myxedema

Generality

The myxedema is a particular form of subcutaneous edema, which occurs following the accumulation of mucopolysaccharides in the dermis.

The main cause of myxedema is severe hypothyroidism, which is the condition in which the thyroid is unable to synthesize a quantity of thyroid hormones adequate to the needs of the human body.

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The presence of myxedema is characterized by several symptoms and signs, including: exophthalmos, swelling of the legs, thickening of the skin, recurrent tiredness, dry skin, mood alterations, muscle cramps, loss of sexual desire, hypertension, bradycardia, etc.

Failure to treat myxedema can have unpleasant consequences, ranging from hypothermia and slow breathing to lack of response and coma (mixed hematoma).

For a diagnosis of myxedema the physical examination, the anamnesis, the blood tests and some specific laboratory tests are fundamental.

Accurate diagnosis makes it possible to identify the precise causes. Knowledge of the cause is essential for the most appropriate treatment planning.

The prognosis depends on the treatability of the causes and the timeliness of the diagnosis.

What is myxedema?

The myxedema is an edema with subcutaneous site, typical of severe hypothyroidism and some forms of hyperthyroidism, which occurs due to the accumulation of mucopolysaccharides in the dermis .

OTHER USES OF THE MIXEDEMA TERM

In the medical field, the term mixedema is also a synonym of severe hypothyroidism .

This is due to the high frequency of appearance of the myxedema, in people suffering from severe hypothyroidism.

ORIGIN OF THE NAME

The word "myxedema" comes from the union of two Greek terms, which are: " myxa " ( μύξα ) and " oidema " ( οἴδημα ). The term "myxa" means "mucus" or "slimy substance", while the term "oidema" means "swelling". Thus, the literal meaning of "myxedema" is "mucus swelling" or "mucous swelling".

Epidemiology

Among people with hypothyroidism, myxedema is more frequent in those who do not follow adequate therapy, in women and in elderly people.

Causes

The main cause of myxedema is hypothyroidism.

However, myxedema may also occur due to some forms of hyperthyroidism, such as the so-called Graves' disease .

According to some statistical surveys, about 5 people out of 100 with Graves' disease (hence 5%) develop myxedema.

WHAT IS HYPOTHYROIDISM?

Doctors speak of hypothyroidism, when the thyroid gland is unable to synthesize a quantity of thyroid hormones adequate to the needs of the entire body. In other words, those suffering from hypothyroidism have a poorly productive thyroid.

There are at least 4 different forms of hypothyroidism: primitive hypothyroidism, secondary hypothyroidism, tertiary hypothyroidism and iatrogenic hypothyroidism .

Primitive hypothyroidism. It means that hypothyroidism results from a specific thyroid dysfunction. The main causes of primitive hypothyroidism are: autoimmune thyroid diseases (eg Hashimoto's thyroiditis ), iodine deficiency following a diet poor in this mineral and partial or total removal of the thyroid gland (for example, for the treatment of a thyroid tumor).
Secondary hypothyroidism. All hypothyroidisms following a pituitary and pituitary hormone (TSH) malfunction are secondary
A pituitary malfunction can be caused by pituitary neoplasms (pituitary adenomas) or lesions affecting the pituitary structure (post-traumatic lesions, post-aneurysm, post-radiotherapy, etc.).
Tertiary hypothyroidism. All hyperthyroidisms following a malfunction of the hypothalamus and the hypothalamic hormonal system (TRH) are tertiary.
Hypothalamus malfunction can be caused by hypothalamus or lesions affecting the hypothalamic structure.
Iatrogenic hypothyroidism. It is hypothyroidism due to incorrect medical treatment. Generally iatrogenic hypothyroidism arises due to excessive doses of antithyroid drugs, administered for the treatment of hyperthyroidism.

WHAT IS HYPERTIROIDISM?

Although hyperthyroidism is a remote cause of myxedema, it is good to briefly review what it is.

Doctors talk about hyperthyroidism when the thyroid gland produces more thyroid hormones than the body needs. In other words, those who suffer from hyperthyroidism have a thyroid that synthesizes more thyroid hormones than those who would actually serve.

As for hypothyroidism, there are at least 4 different forms of hyperthyroidism: primitive hyperthyroidism, secondary hyperthyroidism, tertiary hyperthyroidism and iatrogenic hyperthyroidism .

Primitive hyperthyroidism. It means that hyperthyroidism depends on specific thyroid dysfunction. An example of primitive hyperthyroidism is Graves' disease, also known as Basedow's disease .
Secondary hyperthyroidism. The hyperthyroidisms that arise as a result of an overproduction of TSH by the pituitary gland are secondary. In general, hyper production of TSH by the pituitary gland is a typical consequence of pituitary tumors.
Tertiary hyperthyroidism. Hyperthyroidisms dependent on hyperproduction of TRH by the hypothalamus are tertiary.
Iatrogenic hyperthyroidism. It is hyperthyroidism due to incorrect medical treatment. In general, iatrogenic hyperthyroidism appears due to excessive doses of thyroid hormones, administered to treat hypothyroidism.

MIXEDEMA RISK FACTORS

Risk factors for myxedema include: a clinical history of hypothyroidism, belonging to the female sex, advanced age, surgical removal of the thyroid and the presence of autoimmune diseases.

Symptoms, signs and complications

The characteristic clinical sign of myxedema is swelling where the accumulation of mucopolysaccharides has taken place.

The anatomic sites where the appearance of myxedema is more frequent are the anterior portion of the legs and the eyes .

The myxedema located in the front of the legs leads to the appearance of a condition that doctors call pretibial myxedema .

The myxedema in the eye, on the other hand, determines a condition known as exophthalmos .

What is exophthalmos?

Exophthalmos is the pathological protrusion of one or both eye globes towards the outside of their orbits.

The presence of exophthalmos is generally associated with endocrine diseases.

HYPOTHYROIDISM AND MIXEDEMA

An individual with severe hypothyroidism and myxedema manifests different symptoms and signs, including:

Skin thickening;
Recurrent fatigue;
Weight gain;
Mood changes;
Dry skin;
Brittle hair;
Hair thinning;
Changes in sexual regularity (in women);
Decline in sexual desire;
Muscle cramps;
Pain in the bones and muscles;
Hypertension;
bradycardia;
Word slowdown.

COMPLICATIONS

Failure to treat myema and what causes it (hypothyroidism in general) can lead to various complications - including slowed breathing, chest pain, low body temperature, hypoglycemia or lack of response - to induce coma ( mixed hematoma ).

Hematrous coma represents a serious loss of brain function and requires immediate medical intervention, as the life of the person concerned is in serious danger.

Epidemiology of mixedematous coma

Fortunately, mixed hematoma coma is a rare complication .

Typically, it affects severely hypothyroid older patients and severely hypothyroid female patients.

In addition to the failure to treat hypothyroidism, the risk factors for mixed hematoma include: the winter season, infections, stroke, hypothermia, taking certain medications (eg sedatives, narcotics, anesthetics, etc.), heart failure and episodes of gastrointestinal bleeding.

Diagnosis

For a diagnosis of myxedema, doctors generally resort to a thorough physical examination, a careful medical history, laboratory tests and blood tests .

LABORATORY TESTS AND BLOOD ANALYSIS

Laboratory tests and blood tests are used to measure thyroid hormones and all those parameters that, in the presence of myxedema, are altered in a characteristic manner (eg high cholesterol levels).

IMPORTANCE OF ACCURATE DIAGNOSIS OF CAUSES

A very important aspect of the diagnosis of myxedema is the precise identification of the cause and the characteristics of the latter. For example, in the case of severe hypothyroidism, it is very important to understand where it originated from (if it depends on an autoimmune disease, if it is a secondary hypothyroidism, if it is a tertiary hypothyroidism, etc.).

Therapy

Treatment of myxedema requires adequate treatment of its triggering cause ( causal therapy ) and, when possible, symptomatic therapy against swelling.

MIXEDEMA TREATMENT DUE TO HYPOTHYROIDISM

If hypothyroidism is the cause of myxedema, the treatment consists in treating what reduces the function of the thyroid, where there is the possibility, and in the administration of synthetic thyroid hormones (eg: levothyroxine), in order to remedy the reduced functionality of the thyroid gland.

The administration of synthetic thyroid hormones is an example of hormone replacement therapy .

Hormone replacement therapies must be appropriate to the patient's needs, as:

Excessive intake of synthetic thyroid hormones can lead to hypothyroidism

while:

An insufficient dose of synthetic thyroid hormones may not have the benefits hoped for and let the myxedema persist.

To know in detail the treatment of hypothyroidism, readers can consult the article present here.

REMEDY AGAINST THE GONFIORE BY PRETIBIAL EDEMA

In the case of pretibial myxedema, a useful remedy to accelerate the disappearance of swelling - which in any case depends in the first instance on causal therapy - is to use compression stockings.