Mysterious Encephalopathy (Manjuck, 3/27/2024)

 A link to this presentation is available HERE.

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Thanks to Dr. Janice Manjuck, our amazing ICU director, for an entertaining and information-packed Grand Rounds this week on Evaluation of Encephalopathy in Medical Patients. I learned so much, and cannot wait to have Dr. Manjuck back. She is funnier as a presenter than I am a writer, so please do listen to her talk if you have time! If you do not, here are my brief notes.

Key points:

• When evaluating an altered patients, make sure you know their baseline
• Don't forget to look at vitals: BP (normal for them?), temperature (core) and oxygen saturation
• Labs can be helpful to determine etiology
• Labs include glucose, LFTs, ammonia (increase in mortality regardless of cause), calcium, sodium, thyroid function tests (+/- cortisol), VBG/ABG, carbon monoxide, tox screen, alcohol and drug levels.
• Ask yourself if there is a primary neurological process
• CT (non-con) vs. CTA, vs CTV (if you are concerned about hypercoagulable state), MRI (if CT normal)
• Sometimes medication administration can be diagnostic: D50, naloxone (don't ever give naloxone without suction nearby), thiamine

Altered level of consciousness (ALOC) is a spectrum. Every time you evaluate and examine a patient, you should document their baseline level of consciousness. 

• Alert
• Lethargic ("patient looks like they are just waking up from a heavy sleep")
• Obtunded ("patient looks like they took a sleeping pill)
• Stupor ("patient not waking to shaking"
• Coma

Dr. Manjuck, used a this acronym (a model by a neuro-intensivist) to explain most common reasons for encephalopathies: DOTSS: Drugs, Osmotic demyelination, Thiamine, Structural disease, Seizures)

Drugs

50% of patients with AMS are altered due to a "drug problem" -- either a drug taken by the patient, rx'd to the patient, or not given to the patient. This makes MEDICATION RECONCILIATION a very very very important tool in understanding why a patient is altered. Common meds that are associated with AMS in hospitalized patients and are not immediately recognized include: levodopa, antidepressants, and baclofen. 

Don't forget the half-life and a patient's renal function!

Anti-depressant discontinuation syndrome: FINISH (flu-like syndromes, insomnia, nausea, imbalance, and sensory disturbances including hyperarousal).

Also don't forget meth detox in altered patients

So,  as per Dr. Manjuck's pearl of the talk: "Look at the med list every single day like flossing"

Osmotic demyelination syndrome 

This is a rare but serious cause of AMS in patients with hyponatremia that is corrected too quickly.  Unlike what you may think, this actually happens much LATER than I realized -- 4-7 days AFTER correction. Clinical manifestations include: short term memory loss, dysarthrias and ataxia, flaccid quardiparesis, locked-in syndromes, seizures, and coma. 

Neuroimaging can confirm the diagnosis: "snout" and "trident" sign

ODS occurs really when initial sodium is <120 and MORE likely when it was <110, and it can occur EVEN if it was corrected slowly. 

Goal is to correct 6-8mg max per 24 hours

Thiamine Deficiency

Patients with chronic alcohol use are at high risk for Wernicke's encephalopathy, which presents as change in mental status, oculomotor dysfunction and cerebella dysfunction. 

Structural Abnormalities

10-15% of patients in the ICU with AMS have an abnormal head CT, but that doesn't mean that the abnormal head CT explains the AMS. In order for a structural lesion to cause AMS, you need to have broad disruption of the reticular activating system! This must occur in the dorsolateral upper midpons, upper mid pons, bilateral thalamus, or diffuse bi-hemispheric.

That being said, some structural abnormalities DO cause AMS. These include:

• Posterior reversible encephalopathy syndrome (PRES
• Hydrocephalus
• Diffuse cerebral edema
• Subdural hematoma
• Subarachnoid hematoma
• Diffuse cardioembolic stroke

Seizures

Non-convulsive status epilepticus (NCSE) is largely unrecognized. 

Seizures are not a "binary" thing -- that is, it is not 

The longer it takes to control them, the longer it takes to get rid of them. 

Final take homes from Dr. Manjuck:

• Make sure you do a good neuro exam on Day #1 of admission and every day. And don't forget to document that!
• Your exam should include: level of arousal, speech content, orientation, eye opening, and gross motor exam
• Do a medication reconciliation every single day. Be aware of opiate creep (opiates you didn't even know the patient was taking)
• Toxic-metabolic encephalopathy is very much a diagnosis of EXCLUSION
• Be aware of taking patient OFF anti-coagulation (diffuse cardioembolic stroke is a definite risk)