Thyroid storm Thyrotoxic crisis

Mansoura faculty of medicine

Clinical pharmacology department

Hyperthyroidism

is a condition in which the thyroid gland produces and secretes excessive

amounts of the free (not protein bound circulating in the blood[1]) thyroid

hormones -triiodothyronine (T3) and/or thyroxine (T4)

causes Graves’ disease

Viral infection-------------------lead to sub acute thyroiditis (de quervain )

Neoplasms –like functioning thyroid adenomas autonomously functioning toxic nodules and toxic, multi nodular goiters (TMNGs)

from taking too much thyroid medication. In these cases the thyroid gland itself is not overactive, but there is still too much thyroid hormone in the blood. Untreated, thyrotoxicosis can lead to serious medical complications such as heart rhythm disturbances and Osteoporosis, caused from the long-term effects of hormone overproduction.

Another condition, called subclinical hyperthyroidism, may be diagnosed when you have low levels of thyroid stimulating hormone (TSH) but normal levels of thyroid hormone. Your doctor may treat asymptomatic (without symptoms) subclinical hyperthyroidism to avoid future symptoms.

Graves disease

the most common cause of

hyperthyroidism

It’s autoimmune disease in which

there are abnormal antibodies

(thyroid stimulating

immunoglobulins) activates TSH

receptors

The gland is enlarged and soft

Signs and Symptoms of hyperthyroidism

-hair loss

-Irritability

-Fatigue

-Fast heartbeat

-Weight loss

-insomnia

-Hair loss

-Intolerance to heat

-Increased perspiration

-Muscle aches

-Weakness in upper arms and thighs

-Increased bowel movements

-Decreased menstrual flow

Thyrotoxic crisis

Exaggerated or florid state of thyrotoxicosis"

"Life threatening, sudden onset of thyroid hyperactivity"

May represent end stage of a continuum :

– Thyroid hyperactivity to thyrotoxicosis to Thyrotoxic crisis to thyroid storm

"Probably reflects the addition of adrenergic hyperactivity, induced by a nonspecific stress, into the setting of untreated or undertreated hyperthyroidism"

Relation () hyperthyroidism and

thyrotoxicosis

Hyperthyroidism is a type of thyrotoxicosis in which accelerated thyroid

hormone biosynthesis and secretion by the thyroid gland produce

thyrotoxicosis. However, hyperthyroidism and thyrotoxicosis are not

synonymous This is because, although many patients have thyrotoxicosis

caused by hyperthyroidism, other patients may have thyrotoxicosis resulting

from inflammation of the thyroid gland, which causes the release of stored

thyroid hormone but not accelerated synthesis, or they may have

thyrotoxicosis, which is caused by ingestion of exogenous thyroid hormone.

Differentiating between thyrotoxicosis caused by hyperthyroidism and

thyrotoxicosis not caused by hyperthyroidism is important, because disease

management and therapy differ for each form.

Thyroid Storm

Background Etiology

Most cases secondary to Graves' disease

Some due to toxic multinodular goiter

Rare causes :

Acute thyroiditis

Factitious

Malignancies (most do not efficiently produce thyroid hormones)

Very rare in children

Manifestation

Patients may have a known history of thyrotoxicosis. In the absence of previously diagnosed thyrotoxicosis, the history may include symptoms such as irritability, agitation, emotional liability, a voracious appetite with poor weight gain, excessive sweating and heat intolerance, and poor school performance caused by decreased attention span.

General symptoms

GIT

Neurologic

Cardiac

General symptoms

Fever

Profuse sweating

Poor feeding and weight loss

Respiratory distress

Fatigue (more common in older adolescents)

GIT symptoms Neurological symptoms

Nausea and vomiting

Diarrhea

Abdominal pain

Jaundice[3]

Anxiety (more common in

older adolescents)

Altered behavior

Seizures, coma

Cardiac symptoms

Hypertension with wide pulse pressure

Hypotension in later stages with shock

Tachycardia disproportionate to fever

Signs of high-output heart failure

Cardiac arrhythmia (Supraventricular arrhythmias are

more common, [eg, atrial flutter and fibrillation], but

ventricular tachycardia may also occur.)

causes

Thyroid storm is precipitated by the following factors in individuals with thyrotoxicosis:

Sepsis

Surgery

Anesthesia induction[5]

Radioactive iodine (RAI) therapy[6]

Drugs (anticholinergic and adrenergic drugs such as pseudoephedrine; salicylates; nonsteroidal anti-inflammatory drugs [NSAIDs]; chemotherapy[7] ) and iodinated contrast agents[8]

Excessive thyroid hormone (TH) ingestion

Withdrawal of or noncompliance with antithyroid medications

Diabetic ketoacidosis

Direct trauma to the thyroid gland

Vigorous palpation of an enlarged thyroid

Toxemia of pregnancy and labor in older adolescents; molar pregnancy

Thyroid storm in children

Thyroid storm can occur in children with thyrotoxicosis due to any cause but

is most commonly associated with Graves disease. Other reported causes of

thyrotoxicosis associated with thyroid storm include the following:

Trans placental passage of maternal thyroid-stimulating immunoglobulins in

neonates

McCune-Albright syndrome with autonomous thyroid function[9]

Hyper functioning thyroid nodule

Hyper functioning multinodular goiter

Thyroid-stimulating hormone (TSH)–secreting tumor

With down syndrome and turner syndrome

Laboratory Studies

Thyroid storm diagnosis is based on clinical features, not on laboratory test

findings. If the patient's clinical picture is consistent with thyroid storm, do not

delay treatment pending laboratory confirmation of thyrotoxicosis.

Thyroid studies :Results of thyroid studies are usually consistent with

hyperthyroidism and are useful only if the patient has not been previously

diagnosed.

CBC count: CBC count reveals mild leukocytosis, with a shift to the left.

Liver function tests (LFTs): LFTs commonly reveal nonspecific abnormalities such

as elevated levels of alanine aminotransferase (ALT), aspartate aminotransferase

(AST),

ABG and urinalysis: Measurement of blood gas and electrolyte levels and

urinalysis testing may be performed to assess and monitor short-term

management.

Imaging Studies

The following imaging studies may be indicated:

Chest radiography: Chest radiography may reveal cardiac enlargement due to congestive

heart failure……Radiography may also reveal pulmonary edema caused by heart failure

and/or evidence of pulmonary infection.

CT scanning: Head CT scanning may be necessary to exclude other neurologic conditions if

diagnosis is uncertain after the initial stabilization of a patient who presents with altered

mental status.

ECG is useful in monitoring for cardiac arrhythmias. Atrial fibrillation is the most common

cardiac arrhythmia associated with thyroid storm. Other arrhythmias such as atrial flutter

and, less commonly, ventricular tachycardia may also occur.

Treatment

Medical Care

immediately provide supplemental oxygen, ventilatory support, and intravenous fluids. Dextrose solutions are the preferred intravenous fluids to cope with continuously high metabolic demand.

Aggressively control hyperthermia

antiadrenergic drugs (e.g., propranolol) to minimize sympathomimetic symptoms.

Administer antithyroid medications to block further synthesis of thyroid hormones (THs).

Administer iodine compounds (Lugol iodine or potassium iodide) orally or via a nasogastric tube to block the release of THs (at least 1 h after starting antithyroid drug therapy). If available, intravenous radiocontrast dyes such as ipodate and iopanoate can be effective in this regard. These agents are particularly effective at preventing peripheral conversion of T4 to T3.

Medical care

Administer glucocorticoids (hydrocortisone ) 50mg i.v /6h to decrease

peripheral conversion of T4 to T3. This may also be useful in preventing

relative adrenal insufficiency due to hyperthyroidism.

Treat the underlying condition, if any, that precipitated thyroid storm and

exclude comorbidities such as diabetic ketoacidosis and adrenal insufficiency.

Infection should be treated with antibiotics.

Rarely, as a life-saving measure, plasma pheresis has been used to treat thyroid

storm in adults.

Iodine preparations should be discontinued once the acute phase resolves and

the patient becomes afebrile with normalization of cardiac and neurological

status. Glucocorticoids should be weaned and stopped and the dose of

thioamides adjusted to maintain thyroid function in the normal range. Beta-

blockers may be discontinued once thyroid function normalizes.

Medical care

High-dose propylthiouracil (PTU) is preferred because of its early

onset of action and capacity to inhibit peripheral conversion of T4 to

T3. The US Food and Drug Administration (FDA) had added a boxed

warning, the strongest warning issued by the FDA, to the prescribing

information for PTU.

If the patient is given PTU during treatment of thyroid storm, this

should be switched to methimazole at the time of discharge unless

methimazole is contraindicated. If there is a contraindication for the

use of methimazole, alternative methods to treat hyperthyroidism

should be considered after discharge, such as radioactive iodine or

surgery

Surgical Care

Patients with Graves disease who need urgent treatment of hyperthyroidism

but have absolute contraindications to thioamides may be managed acutely

with beta-blockers, iodine preparations, and glucocorticoids as described.

Subsequently, thyroidectomy may be performed after about 7 days of iodine

administration. Iodine reduces the vascularity of the gland and the risk for

thyroid storm.