Digitalis intoxication with cardiac glycosides
Digitalis poisoning can threaten only people suffering from cardiovascular diseases who, due to objective reasons, are forced to take digitalis glycosides (cardiac glycosides).
In rare cases, these substances are the means of choice for suicide. More rarely, poisoning occurs when using specific medicinal plants: various types of oleander, foxglove, lily of the valley in May, onions and others.
Why does poisoning occur?
Digitalis intoxication most often develops against the background of taking Digoxin, since today it is the most prescribed drug from the group of cardiac glycosides. More rarely, mainly in the hospital, Celanid and Digitoxin are used. The drugs in this group have a narrow therapeutic window. This means that a slight increase in dose can lead to serious and even fatal consequences. Cardiac glycosides accumulate in the body by binding to plasma proteins and circulate for a long time through the bloodstream.
Some circumstances provoke intoxication with cardiac glycosides. These include:
- old age;
- taking unreasonably high doses of the drug;
- severe renal failure, through which digoxin is eliminated from the body;
- severe liver failure, where digitalis drugs are metabolized;
- low concentration in the blood plasma of potassium - on the background of receiving diuretic drugs or in secondary hyperaldosteronism (a condition in which increases the production of aldosterone - the adrenal hormone);
- imbalance of other trace elements (excess calcium in the blood, reduced plasma concentration of magnesium);
- conditions leading to hypoxia (lack of oxygen) in the body: severe heart failure, lung disease, which is complicated by respiratory failure;
- Pathology of the cardiovascular system: ischemic heart disease (including angina pectoris, myocardial infarction, post-infarction cardiosclerosis), myocarditis and other diseases having an inflammatory nature, previous operations, electrocardioversion;
- other conditions, such as excessive formation of thyroid hormones, low plasma protein levels (including those caused by insufficient food intake), hemodialysis, taking certain medications (Verapamil, Cordarone, Quinidine and other antiarrhythmic drugs), taking antibiotics ( macrolides), a violation of the acid-base balance in the body.
Digoxin intoxication develops as a result of an imbalance of electrolytes in cardiomyocytes (heart cells). As a result of blocking the enzyme Na-K-ATPase in the cell accumulates an excessive amount of sodium and calcium. The content of potassium is significantly reduced. Such changes lead to increased heart rate. But at the same time, Digoxin affects the cardiac conduction system. It is able to increase the automatism and the occurrence of ectopic activity, that is, impulses are generated in those parts of the heart muscle, where normally this does not occur. The conduction of impulses in the cardiac holding system slows down. All these changes lead to the fact that there are signs of intoxication with cardiac glycosides, which usually occur.
The first signs of digitalis intoxication
It is possible to suspect an overdose of cardiac glycosides at an early stage, when there are no clinical manifestations. This is assisted by a timely performed electrocardiography, in which certain pathological changes are detected. Various heart rhythm disturbances also appear:
- extrasystole (there are untimely contractions of the myocardium);
- tachycardia (ventricular or atrial) - increased heart rate;
- atrial and ventricular fibrillation (reduced in rhythm);
- blockade (impulses hardly pass through the pathways of the heart).
There are other violations that are better known to professionals. If no action is taken at the initial stage, the corresponding symptoms of digitalis intoxication appear, which will be discussed further.
Symptoms of digitalis intoxication
Depending on the clinical manifestations, symptoms can be divided into several groups.
Symptoms of heart damage:
- arrhythmia, up to asystole (cardiac arrest);
- ischemic manifestations (attacks of chest pain typical of angina).
Disorders of the digestive system:
- decrease or complete lack of appetite;
- loose stools.
- fast fatiguability;
- severe general weakness;
- sleep disorders;
- vestibulopathy (dizziness);
- migraine pain;
- depressive disorders;
- distortion of color perception (everything is seen in yellow and green tones);
- the appearance of spots, points before the eyes;
- blurred vision;
In acute poisoning, the symptoms are more pronounced and appear shortly after the administration of Digoxin: this can take minutes or hours. The condition quickly deteriorates and is accompanied by the occurrence, in addition to the listed symptoms, abdominal pain, convulsions, loss of consciousness, a drop in pressure and cardiac arrest.
In case of digitalis intoxication, treatment includes a number of measures:
- Cancellation of cardiac glycosides.
- Removal of toxin from the body. Reception of sorbents: repeated use of absorbent carbon. Gastric lavage is carried out only in emergency cases with a probe. Perhaps the use of saline laxatives: Karlovy Vary salt, magnesium sulfate or sodium sulfate.
- The introduction of potassium drugs: in severe cases, intravenously, in less dangerous situations, take potassium chloride inside after a meal.
- Antiarrhythmic drugs: the choice of means depends on the type of arrhythmia.
- In case of intoxication with cardiac glycosides, specific drugs are used to reduce their toxic effect: Unithiol or Digitalis-antidote BM.
- In rare cases, resort to pacing.
- Symptomatic treatment: oxygen therapy, intravenous administration of glucose and sodium chloride solutions, psychotropic drugs.
Prevention of digitalis intoxication
In order to avoid the negative effects of drugs digitalis, you must perform a number of conditions.
- Individual selection of the dose for each patient: take into account age (begin treatment of elderly patients with the minimum effective dose), take into account the functional ability of the urinary system and liver function, take into account concomitant diseases.
- Continuous monitoring of blood electrolytes, especially potassium.
- Be sure to follow the changes on the electrocardiogram.
- Control of drugs taken by patients for the treatment of comorbidities (diuretic, antiarrhythmic antibacterial, and so on).
- The most pleasant thing is to include in your diet foods that contain a sufficient amount of the very potassium: raisins, prunes, jacket potatoes, dried apricots and other goodies. Periodic intake of potassium does not hurt either.
Thus, digitalis intoxication is a condition that can be prevented by a reasonable approach to the use of cardiac glycosides.