Neck hyperflexion causing isolated thyroid cartilage fractureâ€”a case report
Neck hyperflexion causing isolated thyroid cartilage fracture–a case report
Isolated thyroid cartilage fracture is very rare, and most cartilage fractures are caused by direct impact to the laryngotracheal complex of the neck. Isolated thyroid cartilage fracture caused by hyperflexion of the neck has not been reported before. We present a case where an unrestrained front seat car passenger struck his forehead on the windshield during a motor vehicle accident. Direct impact of his forehead with sudden and forceful flexion of his neck caused isolated thyroid cartilage fracture without direct impact to the neck. Therefore, injury to the thyroid cartilage should be kept in the list of detailed evaluation with high index of suspicion in patients presenting with trauma mechanism possibly causing neck hyperflexion, even with- out signs of direct Neck trauma.
A 42-year-old unrestrained front seat car male passenger was involved in a motor vehicle accident. He remained in the seat after the car ran into a tree and had not lost consciousness by the time the emergency medical service had arrived. He was then brought to our urban medical center hospital by the emergency medical service within 10 minutes with a neck collar brace and Long spine board protection. On arrival at our emergency department, the patient was not in respiratory distress but exhibited a muffled and hoarse voice. The patient had no dysphagia, odynophagia, trismus, or stridor. The patient’s vital signs were the following: temperature, 35.5?C; pulse, 85 beats/min; blood pressure, 150/93 mm Hg; and respiratory rate, 14 breaths/min. On examination, he had a large laceration about 15 cm in length over his forehead, with a hematoma over his right frontal- temporal area. His neck was supple without edema or ecchymosis, and the trachea was in the midline; however, he did complain of anterior neck “discomfort.”
There were pain and tenderness over the right thoracoab- dominal area, and the initial focus assessment sonography for trauma revealed no abnormal finding. The remainder of the physical examination was normal.
The patient subsequently underwent computerized tomo- graphic (CT) scan of the head and facial bone down to the upper neck, and this suggested a significant scalp hematoma
without obvious brain lesion (Fig. 1A). A fracture of the left thyroid cartilage was found accidentally, when facial bone CT was reviewed by the trauma surgeon (Fig. 1B). Abnormal Liver enzymes (GOT and GPT, 335 and 252 IU/dL, respectively), together with fluid accumulation within the Morrison’s pouch after in repeated focus assessment sonography for trauma, warranted an enhanced abdominal CT. A grade III Liver laceration, right 8th to 11th rib fractures, and spleen laceration with contrast extravasations were demonstrated by the examination (Fig. 2).
The patient underwent emergency laparotomy with splenectomy due to hemodynamic instability and grade
IV spleen laceration and was admitted to the trauma intensive care unit. He was extubated smoothly the next morning without respiratory compromise or distress. The hospital course was unremarkable, and his Neurological examination remained normal. He was discharged 14 days after the incident. At a 2-week follow-up appointment with the trauma surgeon, the patient was doing well without any complications.
Laryngeal injuries can be divided anatomically into supraglottic, tracheal, and infraglottic. Thyroid cartilage is a supraglottic structure of laryngotracheal complex.
Fracture of the thyroid cartilage, avulsion of the attachments of the epiglottis from the thyroid cartilage, and fracture of the epiglottis are included in the supraglottic injuries of laryngotracheal complex . Blunt laryngeal injuries are rare and are not typically seen in isolation; they are usually associated with multiple traumas . Such injuries account for less than 1% of all the cases seen at major trauma centers [3-5]. The most common mechanism of laryngotracheal trauma occurs when the steering wheel or dashboard strikes the neck or throat region of an unrestrained driver during a motor vehicle collision . Local external evidence of neck trauma (bruising, subcutaneous emphy- sema, cuts, abrasions, etc), signs of upper airway obstruction, dysphonia, and dysphagia are hallmarks of laryngotracheal lesions [3,7-10].
Isolated thyroid cartilage fractures are more rarely reported, and most of all these are caused by direct injury to the neck [11-13], except for 2 patients reporting having isolated thyroid cartilage fracture after a sneezing episode [14,15]. Our patient struck his head on the windshield, with his face cut by the broken windshield glass. The contusion in the right frontal-temporal area caused a long laceration over
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Fig. 1 Face bone CT scan demonstrated left thyroid cartilage fracture (white arrow), whereas brain CT showed evidence of scalp hematoma over right frontal-temporal area (arrow).
the forehead and a significant scalp hematoma with left thyroid cartilage fracture. The sudden and forceful flexion of the neck produced a giant inward force causing inner depression of the thyroid cartilage (Fig. 3). The mechanism causing thyroid cartilage fracture during impaction may be the same with sneezing.
Most of the thyroid cartilage fracture was caused by direct neck injury and combined with other associated organ trauma. These multiple injuries may divert the attention of the physician to the obvious finding of injuries and failure to identify this subtle lesion.
In thyroid cartilage fractures, especially at the level of the glottis, patients may present with marked dysphonia or aphonia and a certain degree of laryngeal obstruction . Although some patients may appear deceptively normal at the neck, the diagnosis may be overlooked or become difficult especially in patients who have disturbed con- sciousness or are intubated immediately after the accident.
Fig. 3 Sudden hyperflexion of the neck (arrow) with muscular tension on the thyroid cartilage bone develops a force significant enough to fracture the thyroid cartilage.
The change of mental status may relate to transitory hypoxia caused by upper airway obstruction, rather than head trauma [3,17].
In our patient, his consciousness was clear and the neck was intact. The thyroid cartilage fracture was found accidentally by the trauma surgeon when reviewing the brain and facial bone CT scan film, which was even missed in the radiologist’s report.
The subtle fracture may be missed, delayed, or over- looked because other major trauma such as head injury and liver and spleen laceration with internal bleeding diverts attention, in the face of normal appearance of the neck. Therefore, high index of suspicion and timely recognition of acute laryngeal injury are imperative because there may be delay or even misdiagnosis, and the consequence may be fatal if upper airway obstruction by edema should develop.
Hsing-Lin Lin MD Liang-Chi Kuo MD Chao-Wen Chen MD Yuan-Chia Cheng MD Wei-Che Lee MD Department of Trauma
Kaohsiung Medical university hospital Kaohsiung Medical University Kaohsiung 807, Taiwan Department of Emergency Medicine
Kaohsiung Medical University Hospital Kaohsiung Medical University Kaohsiung 807, Taiwan
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