Regarding the assessment of the cervical spine in a trauma patient, which ONE of the following statements is TRUE?
Answer: B: During assessment of the cervical spine in trauma in awake and alert adults, both NEXUS criteria and Canadian cervical spine decision rule can be applied to identify patients who require further imaging to exclude cervical spine injury. Both have very high sensitivities in detection of fractures (99% and 100% respectively) but their specificities are limited. The specificity of NEXUS criteria is only 12.9% and Canadian cervical spine rule is 42.5%. Both rules can be applied together when clearing the cervical spine. However, these are only decision support tools, hence good assessment of the patient with a focused neurological examination and the checking of the range of cervical spine motion is essential before spinal clearance.
With cervical spine plain films, some of the fractures can be missed despite the adequacy of the films. Patients who have persistent symptoms in spite of having normal plain films will require CT to exclude bony injury or MRI to rule out cord and ligamentous injury. In older patients, the chance of fracture is said to be twice as high as younger patients. Odontoid fractures are common in this age group but diagnosis can be missed when plain films alone are used.
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Regarding injuries to the spine, which ONE of the following statements is CORRECT?
Answer: C: Bilateral interfacetal dislocation occurs with disruption of all ligamentous structures secondary to hyperflexion allowing articular masses of one vertebra to dislocate superiorly and anteriorly into the intervertebral foramen of the vertebra below. On radiographs, the vertebral body is dislocated anteriorly at least 50% of its width. Sacral injuries are relatively rare and usually occur in conjunction with pelvic fractures. Despite the rarity of sacral injuries, associated neurological injuries are not uncommon and unrecognised and inadequately treated sacral fractures may lead to painful deformity and progressive loss of neurological function. Potential neurological injuries in patients with a sacral fracture include those involving the cauda equina, the umbosacral plexus, the sacral plexus, and the sympathetic and parasympathetic chains. Several classification systems exist to help predict the neurological deficits and establish treatment protocols. The Denis three-zone classification system is based on fracture anatomy. Zone-I fractures occur lateral to the sacral foramina and are the most common fracture pattern. Neurological injury occurs in approximately 6% of patients and typically involves the L4 and L5 nerve roots. Zone-II fractures are the second most common pattern. These injuries consist of a vertical transforaminal fracture without involvement of the sacral spinal canal. An associated neurological injury is found in 28% of patients, and it most frequently affects the L5, S1 or S2 nerve root. Any sacral fracture involving the spinal canal is classified as a zone-III injury. This fracture subtype occurs the least but is associated with the highest prevalence and severity of neurological injury, which affects approximately 57% of patients. Bowel and bladder control or sexual function is impaired in about 76% of patients with a neurological injury in this group.
A Jefferson fracture involves the anterior and posterior arches of C1 vertebra and occurs when the cervical spine is subjected to an axial load. The occipital condyles are forced downwards and produce a burst fracture by driving the lateral masses of C1 apart. A Hangman fracture involves both pedicles of C2 and occurs in extension.
Teardrop fractures to the anterioinferior part of the cervical vertebra can occur in flexion and extension and despite appearing small and insignificant on plain radiography, is associated with significant and complete disruption of the ligamentous structures at the level of the injury. These fractures are unstable.
Regarding the assessment of a patient with a cervical spinal cord injury (SCI), all of the following statements are true EXCEPT:
Answer: C: Cervical SCIs are associated with paralysis of intercostal and abdominal wall muscles. The phrenic nerve supplying the diaphragm originates from C3,4 and 5 nerve roots. In C5 injury diaphragmatic function is intact; however, about half of these patients still require short-term mechanical ventilation (MV). With injury at C4 level, all patients will need MV as there is a partial loss of diaphragmatic function. Injury at C3 or above, all need MV with half needing long-term ventilation. Early hypoxaemia is very common in patients with a cervical SCI. One of the goals of ED intervention should be to prevent this hypoxaemia as it is known to cause secondary injury to the cord producing worse outcome. A patient with a cervical SCI at C5 level or above should strongly be considered for advanced airway management and MV before respiratory failure sets in.
Unopposed vagal activity in the face of loss of sympathetic innervation may cause severe bradycardia, especially in high SCI. About 16% of patients will have asystolic cardiac arrest likely to be triggered by tracheal suctioning. Pre-treatment with atropine may prevent this.
Central cord syndrome is an incomplete SCI. An incomplete SCI is where motor, sensory or both functions are partially preserved below the neurological level of injury. This functional assessment cannot be done if the patient is in the spinal shock stage and should be done when the spinal shock is resolved. Four incomplete cord syndromes have been described:
Except for anterior cord syndrome, a good prognosis can be expected for patients with other incomplete syndromes if the cord injury is managed appropriately. Central cord syndrome is usually seen in elderly patients with hyper-extension injuries. This results in quadriparesis where a higher degree of weakness can be elicited in the upper limbs than in the lower limbs. Some loss of pain and temperature sensation may occur with a similar pattern of distribution.
Spinal shock is characterised by which ONE of the following?
Answer: C: Spinal shock is a term used to describe the state of transient physiological, rather than anatomical, loss or depression of spinal cord sensory and motor functions (somatic functions) below the level of a complete or incomplete injury that occurs soon after the cord injury. This may last for days to weeks. Because of the loss of functions below the level of injury during spinal shock an incomplete cord injury may appear as a complete cord injury and hence the spinal shock is not predictive of functional outcome. Flaccid paralysis below the level of the lesion including that of bladder and bowel occurs in spinal shock. Priapism is an associated feature in some patients. When spinal shock resolves, the bulbocavernous reflex usually returns first.
In contrast, the neurogenic shock is secondary to peripheral sympathetic denervation due to cord injury at cervical or thoracic levels. The neurogenic shock is manifested by a triad of hypotension, bradycardia and hypothermia. The sympathetic denervation causes reduced systemic arteriolar tone and systemic vascular resistance leading to hypotension. Warm and vasodilated peripheries cause heat loss leading to hypothermia. If the cord injury is above T1–T4 level sympathetic innervation to the heart is lost, but parasympathetic supply through the vagus nerve remains unopposed leading to bradycardia.
Regarding ED management of a young adult with an acute spinal cord injury, which ONE of the following statements is TRUE?
Answer: D: Hypotension in a patient who had trauma and that resulted in SCI, should be considered as having ongoing blood loss (haemorrhagic shock) until proven otherwise. Other potential courses of hypotension include tension pneumothorax, cardiac tamponade, myocardial injury, intoxication with drugs and alcohol and neurogenic shock. While searching for a cause of potential haemorrhagic shock, hypotension should be promptly corrected with fluid resuscitation. Vasopressors should be used once the volume is restored. Hypotension contributes to secondary injury to the cord.
During rapid sequence intubation, suxamethonium can be used as a paralytic agent in patients with an acute spinal cord injury. However, after the first week and up to about 6 months suxamethonium should not be used because life-threatening hyperkalaemia may occur due to denervation injury.
There is no high-quality evidence to suggest that the use of corticosteroids is clinically beneficial. Instead, the currently available evidence suggests harmful side effects such as sepsis are associated with this therapy. The controversy remains and the current use of corticosteroids is not widespread. Acute gastric distension and paralytic ileus develop early and abdominal distension affects ventilation. Subsequently, early insertion of a nasogastric tube should be done in the ED. Also, early urethral catheterisation prevents over distension of the bladder.
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