Certified Neuroscience Registered Nurse (CNRN) Practice Exam

Why do MS patients being treated with Tysabri require intensive long-term monitoring?

1. There is a 1/1000 risk of developing progressive multifocal leukoencephalopathy

2. There's a chance of allergic reaction

3. Side effects include severe headaches

4. It may cause weight gain

The correct answer is: There is a 1/1000 risk of developing progressive multifocal leukoencephalopathy

Patients with Multiple Sclerosis (MS) being treated with Tysabri (natalizumab) require intensive long-term monitoring due to the associated risk of developing progressive multifocal leukoencephalopathy (PML), which occurs in approximately 1 out of every 1,000 patients treated with the medication. PML is a serious and potentially fatal brain infection caused by the John Cunningham virus (JCV). This virus is commonly dormant in the population but can become activated in patients who are immunocompromised, such as those receiving immunosuppressive treatments like Tysabri. The incidence of PML increases with the duration of treatment, the presence of prior immunosuppressive therapy, and the presence of antibodies to JCV. Therefore, ongoing monitoring for any early signs or symptoms of PML is critical for timely intervention, as the condition can rapidly lead to severe neurological impairment or death if not recognized and managed promptly. While allergic reactions, side effects such as severe headaches, and issues like weight gain are concerns associated with medication use, they are not as critical to monitor as the risk of PML, which poses a significant threat to the patient's health and neurological function. Thus, the focus on intensive long-term monitoring