Thyroid storm induced by strangulation.

Abstract: Thyroid storm most often occurs in patients with known thyrotoxicosis. This report discusses a severe case of thyroid storm developing as a direct result of strangulation in a patient without a preexisting history of thyroid disease. Classification and treatment of this entity are discussed.

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Thyroid storm, or thyrotoxic crisis, is an uncommon and severe form of hyperthyroidism, manifesting clinically as the triad of altered mental status, hyperpyrexia, and adrenergic activation (tachycardia, high-output cardiac failure, and gastrointestinal dysfunction). It may occur in patients with a history of thyrotoxicosis who suffer acute stress, resulting in life-threatening decompensation. (1-5) To our knowledge, thyroid storm in the absence of underlying hyperthyroidism has not previously been reported. We present one such case in a patient with direct trauma to the thyroid gland.

Case Report

A 37-year-old woman was brought to the emergency department (ED) after being assaulted. At the scene, paramedics found her with a tourniquet tied around her neck. Her heart rate was 160 beats/min and her Glasgow Coma Scale score was 3. At arrival in the ED, her blood pressure was 122/59 mm Hg, her heart rate was 156 beats/min, her respiratory rate was 38 breaths/min, and her oxygen saturation was 99%; her temperature was not recorded. The Glasgow Coma Scale score was 11 and she was noted to be severely agitated. Resuscitation according to Advanced Trauma Life Support protocols was initiated and the patient was immediately intubated for airway protection.

Physical examination revealed a circumferential cervical contusion along with cervicofacial ecchymoses and petechiae. Rectal and vaginal lacerations were also noted and the remainder of the examination was unremarkable. An electrocardiogram showed sinus tachycardia. Radiographs of the cervical spine and chest revealed no injuries and computed tomography of the head, cervical spine, chest, abdomen, and pelvis were normal.

The patient was presumed to have an anoxic-ischemic encephalopathy secondary to strangulation and was admitted to the surgical intensive care unit (SICU). At arrival, her temperature was 101.7[degrees]F; this remained elevated despite administration of acetaminophen and cooling measures. The patient's tachycardia persisted despite appropriate fluid resuscitation, and over the next 72 hours she developed multiple organ dysfunction, which included hypotension, bilateral pulmonary infiltrates, a decreased Pa[O.sub.2]/Fi[O.sub.2] ratio, elevated creatinine, coagulopathy, hyperbilirubinemia, and thrombocytopenia.

Organ dysfunction improved with supportive therapy, but the patient remained febrile and tachycardic with alternating lethargy and agitation. She subsequently developed profuse diarrhea. Neurology consultation was obtained and electroencephalography revealed generalized conduction slowing, supporting the diagnosis of diffuse cerebral anoxia. Magnetic resonance imaging of the brain, however, failed to confirm this diagnosis and the working diagnosis of anoxic-ischemic brain injury was brought into question.

A new working diagnosis of thyroid storm was made on the basis of the patient's persistent tachycardia, mental status changes, and fever. The presence of goiter could not be assessed by physical examination because of generalized cervical edema from the strangulation. Plasma thyroid function tests were obtained, and these results were consistent with thyrotoxicosis. Thyroidstimulating hormone (TSH) was below 0.01 mU/L (normal range, 0.40-5.00 mU/L), thyroxine was 19.3 [micro]g/dL (normal, 5.0-12.0 [micro]g/dL), free thyroxine index was 26.4 [micro]g/dL (normal, 5.0-12.0 [micro]g/dL), and triiodothyronine resin uptake was 0.73 (normal, 0.66-1.27 [micro]g/dL). The tests were repeated twice, yielding similar results.

Treatment was instituted according to guidelines from the American Thyroid Association, (6) resulting in dramatic clinical improvement. Remarkably, the agitation, hyperthermia, and tachycardia improved 2 days after therapy was started. Within a week, mechanical ventilation was successfully discontinued and the patient became alert and oriented. She was transferred to the ward and had an otherwise uncomplicated hospital course.

Before discharge, the patient and her family were questioned about symptoms suggestive of occult hyperthyroidism before the assault, which they uniformly denied. In addition, the patient exhibited no signs of longstanding hyperthyroidism. Specifically, she had no exophthalmos; her hair was neither thin nor friable; and her fingernails were not soft, irregular, or distally separated from the nailbed (Plummer nails). These findings suggest that the patient was euthyroid before the assault. As additional evidence, an admission TSH level was retrospectively determined using blood drawn in the ED, and this value was 0.65 mU/L, which is within the normal range of 0.40 to 5.00 [micro]g/dL. A thyroxine level could not be obtained. The patient did not attend scheduled follow-up appointments.

Discussion

Thyrotoxicosis refers to the biochemical and physiologic changes that result from excess circulating thyroid hormone. It ranges in manifestation from an asymptomatic laboratory abnormality to life-threatening multiple organ dysfunction. The latter is referred to as thyrotoxic crisis, or thyroid storm, and is not considered an independent process but rather an extreme manifestation of hyperthyroidism. It is usually precipitated by acute stress in a patient with poorly controlled underlying disease. (2-5) McArthur et al (1) compared it to diabetic ketoacidosis: "like ketosis in diabetes mellitus ... storm represents the inability of the patient any longer to adjust to the strain imposed by hyperthyroidism." The presence of a precipitating event is considered a key clinical feature and trauma is frequently cited as a potential cause. A literature search identified seven cases of post-traumatic thyroid storm reported since 1966. (7-13) There was evidence of preexisting thyrotoxicosis, albeit undiagnosed, in each case.

The case reported here is unique because there is evidence that the patient may not have had underlying thyrotoxicosis. We hypothesize that direct thyroid gland trauma during strangulation may have caused release of excess hormone, leading to storm in a patient without underlying disease. The diagnosis of thyroid storm accounts for the clinical presentation in the ED, the persistence of symptoms in the SICU, and the rapid improvement when thyrolytic therapy was instituted. The low TSH and elevated thyroxine levels, serially measured in the SICU, support the diagnosis. The normal TSH in the ED strongly suggests the absence of excess circulating thyroid hormone before strangulation, because otherwise the TSH would have been suppressed.

The accuracy of our hypothesis must be tempered by the limitations of some of our data, which were retrospectively obtained. As we have shown, the patient's admission history and physical examination indicate that she was euthyroid before the strangulation. However, this cannot be proved conclusively on the basis of the admission TSH level, which could have been falsely normal because it was obtained from a stored sample. Alternatively, it is possible that the patient was hyperthyroid before admission and she had an inappropriately normal TSH level, suggesting that her pituitary-hypothalamic-thyroid axis was abnormal. However, her hospital course does not support this conclusion. Next, it is also possible that the reduced TSH in the SICU was a result of medication, but this is unlikely because the patient did not receive any drug known to suppress TSH and the suppression was quite profound. Finally, it is possible that the reduced TSH was a result of nonthyroidal illness and, indeed, the patient's early hospital course is consistent with sepsis, which could lower the TSH. However, no septic source was identified and the patient's condition improved dramatically in the absence of antimicrobial therapy.

The diagnosis of thyroid storm is based on clinical findings and may be difficult in light of confounding variables present in the SICU. To this end, Burch and Wartofsky (3) developed a quantitative scale of diagnostic criteria for storm. According to this scale, our patient received the maximum possible score in almost all categories, including thermoregulatory dysfunction (temperature > 103.9[degrees]F), central nervous system effects (coma), gastrointestinal dysfunction (diarrhea and unexplained jaundice), heart rate (> 139 beats/min), congestive heart failure (pulmonary edema), and the presence of a precipitant history. The total score was 130 of a possible 140 and she only missed points for absence of atrial fibrillation. In fact, this score is almost three times that required for definitive diagnosis of storm based on the scale.

In the past, surgeons frequently observed thyroid storm during thyroidectomy for Graves disease or toxic multinodular goiter. Today, advances in pharmacology allow control of thyrotoxicosis before surgical intervention, and thyroid storm has become a less common entity. To our knowledge, this report represents a unique case of thyroid storm after direct thyroid trauma and with no antecedent hyperthyroidism. Moreover, it serves to illustrate that trauma surgeons should remain aware of the presentation and treatment of this condition. The Burch and Wartofsky scale is a useful tool for distinguishing thyroid storm from other forms of hyperthyroidism so that appropriate medical management can be initiated.

Accepted April 23, 2003.

Copyright [c] 2004 by The Southern Medical Association

0038-4348/04/9706-0608

References

1. McArthur JW, Rawson RW, Means JH, et al. Thyrotoxic crisis. JAMA 1947;134:868-874.

2. Waldstein SS, Slodki SJ, Kaganiec GI. A clinical study of thyroid storm. Ann Intern Med 1960;52:626-642.

3. Burch HB, Wartofsky L. Life-threatening thyrotoxicosis: Thyroid storm. Endocrinol Metab Clin North Am 1993;22:263-277.

4. Tietgens ST, Leinung MC. Thyroid storm. Med Clin North Am 1995;79:169-184.

5. Larsen PR, Davies TF, Schlumberger MJ, et al. Thyroid physiology and diagnostic evaluation of patients with thyroid disorders, in Larsen PR, Kronenberg HM, Melmed S, et al (eds): Williams Textbook of Endocrinology. Philadelphia, W.B. Saunders Co., 2003, ed 10, pp 331-373.

6. Singer PA, Cooper DS, Levy EG, et al. Treatment guidelines for patients with hyperthyroidism and hypothyroidism: Standards of Care Committee, American Thyroid Association. JAMA 1995;273:808-812.

7. Jacobs RR. Acute hyperthyroidism precipitated by trauma. South Med J 1979;72:890-891.

8. Doussin JF, Dubost J, Banssillon V. Posttraumatic hyperthyroxinemia or hyperthyroidism [in French]. Ann Fr Anesth Reanim 1985;4:72-74.

9. Barker DE, Strodel WE. Hyperthyroid crisis. J Ky Med Assoc 1988;86:371-373.

10. Gregg-Smith SJ. Thyroid storm following chest trauma. Injury 1993;24:422-423.

11. Yoshida D. Thyroid storm precipitated by trauma. J Emerg Med 1996;14:697-701.

12. Anwar N, Dyrna A. Thyrotoxic crisis: A difficult diagnosis in a polytrauma patient--a case report [in German]. Anaesthesiol Reanim 1996;21:51-52.

13. Naito Y, Sone T, Kataoka K, et al. Thyroid storm due to functioning metastatic thyroid carcinoma in a burn patient. Anesthesiology 1997;87:433-435.

RELATED ARTICLE: Key Points

* Thyroid storm rarely occurs without preexisting thyroid disease.

* Strangulation of the neck can cause thyroid storm.

* The diagnosis of thyroid storm can be distinguished from other common intensive care unit entities using specific clinical criteria.

Jesus I. Ramirez, MD, Patrizio Petrone, MD, Eric J. Kuncir, MD, FACS, and Juan A. Asensio, MD, FACS

From the Division of Trauma and Critical Care, Department of Surgery, Keck School of Medicine, University of Southern California, LAC + USC Medical Center, Los Angeles, CA.

Reprint requests to Juan A. Asensio, MD, FACS, Unit Chief, Surgery Trauma "A" Service, Keck School of Medicine, LAC + USC Medical Center, 1200 N. State Street, Room 10750, Los Angeles, CA 90033. Email: [e-mail]