105. A 70 year old male is admitted to the hospital with a left hemiparesis and altered consciousness. He is on aspirin 75 mg OD, atrovostatin 10mg OD and glibenclamide 15mg daily. His wife says he has been unwell for a couple of days and he has been off food. He has however, still been giving him all his medications. Which of the following tests is going to be most useful in finding a immediately reversible cause for his symptoms

**Core Concept**
The patient's presentation of left hemiparesis and altered consciousness suggests a possible stroke or cerebral vasculature compromise. The patient's medication regimen includes anticoagulation with aspirin, which increases the risk of bleeding. The patient's altered mental status and hemiparesis may be related to a hemorrhagic stroke or other intracranial hemorrhage.

**Why the Correct Answer is Right**
The patient's symptoms are suggestive of a hemorrhagic stroke, and the most useful test to diagnose this condition would be a non-contrast computed tomography (CT) scan of the brain. This test can quickly identify acute hemorrhage as a cause of the patient's symptoms. A CT scan is preferred because it is faster and more sensitive than magnetic resonance imaging (MRI) for detecting acute hemorrhage. The CT scan can also help to rule out other causes of the patient's symptoms, such as ischemic stroke or other intracranial pathology.

**Why Each Wrong Option is Incorrect**
**Option A:** A lumbar puncture (LP) may be useful in diagnosing conditions such as meningitis or subarachnoid hemorrhage, but it is not the most immediate test for diagnosing a hemorrhagic stroke. LP can also cause further complications in a patient with a possible intracranial hemorrhage.

**Option B:** An electroencephalogram (EEG) may be useful in diagnosing seizures or encephalopathy, but it is not useful in diagnosing a hemorrhagic stroke. EEG can also be affected by sedatives and other medications that the patient is taking.

**Option C:** An MRI of the brain may be useful in diagnosing conditions such as ischemic stroke, but it is not as sensitive as a CT scan for detecting acute hemorrhage. MRI is also not as readily available as CT and may take longer to perform.

**Option D:** A complete blood count (CBC) may be useful in diagnosing conditions such as anemia or infection, but it is not useful in diagnosing a hemorrhagic stroke. CBC can also be affected by medications such as aspirin.

**Clinical Pearl / High-Yield Fact**
In a patient with suspected stroke, a non-contrast CT scan of the brain is the preferred initial imaging study because it is faster and more sensitive than MRI for detecting acute hemorrhage.

**Correct Answer:** C. MRI of the brain may be useful in diagnosing conditions such as ischemic stroke, but it is not as sensitive as a CT scan for detecting acute hemorrhage.

✓ Correct Answer: A. Blood glucose levels