Euthyroid sick syndrome

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
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Euthyroid sick syndrome
Synonyms	Non-thyroidal illness syndrome
Pronounce	N/A
Specialty	N/A
Symptoms	Altered thyroid hormone levels without intrinsic thyroid disease
Complications	Potential misdiagnosis of hypothyroidism or hyperthyroidism
Onset	During acute or chronic illness
Duration	Temporary, resolves with recovery from illness
Types	N/A
Causes	Severe illness, starvation, major surgery, trauma
Risks	Hospitalized patients, especially in intensive care units
Diagnosis	Abnormal thyroid function tests in the context of illness
Differential diagnosis	Hypothyroidism, hyperthyroidism, thyroiditis
Prevention	N/A
Treatment	Generally none, treat underlying illness
Medication	N/A
Prognosis	Good, resolves with recovery from illness
Frequency	Common in hospitalized patients
Deaths	N/A

Euthyroid sick syndrome (ESS), also known as non-thyroidal illness syndrome (NTIS), is a condition characterized by abnormal thyroid hormone levels in the absence of thyroid illness. It is commonly observed in patients with severe illnesses such as starvation, sepsis, and surgery.

Etiology

The exact cause of ESS is unknown, but it is believed to be a result of the body's response to severe illness or stress. The body may reduce the levels of thyroid hormones in the blood in an attempt to conserve energy and resources. This is often seen in patients with critical illnesses, severe infections, or those undergoing major surgery.

Clinical Features

Patients with ESS typically present with low levels of triiodothyronine (T3) and thyroxine (T4) in the blood, despite having a normal or low thyroid-stimulating hormone (TSH) level. This is often accompanied by non-specific symptoms such as fatigue, weight loss, and cold intolerance.

Diagnosis

Diagnosis of ESS is primarily based on laboratory findings. A low serum T3 level is the most common finding, followed by a low T4 level. However, the TSH level is usually normal or slightly decreased. Other tests, such as the reverse T3 test, may also be used to confirm the diagnosis.

Treatment

Treatment of ESS primarily involves addressing the underlying illness or condition. Once the underlying condition is treated, the thyroid hormone levels usually return to normal. In some cases, thyroid hormone replacement therapy may be necessary.

Prognosis

The prognosis of ESS depends on the severity of the underlying illness. In most cases, the thyroid hormone levels return to normal once the underlying condition is resolved. However, in severe cases, ESS can lead to complications such as myxedema coma, which is a life-threatening condition.

Gallery

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  Thyroid system
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  Symptoms of lost appetite

See Also

• Thyroid
• Thyroid hormones
• Thyroid function tests
• Myxedema coma