Hyperkalemia in the elderly

Introduction to hyperkalemia in the elderly Hyperkalemia refers to serum potassium >5.5mmol / L, the total potassium in the body does not necessarily increase, but the distribution of potassium inside and outside the cell is not normal. Unless the kidney itself is diseased, the kidney function of the elderly is not reduced; therefore, hyperkalemia is less common than potassium. basic knowledge Sickness ratio: 0.05%-0.08% Susceptible people: the elderly Mode of infection: non-infectious Complications: arrhythmia

The cause of hyperkalemia in the elderly

(1) Causes of the disease

Kidney disease is still the main cause of hyperkalemia in the elderly, such as acute oliguric renal failure, chronic kidney disease combined with excessive potassium intake, active gastrointestinal bleeding or low renin hyperaldosteronism (especially diabetic nephropathy) Older hyperkalemia is also caused by drugs, mainly potassium-sparing diuretics, non-steroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors and -adrenergic blockers, in addition to metabolism Acidosis (such as diabetic ketoacidosis) and adrenal insufficiency.

(two) pathogenesis

Hyperkalemia causes excessive depolarization of neuromuscular cells, lowers the resting potential of the cell membrane, reduces stress, slows conduction, and shortens action potential.

Prevention of hyperkalemia in the elderly

Older people need to regularly monitor changes in blood potassium if they use potassium-sparing diuretics, oral or intravenous potassium supplementation.

Hyperkalemia complications in the elderly Complications arrhythmia

Can be complicated by arrhythmia, ventricular fibrillation and ventricular arrest, severe hyperkalemia and limb soft palate, ventricular pacing, severe hyperkalemia and soft paralysis.

Hyperkalemia symptoms in the elderly Common symptoms Hyperkalemia arrhythmia paralysis ventricular fibrillation thrombocytosis

Until arrhythmia, hyperkalemia often has no symptoms, or only a less defined weakness and paresthesia. The early changes in ECG are T-wave high-point and QTc interval shortening (indicating blood potassium level >5.5mmol/L). With the further increase of serum potassium, there may be stagnation and ventricular arrhythmia, accompanied by QRS complex widening and prolonged PR interval. Finally, ventricular fibrillation or ventricular arrest may occur, and severe hyperkalemia may also be delayed. Sexual muscle paralysis.

Examination of hyperkalemia in the elderly

Serum potassium levels >5.5mmol / L, the overall potassium is often too much or normal; if normal, the distribution of potassium inside and outside the cells is not normal.

Electrocardiogram examination: When the serum potassium level is above 6mmol/L, about 25% of patients can have ECG changes. When serum potassium reaches 8mmol/L, 80% of patients have ECG changes, and serum potassium can reach 810mmol/L. Severe arrhythmia or even cardiac arrest, typical electrocardiogram of hyperkalemia shows high T wave, shortened QT interval, P wave disappears when severe, QRS wave widens, further ST segment and T wave fuse, T wave broadens , together with the QRS wave to form a biphasic wave shape, and finally ventricular fibrillation.

Diagnosis and differential diagnosis of hyperkalemia in the elderly

Diagnostic criteria

Serum potassium levels >5.5mmol / L repeated confirmation, accompanied by the corresponding ECG changes, can be diagnosed, otherwise, pseudohyperkalemia should be excluded: 1 long time to stop bleeding before blood draw, 2 specimens hemolysis , 3 specimens stored for too long, 4 thrombocytopenia.

Differential diagnosis

Acute renal failure oliguria

Hyperkalemia is one of the common causes of death in oliguria. The disease should be differentiated from pre-renal oliguria. The latter is caused by insufficient renal blood perfusion. The degree of hyperkalemia is mild and slow, and renal function is also impaired. Lighter, the ratio of urine osmotic pressure to blood osmotic pressure is >2, which is helpful for differential diagnosis.

2. Chronic renal insufficiency

In the advanced stage of chronic renal insufficiency, blood potassium can be increased, urine relative density is low and fixed, urine has protein, cast, red blood cells and white blood cells, plasma urea nitrogen and creatinine are often increased, carbon dioxide binding is often reduced, according to medical history Symptoms and laboratory tests, diagnosis is generally not difficult, many factors such as infection, acidosis, a large number of application of potassium-sparing diuretics, input of blood, etc. can cause a sharp or significant increase in serum potassium.

3. Low renin low aldosteronism

This disease is due to the reduction of aldosterone formation caused by renin deficiency. The main clinical manifestations are hyperkalemia and metabolic acidosis. This disease should be differentiated from Addison disease. Both have aldosterone reduction and hyperkalemia, but low. Renin low aldosteronism has plasma, decreased renin activity, normal plasma cortisol and ACTH values, and no clinical features of Addison disease, such as hyperpigmentation, weakness and loss of water.

4.1-hydroxylase deficiency

Patients with complete 1-hydroxylase deficiency, due to insufficient secretion of cortisol and aldosterone, may have significant dehydration, hyperkalemia, hyponatremia and metabolic acidosis, due to increased secretion of ACTH, stimulate the secretion of androgen in the adrenal cortex Therefore, female patients are masculine, and male patients are precocious.

5. Hyperkalemia periodic paralysis

The symptoms of this disease are similar to hypokalemia and periodic paralysis. The muscles are weak and paralyzed, but the episodes are more frequent. Each episode lasts for several minutes to several 10 minutes. When the seizure, serum potassium increases, and the electrocardiogram has corresponding performance. This disease is rare. More men, usually starting before the age of 10, often caused by intense exercise, wet and cold environment, after taking potassium salt.

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