spinal cord injury ( sci ) is the most devastating form of neurological injury , disturbing the normal sensory , motor , and/or autonomic functions .
the annual incidence of sci in the usa is about 40 cases per million of population .
sci is caused principally by trauma ( e.g. traffic injuries , falls , and violence ) .
the risk of death is highest in the first year after sci and varies by level and severity of injury .
cardiovascular disease is one of the principal causes of death.3 , 4 in the usa , diseases of the circulatory system are the most common causes of death . in norway ,
the main causes of death following the experience of a sci are pneumonia / influenza , ischemic heart disease , and urogenital disease . in patients with acute cervical scis ( rather than thoracolumbar scis ) , cardiovascular deficits , including severe bradycardia , asystole , and loss of peripheral vascular tone , are known complications.5 , 6 acute autonomic imbalances developing after disruption of the sympathetic pathway ( located in the cervical cord ) are  thought to trigger such cardiovascular events.5 , 6 , 7 although autonomic dysfunction developing after sci can have fatal consequences , including cardiac arrest , many clinicians do not recognize such risks , and the conditions are often misdiagnosed . here
a 26-year - old male pedestrian was admitted to hospital via the emergency room after a traffic accident .
he was mentally alert and complained of weakness and numbness of both the upper and lower extremities . on physical and neurological examination , no external injuries were evident except for an abrasion on the left arm .
the baseline electrocardiogram ( ecg ) revealed sinus bradycardia ( 57  beats / min , fig .  1 ) .
initial chest and abdominal computed tomography ( ct ) did not reveal any abnormality or trauma - related injury .
a skull fracture , with a small subdural hemorrhage at the right frontal convexity was evident on brain and facial ct .
spinal ct revealed acute fractures at the c67 bilateral articular facets and the right - side lamina of c6 ( fig . 
2b ) . on the first day of admission , the patient underwent microscopy - assisted corpectomy and discectomy with anterior interbody fusion .
postoperatively , the patient remained in the icu for monitoring . on the fifth postoperative day ( pod ) , a pneumonic infiltration with pleural effusion was evident on a follow - up chest x - ray ( fig .  3 ) .
bronchoscopy was performed , and a large volume of purulent secretion was evident in the dependent portion .
the patient was transferred to the division of pulmonology for further respiratory treatment in an icu .
antibiotics were commenced , ventilator support put in place , and a tracheostomy performed . during the icu
stay , intermittent bradycardia ( 3055  beats / min ) was evident , without specific symptoms ; his vital signs were stable .
intravenous atropine ( 0.25  mg ) was given twice to treat severe bradycardia ; the heart rate was recovered in a few seconds .
echocardiography revealed no specific abnormality , and the left ventricle exhibited normal systolic function ( ejection fraction 60% ) . on the 22nd pod ,
chest ct was scheduled for differential diagnosis of a pulmonary thromboembolism . during a positional change
prior to imaging in the ct suite , the heart rate fell to 23  beats / min , and blood pressure was not palpable at the carotid artery .
after immediate cardiac massage over 1  min , the patient was resuscitated and exhibited stable vital signs .
holter monitoring was performed on the day after cardiac arrest ( fig .  4 ) .
however , 26 pauses were evident , the longest of which was 17.9  s. a temporary cardiac pacemaker was initially placed because of the patient 's poor general condition and the risk of infection . on the 31st pod ,
the patient was transferred to the department of rehabilitation after ventilator weaning on the 90th pod and was discharged 2 months later .
cardiovascular complications , such as bradycardia , arterial hypotension , and loss of peripheral vascular tone , are common complications of acute sci.3 , 4 such cardiovascular phenomena are usually observed in patients with upper thoracic or cervical scis .
bradycardia is the most common form of dysrhythmia developing after sci , especially in the acute phase of injury .
several studies have shown that almost all patients with complete cervical scis will develop bradycardia , and 16% will suffer cardiac arrest.5 , 9 cardiac dysfunction usually commences within 35 days after injury , and it typically resolves in 68 weeks.8 , 10 although bradycardia developing after acute sci is usually temporary , there is a real risk of cardiac arrest , and adequate management is required .
treatment of bradycardia in sci patients generally involves administration of oxygen , atropine , inotropes , and aminophylline .
temporary and permanent pacemakers have been placed in patients who are refractory to general treatment and experience life - threatening events such as cardiac arrest.10 , 11 we recommend that patients with acute scis should be admitted to icus or similar high - care settings in order to facilitate acute cardiopulmonary management ; this is especially important if a patient has a high - level sci or exhibits hemodynamic instability .
several studies have shown that icu monitoring and aggressive medical management improve the outcomes of patients with acute scis.12 , 13 additionally , such patients can develop multiple ( cardiovascular , respiratory , and urinary ) complications , trophic skin changes , and heterotopic ossification . hence , a multidisciplinary icu approach is needed to minimize various problems .
however , most clinicians do not recognize the risk of severe bradycardia that can trigger cardiac arrest and often misdiagnose the conditions that then would develop . in our case ,
the patient was transferred from the department of orthopedics to the division of pulmonology because he developed respiratory complications and thus required further icu care after surgery .
the patient usually self - recovered and was stable , and showed no specific symptoms . on the 22nd pod , a ct to explore the possibility of pulmonary thromboembolism
was planned because the hypoxia was persistent and the d - dimer level was elevated . however , the patient went into cardiac arrest during a positional change in the ct suite located outside the icu .
consequently , a cardiac pacemaker was inserted after asystole was confirmed by 24-h holter monitoring .
disruption of the supraspinal sympathetic pathways , inducing parasympathetic dominance , by a cervical sci , is the major cause of cardiovascular instability.15 , 16 the preganglionic sympathetic nerve fibers exit the spinal cord at the first - to - fourth thoracic vertebrae ( t1t4 ) and are controlled by higher centers via messages transmitted through the cervical spinal cord .
however , the parasympathetic system is controlled by the vagus nerve , which originates in the medulla .
thus , the extent of sympathetic dysfunction is related to the location and severity of the sci .
any increase in vagal reflexes , as might be induced by tracheal suctioning , a hypoxic episode , or a change in posture , can precipitate a bradycardia  event .
other studies have shown that the sympathetic hypoactivity gradually improves within 46 weeks after injury.5 , 16 the proportion of sci patients requiring a pacemaker ranges from 9% to 17%.5 , 10 , 18 percutaneous cardiac pacing is only a temporary tool employed in emergency situations .
such a pacemaker is associated with risks of injury , skeletal muscle contraction , and pacing failure , and it suffices only until permanent transvenous cardiac pacing can be established .
cardiac pacemaker implantation is indicated for patients with high - level scis and continuing symptomatic bradycardia and they do not respond to medical management or suffer recurrent cardiac arrests .
sanghvi et  al described a patient with a traumatic c7d1 dislocation who experienced continuous severe bradycardia and cardiac arrest for 2 months after injury .
gilgoff et  al reported a patient with a c2 sci causing complete quadriplegia ; the patient experienced symptomatic bradycardia for 21 months after injury despite intensive medical management .
clinical improvement was evident after insertion of a cardiac pacemaker . in conclusion , patients who suffer scis are at risk of severe bradycardia and cardiac arrest attributable to dysfunction of the autonomic nervous system .
the risks are highest during the acute phase of injury and in patients with upper thoracic or cervical scis . monitoring in an icu , careful assessment of autonomic dysfunction , and aggressive medical management ,
in addition , procedures that may increase vagal reflexes should be very carefully performed after prior preparation for a possible emergency situation that may develop very rapidly .
 bradycardia is the most common form of dysrhythmia developing after disruption of the sympathetic pathway by a spinal cord injury ( sci ) , and it can have fatal consequences , including cardiac arrest . here , we report a case of cardiac arrest developing after cervical sci attributable to sympathetic hypoactivity . 
 a 26-year - old male pedestrian was admitted after a traffic accident . 
 radiologically , fractures were apparent at the c67 bilateral articular facets , and cord contusion with hemorrhage was evident at c47 . during his stay in icu , intermittent bradycardia was noted , but the symptoms were not specific . on the 22nd postoperative day , the patient was taken to the computed tomography suite for further evaluation and experienced cardiac arrest during a positional change . 
 after immediate cardiac massage , the patient was resuscitated . 
 we scheduled holter monitoring , which detected 26 pauses , the longest of which was 17.9  s. the patient underwent cardiac pacemaker insertion . 
 no further cardiac events were noted . 
Introduction
Case report
Discussion