Introduction: Cervical medullary injury is a severe type of spinal cord injury that can lead to neurogenic bladder and neurogenic rectum, which increases the risk of autonomic dysreflexia (AD) in patients. Autonomic dysreflexia is a common group of clinical syndromes characterized by autonomic dysfunction after spinal cord injury in the T6 or higher level. If left untreated, AD can lead to severe complications such as hypertensive crisis, paroxysms, intracranial hemorrhage, and even death. Nursing interventions are crucial in selecting the timing of catheterization for a patient with frequent AD during intermittent catheterization for cervical medullary injury, enhancing the overall quality of care for patients with cervical medullary injury. Case Presentation: This study focused on a tetraplegic patient with a cervical medullary injury who developed AD during intermittent catheterization. The factors influencing AD during intermittent catheterization were explored through a literature review, urodynamics, and a bladder scanner. The nursing interventions implemented included active control of AD, personalized assessment of the risk of abnormal autonomic dysreflexia, prevention, early identification, acute episode management, precise bladder management, and implementation of a personalized care plan. After 31 days of treatment, the number of AD episodes was significantly reduced, leakage was decreased, and urine volume was controlled in the normal range with good results. The key points of care included timely control of urine output, selection of the best catheterization timing, and other health education methods. The nursing interventions played an active and effective role in maintaining normal bladder function, and the patient resumed regular intermittent catheterization. Conclusions: Nursing interventions are vital in managing patients with cervical medullary injuries who require intermittent catheterization. A comprehensive nursing care plan that includes personalized assessment and management of AD can significantly improve outcomes for these patients and prevent the occurrence of AD, ultimately leading to a better quality of life.