Hypernatremia in the elderly

Introduction to hypernatremia in the elderly Serum sodium levels >145mmol / L, accompanied by elevated plasma osmotic pressure, known as hypernatremia, senile hypernatremia, common in elderly hospitalized patients, mainly due to water loss, a small number of injections due to excessive hypertonic NaCl cause. basic knowledge The proportion of illness: 0.005% Susceptible people: the elderly Mode of infection: non-infectious Complications: Hypertension Heart Failure Pulmonary Edema Coma

The cause of hypernatremia in the elderly

(1) Causes of the disease

The main reasons are reduced water intake, increased water loss, water loss over sodium loss, such as high heat and deep breathing due to recessive water loss, gastrointestinal disease of osmotic watery diarrhea, and permeability caused by uncontrolled diabetes. Diuretic, old and frail, unresponsive, weakened thirst, etc., common in the elderly; central diabetes insipidus, or acquired peripheral urine due to chronic kidney disease, hypercalcemia, hypokalemia, etc. Insufficiency is also seen in the elderly; it is rare because of excessive sodium input, often due to improper treatment.

(two) pathogenesis

Excessive blood sodium leads to hypertonic state of the blood, causing dehydration of cells, especially dehydration of brain cells, causing a series of neurological symptoms.

Prevention of hypernatremia in the elderly

When rehydration, attention should also be paid to potassium supplementation and urine output. For those with heart disease, special care should be taken to prevent heart failure.

Complications of hypernatremia in the elderly Complications, high blood pressure, heart failure, pulmonary edema, coma

Complicated with high blood pressure, heart failure or pulmonary edema, convulsions, coma and so on.

Symptoms of hypernatremia in the elderly Common symptoms Hypernatremia polyuria hypotension sleepiness weakening water sodium accumulation dyspnea dehydration skin elasticity poor convulsion

Mild hypernatremia can be characterized as non-specific weakness, headache, irritability or lethargy, severe hypernatremia (blood sodium >150mmol / L) can occur tremor, convulsions, convulsions, or dullness, wood Stiff, coma, the clinical signs are mainly volume loss and dehydration, such as weight loss, poor skin elasticity, mucous membrane dryness and orthostatic hypotension, in addition, there are still primary disease manifestations such as obvious polyuria (diabetes insipidus), high fever (Infection), etc. If high-sodium injections are caused by hypertonic saline, there are symptoms of heart failure such as high blood pressure, difficulty breathing, and cough.

Examination of hypernatremia in the elderly

Laboratory tests, in addition to elevated blood sodium levels, can still find hematocrit, serum osmotic pressure, BUN and Cr levels increased blood concentration changes, due to the decline in renal concentrating function of the elderly, the urine osmotic pressure is often not significantly increased.

When combined with heart failure and edema, the ECG showed abnormal performance.

Diagnosis and differential diagnosis of hypernatremia in the elderly

Diagnostic criteria

Serum sodium level>145mmol/L, with high plasma osmotic pressure can be diagnosed, urine osmotic pressure can help identify the cause: urine osmotic pressure <300mOsm / kg for diabetes insipidus (including central and renal) , >800mOsm/kg are mostly non-dominant dehydration, primary drinking water is too small or sodium salt infusion is too much, between the two can be partial central diabetes insipidus, central diabetes insipidus Reduced blood volume, or renal diabetes insipidus and osmotic diuresis, further based on medical history and water-free compression test or determination of blood antidiuretic hormone (ADH) levels and other clear causes.

Differential diagnosis

Diabetes insipidus

Also known as pituitary diabetes insipidus, is the lack of ADH secretion in the posterior pituitary, the cause of the disease is unknown, the clinical features are polydipsia, polydipsia, polyuria (day urine volume can reach 5 ~ 10L), urine relative density is low (1.001 ~ 1.005), low osmotic pressure (50 ~ 200mmol / L), clinically divided into idiopathic diabetes insipidus and secondary diabetes insipidus, the latter is due to hypothalamic pituitary tumors, brain trauma, surgery, inflammation Caused, when the lesions involve the thirst center of the hypothalamus and lose thirst, often because of the inability to replenish water in time, resulting in severe dehydration, or even death, when suspected diabetes insipidus should be done banned vasopressin test and plasma ADH determination To confirm the diagnosis, if necessary, head CT and X-ray examination should be performed to exclude pituitary tumors.

2. Renal diabetes insipidus

For hereditary diseases, the clinical manifestations are similar to those of diabetes insipidus. Most of the patients are boys. The disease occurs several months after birth. After the injection of vasopressin, the urine volume is not reduced, the urine specific gravity is not increased, and the plasma ADH concentration is significantly increased. Different from pituitary diabetes insipidus.

3. Interstitial nephritis and severe renal dysfunction

Caused by a large number of causes, in addition to pyelonephritis, drugs (lithium salt, dicycline, etc.), low potassium, high calcium, urinary tract obstruction, gout, etc. can cause the disease, hypernatremia, polyuria, dehydration According to the medical history, renal function test and serum electrolyte measurement can be used for differential diagnosis.

4. Diabetic hyperosmolar coma

More common in elderly patients, mild diabetes before the onset of illness or even diabetes, often due to infection, the use of diuretics or glucocorticoids induced, clinical manifestations in addition to hypernatremia, dehydration is mainly neurological symptoms, such as not Clear, lethargy, hemiplegia, aphasia, convulsions, etc., easily confused with cerebrovascular accidents, this disease should be differentiated from hypernatremia caused by osmotic diuretics.

5. Idiopathic hypernatremia

The cause is unknown and clinically rare. The diagnostic criteria are:

1 persistent hypernatremia;

2 no obvious dehydration and thirst;

3 When the urine is banned, the urine becomes hypertonic, indicating that the body still has the ability to secrete ADH;

4 renal tubules still respond to ADH, the use of vasopressin can cause water retention, it is believed that this disease is the "threshold increase" syndrome of ADH release.

In addition, it should be differentiated from endocrine disorders such as primary aldosteronism and hypercortisolism.

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