Thyroid Storm and the AACN Synergy Model
Submitted by Deborah L. Bray, RN, BSN, CNS
At the time of this writing, Deborah L. Bray, RN, BSN, CNS was a graduate nursing student at Murray State University.
In the Eye of the Storm: Recognizing Thyroid Storm and Applying the AACN Synergy Model
Thyroid storm, or thyrotoxic crisis is a rare, but critical hypermetabolic state requiring emergent treatment. According to Dahlen (2002), the disease state results from the overproduction and release of thyroid hormones triiodothyronine (T3) and thryroxine (T4) which increases cellular function systemically. Thyroid storm occurs most often from Grave’s disease either undiagnosed or undertreated (Kaplow & Hardin, 2007). Other precipitants of thyroid storm can include pregnancy, surgery, trauma, induction of anesthesia, diabetic ketoacidosis, infection, myocardial infarction, and noncompliance with anti-thyroid medications (Belfort, 2006). Only 1-2% of persons with hyperthyroidism will develop thyroid storm; however, the mortality rate can be as high as 50-90% if left untreated (Dulak, 2005). Nurses should be aware of the signs and symptoms of thyroid storm, so that prompt intervention may occur and mortality be decreased.
The American Association of Critical Care Nurses (AACN) Synergy Model provides a framework for nursing practice. The model links patient characteristics with nursing competencies to provide optimal patient outcomes (Curley, 1998). According to Curley (1998), when patient characteristics match nursing skill sets, synergy occurs moving the patient and nurse more successfully toward a common goal. The purpose of this article is to discuss and apply the Synergy Model in the complex patient experiencing thyroid storm. A case study will illustrate how to match patient characteristics during thyroid storm with nurse competencies for the best patient outcomes.
Pathophysiology of Hyperthyroidism
In order to understand the disease state of thyroid storm, one must understand the physiology of the thyroid gland and hyperthyroidism. The thyroid hormones orchestrate the regulation of metabolism within nearly all areas of the body. The thyroid gland is regulated by a negative feedback system. The hypothalamus secretes thyrotropic releasing hormone (TRH) which stimulates the anterior pituitary to release thyroid stimulating hormone (TSH) into the circulation. TSH in turn activates the thyroid gland to produce and release the thyroid hormones T3 and T4. Iodine is also required to produce thyroid hormone. T4 is produced entirely by the thyroid gland while 80% of T3 is produced in the peripheral tissues by the conversion of T4 to T3. The levels of thyroid hormone (T3 and T4) in the circulation provide negative feedback to the hypothalamus and the anterior pituitary to inhibit further TRH and TSH release (Andreoli, Carpenter, Griggs & Benjamin, 2007; Kumrow & Dahlen, 2002).
Hyperthyroidism is a result of excess circulating thyroid hormone. Hyperthyroidism occurs most often in young women and is evidenced by an increase in cellular metabolism which may be manifested by weight loss, palpitations, nervousness, loose stools, heat intolerance, hair loss, and insomnia. (Gittoes & Franklin, 1998; Kumrow & Dahlen, 2002). The most severe expression of hyperthyroidism is thyrotoxocosis, otherwise known as thyroid storm, which can be precipitated by various events as discussed earlier. Signs and symptoms of thyroid storm include hypermetabolism with high fever and sweating; cardiovascular symptoms including tachycardia, atrial fibrillation, or congestive heart failure; neurological symptoms such as agitation, tremor, and mental status change; gastrointestinal symptoms with diarrhea, nausea, and vomiting; supporting laboratory evidence such as a low TSH, high free T4 and or high T3. (Belfort, 2006; Kaplow & Hardin, 2007).
The thyroid hormones, T3 and T4, are bound to plasma protein in the circulation. The unbound or free thyroid hormones actually regulate the negative feedback system; therefore, evaluating the free hormone levels is important as well as evaluating the total hormone levels. Normal thyroid function test values include the following and may vary slightly in different laboratories: total thyroxine (T4) 4.5-12.0 µg/dl, free T4 0.7-1.9 ng/dl, total triiodothyronine (T3) 80-180ng/dl, free T3 230-619 pg/dl, and thyroid stimulating hormone (TSH) 0.5-6 µU/ml (Kumrow & Dahlen, 2002).
Rachel is a 22 year old white female found by her roommate to be confused, agitated, diaphoretic, and incontinent of diarrhea stool. The patient was brought by her roommate to a local hospital emergency room for evaluation. The roommate states she is concerned her friend has the flu because she has had fever, nausea, diarrhea, and diaphoresis for the past 24 hours. Rachel had no known prior medical problems.
On arrival to the hospital, Rachel’s vital signs are: temperature 104.5° F, blood pressure 144/68, pulse 158, and respiratory rate of 32. The cardiac monitor shows sinus tachycardia and oxygen saturation is 96%. The patient is restless with tremors noted. The following physical assessment information was obtained: pupils are equal, round, and reactive to light; skin is warm, moist, and face is flushed; mucus membranes are moist, no jugular vein distention, no lymphadenopathy, no nuchal rigidity, and a slightly enlarged palpable thyroid gland is noted. Lungs are clear to auscultation. Cardiac exam reveals tachycardia, but regular rhythm without murmur, rub or gallop. Abdomen is soft and non-tender. Bowel sounds are hyperactive. Pedal pulses present, no pedal edema noted.
Social history includes that Rachel is single and lives with her roommate. She graduated from college 6 months ago and works as a waitress. The patient is presently without health insurance and family lives several hours away. Rachel’s family has been contacted by phone and they report no history of any health conditions. She takes no regular medications other than birth control. She denies use of illicit drugs, but does drink alcohol 2 to 3 drinks weekly. Her roommate reports the patient has been in good health until recently and has noticed a significant weight loss in Rachel over the past 2 months. Rachel’s family is supportive and on the way to the hospital.
Differential diagnoses include sepsis, drug toxicity, meningitis, psychiatric disorder, and thyroid storm. Various lab studies such as CBC, CMP, Glucose, Liver enzymes, BUN, creatinine, serum calcium, CPK, Free T4, T3, and TSH were ordered. Blood and urine cultures were negative. Chest x-ray findings were normal. Electrocardiogram shows sinus tachycardia at rate of 158 without ischemic changes. A lumbar puncture was performed with normal glucose and protein without white blood cells. Based on these findings, sepsis and meningitis were ruled out. Urine and blood toxicity screens were negative ruling out drug toxicity. The etiology being related to a psychiatric disorder seemed unlikely with evidence of high fever. Refer to Table 1 for a listing of pertinent lab results. Based on the findings of low TSH in the face of elevated T3 and T4 and the patient’s clinical presentation, a diagnosis of thyroid storm was made.
Critical care nurses should rely on the use of assessment skills to recognize the hypermetabolic state of thyroid storm so that treatment is not delayed. The cardinal signs of thyroid storm include high fever, marked tachycardia, atrial fibrillation, heart failure, neurological symptoms such as agitation and restlessness, and gastrointestinal symptoms such as nausea, vomiting, and diarrhea (Kaplow & Hardin, 2007). Early recognition of this myriad of signs can improve outcomes and decrease mortality with thyroid storm.
The treatment goals of thyroid storm include: 1) blocking the production of thyroid hormones in the thyroid gland 2) inhibiting release of hormones from the thyroid gland 3) beta adrenergic blockade 4) identification of the precipitating event and 5) supportive therapy (Kaplow & Hardin, 2007). Once symptoms are recognized, treatment should begin immediately and should not be delayed waiting for the return of lab results (Dulak, 2005).
The patient should be admitted to the critical care unit. Immediate nursing interventions for supportive care should include establishing intravenous (I.V.) access for hydration and replacement of fluid and electrolytes lost from vomiting and diarrhea. A nasogastric tube should be placed to administer anti-thyroid medication if the patient is unable to swallow as these medications do not come in an available I.V. form. Oxygenation is a priority and blood gases should be evaluated and oxygen therapy initiated (Dahlen, 2002; Dulak, 2005; Young, 1999).
Critical care nurses should be familiar with the regimen of medications administered during thyroid storm. The first medication administered should be an anti-thyroid medication such as propylthiouracil (PTU) which blocks the synthesis of thyroid hormones and inhibits the peripheral conversion of T4 to T3. The dosage is 200-250mg every 4 hours orally or via gastric tube. The nurse should monitor for signs of bleeding and a decreased platelet count. Methimazole, another anti-thyroid medication does not work in the periphery as PTU does; therefore, PTU is the anti-thyroid medication of choice during thyroid storm (Dahlen, 2002; Dulak, 2005; Kaplow & Hardin, 2007).
One to two hours later, a potassium iodide solution such as Lugol’s solution should be administered to prevent the release of stored thyroid hormone into the system. Timing of this medication is important as early administration of iodide may cause the body to synthesize more T4, worsening the toxic state. The dosage is 8 drops every 6 hours orally or via gastric tube (Dahlen, 2002; Dulak, 2005; Kaplow & Hardin, 2007).
Hydrocortisone administration is useful as the thyrotoxic state depletes cortisol from the adrenal glands. The nurse should administer 100mg I.V. every 8 hours and monitor glucose and electrolytes as well as for signs of fluid overload (Dahlen, 2002; Dulak, 2005; Kaplow & Hardin, 2007).
Combating the beta-adrenergic effects of thyroid storm such as tachycardia, tremors, and restlessness involves the administration of a beta blocker. The nurse should expect to administer Propanolol 60-120mg I.V. every 6 hours. The patient should have continuous cardiac monitoring. Propanolol is the drug of choice because it not only has beta blocking properties to reduce heart rate, but it also blocks conversion of T4 to T3, thereby decreasing the overall thyroid hormone levels. Propanolol should not be used in patients with chronic lung disease due the potential for bronchospasm. In that case, a beta-1 selective blocker would be a better choice. (Dahlen, 2002; Dulak, 2005; Kaplow & Hardin, 2007).
The critical care nurse can provide additional supportive care measures during thyroid storm. Interventions for alleviating the high fever associated with thyroid storm include use of a cooling blanket, ice packs, and fans. Shivering should be avoided as this can increase body temperature. Acetaminophen is the anti-pyretic of choice because aspirin or salicylates can increase the circulating levels of thyroid hormone. Treat dehydration and electrolyte imbalance with I.V. fluids, typically those containing dextrose to replace hepatic stores of glycogen depleted during thyroid storm. The patient should receive continuous cardiac monitoring to watch for life-threatening dysrhythmias and other interventions such as vagal maneuvers may be indicated to decrease heart rate. Insertion of a pulmonary artery catheter may be needed for hemodynamic monitoring for those patients who develop congestive heart failure (Dahlen, 2002; Dulak, 2005).
Finally, once the patient is stabilized, the precipitating event for thyroid storm should be treated aggressively. This event may include severe infection in which case antibiotics will be administered. Most commonly the event is an undiagnosed hyperthyroid condition such as Grave’s disease. Treatments for Grave’s disease include radioactive iodine, anti-thyroid medications, or thyroidectomy (Dahlen, 2002; Dulak, 2005).
Application of the Synergy Model
The Synergy Model describes eight patient characteristics that provide a common ground for assessing each unique patient’s needs along a continuum from health to illness (Curley, 1998). These characteristics are resiliency, vulnerability, stability, complexity, resource availability, participation in care, participation in decision making, and predictability. The patient’s characteristics may fluctuate as the patient’s condition changes over time. Recognizing these changes allows the nurse with the appropriate competencies to be better matched with patient to synergize the best patient outcomes (Hardin & Hussey, 2003)
In the case study, Rachel can be described as being resilient because she is young and strong with high endurance and is able to mount a response to her illness. She is vulnerable to the various stressors thyroid storm presents and her condition is presently unstable. Rachel’s case is complex because several body systems are entangled, namely the cardiovascular system and the endocrine system. She has moderate resource availability as evidenced by lack of health care insurance, but a strong family and social support system. Rachel is able to participate in her care at a moderate level, but still requires assistance from her family and nursing staff. Rachel is limited in her decision making ability at the present time due to her course of illness and depends on her family to make decisions regarding her care. Finally, Rachel’s case is moderately unpredictable as there is an expected course of events; however, these events may waver or change with time. The holistic view of Rachel’s characteristics aids in the development of a care plan that can match the nurse with appropriate competencies to care for Rachel’s complex needs.
Nursing competencies capitalize on the strengths and skills of individual nurses and exist on a continuum from novice to expert. Matching nurses’ compentencies to particular patient needs and characteristics will result in synergistic care and outcomes. Nurse competencies within the Synergy Model are clinical judgment, advocacy and moral agency, caring practices, collaboration, systems thinking, response to diversity, facilitator of learning, and clinical inquiry (Curley, 1998).
After evaluating Rachel’s patient characteristics, the nursing competencies that will be a priority are clinical judgment, collaboration, systems thinking, facilitation of learning, and clinical inquiry. The nurse caring for Rachel will need to be an expert in these competencies.
The critical care nurse will use clinical judgment to synthesize and interpret Rachel’s assessment results and make decisions about her care. She will look at Rachel’s overall needs and collaborate with the multi-disciplinary team. Collaboration will take place with the social worker to help Rachel and her family work through issues such as lack of health insurance and need for regular medical follow-up.
The critical care nurse would need to be proficient in systems thinking. A holistic view of the patient would be necessary to integrate and apply a variety of strategies related to patient care. For example in thyroid storm, the nurse would need to implement a variety of strategies to decrease Rachel’s high fever: acetaminophen, cooling blanket, and ice packs to the groins. In addition, the nurse would need to be monitoring the cardiovascular system and administering medication for tachycardia and arrhythmias.
As an expert facilitator of learning, the critical care nurse tailors an educational program on thyroid disease to meet the needs of Rachel and her family. The expert nurse realizes that the patient and family will have various treatment options for hyperthyroidism. The goal of the nurse is to facilitate the patient and family in learning about these options and making the best decision possible.
Caring for Rachel will also require the nursing competency of clinical inquiry. The critical care nurse will provide care following practice standards and guidelines for the treatment of thyroid storm, but she will not be afraid to question or deviate from these standards if newer research can help improve patient care. The nurse who is an expert in clinical inquiry will bring evidence based practice to the bedside.
Outcome of Case Study
Rachel was admitted to the intensive care unit and received aggressive rehydration with dextrose containing I.V. fluids. Due to the patient’s increase in mental confusion, a nasogastric tube was placed to administer PTU every 4 hours. The first dose of iodide in the form of Lugol’s solution was administered one hour after the first dose of PTU and continued every 6 hours. Propranolol was administered every 6 hours for tachycardia and restlessness. Hydrocortisone was given to increase depleted adrenal stores of cortisol.
Rachel received acetaminophen every 4 hours for her high fever. In addition, a cooling blanket and ice packs to the axilla and groins were applied. Continuous cardiac monitoring was in place and hemodynamic monitoring was not needed.
Rachel stabilized within 24 hours and several days later after thyroid antibody tests returned, she received the diagnosis of Grave’s disease. After educating the patient and family about all available treatment options, a total thyroidectomy was decided upon. The patient underwent surgery without complication and will receive thyroid replacement therapy for life. Rachel and her family were educated on the basics of thyroid disease including signs and symptoms to report. Rachel was referred by the social worker to a family free clinic in the area that can provide free medical follow-up as well as free medications until she finds a job with health insurance.
Thyroid storm is a rare, life-threatening illness that involves critical and complex care. The Synergy Model can provide a framework to help match complex patient needs and characteristics during thyroid storm with nursing competencies to synergize patient outcomes. Early recognition of the signs thyroid storm and prompt intervention are the key to survival during the eye of the storm.
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Pertinent Laboratory Findings
Lab Test Result High, low, normal
White blood cells 3,700/mm3 Normal
Hemoglobin 14.2 gm/dL Normal
Hematocrit 38.2% Normal
Platelets 92,000/uL Low
Glucose 82 mg/dL Normal
Creatinine kinase (CPK) 3594 IU/L High
TSH <0.01 µU/ml Low
Free T4 6.22 ng/dl High
T3 243 ng/dl High