Thyroid rupture: An unusual presentation after blunt trauma to neck

Clinical History

A 35-year-old-male patient who fell on a hanging wire at a construction site after being hit by a bike, presented to our department with complaints of pain and swelling on the neck. No respiratory complaints or restriction of neck movements. On examination, we found tenderness and swelling on the injured part. Laryngoscopy report showed no significant abnormality.

Imaging Findings

Ultrasound of neck revealed an ill-defined 2*2 cm hypoechoic lesion on the isthmus and left lobe of the thyroid extending into prethyroid muscles with disruption of the left lobe of the thyroid gland. A provisional diagnosis of thyroid gland rupture with haematoma was given and CECT was advised. On CECT, intrathyroid and perithyroid haematoma was noted along with the separation of the left lobe of the thyroid gland from the isthmus. As the airway was clear without any evidence of active bleeding, the patient was managed conservatively and discharged after 4 days with advice to follow up.

Discussion

Though blunt trauma to the neck is common with resultant injury to bones and other soft tissues like vessels, muscles or trachea, isolated thyroid gland injury is rare in a previously normal thyroid gland. Thyroid gland injury is more common in goitrous glands due to their larger size and increased vascularity. [1, 2]
In 1894, Simon reported the first fatal case of thyroid injury following neck trauma. [1] Thereafter, in 2006, Heizmann et al performed a retrospective review of the published case reports and proposed the classification of blunt thyroid injuries and their treatment algorithm. [3] Then, Von Ahnen et al in 2014 analysed 34 case reports on traumatic thyroid rupture and provided a clinically viable revised classification and treatment algorithm. [4]
The modes of injury include trauma from automobile accidents, fall, strangulation or sports injuries or very rarely from weight lifting. The patient presents with pain and swelling in the neck. There may be respiratory distress, hoarseness and dysphagia due to compromise of the aerodigestive tract. [1, 2]
Imaging modalities like ultrasonography and computed tomography are essential in evaluation of thyroid injuries. Ultrasonography can readily detect the presence of haematoma which can appear as a lesion of varied echogenicity surrounding the thyroid gland and can also evaluate its extension into the surrounding soft tissues. In addition, it can also identify any thyroid parenchymal disruption and look for any fluid collections. It can also determine the feasibility of percutaneous or surgical drainage. CECT is useful for better delineation of the haematoma and to look for thyroid gland rupture. It is also essential for the evaluation of the surrounding structures like vessels, muscles, spine, larynx, trachea and oesophagus to identify any vessel rupture, active bleeding, any fractures or airway compromise. [1, 2]
Other investigations like larynogoscophy are also important to rule out laryngeal injuries like laryngeal oedema, haematoma or lacerations and any tracheal injury.
Thyroid gland injury can lead to transient hyperthyroidism or rarely thyroid storm due to rupture of the gland and release of the hormones into the blood. Therefore, evaluation of the thyroid hormone levels is important to identify this potentially lethal complication. [2] In 2007, Delikoukos et al studied 231 patients with neck trauma and reported thyrotoxic crisis in 2 out of 4 patients with isolated thyroid gland injuries. [5]
Previously, thyroid gland injuries were managed with surgical evacuation and debridement. But now, patients with stable haematomas and without any evidence of airway compromise are being managed conservatively. [1, 2]

Differential Diagnosis List

Final Diagnosis

Thyroid gland rupture

URL:	https://eurorad.org/case/15412
DOI:	10.1594/EURORAD/CASE.15412
ISSN:	1563-4086