ASAS due to spinal cord infarction is very rare and the diagnosis is challenging when encountered in a previously healthy young patient. Our patient was previously healthy, and extensive investigations including laboratory screening for autoimmune-associated vasculitis, infections, hypercoagulopathies, and CSF analysis identified no risk factors. Severe neck pain 2 days before admission was an alarming sign of ASAS, but it might be impossible to consider ASAS in a patient without any risk factors and MRI did not seem to reveal any abnormalities on admission. Young patients have been described in several previous studies, but those cases mostly involved children, adolescents, or young patients with previous trauma or angioma.7–9 Emergency physicians must therefore consider ASAS when encountering a patient with sudden onset of quadriplegia, even if the patient is previously healthy and young.
MRI findings in the early stage are usually ambiguous, and correct interpretation is difficult for emergency physicians, but ASAS must be considered once spinal epidural hematoma has been ruled out by CT and MRI. We have previously reported that MRI can detect ASAS using a combination of DWI with ADC mapping in the early stage.6
No standardized guidelines have been set for the treatment of ASAS. A previous retrospective study did not show any difference in the clinical course of patients who received antiplatelet therapy, even if they received treatment with corticosteroids or anticoagulation (heparin).10 We used edaravone for 14 days, heparin for 21 days, aspirin and steroid pulse therapy (methylprednisolone 1000 mg/day for 5 days first and 3 days later) in the early stage. She was able to move her left arm with biceps MMT 4/5, and right arm with biceps MMT 3/5 (Table 1) on hospital day 48, although sensory deficit remained below the T4 level, which was much better than we had predicted. These effects might have been due to early combination therapy with edaravone, heparin, aspirin, and steroid usages. In contrast, no previous ASAS cases used such a combination therapy and neurological outcomes were unfavorable. Long cord lesions, severe initial impairment with weakness and female sex have been reported as predictors of unfavorable outcomes.11,12 In our case, the patient had all these unfavorable predictors, but could move her left hand and eat unassisted. However, she could not stand unaided, was wheelchair-bound and was still experiencing bladder dysfunction when transferred from our facility. Symptoms were better than we predicted based on initial MRI showing long cord lesions from C3 to T1 and complete flaccid quadriplegia without pain or temperature sensation.
In conclusion, ASAS can cause sudden onset of neck pain with quadriplegia in a young healthy woman, and DWI of the spine should be considered for early diagnosis of ASAS. Early combination treatment with edaravone, antiplatelet agents, corticosteroids and anticoagulants heparin, and aspirin with steroid pulse might be beneficial for patients with ASAS.