Background: Little is known about clinical features and lesion topography in patients with dyspnic medullary infarction (MI). We aimed to evaluate the frequency and the clinicoradiological profile in dyspnic MI patients.
Methods: Clinical records and magnetic resonance (MR) imaging findings were reviewed serially in 2144 inpatients (1211 men and 933 women) with acute ischemic stroke from 2007 to 2013. The prevalence and the clinicoradiological features were analyzed in DMI patients. Patients with extensive infarction in the brainstem or the posterior circulation area, and cerebral hernia were excluded.
Results: Ninety-five patients (47 men and 48 women) developed MI. Six patients (2 men and 4 women) had respiratory dysfunction. The prevalence of dyspnic MI was 6.3% (4.3% in men and 8.3% in women) in MI patients, and 0.3% (0.2 % in men and 0.4% in women) in cerebral infarction patients. Neurological examination revealed cough syncope after hiccup, circulatory failure, bulbar palsy, sensory deficits or dysuria in dyspnic MI patients. The prognosis was poor in 4 patients, and recovered in each one patient with and without intervention. The mean age (SD) was 70.0 (22.0) years. MR imaging disclosed three types of lesion topography: 1) the bilateral medial and the right tegmental lesions in the upper and the middle medulla oblongata, 2) the right-predominant extensive lesions in the lower medulla oblongata, and 3) the left lateral and tegmental lesions in the lower medulla oblongata. MR angiography and cerebral angiography showed severe degree of atherosclerotic changes, dural arteriovenous fistula or dissection in the vertebral artery.
Conclusion: The present study indicated that the prevalence of dyspneic MI was 0.3% among patients with ischemic stroke and 6.3% among MI patients. The symptomatic profile suggested cough, hiccup and additional damages of the urinary center and the circulatory center near the respiratory center in the medulla oblongata. The pathognomonic lesions were found unilaterally or bilaterally in the distinct medullary territory, including the medullary tegmentum. Arteriosclerosis, arterial dissection and vascular malformation of the vertebral artery could play a crucial role in the pathogenesis of the distinct lesion topography.