Quiz 23

A 64 year old man, previously in excellent health - is brought to the ER with sudden onset confusion. He does not remember where he lives, nor does he know his wife's name. He cannot recognize any of his family. He asks his wife over and over again about why he is in the hospital. Besides this, his neurological exam is normal. He is very jovial and makes sense. He is alert, afebrile, without any evidence of trauma. His labs, including a CT scan of his head and Sodium/K/CO2/ABG/BUN/Cr/Glucose/CBC/Alcohol level/Drug screen are normal.
6 hours later, he has completely recovered.

Q1. Your next step should be to:

1. Get an ultrasound of his carotids
2. Get an MRI to view the white matter carefully
3. Get an angiogram to view his vasculature
4. Do no further testing
5. Get CSF for analysis

The answer is choice 4. (Do no further studies). The patient has typical Transient global amnesia. He has no focal deficit and has sudden loss of short term memory and mild confusion with preserved intellect. The etiology of this is unknown. Patients have normal lab results. Although memory to person may be preserved, it is a funny situation where the patient will ask the same questions over and over again within a matter of minutes.

One of my patients recognized his wife but repeatedly asked her "how did I get here?" and "why have you brought me here?". His wife was worried but holding her stomach and laughing. He completely recovered few hours later. The episode usually terminates within 2-12 hours.

Q2. In your workup of the patient, you find that the patient has tested positive on ELISA for lymes disease.

1. Get CSF for analysis
2. Culture blood
3. Tests for syphilis to test for cross reactivity
4. Western Blot test for Lymes disease
5. Nerve conduction in the facial nerve

The answer is choice 4. (Western Blot for Lymes disease). This is almost algorithmic. If you come across a Positive Lyme titer, the current recommendations are to test for it with Western Blot test. As one ages, the frequency of positive Lyme titer using ELISA increases (10% @ age 70). In this case, it may be a false positive ELISA result as sudden confusion is not a feature of lymes disease. Facial nerve paralysis is possible with lymes disease but in a patient without any facial deficit, nerve conduction is no use. In a 64 year old person, the likelihood of syphilis presenting is low. As far as cross reactivity is concerned, patients with a positive VDRL can have false positive Lyme ELISA but not the other way around. Diseases that give false positive ELISA are SLE, RA, Mono & Echo virus.