Introduction to hyponatremia

Introduction

The normal value of blood sodium is 142 mmol/L (135-145 mmol/L), and the blood sodium is lower than 135 mmol/L.Hyponatremia. Urine sodium content: normal adult 70 ~ 90mmol / 24h, about sodium chloride 4.1 ~ 5.3g. If the urine Na+<34.19mmol/L or absent, it indicates that Na+ is absent in the body. Hyponatremia is a clinically common electrolyte disorder, and sodium and water are closely interdependent. The blood sodium concentration is lowered, and the osmotic pressure of plasma is also generally lowered, so hyponatremia is also called hyponatremia hypotonic syndrome. The plasma sodium concentration that should be clearly determined does not indicate the total amount of sales in the body and the distribution of sodium in the body. The measured decrease in plasma sodium concentration is not sufficient to confirm sodium deficiency in the body. For example, in the case of dilute hyponatremia, the total amount of sodium in the body does not decrease, and sometimes even increases. However, since the increase in water in the total solution is more pronounced than the increase in sodium, the plasma sodium concentration is lowered.

Cause

Etiology classification

There are many methods for classification. The changes in extracellular fluid volume are not considered from hyponatremia. The more complete causes are classified as:

(a) sodium loss hyponatremia

Loss of sodium is accompanied by loss of water, but the loss of salt is greater than the loss of water through the intake of water or the compensation of the body. Therefore, sodium hyponatremia is hypotonic, including hypotonic dehydration, ie hyponatremia. There is a decrease in the capacity of extracellular fluid. Common in vomiting, diarrhea, gastrointestinal drainage, large loss of gastrointestinal digestive juice, a lot of sweating, severe burns, large amount of exudate, drainage of pleural effusion, ascites, renal dysfunction, adrenal insufficiency, ADH secretion abnormal syndrome, diabetes Acidosis, a large number of diuretics and so on.

(two) dilute hyponatremia

Refers to excessive water retention in the body, the overall amount of water is too much, the total amount of sodium in the body does not change or slightly increase, due to blood dilution and manifested hyponatremia, which is also hypotonic. Common in mental polydipsia, patients drink plenty of water, the kidneys are too late or can not be completely discharged; brain diseases, malignant tumors, lung lesions and surgical, trauma and other stress stimuli, abnormal increase in ADH secretion; and hypothyroidism, etc. . The blood volume of patients with dilute hyponatremia can be slightly increased, so the urine sodium is not reduced. The osmotic pressure of >20mmol / L can be reduced from normal 285 mmol / L to 240 mmol / L, and serum sodium is usually 130 ~ 140. Mmmol / L or lower.

(3) Increased total amount of hyponatremia sodium

This primary factor is sodium retention, while water retention > sodium retention, and lead to lower blood sodium, also known as expansive hyponatremia. Common in congestive heart failure, cirrhosis, decompensation, nephrotic syndrome and acute, chronic renal failure. This type of hyponatremia is mostly gradual and often maintains a new balance under certain hypotonic conditions. Patients often have hypokalemia, hypoproteinemia, low urine output, urinary sodium often <20 mmol / L, high urinary potassium, high urine relative density.

(4) Asymptomatic hyponatremia

Mainly seen in chronic wasting diseases such as severe tuberculosis. Advanced cancer, cachexia, malnutrition, etc., this mechanism is not clear, so it is called idiopathic hyponatremia. The nomenclature of asymptomatic hyponatremia is inadequate because many cases of early or slow progression of hyponatremia are asymptomatic.

(5) pseudohyponatremia

Hyperlipidemia, hyperproteinemia such that a large amount of highly permeable substances such as hyperglycemia and mannitol are present in the blood. The blood sodium concentration is lowered, which is called pseudohyponatemia. In general, when the total serum lipid is 60 g/L or the total serum protein is 140 g/L, the blood sodium concentration is reduced by about 5%.

(6) Cerebral salt loss syndrome

Caused by hypothalamus or brain stem injury, leading to neurological regulation of the kidney, osmotic diuresis in the distal tubules, increased sodium, chlorine, and potassium in the urine, and decreased in the blood.

Clinically, hyponatremia is sometimes a single cause, but it is often complex. When analyzing the etiology and pathogenesis of hyponatremia, it needs to be fully understood and considered.

For the treatment of hyponatremia and dilute hyponatremia, see "hypotonic water loss", "excessive water and water poisoning". Therapeutic hyponatremia is mainly for the treatment of primary disease.

mechanism

The loss of body fluid is often accompanied by the loss of water with certain solute (electrolyte). For example, diarrhea can cause a large amount of digestive juice to be lost. The digestive juice is basically isotonic. Although the loss of isotonic fluid does not directly cause hypotonicity or low sodium. Hypertension, but reduced blood volume can cause thirst, after inhalation or infusion of hypotonic fluid, hypotonic or hyponatremia occurs. The first is caused by hypotonic extracellular fluid. The main reaction of the body during hypotonic is water diuretic to discharge excess water. The discharge of water is mainly done by the kidney. The mechanism is as follows: 1. The upper osmotic pressure receptor is accepted. Stimulation reduces the release of ADH in the posterior pituitary. 2 There is enough liquid to be filtered out through the glomerulus and reach the dilution section of the renal tubule, ie the ascending branch of the myelin and the distal convoluted tubule. 3 The function of the tubule dilution section is normal, and the reabsorption of sodium is ensured by the action of aldosterone. Since ADH reduces the permeability of the distal renal tubular epithelial cells to water, the water absorption is reduced. As a result, a large amount of moisture is discharged. The kidney's drainage capacity can reach 15-20L per day. Kidney regulation of water and sodium is essential. If any cause causes urinary dilution disorder, such as abnormal increase in ADH release, glomerular filtration reduction, and impaired renal dilution function, water will be stored in the body. On the other hand, hypotonic extracellular fluid will inevitably lead to the exchange of fluid between the intracellular fluid and the extracellular fluid, and maintain a new balance. Because the kidneys are against water. The regulation and mobilization of salt metabolism requires a certain period of time. Therefore, the extracellular fluid is seriously hypotonic or the water is stored too fast, which will cause the extracellular fluid to transfer a large amount of water into the cells, causing intracellular edema (water poisoning).

diagnosis

The prominent symptom in the early stage of hypernatremia is thirst. In severe cases, the brain cells are dehydrated and mainly manifest symptoms of the nervous system such as irritability, lethargy, hyperreflexia, increased muscle tone, and later convulsions, convulsions, and coma.

Hyperkalemia: serum potassium is higher than 5.5mmol / L. Muscle weakness can occur in the early stage, severe abdominal reflexes disappear, muscle paralysis, and even respiratory muscles are paralyzed. The early circulatory rate of the circulatory system is slow, severe arrhythmia, and even ventricular fibrillation leads to cardiac arrest.

Patients with mild hypokalemia often have no obvious clinical signs, and may have weak body weakness, soft limbs, weakened or disappeared biliary reflexes, severe respiratory paralysis and cardiac dysfunction m heart rhythm disorder, heart enlargement, and even heart Stopping in.

Hypercalcemia: When serum protein is normal, serum calcium is increased by > 2.75 mmol / L. In addition to the signs of the primary disease, the main signs of hypercalcemia are mood changes, depression, increased reflexes, decreased pain, weakness of the proximal muscles, and gait instability. In addition, attention should be paid to the symptoms of impaired renal function and changes in cardiac function.

During the follicular phase of the normal menstrual cycle, the serum testosterone concentration averages 0.43 ng/ml, and the upper limit is 0.68 ng/ml. If it exceeds 0.7 ng/ml (=2.44 nmol/L), it is hyperandrogenemia, also known as high testosterone. Blood. It is a common gynecological endocrine disease. More common are menstrual changes such as menstrual thinning, amenorrhea or dysfunctional uterine bleeding, no ovulation, infertility. Some have masculine changes, such as hairy, enlarged throat, and low pitch. Some obesity, hemorrhoids, breast dysplasia, poor uterine development, ovarian enlargement, a few cases of clitoris hypertrophy.

Phosphorus metabolism disorder caused by lower than normal phosphate concentration in circulating blood. Also known as hypophosphatemia. The table is currently hemolysis, burnout, weakness and convulsions.

Hyperuricemia, also known as gout, is a group of diseases caused by dysbial metabolic disorders. Its clinical features are hyperuricemia and the resulting recurrent attacks of gouty acute arthritis and tophi deposits. Chronic arthritis and joint deformity, often involving the kidney caused by chronic interstitial nephritis and uric acid kidney stones. The disease can be divided into two major categories: primary and secondary. The cause of primary disease is mostly unclear due to a small number of enzyme defects. It is often accompanied by hyperlipidemia, obesity, diabetes, hypertension, arteriosclerosis and crown. Heart disease, etc., is a hereditary disease. Secondary people can be caused by a variety of causes such as kidney disease, blood diseases and drugs.

Systemic atherosclerosis and thrombosis can occur early in patients with homocystinuria and cystathione.

Hyperviscosity (or hyperviscosity) is a clinical pathological syndrome characterized by an increase in blood rheology parameters due to elevated blood viscosity factors, blood transition, and slow blood flow. .

Galactosemia is a toxic clinical metabolic syndrome with increased blood galactose. Most children have lactation, vomiting, nausea, diarrhea, weight loss, hepatomegaly, jaundice, bloating, hypoglycemia, proteinuria, etc., due to galactose in breastfeeding or artificial feeding. The performer should consider the possibility of galactosemia, and the relevant laboratory tests should be carried out. If the measures can be detected and taken in time, cataracts and mental retardation can occur rapidly.

Hypoxemia refers to insufficient oxygen in the blood. The arterial partial pressure of oxygen (pao2) is lower than the normal lower limit of the same age, and the main manifestation is the decrease of blood oxygen partial pressure and blood oxygen saturation. Adult normal arterial oxygen partial pressure (PaO2): 83-108 mmHg. A variety of causes, such as central nervous system disorders, bronchial, pulmonary lesions, etc. caused by ventilation and / or ventilation dysfunction can lead to hypoxia. Due to the degree of hypoxemia, the speed and duration of hypoxia, the impact on the body is also different. Hypoxemia is one of the most common critical illnesses in respiratory diseases and one of the important clinical manifestations of respiratory failure.

Cryoglobulinemia:

1. Purpura is the most common skin condition, such as cold urticaria, Raynaud phenomenon, acral cyanosis and reticular bluish, skin necrosis and ulceration.

2. Arthralgia is a common symptom in patients with mixed cryoglobulinemia. It often occurs in the hands and knee joints. It is polyarticular pain, symmetrical or asymmetrical, and occasionally joint swelling.

3. Renal damage can be manifested as acute and chronic nephritis, but also nephrotic syndrome, renal failure.

4. The nervous system is mainly peripheral neuropathy. Others such as hepatosplenomegaly, severe abdominal pain, pericarditis and generalized lymphadenopathy.

5. Laboratory examination of more than 90% of type I and more than 80% of patients with type II cold blood globulin content > 1mg / ml, more than 80% of patients with type III <1mg / ml.

Caroteneemia is a yellow-stained skin caused by high levels of carotene in the blood. Carotene is a lipid pigment that gives normal skin a yellow color.

Toxemia in pregnancy is a syndrome of ketosis, acidosis, hypoglycemia and liver failure. Most occur in the middle and late pregnancy. The symptoms of the milder are not obvious. In severe cases, the spirit is depressed, the breathing is difficult, the urine volume is severely reduced, and the exhaled gas has a ketone smell. Abortion, ataxia, convulsions and coma can occur before death. Hematological examination showed an increase in non-protein nitrogen, decreased calcium, increased phosphorus, and positive acetone test.

There is no hypoxemia during hypercapnia. Although PaCO2 has a lower pH value, there is only a temporary neurological inhibition in the clinic, which is characterized by slow response or coma.

Hypoproteinemia: mainly manifests malnutrition. The proteins in the blood are mainly plasma proteins and hemoglobin contained in red blood cells. Plasma proteins include plasma albumin, various globulins, fibrinogen and a small amount of binding proteins such as glycoproteins, lipoproteins, etc., in a total amount of 6.5 to 7.8 g%. If the total plasma protein is less than 6.0 g%, it can be diagnosed as hypoproteinemia.

Primary hypergastrinemia: CT cells proliferate due to genetic or chronic inflammation and Helicobacter pylori infection, which in turn increases the secretion of gastrin and absorbs blood into the blood, producing hypergastrinemia.

Endotoxemia is a pathophysiological manifestation caused by bacteria in the blood or bacteria in the lesion releasing a large amount of endotoxin to the blood, or by injecting a large amount of liquid contaminated by endotoxin. Clinical manifestations of chills, chills, hyperthermia, white blood cells and neutrophils increased. There is no restriction on a system that tends to or find multiple systems with migratory inflammation and multiple organ dysfunction. There is often a history of infection before the disease. In particular, those who have a basic disease that seriously affects the body's defense function, and who cannot control fever and other signs of systemic infection with general antibacterial drugs, should consider the possibility of endotoxemia. If there are defects or ecchymoses in the skin and mucous membranes, or complicated with septic shock, the clinical diagnosis of endotoxemia is basically established.

Hypermagnesemia: plasma magnesium is higher than 0.85mmol / L for hypermagnesemia, clinically less common, except for renal failure, most of which are iatrogenic, and related to the use of magnesium-containing drugs. This disease is most common in patients with renal dysfunction who have progressed to uremia. Hypermagnesemia mainly causes neuromuscular synaptic block. The early manifestations of neuromuscular disorders are similar to uremia; they are easily overlooked. Hypermagnesemia should be considered in the presence of postural pus and blood pressure, bradycardia, weakening of deep reflexes, disappearance, muscle weakness, muscle paralysis, cardiac blockade, cardiac arrest, lethargy, and coma.

Magnesium deficiency: early magnesium deficiency often has nausea, vomiting, anorexia, and weakness. Abnormal magnesium deficiency often causes neuromuscular and behavioral abnormalities, such as fibrillation, tremor, ataxia, convulsions and rigidity, nystagmus, hyperreflexia, and are easily induced by sound, light, and mechanical stimulation. Patients often have significant painful brachiopods, Trousseau or Chvostek. Sometimes the mental disorder is abnormal and the orientation is lost.