Hyponatremia
Description:
The hyponatremia is a state at which concentration of ions of sodium in a blood plasma falls lower than 135 mmol/l (normal — 150 mmol/l). The hyponatremia is caused by a wide range of pathology.
Hyponatremia symptoms:
At most of patients the symptomatology is absent, but symptoms of the disease causing a condition of a hyponatremia can be shown.
The strong hyponatremia can cause osmotic redistribution of water from a blood plasma in organism cells, including brain cells. Typical symptoms in this case include dizziness, vomiting, headaches and a febricula. In process of an uglubeniye of a hyponatremia there can be a confusion of thoughts, catalepsy (stupor) and a coma. As dizziness in itself is an incentive for excretion of ADG (antidiuretic hormone), there is a possibility of a cycle of self-strengthening of effect (positive feedback).
When osmolarity of a blood plasma is low, the volume of extracellular liquid in an organism can be in one of three states:
Low volume:
Loss of water is followed by sodium loss.
Excessive sweating
Burns
Vomiting
Diarrhea (diarrhea)
Excess mocheotdeleniye
Owing to the use of diuretics (especially tiazida)
Addison's disease
Cerebral syndrome of salt insufficiency
Other diseases of kidneys
Normal volume:
syndrome of inadequate secretion of ADG (SIADH)
At some cases of a psychogenic polydipsia (insatiable thirst)
In case of SIADH demeclocycline as the antagonist of ADG can have salutary effect.
The increased volume:
At the same time water keeps in an organism.
Heart failure
Low level of secretion of thyroid hormones and cortisol
Cirrhosis
Nephrosis
Majority of cases of a psychological polydipsia (insatiable thirst)
Hyponatremia reasons:
Abnormally low concentration of sodium in blood needs to be investigated in interrelation with osmolarity of a blood plasma and volume of extracellular liquid of the patient.
In most cases the hyponatremia is connected with decrease in osmolarity of a blood plasma. The vast majority of cases of a hyponatremia at adults is connected with a superactivity of ADG (antidiuretic hormone) (ADG is hormone which regulates balance of water in an organism, but do not salt). Therefore, the patient with a hyponatremia can be considered as the patient with a superactivity of ADG. The task of the doctor in that case consists in definition of the reason of a superactivity of ADG.
Patients with loss of volume have liquids (blood), secretion of ADG is increased as reduction of volume of blood is a natural incentive for secretion of ADG. Thereof kidneys of the patient hold water and excrete very concentrated urine. Treatment is simple — recovery of volume of blood of the patient, thus switching off of a signal of excretion of ADG.
At some patients with a hyponatremia the volume of blood is normal. These patients have an increased level of activity of ADG and the subsequent deduction of water can be connected with the physiological reasons of deduction of ADG such as pain or dizziness. The syndrome of inappropriate ADG (SIADH) is other possible reason. At this syndrome of ADG it is allocated constantly, with level norms are significantly higher and most often is side effect of some medicines, problems with lungs (such as pneumonia or abscess), brain diseases, or certain types of cancer (the most often small-celled carcinoma of lungs).
The third group of patients with a hyponatremia is characterized by presence peripheral Edens (hypostasis). Liquid in edematous fabric does not participate in circulation and stagnates. As a result the free volume of blood decreases, and it in turn leads to ADG excretion. Treatment of such patients has to be directed to elimination of the reasons of hypostases. In many cases it is absolutely difficult as cirrhosis or heart disease which treatment cannot be considered simple in any way can be the real reasons.
It is separately necessary to consider the patients consuming diuretics. These drugs increase release of liquid with mochy and as a result reduction of volume of blood. As it was already mentioned above, reduction of volume of blood is an incentive for ADG and deduction of water kidneys.
The modern surge in mortality from a hyponatremia is connected with excess water consumption under the influence of Metilendioksimetamfetamin ("ecstasy"). Also Almond et al. [1] found an easy hyponatremia in 13% of runners during the Boston marathon, and life-threatening (sodium level in blood is lower than 120 mmol/l) in 0,6%. The runners putting on weight during the running because of excess water consumption are exposed to the greatest risk.
Treatment of the Hyponatremia:
It is necessary to treat the reason of an illness and to carry out intravenous injections of saline solution. It is important to note that sudden recovery of volume of blood causes the termination of excretion of ADG. Respectively, the normal diuresis of water in kidneys begins. It can lead to the sudden and essential growth of serumal concentration of sodium and increases risk of a myelinosis central Varoliyev Bridge. This syndrome is characterized by serious damage of a nervous system, often irreversible.
Because of risk of a myelinosis patients with a low volume of liquid can need injections not only normal (salt) saline solution, but also water. These measures provide smoother growth of concentration of sodium in serum in process of growth of volume of blood and smoother decrease in the ADG level.
