A female client with hypothyroidism (myxedema) is receiving levothyroxine (Synthroid), 25 mcg P.O. daily. Which finding should nurse Hans recognize as an adverse drug effect?
a. Dysuria
b. Leg cramps
c. Tachycardia
d. Blurred vision
Answer C.
Levothyroxine, a synthetic thyroid hormone, is given to a client with hypothyroidism to simulate the effects of thyroxine. Adverse effects of this agent include tachycardia. The other options aren’t associated with levothyroxine.
What is tachycardia?
We talk about tachycardia when, at rest, apart from physical exercise, the heart beats too quickly, at more than 100 beats per minute. A heart normally beats when it is between 60 and 90 beats per minute.
In case of tachycardia, the heart beats rapidly, and sometimes irregularly. This acceleration of the heartbeat may be permanent or transient. It can in some cases cause no sign. In other cases, it can cause dizziness, lightheadedness, palpitations, or even loss of consciousness. Tachycardia can range from a mild disorder to a very serious disorder that can lead to cardiac arrest.
There are several types of tachycardia:
- Sinus tachycardia: it is not due to a heart problem but to an adaptation of the heart to a particular circumstance. It is called sinus because the general rhythm of the heartbeat is determined by a specific location of this organ called the sinus node (area normally source of regular electrical pulses and adapted resulting in cardiac contractions). This sinus acceleration of the heart can be normal, as when it is related to physical exertion, lack of oxygen at altitude, stress, pregnancy (the heart is accelerating naturally at this time of life) or taking an exciting like coffee.
In the case of physical exercise for example, the heart accelerates to bring more oxygen to the muscles that work. It is therefore an adaptation. In the case of altitude, oxygen is more rare, the heart is accelerating to provide enough oxygen to the body despite its scarcity in the air.
But this sinus acceleration of the heart can be linked to an abnormal situation in which the heart adapts by accelerating its rhythm. This happens for example in case of fever, dehydration, intake of toxic substance (alcohol, cannabis, certain drugs or drugs), anemia or hyperthyroidism.
In the case of dehydration for example, the volume of liquid in the vessels being decreased, the heart accelerates to compensate. In the case of anemia, the lack of red blood cells causing a lack of oxygenation, the heart accelerates its pace to try to bring enough oxygen to all organs of the body. In the case of sinus tachycardia, quite often, the person does not realize that his heart beats quickly. This tachycardia can be discovered by the doctor.
Sinus tachycardia can also be related to a tired heart. If the heart fails to contract effectively enough, the sinus node requires it to contract more often to provide enough oxygen throughout the body.
- Tachycardia related to a heart problem: it is fortunately more rare than sinus tachycardia. The heart having an abnormality, it accelerates while the body does not need a beating heart faster.
- Tachycardia related to Bouveret's disease: it is relatively frequent (more than one in 450 people) and most often relatively benign. This is an anomaly in the electrical system of the heart. This anomaly leads at times to sudden tachycardia seizures for some time before stopping just as abruptly. The heart can then beat at over 200 per minute. This is embarrassing and often leads to discomfort to lie down for a while. Despite this anomaly, the hearts of these people are not sick and this problem does not diminish life expectancy.
Wolf-Parkinson White syndrome is another type of tachycardia that also corresponds to an abnormality of the heart's electrical system. It is called supraventricular paroxysmal tachycardia.
- Ventricular tachycardias: these are accelerated contractions of the ventricles of the heart related to a heart disease (various diseases). Ventricles are pumps used to send oxygen-rich blood throughout the body (left ventricle) or oxygen-poor blood to the lungs (right ventricle). The problem is that when the ventricles begin to beat much too quickly, the cavity of the ventricle does not have time to fill with blood. The ventricle no longer plays an effective pump role. There is then a risk of stopping the effectiveness of the heart so a deadly risk.
Ventricular tachycardia is therefore a cardiological emergency. Some cases are relatively mild and others extremely serious.
In the most severe cases, ventricular tachycardia may progress to ventricular fibrillation corresponding to desynchronized contractions of muscle fibers. Instead of contracting all at the same time at the level of the ventricles, the muscle fibers contract each a little at any time. The cardiac contraction then becomes ineffective for ejecting the blood, and this has the same effect as a cardiac arrest. Hence the gravity. Using a defibrillator can save the person.
- Atrial or atrial tachycardia: this is an acceleration of the contraction of part of the heart: the atria. The latter are small cavities, smaller than the ventricles, whose function is to eject the blood to the left ventricle for the left atrium and to the right ventricle for the right atrium. In general, the rate of these tachycardias is high (240 to 350), but the ventricles beat more slowly, often one time out of two compared to the atria, which remains very fast. The person may not be embarrassed in some cases, or collect it in other cases.
a. Dysuria
b. Leg cramps
c. Tachycardia
d. Blurred vision
Answer C.
Levothyroxine, a synthetic thyroid hormone, is given to a client with hypothyroidism to simulate the effects of thyroxine. Adverse effects of this agent include tachycardia. The other options aren’t associated with levothyroxine.
What is tachycardia?
We talk about tachycardia when, at rest, apart from physical exercise, the heart beats too quickly, at more than 100 beats per minute. A heart normally beats when it is between 60 and 90 beats per minute.
In case of tachycardia, the heart beats rapidly, and sometimes irregularly. This acceleration of the heartbeat may be permanent or transient. It can in some cases cause no sign. In other cases, it can cause dizziness, lightheadedness, palpitations, or even loss of consciousness. Tachycardia can range from a mild disorder to a very serious disorder that can lead to cardiac arrest.
There are several types of tachycardia:
- Sinus tachycardia: it is not due to a heart problem but to an adaptation of the heart to a particular circumstance. It is called sinus because the general rhythm of the heartbeat is determined by a specific location of this organ called the sinus node (area normally source of regular electrical pulses and adapted resulting in cardiac contractions). This sinus acceleration of the heart can be normal, as when it is related to physical exertion, lack of oxygen at altitude, stress, pregnancy (the heart is accelerating naturally at this time of life) or taking an exciting like coffee.
In the case of physical exercise for example, the heart accelerates to bring more oxygen to the muscles that work. It is therefore an adaptation. In the case of altitude, oxygen is more rare, the heart is accelerating to provide enough oxygen to the body despite its scarcity in the air.
But this sinus acceleration of the heart can be linked to an abnormal situation in which the heart adapts by accelerating its rhythm. This happens for example in case of fever, dehydration, intake of toxic substance (alcohol, cannabis, certain drugs or drugs), anemia or hyperthyroidism.
In the case of dehydration for example, the volume of liquid in the vessels being decreased, the heart accelerates to compensate. In the case of anemia, the lack of red blood cells causing a lack of oxygenation, the heart accelerates its pace to try to bring enough oxygen to all organs of the body. In the case of sinus tachycardia, quite often, the person does not realize that his heart beats quickly. This tachycardia can be discovered by the doctor.
Sinus tachycardia can also be related to a tired heart. If the heart fails to contract effectively enough, the sinus node requires it to contract more often to provide enough oxygen throughout the body.
- Tachycardia related to a heart problem: it is fortunately more rare than sinus tachycardia. The heart having an abnormality, it accelerates while the body does not need a beating heart faster.
- Tachycardia related to Bouveret's disease: it is relatively frequent (more than one in 450 people) and most often relatively benign. This is an anomaly in the electrical system of the heart. This anomaly leads at times to sudden tachycardia seizures for some time before stopping just as abruptly. The heart can then beat at over 200 per minute. This is embarrassing and often leads to discomfort to lie down for a while. Despite this anomaly, the hearts of these people are not sick and this problem does not diminish life expectancy.
Wolf-Parkinson White syndrome is another type of tachycardia that also corresponds to an abnormality of the heart's electrical system. It is called supraventricular paroxysmal tachycardia.
- Ventricular tachycardias: these are accelerated contractions of the ventricles of the heart related to a heart disease (various diseases). Ventricles are pumps used to send oxygen-rich blood throughout the body (left ventricle) or oxygen-poor blood to the lungs (right ventricle). The problem is that when the ventricles begin to beat much too quickly, the cavity of the ventricle does not have time to fill with blood. The ventricle no longer plays an effective pump role. There is then a risk of stopping the effectiveness of the heart so a deadly risk.
Ventricular tachycardia is therefore a cardiological emergency. Some cases are relatively mild and others extremely serious.
In the most severe cases, ventricular tachycardia may progress to ventricular fibrillation corresponding to desynchronized contractions of muscle fibers. Instead of contracting all at the same time at the level of the ventricles, the muscle fibers contract each a little at any time. The cardiac contraction then becomes ineffective for ejecting the blood, and this has the same effect as a cardiac arrest. Hence the gravity. Using a defibrillator can save the person.
- Atrial or atrial tachycardia: this is an acceleration of the contraction of part of the heart: the atria. The latter are small cavities, smaller than the ventricles, whose function is to eject the blood to the left ventricle for the left atrium and to the right ventricle for the right atrium. In general, the rate of these tachycardias is high (240 to 350), but the ventricles beat more slowly, often one time out of two compared to the atria, which remains very fast. The person may not be embarrassed in some cases, or collect it in other cases.
How does the heart rate vary?
The heart rate varies according to the oxygen needs of the body. The more oxygen the body needs, the faster the heart beats, to further circulate the red blood cells, our oxygen carriers. Thus, during a physical exercise, our muscles needing more oxygen, the heart accelerates. The acceleration of the heart rate is not the only adaptation of our heart, it can also beat stronger, that is to say, contract in a more powerful way.
The rhythm of the heartbeat is also determined by the very functioning of the heart. It can, in some heart diseases, exist misfires in the way of the heart to determine its rhythm.
Postural orthostatic tachycardia syndrome (STOP):
People with this STOP have difficulty going from lying posture to vertical posture. During this change of position, the heart accelerates excessively. This increase in heart rate is often accompanied by a headache, feeling sick, tired, nauseated, sweating, discomfort in the chest and sometimes even fainting. This problem may be related to certain diseases, such as diabetes, or taking certain medications. It is treated with a good supply of water and mineral salts, a physical training program of the legs to improve the return of venous blood to the heart, and possibly medications such as corticosteroids, beta-blockers or other treatments.
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Endocrine Disorders