Nikesh Ardeshna, MD
Dr. Ardeshna is the Medical Director of Adult Epilepsy Services at Royal Oak Hospital, Beaumont Health System, in Royal Oak, Michigan.
A 56-year-old female is admitted after being found unresponsive at home. Blood pressure in the ED was 250/120, temperature 98.3, and creatanine 9.63. An initial CT of the head is negative, MRI brain does not reveal any acute abnormalities. The patient is intubated for airway protection. Medical history includes hypertension, diabetes, and end-stage renal disease on hemodialysis. History from the patient’s family indicates that the patient had missed her last two hemodialysis sessions, and is not always complaint with her medications. An EEG shows frequent triphasic waves.
The most likely diagnosis for the patient is:
A. Stroke
B. Meningitis/encephalitis
C. Head trauma
D. Metabolic encephalopathy, combination of hypertensive emergency and renal failure
The correct answer is D—metabolic encephalopathy. The patient is unresponsive due to uncontrolled blood pressure and severe renal failure.
Frequent causes of triphasic waves on an EEG include:
A. Renal failure
B. Hepatic failure
C. Medications
D. All of the above
The correct answer is D—all of the above. Metabolic imbalances are the most common causes of triphasic waves on an EEG.
Typical EEG features of triphasic waves include:
A. Three phases in each waveform
B. An anterior-posterior lag
C. Mostly, frontally predominant
D. All of the above.
Again, the correct answer is D—all of the above. All of the above are classic defining features of triphasic waves on an EEG.
