infarct in the lateral medulla , resulting in the clinical syndrome called wallenberg syndrome , is known to be associated with multitudes of peculiar symptoms in patients . commonly encountered features are contralateral body sensory loss to pain and temperature , ipsilateral facial sensory loss , vertigo , nausea , dysphagia , hoarseness , ipsilateral ataxia , and ipsilateral horner 's syndrome with sympathetic nerve dysfunction . we present a patient who developed intermittent rhinorrhea subsequent to ischemic stroke of the lateral medulla and cerebellum in the distribution of the posterior inferior cerebellar artery . a 74-year - old woman with atrial fibrillation , severe mitral valve regurgitation with past valve repair , coronary artery disease , hypertension , and hyperlipidemia was taken off warfarin anticoagulation in anticipation of cardiac catheterization . she then had a sudden onset of dizziness , spinning , lightheaded sensation , change in facial sensation , and horizontal diplopia . a brain mri 4 days after onset showed an acute infarct in the right posterior inferior cerebellar artery distribution , including the right lateral medulla and inferior cerebellum ( fig . 1 ) . approximately 1 month later , the patient noticed episodes of clear secretion from her nose , with the right side more affected than the left . she felt something strange was happening to her , and she had a funny feeling in her throat , a runny nose with clear fluid , and sometimes tearing , but was not able to complete sneezing . this occurred 03 times per day lasting for 515 min each time , sometimes triggered by stress , showering , or walking up steps . she was perplexed by her inability to sneeze and embarrassed and disgusted by the episodic rhinorrhea . in addition to the intermittent rhinorrhea and inability to sneeze , her persistent symptoms included constant lightheadedness and numbness of the left leg , arm , and left side of the lip . her gait had improved to walking with a walker or cane . she denied any problems with swallowing or weakness during the course of her illness . on examination , she was mildly hypertensive and the functioning of her cranial nerves was notable for normal pupils and symmetric eyelids without horner 's syndrome , intact facial sensation , and intact facial , tongue and palate movements . there was also length - dependent loss of vibration and loss of pinprick sensation in the lower extremities . coordination testing , including finger - to - nose and heel - to - shin tests , was normal . the symptoms of intermittent rhinorrhea remained unchanged at the last evaluation , 7 months after her stroke . chen et al .   reported the occurrence of contralateral rhinorrhea after a right caudate infarct . like our patient , the rhinorrhea in the reported patient started late , 2 months after stroke , and was intermittent , but rhinorrhea was induced by mastication or swallowing . we believe that in our patient , a right lateral medullary infarct caused ipsilateral rhinorrhea due to autonomic sympathetic nerve dysfunction . experimental unilateral extirpation of the sympathetic nerve at the superior cervical ganglion results in ipsilateral rhinorrhea can be a part of the autonomic symptom of cluster headache and sunct ( short - lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing ) . it is not clear why the phenomenon in our patient is intermittent or why it was delayed in onset . internal carotid artery dissection can be associated with a clinical picture consistent with cluster headaches . in studies by frigerio et al .   and rigamonti et al . , three patients with carotid artery dissection had paroxysmal head pain and autonomic symptoms typical of cluster headaches , occurring several times a day and lasting from 30 min to 2 h. though the lesions in carotid artery dissections differ from those in our patient , these cases illustrate that autonomic symptoms can be intermittent after sympathetic injury .
lateral medullary infarction , known as wallenberg syndrome , can be accompanied by sympathetic dysfunction . 
 we report a case of unilateral intermittent rhinorrhea that started after an ischemic stroke in the ipsilateral lateral medulla and cerebellum . 
 rhinorrhea might be mediated by dysfunction of the sympathetic autonomic system .