A symmetric high-voltage, triphasic slow wave pattern is seen on EEG in the following –
**Core Concept**
The triphasic slow wave pattern on EEG is a characteristic electroencephalographic finding associated with a specific type of encephalopathy. This pattern is a result of abnormal electrical activity in the brain, which can be caused by various factors such as metabolic disorders, infections, or toxic substances.
**Why the Correct Answer is Right**
The triphasic slow wave pattern is typically seen in hepatic encephalopathy, a condition characterized by cognitive impairment and altered mental status due to liver dysfunction. The pathophysiology of this pattern is thought to be related to the accumulation of ammonia and other neurotoxic substances in the brain, which disrupt normal brain function. The triphasic slow wave pattern is often seen in patients with advanced liver disease, particularly those with a history of cirrhosis or liver failure.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the triphasic slow wave pattern is not typically associated with uremic encephalopathy, which is more commonly seen in patients with renal failure.
* **Option B:** This option is incorrect because the triphasic slow wave pattern is not a characteristic finding in subarachnoid hemorrhage, which is typically associated with a different type of EEG abnormality.
* **Option C:** This option is incorrect because the triphasic slow wave pattern is not typically associated with hypothyroidism, which can cause a variety of EEG abnormalities but not the triphasic slow wave pattern.
**Clinical Pearl / High-Yield Fact**
Hepatic encephalopathy is a medical emergency that requires prompt treatment, including lactulose and other medications to reduce ammonia levels. The triphasic slow wave pattern on EEG is a critical diagnostic clue that can help identify patients with this condition.
**Correct Answer: D. Hepatic encephalopathy**