Management of emergencies. IX. Thyrotoxic storm

The Pharmacotherapy of Thyroid Storm

A review of thyrotoxic storm is presented. Included are causes, symptomatology, and mortality rates. Special emphasis is placed on the strong correlation between adrenergic blockade and success rates in treating thyrotoxic storm. Pharmacotherapy of the acute storm patient is discussed in detail with respect to agents that (1) decrease production of thyroid hormones; (2) block release of preformed thyroid hormones from the gland; (3) blunt the effects of excess thyroid hormones on the various target organs (e.g., CNS and heart); and (4) serve to decrease the metabolic strain on all organ systems caused by thyrotoxic storm.

Modulation of central glucocorticoid receptors in short- and long-term experimental hyperthyroidism

Hyperthyroidism is associated with a significant increase in circulating glucocorticoid levels and hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. The aim of this study was to examine whether the HPA axis hyperactivity observed in hyperthyroidism may be explained by a disturbed feedback inhibition of endogenous glucocorticoids through two specific intracellular receptors in the brain: the high affinity mineralocorticoid receptor (MR) and the lower affinity glucocorticoid receptor (GR). Cytosolic receptor binding and gene expression was assessed in rats with short (7 days) and long standing (60 days) eu- and hyperthyroidism. Glucocorticoid receptor number and binding affinity (Kd) in the hippocampus were measured using [(3)H2]-dexamethasone radioreceptor assay. In situ hybridization was employed to examine the effects of hyperthyroidism on the GR and MR mRNA levels in the hippocampus and the pituitary. Both short- and long-term hyperthyroid rats showed pronounced reduction in the concentration of cytosolic GR in the hippocampus, without changes in binding affinity or changes in GR expression. In contrast, GR mRNA in the pituitary increased after 7 days and decreased after 60 days of thyroxin treatment. MR mRNA was moderately affected. Hyperthyroidism is associated with significant decreases in hippocampal GR levels supporting the hypothesis that hyperactivity of the HPA axis observed in experimentally induced hyperthyroidism may be attributed, at least in part, to decreased negative feedback at the level of the hippocampus. These findings further support the notion that a central locus is principally responsible for the hyperactivity of the HPA axis observed in hyperthyroidism.

Effects of experimentally induced hyperthyroidism on central hypothalamic-pituitary-adrenal axis function in rats: in vitro and in situ studies

Hyperthyroidism is associated with hypercorticosteronemia, although the locus that is principally responsible for the hypercorticosteronism remains unclear. The purpose of this study was to assess the effects of hyperthyroidism on the functional integrity of the hypothalamic-pituitary-adrenal (HPA) axis, to identify the locus in the HPA axis that is principally affected, and address the time-dependent effects of alterations in thyroid status. The functional integrity of each component of the HPA axis was examined in vitro and in situ in sham-thyroidectomized male Sprague-Dawley rats given placebo or in thyroidectomized rats given pharmacological dose (50 μg) of thyroxin for 7 or 60 days. Basal plasma corticosterone and corticosterone binding globulin (CBG) concentrations were significantly increased in short- and long-term hyperthyroid rats, and by 60 days. Basal plasma ACTH levels were similar to controls. Both hypothalamic CRH content and the magnitude of KCL- and arginine vasopressin (AVP)-induced CRH release from hypothalamic culture were increased in long-term hyperthyroid rats. There was a significant increase in the content of both ACTH and β-endorphin in the anterior pituitaries of both short- and long-term hyperthyroid animals. Short-term hyperthyroid rats showed a significant increase in basal POMC mRNA expression in the anterior pituitary, and chronically hyperthyroid animals showed increased stress-induced POMC mRNA expression. Adrenal cultures taken from short-term hyperthyroid rats responded to exogenous ACTH with an exaggerated corticosterone response, while those taken from 60-day hyperthyroid animals showed responses similar to controls. The findings show that hyperthyroidism is associated with hypercorticosteronemia and HPA axis dysfunction that becomes more pronounced as the duration of hyperthyroidism increases. The evidence suggests that experimentally induced hyperthyroidism is associated with central hyperactivity of the HPA axis.

Effects of short- and long-duration hypothyroidism on function of the rat hypothalamic-pituitary-adrenal axis

The effects of hypothyroidism on the functional integrity of the hypothalamic-pituitary-adrenal (HPA) axis were investigated in adult male rats. HPA axis function was examined in vivo in sham-thyroidectomized male Sprague-Dawley rats or in thyroidectomized rats for 7 (short-term hypothyroidism) or 60 (long-term hypothyroidism) days. Peripheral ACTH and corticosterone responses to insulin-induced hypoglycemia and interleukin (IL)-1α stimulation were used to indirectly assess the hypothalamic CRH neuron. Hypothyroidism resulted in exaggerated ACTH responses to both hypoglycemic stress and IL-1α administration. The adrenal cortex of hypothyroid animals showed a significant reduction in adrenal reserves, as assessed by its response to low-dose ACTH, following suppression of the HPA axis with dexamethasone. Hypothyroid rats were also associated with significant decreases in cerebrospinal fluid corticosterone concentrations and decreased adrenal weights. The findings suggest that experimentally induced hypothyroidism is associated with a mild, yet significant, adrenal insufficiency, which involves abnormalities in all components of the HPA axis.

Adrenal function in cats with hyperthyroidism

Adrenal function may be altered in animals with hyperthyroidism. The aim of the study was to assess adrenal function of hyperthyroid cats (n = 17) compared to healthy cats (n = 18) and cats with chronic diseases (n = 18). Adrenal function was evaluated by adrenocorticotropic hormone (ACTH) stimulation test and the urinary cortisol to creatinine ratio (UCCR) was determined. Length and width of both adrenal glands were measured via ultrasound. Hyperthyroid cats had significantly higher cortisol levels before and after stimulation with ACTH than the other groups. However, the UCCR was not elevated in hyperthyroid cats. The size of the adrenal glands of hyperthyroid cats was not significantly different from the size of those of healthy cats. The results indicate that cats with hyperthyroidism have a higher cortisol secretory capacity in a hospital setting. The normal size of the adrenal glands suggests that cortisol levels may not be increased permanently.

[A case of thyroid crisis in acute tonsillitis treatment]

We report a case of fatal thyroid crisis induced by acute tonsillitis. A 33-year-old woman with untreated hyperthyroidism developed thyroid crisis during acute tonsillitis treatment. The four days passing from crisis onset to treatment initiation unduly compromised her condition, resulting in death. Such cases point up the need for prompt thyroid crisis diagnosis and treatment, the difference between a proactive life-sustaining response and a negative mortal result.

Atrial fibrillation from thyroid storm

BACKGROUND

Thyroid storm is an often-discussed but rare presentation to emergency departments (EDs). The clinical presentation of a thyroid storm is the result of a hyperthyroid state that may result in significant morbidity or disability, or even death. Typically, patients are aware of their hyperthyroid condition, and may be able to recognize an episode of thyroid storm. However, the first presentation of hyperthyroidism could, in fact, be from thyrotoxic crisis.

OBJECTIVES

To review the presentation of thyroid storm, including tachycardia, hyperpyrexia, agitation, and altered mental status, which can be easily misdiagnosed as drug intoxication.

CASE REPORT

We present the case of an otherwise healthy young adult who was sent to the ED by an outpatient care provider for generalized and vague symptoms of "feeling unwell" that was eventually diagnosed in the ED as thyrotoxic crisis.

CONCLUSION

We use this case to emphasize that thyrotoxic crisis should be at least considered in the differential diagnosis of a patient with this presentation, and to highlight how, even with apparently usual and effective treatments, a patient may still decompensate.

Thyroid storm

Despite earlier recognition and treatment of hyperthyroidism, thyroid storm remains a life-threatening, although fortunately rare, medical emergency. Prompt recognition and aggressive treatment employing a multifaceted approach are generally effective at correcting the homeostatic decompensation that is the hallmark of thyroid storm. Research is furthering understanding of the cellular actions of thyroid hormone and may lead to additional, even more effective treatment modalities in the future.

Thyroid emergencies

Thyroid storm is a rapid decompensation of severe hyperthyroidism which can best be described by the three criteria of hyperthermia, tachycardia and altered mental state with severe agitation. There has to be a precipitating factor such as infection, iodine contamination, surgery or even I-131 treatment. Severe hyperthyroidism not fulfilling the criteria of thyroid storm can also be an indication for emergency treatment, particularly in the elderly with heart disease. Suppressed serum TSH and elevated free T4 levels are essential to confirm the diagnosis. When rapidly available, radioiodine uptake of the thyroid can be useful. Therapy aims at rapidly reducing the active circulating hormone pool, hypermetabolic state, tachycardia, and finally hormone synthesis. Thyroid secretion can be blocked by ioipanoic acid or ipodate while hypermetabolic state can be reduced with beta-blockers or calcium channel-blockers. Treatment of hyperthyroidism in patients with iodine contamination is a real therapeutic challenge. Myxoedema coma, a complication of severe hypothyroidism, is defined by hypothermia (rectal temperature less than 36 degrees C), bradycardia, slow mentation, precipitating factor such as infection or drug overdose, and increased serum creatine phosphokinase levels. Diagnosis of severe hypothyroidism should be confirmed by serum measurements of TSH and free T4. Treatment consists of general supporting measures including rewarming, correction of serum electrolyte disturbances, and adequate alimentation. Thyroid hormone treatment should initially be aggressive using either 300-400 micrograms of T4 or 20-40 micrograms of T3 intravenously. Cortisone therapy may be added. Patients should be under close monitoring as arrhythmias and myocardial infarction are frequent complications of myxoedema coma and/or its treatment with thyroid hormones.

Psychotic states associated with disorders of thyroid function

Thyroid-related psychoses continue to pose diagnostic and treatment challenges for clinicians. Two case histories illustrate diverse clinical states associated with hyper- and hypo-thyroidism respectively and highlight the need to consider the possibility of thyroid disorder in all patients presenting with acute psychotic mental disorder. They also demonstrate treatment methods directed at control of psychotic symptoms and restoration of an euthyroid state.

Antepartal nursing management of Grave's disease

The signs and symptoms of Grave's disease may be difficult to distinguish from the normal thyroid changes that occur in pregnancy. A brief review of thyroid physiology, thyroid changes during pregnancy, the effect of Grave's disease during pregnancy on the woman and fetus, and an assessment tool for use during the antepartal period is presented. Recommendations of specific areas of need seen in the pregnant Grave's patient during the antepartal period are also outlined.

Thyroid storm and myxedema coma

This article describes the clinical recognition of, and pathophysiological mechanisms underlying the development of, thyroid storm and myxedema coma. Effective therapeutic management of these conditions depends on a clear understanding of the physiological adaptations occurring in hyperthyroidism and hypothyroidism, and of how precipitating events may produce these decompensated states.

Thyroid storm during beta blockade

A thyrotoxic patient who had received beta-adrenoceptor blockers pre-operatively suffered an episode of severe heart failure immediately following thyroidectomy and required artificial ventilation of the lungs for six hours. The possible causes are discussed and the likelihood of thyroid storm unmitigated by beta adrenergic blockade suggested.

Thyrotoxic crisis following eclampsia and induction of labour

A patient was diagnosed to be thyrotoxic and commenced on medications, but it was not known that she was 13 weeks pregnant at the time. She failed to take the medications and presented at 25 weeks with eclampsia and thyrotoxic crisis. Her management is discussed.

Schizophrenia-like psychosis in thyroid crisis

Very few cases of thyrotoxic psychoses have been reported during the last twenty years. Recent authoritative reviews on the management of thyrotoxicosis and its complications (Ingbar, 1966; Trotter, 1967) scarcely mention psychotic reactions. It seems that such conditions have become increasingly rare since the advent of modern anti-thyroid treatment. The present report attempts to summarize what is known about these disorders, and describes the clinical features, treatment and subsequent course of a schizophrenia-like psychosis which developed during thyroid crisis.