Seizure Pathophysiology and Types of Seizures
Seizure Pathophysiology and Types of Seizures ( 3 Questions)
A nurse is assessing a client who has been taking phenytoin for seizure control. The nurse suspects phenytoin toxicity based on which of the following findings?
Nystagmus is a sign of phenytoin toxicity, which is caused by overdose, dosage changes, drug interactions, or physiological alterations. Nystagmus is a rapid, involuntary movement of the eyes, which can impair vision and balance. Nystagmus can occur at phenytoin levels above 20 mcg/mL¹².
Choice B is wrong because bradycardia, or slow heart rate, is not a common sign of phenytoin toxicity. Bradycardia can occur in rare cases of phenytoin overdose, especially if the drug is given intravenously too fast¹⁵. However, it is not a reliable indicator of phenytoin toxicity.
Choice C is wrong because hypertension, or high blood pressure, is not a sign of phenytoin toxicity. Hypertension can occur in some patients with seizures, but it is not related to phenytoin levels. Normal blood pressure ranges are less than 120/80 mm Hg for adults⁷⁹.
Choice D is wrong because hyperreflexia, or increased reflexes, is not a sign of phenytoin toxicity. Hyperreflexia can occur in some neurological disorders, such as multiple sclerosis or spinal cord injury, but it is not associated with phenytoin levels. Normal reflexes are graded from 0 to 4+, with 2+ being the average.
Nystagmus is a sign of phenytoin toxicity, which is caused by overdose, dosage changes, drug interactions, or physiological alterations. Nystagmus is a rapid, involuntary movement of the eyes, which can impair vision and balance. Nystagmus can occur at phenytoin levels above 20 mcg/mL¹².
Choice B is wrong because bradycardia, or slow heart rate, is not a common sign of phenytoin toxicity. Bradycardia can occur in rare cases of phenytoin overdose, especially if the drug is given intravenously too fast¹⁵. However, it is not a reliable indicator of phenytoin toxicity.
Choice C is wrong because hypertension, or high blood pressure, is not a sign of phenytoin toxicity. Hypertension can occur in some patients with seizures, but it is not related to phenytoin levels. Normal blood pressure ranges are less than 120/80 mm Hg for adults⁷⁹.
Choice D is wrong because hyperreflexia, or increased reflexes, is not a sign of phenytoin toxicity. Hyperreflexia can occur in some neurological disorders, such as multiple sclerosis or spinal cord injury, but it is not associated with phenytoin levels. Normal reflexes are graded from 0 to 4+, with 2+ being the average.