalemia, with a special emphasis on sodium-glucose-cotransporter 2 inhibitors and potassium-binding agents, including patiromer and sodium zirconium cyclosilicate.

Hyporeninemic hypoaldosteronism in a patient with diabetes mellitus: an unforgettable case report

A 58-year-old man presented with a 3-year history of chronic and intermittent hyperkalemia requiring recurrent attendances to the emergency department for urgent treatment. His medical history included secondary diabetes mellitus following a bout of acute pancreatitis and a previous splenectomy for a spontaneous splenic rupture. He also had a history of prolonged use of non-steroidal anti-inflammatory drugs for back pain and painful neuropathy. He was not on any medication or diet that would cause a raised serum potassium level and his renal function was normal. He was on a basal-bolus insulin regimen but his diabetes control had been poor for several years. As the hyperkalemia had gone on for so long in the presence of normal renal function, he went on to have further tests. Adrenal insufficiency had been ruled out following a short Synacthen test. Further investigations revealed low serum aldosterone levels and inappropriately low serum renin levels in the presence of hyperkalemia. This was suggestive of hyporeninemic hypoaldosteronism (HH). He was then treated with fludrocortisone and furosemide and his serum potassium levels remained normal. Additionally, he did not require any more emergency admissions to treat hyperkalemia thereafter. It was concluded that the HH-induced hyperkalemia was caused by diabetes mellitus or due to a combination of diabetes and prolonged use of non-steroidal anti-inflammatory drugs. The absence of renal impairment may have contributed to the delay in diagnosis. HH is a commonly overlooked cause of hyperkalemia. This case highlights the fact that it should always be suspected when unexplained hyperkalemia is found in patients with only mild-moderately impaired renal function, especially in the presence of diabetes mellitus.

Adrenal Insufficiency in the Intensive Care Setting

In the intensive care setting, the question of adrenal insufficiency arises most frequently in patients whose endogenous adrenal function may be suppressed by pre ceding glucocorticoid therapy or in patients with the acquired immunodeficiency syndrome. Less often the question arises in patients whose adrenal tissue may have been destroyed by autoimmune disease, tuber culosis, meningococcal or other infection, hemorrhage, or replacement by malignancy, or in patients whose adrenal function has been suppressed by certain drugs. Measurements of plasma adrenocorticotrophic hor mone (ACTH), cortisol, aldosterone, and renin levels and the response of cortisol and aldosterone to exoge nously administered ACTH form the basis for clinically evaluating the adequacy of a patient's adrenal function. The naturally occurring glucocorticoid, hydrocortisone, remains the cornerstone of adrenal replacement therapy along with appropriate fluid and electrolyte administra tion. In rare instances the addition of a mineralocor ticoid is necessary. A brief review of the use of mega- dose glucocorticoids in the treatment of sepsis, shock, and the adult respiratory distress syndrome is included.

Adoption of Spironolactone Therapy for Older Patients With Heart Failure and Left Ventricular Systolic Dysfunction in the United States, 1998–2001

Background— Concerns have been raised about the appropriateness of spironolactone use in some patients with heart failure. We studied the adoption of spironolactone therapy after publication of the Randomized Aldactone Evaluation Study (RALES) in national cohorts of older patients hospitalized for heart failure.

Methods and Results— This is a study of serial cross-sectional samples of Medicare beneficiaries ≥65 years old discharged after hospitalization for the primary diagnosis of heart failure and with left ventricular systolic dysfunction. The first sample was discharged before (April 1998 to March 1999, n=9758) and the second sample after (July 2000 to June 2001, n=9468) publication of RALES in September 1999. We assessed spironolactone prescriptions at hospital discharge in patient groups defined by enrollment criteria for the trial. Using multivariable logistic regression, we identified factors independently associated with prescriptions not meeting these criteria. Spironolactone use increased >7-fold (3.0% to 21.3% P <0.0001) after RALES. Of patients meeting enrollment criteria, 24.1% received spironolactone, as compared with 17.4% of those not meeting the criteria. Of all prescriptions after RALES, 30.9% were provided to patients not meeting enrollment criteria. Spironolactone was prescribed to 22.8% of patients with a serum potassium value ≥5.0 mmol/L, to 14.1% with a serum creatinine value ≥2.5 mg/dL, and to 17.3% with severe renal dysfunction (estimated glomerular filtration rate <30 mL · min −1 · 1.73 m − 2 ). In multivariable analyses, factors associated with prescriptions not meeting enrollment criteria included advanced age, noncardiovascular comorbidities, discharge to skilled nursing facilities, and care provided by physicians without board certification.

Conclusions— Spironolactone prescriptions increased markedly after the publication of RALES, and many treated patients were at risk for hyperkalemia. Simultaneously, many patients who might have benefited were not treated. These findings demonstrate the importance of balancing efforts to enhance use among appropriate patients and minimizing use in patients at risk for adverse events.

Hypertension in the metabolic syndrome and diabetes: pathogenesis, clinical studies, and treatment

The increasing prevalence of obesity, hypertension, and abnormal glucose metabolism is a major challenge to health care in industrialized societies. This brief review summarizes the mechanistic evidence and clinical studies related to the problem of hypertension in the metabolic syndrome and diabetes to allow clinicians to provide more effective and enlightened management of these common, interrelated problems.

Renin-aldosterone system can respond to furosemide in patients with hyperkalemic hyporeninism

Thirty-four patients (65.3+/-3.3 years of age, mean+/-SEM) with hyperkalemia (serum potassium >5.0 mEq/L) had measurement of their renin-aldosterone system. Nineteen patients (56%) had plasma renin activity (PRA) >1.5 ng/mL/h, which was not low, while 15 (44%) had PRA <1.5. Twelve of the 15 hyporeninemic hyperkalemic patients were studied to determine whether their renin-aldosterone system responded to 2 weeks of furosemide, 20 mg daily. Four were nonresponders: PRA averaged 0.3+/-0.1 ng/mL/h, and it did not increase with furosemide or respond to captopril before or after furosemide. Eight patients were responders: PRA averaged 0.6+/-0.2 ng/mL/h and increased with furosemide to 5.5+/-3.4 ng/mL/h. Captopril failed to increase PRA before furosemide, but PRA increased to 15.3+/-8.4 ng/mL/h after furosemide. Plasma aldosterone was low in both nonresponders and responders (3.5+/-1.2 ng/dL vs 5.8+/-2.5 ng/dL) and did not increase significantly with furosemide (4.3+/-1.7 ng/dL vs 8.7+/-2.5 ng/dL). Serum potassium did not fall and therefore did not limit the rise in aldosterone. Renin responders had greater body weight, were predominantly female (6/8 vs 2/4) and were more likely to have diabetes mellitus (7/8 vs 0/4). Plasma atrial natriuretic peptide (ANP) fell with furosemide in 8 of 8 responders and in 1 of the 2 nonresponders in whom it was measured. Neither group had suppressed plasma prorenin levels, indicating no suppression of renin gene expression. These results indicate that many hyperkalemic patients do not have suppressed PRA. Further, a majority of patients with suppressed PRA have high levels of ANP and can respond to diuretic therapy with a rise in PRA and a fall in ANP, suggesting physiologic suppression of the renin system by volume expansion. A minority of hyperkalemic patients with suppressed PRA had PRA that did not increase under these study conditions.

Trimethoprim/sulfamethoxazole and metabolic acidosis in HIV-infected patients

OBJECTIVE

To describe a retrospective study of six HIV-positive individuals with compensated metabolic acidosis while receiving intravenous trimethoprim/sulfamethoxazole (TMP/SMX).

CASE SUMMARY

Six HIV-infected patients were treated for Pneumocystis carinii pneumonia (PCP) with high-dose intravenous TMP/SMX. In spite of a favorable clinical and radiologic course, all six patients developed compensated metabolic acidosis 3-5 days after the start of treatment. This potential complication of TMP/SMX use was successfully managed with conservative treatment (cessation of therapy with or without additional administration of intravenous bicarbonate).

DISCUSSION

TMP/SMX is first-line therapy for PCP in HIV-positive individuals, despite a high frequency of toxic effects in these patients. In addition to the cases reported here, only two other reports of metabolic acidosis secondary to TMP/SMX use in HIV-infected patients have been published in the literature. The precise mechanism of this untoward effect is not fully understood, although renal tubular acidosis induced by TMP/SMX could be implicated.

CONCLUSIONS

TMP/SMX toxicity should be considered in the differential diagnosis of HIV-infected patients with acute metabolic acidosis. Metabolic acidosis can be expected to resolve shortly after discontinuation of the drug.

Algorithms for diagnosing some electrolyte disorders

The differential diagnosis of electrolyte disorders has traditionally been framed in terms of pathophysiology, and analysis of clinical problems has usually proceeded in the same way. However, easier access to rapid-response laboratory analysis has prompted physicians who encounter patients with serious electrolyte abnormalities to try to establish the cause by quickly obtaining further simple tests. In that vein, this article and the algorithms that are presented are intended to assist the preliminary laboratory differential diagnosis of low and high serum levels of sodium, potassium, and calcium.

Flow diagrams for the diagnosis of acid-base disorders

This article discusses flow diagrams and tables intended to provide a systematic approach to the rapid laboratory differential diagnosis of acid-base disorders in the emergency department.

Hyperkalemia in the elderly: drugs exacerbate impaired potassium homeostasis

OBJECTIVE

To review the pathophysiology underlying the predisposition to hyperkalemia in the elderly; the medications that disrupt potassium balance and promote the development of hyperkalemia in the elderly; the prevention of hyperkalemia in elderly patients treated with potassium-altering medications; and the appropriate management of hyperkalemia when it develops.

METHODS AND MAIN RESULTS

A MEDLINE search of the literature (1966-1996) using the terms hyperkalemia, drugs, elderly, and treatment was conducted and pertinent review articles, textbooks, and personal files were consulted. Elderly subjects appear to be predisposed to the development of hyperkalemia on the basis of both innate disturbances in potassium homeostasis and comorbid disease processes that impair potassium handling. Hyperkalemia in the elderly is most often precipitated by medications that impair cellular uptake or renal disposal of potassium. This electrolyte disorder is best prevented by recognition of at-risk physiology in the aged, avoidance of therapy with certain high-risk medications, and monitoring of plasma potassium concentration and renal function at intervals appropriate for the medication prescribed. Management of hyperkalemia entails identification of the clinical manifestations of severe hyperkalemia, stabilization of cardiac tissue, promotion of cellular potassium uptake, and ultimately removal of potassium from the body.

CONCLUSIONS

Geriatric patients should be considered at risk of developing hyperkalemia, especially when they are prescribed certain medications. Potassium levels should be monitored at appropriate intervals when these patients are treated with potassium-altering medications. Appropriate management of hyperkalemia in the elderly can avoid life-threatening neuromuscular and cardiac complications.

Hyperkalaemia in diabetes: prevalence and associations

Hyperkalaemia is associated with diabetes, but there are no recent reports of its prevalence and associations. Serum potassium concentrations were measured in all 1764 patients attending a diabetic clinic over a 12-month period and found to be > 5.0 mmol/l in 270 (15%), and > 5.4 mmol/l in 67 (4%). There was no other evident cause of hyperkalaemia in 41 of these 67 patients. These data serve to highlight the risk of dangerous hyperkalaemia in diabetic patients, particularly with concurrent administration of angiotensin-converting-enzyme inhibitors and potassium-sparing diuretics.

Type IV renal tubular acidosis and spironolactone therapy in the elderly

Spironolactone therapy is a well-known cause of hyperkalaemia, but in susceptible patient, it may also be associated with metabolic acidosis. We report a case of severe renal tubular acidosis (Type IV) with life-threatening hyperkalaemia caused by spironolactone, and discuss the mechanisms by which this may occur.

Severe hyperkalemia in two patients with diabetes after cosyntropin administration

Some patients with diabetes mellitus are at increased risk for the development of hyperkalemia. Included in this group are patients with glucose-induced hyperkalemia who may have renal insufficiency, hyporeninemic hypoaldosteronism, or other impediments to the release or action of aldosterone. In an unusual demonstration of this abnormality, two patients with diabetes, who form the basis of our report, became markedly hyperglycemic and hyperkalemic after cosyntropin administration. To our knowledge, this complication of adrenocorticotropic hormone (ACTH) stimulation testing has not been previously reported. It should therefore be emphasized that the use of cosyntropin as a diagnostic agent can provoke severe hyperglycemia and hyperkalemia in a susceptible subgroup of patients with diabetes mellitus.

Systolic hypertension in the elderly: reasons not to treat

Isolated systolic hypertension in the elderly is associated with increased morbidity and mortality. Accurate measurement of blood pressure in older patients is difficult. Therapy can be associated with various complications, and the special problems of the elderly, such as orthostatic hypotension and hyperkalemia, should be carefully considered. Drugs should be used in low doses and changes in dosage should be made infrequently. Patients should be monitored frequently for untoward effects of therapy. The benefits of blood pressure reduction and the optimal degree of blood pressure reduction remain unknown.

Hyperkalemia in the elderly

Physiologic and pathologic events that occur in patients as they grow older may result in distal renal tubular dysfunction, as well as decreased levels of plasma renin activity and plasma aldosterone. Such alterations result in a tendency toward hyperkalemia. A syndrome termed hyporeninemic hypoaldosteronism, associated with hyperkalemia, has been frequently described in elderly patients. The common occurrence of hyperkalemia in the elderly may be aggravated by the use of drugs that either further suppress renin and/or aldosterone or interfere with distal tubular potassium excretion. Some patients with hyporeninemic hypoaldosteronism respond to diuretic therapy. The recognition of the possible development of severe hyperkalemia in the elderly patient may avoid serious and even fatal complications of this electrolyte disorder.

Diseases of the adrenal cortex

The adrenal cortex is functionally a three-dimensional gland that secretes glucocorticoids, mineralocorticoids, and sex steroids. Of these three classes of steroids only the gluco- and mineralocorticoid hormones are necessary to sustain life. The availability of sensitive and specific radioimmunoassays has permitted accurate measurement of practically every steroid hormone secreted by the adrenal cortex. As in other endocrinopathies, suppression studies are employed when hyperfunction is suspected, while provocative tests are used to detect hypofunction. These dynamic studies enable the clinician to evaluate the functional status of the adrenal cortex. The anatomic configuration of the adrenal cortices is delineated by high-resolution computed tomography (and magnetic resonance imaging), obviating the need for invasive procedures such as venography or arteriography. The disorders of the adrenal cortex can be viewed from the dual perspectives of hyperfunction and hypofunction. Clinical expressions of hyperfunctional adrenocortical syndromes include Cushing's syndrome, primary hyperaldosteronism, and the adrenogenital syndrome. The expressions of hypofunctional syndromes include Addison's disease and selective hypoaldosteronism. The diagnosis and treatment of these disorders are outlined in this issue.

Hyporeninemic hypoaldosteronism associated with acquired immune deficiency syndrome

Four patients with the acquired immune deficiency syndrome (AIDS) and persistent unexplained hyperkalemia were studied. Testing with cosyntropin (0.25 mg intravenously) revealed normal baseline and stimulated cortisol levels and adequate aldosterone stimulation. The baseline aldosterone level was low for the degree of hyperkalemia. Renin/aldosterone stimulation testing was performed by intravenous injection of 80 mg of furosemide followed by four hours of upright posture. This study showed low baseline renin and aldosterone levels and inadequate renin and aldosterone stimulation. Three patients were subsequently treated with fludrocortisone (0.1 to 0.2 mg per day), with normalization of serum potassium levels. It is concluded that hyporeninemic hypoaldosteronism is responsible for hyperkalemia in some patients with AIDS and that treatment with fludrocortisone is effective in these cases.

Hyporeninemic hypoaldosteronism in children with chronic renal failure

The syndrome of hyporeninemic hypoaldosteronism (SHH) is not infrequent in adults with chronic renal failure caused by chronic tubulointerstitial nephritis, but it has been reported rarely in children. We present a systematic study of the interrelation between renal excretion of potassium and the renin-aldosterone axis in 23 children with CRF of different and unselected causes. Twenty children with chronic renal failure never had hyperkalemia, and both renin and aldosterone were normally stimulated by intravenous administration of furosemide, whereas three patients had moderate hyperkalemia (serum potassium concentration between 5.3 and 5.6 mEq/L) and failed to raise plasma renin activity and aldosterone values in response to furosemide. There three patients with SHH had lower basal and stimulated values of fractional potassium excretion than did patients with normokalemic chronic renal failure. Fractional potassium excretion was curvilinearly related to glomerular filtration rate (GFR), but in all three patients with SHH it was lower than expected for the level of GFR present. Fractional sodium excretion was also related to GFR, but no abnormalities were found. Two patients had hyperchloremic metabolic acidosis. After furosemide administration, they excreted an acid urine with low ammonium content, features characteristic of type 4 or hyperkalemic renal tubular acidosis. Prostaglandin E2 excretion was also significantly related to GFR, and appeared appropriate in two patients with SHH. The identification of three patients with SHH among 23 with chronic renal failure of unselected causes suggests that this entity is not rare in childhood.

Hyperkalemic left bundle branch block and hyporeninemic hypoaldosteronism (hyperkalemic left bundle branch block)

A 70-year-old woman was admitted to the intensive coronary care unit with suspected myocardial infarction. During the follow-up period, the patient twice developed left bundle branch block, which was shown to be related to high serum potassium levels secondary to hyporeninemic hypoaldosteronism and moderate renal failure.

Adrenocortical insufficiency

Adrenocortical insufficiency causes difficulty in diagnosis and morbidity out of proportion to its rarity, because of the non-specific, multi-system nature of the clinical features. Most of these are due to cortisol deficiency. Prominent features are well-known ones such as weight loss and asthenia, and hypoglycaemia. Less prominent in recent accounts are those due to failure of cellular sodium export and to vasopressin excess, which are frequent and clinically significant. For this reason, the clinical features of isolated ACTH deficiency, isolated glucocorticoid deficiency and Addison's disease overlap greatly. In addition, cortisol deficiency has secondary endocrine effects, e.g. glucocorticoid-reversible hypothyroidism, hyperprolactinaemia and hypercalcaemia. Further overlap between the various steroid insufficiency syndromes occurs because of the association of various organ-specific autoimmune endocrinopathies with Addison's disease. Over 80% of Addison's disease is of the autoimmune type, though almost any systemic destructive process can cause similar steroid insufficiency. Demonstration of adrenal insufficiency requires various combinations of tetracosactrin adrenal stimulation tests, and hypoglycaemia or equivalent tests, if the cause is ACTH deficiency but the correct test can only be chosen to suit a firm clinical diagnosis. The treatment of adrenocortical insufficiency is described.

Hyperkalaemia in diabetes mellitus--potential hazards of coexisting hyporeninaemic hypoaldosteronism

Two patients with insulin-dependent diabetes mellitus (Type I), developed severe, life-threatening hyperkalaemia, the first following treatment with spironolactone, the second during treatment for staphylococcal septicaemia when glucose-induced hyperkalaemia occurred. Investigations demonstrated co-existing hyporeininaemic hypoaldosteronism. Prompt recognition of this combined hormone-deficiency syndrome led to appropriate treatment and recovery. The biochemical features and clinical importance of hyporeninaemic hypoaldosteronism are discussed.

Hyperkalemic hyperchloremic metabolic acidosis in sickle cell hemoglobinopathies

This report describes the occurrence of hyperkalemic hyperchloremic metabolic acidosis in six patients with sickle cell hemoglobinopathies. Three patients had sickle cell anemia, two had sickle cell trait and one had S-C disease. In all patients, decreased renal potassium excretion was demonstrated by the finding of a fractional potassium excretion lower than that of control subjects with comparable glomerular filtration rates. Two patterns of impaired urinary acidification were discerned. Four patients had a urinary pH above 5.5 in the presence of systemic acidosis and, thus, were classified a having distal renal tubular acidosis. The remaining two patients had very low rates of ammonium excretion despite intact capacity to lower urinary pH below 5.5 during systemic acidosis; this pattern was ascribed to selective aldosterone deficiency. Sickle cell hemoglobinopathies should be included in the differential diagnosis of hyperkalemic hyperchloremic metabolic acidosis.