Abstracts

Rationale: Tonic spasm has been reported in the setting of MS, NMO, and vascular events. Mathews et al. first recognized brief, painful, and paroxysmal flexor contractions of the extremities and referred to them as "tonic seizures" in 1958. Methods: A systematic review of the literature (through June 2016) for studies reporting on cases, treatments, and the mechanism of tonic spasm was performed using PRISMA guidelines to explore the current definitions, mechanisms, and treatments for tonic spasm. We report a case of tonic spasms arising from the spinal cord presenting as epileptic seizures with subsequent cardiac arrest. Results: A 58-year-old woman was referred to our inpatient EMU for evaluation of 11 years of recurrent episodes of "twitching-like" movements of both arms, followed by stiffening in all four extremities. She also reported the inability to speak and difficulty breathing during the episodes. She denied loss of consciousness or confusion. The attacks began suddenly, occurring 1 to 50 times per day, lasting seconds to minutes, and were extremely distressing and painful. The episodes first occurred about three months after an ACDF surgery for spinal stenosis. Her admission exam was unremarkable. On day two of admission, she started to have a typical episode. She developed shortness of breath, generalized pain, and started having brief and frequent stereotyped tonic contractions of all extremities. The contractions involved the upper trunk, including the chest wall. The tonic spasmodic movements became more prolonged and sustained, causing dyspnea with hypoxemia for several minutes. EEG during the event showed rhythmic EMG artifact with no epileptiform activity suggestive of a non-epileptic etiology. She eventually became very pale, unresponsive, and subsequently developed cardiac arrest. CPR was instituted, with ROSC achieved within five minutes. She was intubated and transferred to the ICU, where she then developed several further attacks, triggered by passive movements and stimulation of the upper airways. MRI of the brain was unremarkable, however, the cervical spine MRI showed a subtle linear area of myelomalacia at the level C3 to C5. She was started on carbamazepine with a significant decrease in the frequency of the episodes. Oral clonazepam was then added to the regimen. The resulting clinical response was dramatic, with an eventual complete cessation of the crisis and events. Conclusions: To our knowledge, this is the first reported case of tonic spasm preceded by a cervical surgery. The mechanism of the attacks is debated, but existing anecdotal studies suggests ephaptic activation as the pathophysiology of this condition. Patients in similar case reports had multiple brain and spine lesions; therefore an exact localization was not identifiable. Our case is unique however; as it suggests that tonic spasm is related to the cervical spinal cord injury, given the temporal relationship to our patient's cervical spine injury and her normal brain imaging. This study highlights the importance of the evaluation of epileptic and non-epileptic events in the EMU as the standard diagnostic test to further clarify the etiology and treatment. Funding: NONE