CNRN Neuroscience Registered Nurse Certification 4 — Questions and Answers
Question 1: Which EEG pattern is pathognomonic of herpes simplex encephalitis?
- Periodic lateralized epileptiform discharges (PLEDs) in the temporal region (Correct answer)
- Generalized 3 Hz spike-and-wave complexes
- Burst-suppression pattern diffusely
- Triphasic waves over frontal regions
Correct answer: Periodic lateralized epileptiform discharges (PLEDs) in the temporal region
HSV encephalitis characteristically produces periodic lateralized epileptiform discharges (PLEDs) maximal in the temporal lobes, correlating with its predilection for temporal lobe involvement.
Question 2: A patient with Parkinson's disease is NPO post-operatively and cannot take oral carbidopa-levodopa. The nurse recognizes the greatest risk is:
- Neuroleptic malignant-like syndrome from abrupt dopaminergic withdrawal (Correct answer)
- Aspiration pneumonia from dysphagia
- Severe constipation from reduced motility
- Orthostatic hypotension from anesthesia interaction
Correct answer: Neuroleptic malignant-like syndrome from abrupt dopaminergic withdrawal
Abrupt withdrawal of dopaminergic therapy in Parkinson's disease can precipitate a potentially fatal neuroleptic malignant-like syndrome with hyperthermia, rigidity, and altered consciousness.
Question 3: The nurse is reviewing a patient's MRI report that states 'diffusion restriction in the left MCA territory.' This finding is most consistent with:
- Acute ischemic stroke within hours of onset (Correct answer)
- Subacute infarction 2–3 weeks old
- Vasogenic edema from a tumor
- Chronic lacunar infarction
Correct answer: Acute ischemic stroke within hours of onset
Diffusion-weighted imaging (DWI) restriction indicates cytotoxic edema from acute ischemia, appearing within minutes and persisting for approximately 10–14 days.
Question 4: Which intervention is most appropriate for a patient with increased ICP who has a PaCO2 of 52 mmHg?
- Increase ventilator rate to target PaCO2 35–40 mmHg (Correct answer)
- Decrease ventilator rate to promote CO2 retention
- Administer sodium bicarbonate to correct respiratory acidosis
- Obtain a chest X-ray to evaluate for pneumothorax
Correct answer: Increase ventilator rate to target PaCO2 35–40 mmHg
Hypercapnia causes cerebral vasodilation and worsens ICP; controlled ventilation targeting PaCO2 35–40 mmHg reduces ICP by promoting mild vasoconstriction.
Question 5: A patient post-transsphenoidal hypophysectomy develops polyuria with urine output of 600 mL/hr, urine specific gravity of 1.001, and serum sodium of 149 mEq/L. The nurse should prepare to administer:
- Desmopressin (DDAVP) (Correct answer)
- Furosemide
- 3% normal saline
- Vasopressin titration infusion
Correct answer: Desmopressin (DDAVP)
These findings indicate central diabetes insipidus from posterior pituitary damage; DDAVP (synthetic ADH) is the treatment of choice.
Question 6: When caring for a patient in a barbiturate coma for refractory ICP, which monitoring parameter guides therapy titration?
- Continuous EEG monitoring for burst-suppression pattern (Correct answer)
- Serial ICP waveform analysis
- Daily serum barbiturate levels
- Hourly neurological assessments
Correct answer: Continuous EEG monitoring for burst-suppression pattern
Burst-suppression on continuous EEG is the target endpoint for barbiturate coma therapy, indicating maximal metabolic suppression with minimal risk of overdose.
Question 7: A patient presents with sudden-onset unilateral facial drooping, arm weakness, and speech difficulty that completely resolved within 45 minutes. This presentation best describes:
- Transient ischemic attack (TIA) (Correct answer)
- Todd's paralysis
- Hemiplegic migraine
- Completed ischemic stroke
Correct answer: Transient ischemic attack (TIA)
A TIA presents with focal neurological deficits that resolve completely, typically within 24 hours (often <1 hour), without evidence of acute infarction on imaging.
CNRN Neuroscience Registered Nurse Certification 4
Which EEG pattern is pathognomonic of herpes simplex encephalitis?