Thyrotoxicosis due to Thyroid Hematoma Precipitated by Anticoagulation Therapy

Abstract

Intrathyroidal bleeding of non-traumatic origin is of rare occurrence. It can be increased by the use of anticoagulant agents. We report the case of an elderly woman with history of nontoxic multinodular goiter that developed a spontaneous thyroid hemorrhage precipitated by the use of oral anticoagulants (acenocoumarol) for atrial fibrillation. She presented with compressive signs (dyspnea, dysphagia and dysphonia). Cervical computed tomography showed enlarged, heterogeneous thyroid gland, with diffuse infiltration of thyroid lodge with collections measuring for the most voluminous 50x70mm, pushing trachea but that remains permeable. Biological findings revealed increased levels of thyroxine and triiodothyronine with a decreased levels of thyroidstimulating hormone. She was treated with steroids, antibiotics and antithyroid medication in the face of a destructive hyperthyroidism. Evolution was good and a total throidectomy was performed after a month. Only few cases of non traumatic thyroid hemorrhage are described in the literature. It is a potentially life-threatening condition by compression of aerodigestive tract and adjacent vascular axes. Our report is to our knowledge the first case of intrathyroidal bleeding due to acenocoumarol causing transient thyrotoxicosis. It illustrates a rare but potentially lethal complication of anticoagulants especially in elderly population.

Keywords: Thyroid gland; Hemorrhage; Anticoagulation; Thyrotoxicosis

Abbreviations

CT: Cervical Computed Tomography; T4: Thyroxine; T3: Triiodothyronine; TSH: Thyroid-Stimulating Hormone; INR: International Normalized Ratio

Introduction

Spontaneous thyroid hematoma is a rare occurrence that can be favored by anticoagulation therapy. Any neck swelling can be life-threatening by compression of the upper aero digestive tract and adjacent vascular axes. We report the case of a thyroid hematoma revealed by compressive signs in a patient with a history of a nontoxic multinodular goiter treated with vitamin K antagonist (acenocoumarol) for atrial fibrillation. Subsequent course was marked by installation of hyperthyroidism of destructive mechanism following the thyroid hematoma.

Case Presentation

We report the case of an 80-year-old patient with a history of nontoxic multinodular goiter, recently started on vitamin K antagonists (acenocoumarol) for atrial fibrillation, who presented to the emergency department for a progressively increasing neck swelling, causing mild sore throat, breathing difficulty and dysphagia to solids. She also complained of palpitations and a change in her voice.

On examination the patient was asthenic, pale, dyspneic with respiratory rate of 32 cycles/minutes, tachycardia of 120 beats/minutes, blood pressure of 100/60mmHg, and oxygen saturation of 99% under four liters of oxygen. There was a diffuse anterior neck swelling of approximately 08 x 07cm that was very painful on palpation, firm and mobile. The presence of extensive spontaneous bruising in both arms was suggestive of vitamin k antagonist intoxication.

Laboratory findings showed INR of 7 (therapeutic goal for atrial fibrillation 2.0-3.0) with poorly tolerated 6g/dl anemia. TSH level was low at 0.02mIU/L, with an elevated free T4 level at 40pmol/l indicative of hyperthyroidism. Leukocyte count was at 13 400/mm3 predominantly neutrophils with an elevated C-reactive protein at 250mg/L. Blood electrolytes, renal and liver function were normal.

Urgent CT of the neck was done, which showed an enlarged, heterogeneous thyroid gland, with diffuse infiltration of thyroid lodge with collections measuring for the most voluminous 50x70mm (Figure 1). Treatment was based on frozen fresh plasma and red blood cells transfusion with discontinuation of anticoagulation therapy, oxygen therapy, intravenous steroids and antibiotics. Antithyroid medications were initiated for control of increase sympathetic activity before planning surgery. Total thyroidectomy was perfomed after a month with a good evolution.

    

    

    Figure 1: (A) Axial section injected CT showing a predominantly liquid
thyroid collection pushing the axis aero-digestive and vasculo-nervous but
that remain permeable. (B) Sagittal section CT showing a large nodular goiter
associated with a large infiltration of the thyroid compartment with poorly
limited collections.