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Flashcards in Lab tests Deck (17)
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1
Q

What can cause elevated protein in CSF?

A

Infection, demyelination, tumor, sarcoidosis, and age

2
Q

What does a positive EBV PCR from CSF in an AIDS patient (or immunocompromised) indicate?

A

Highly suggestive of a CNS lymphoma

3
Q

What conditions can cause oligoclonal bands in CSF?

A

Demyelination (e.g. MS), infection (e.g. Lyme disease), noninfectious inflammatory processes (e.g. SLE)

4
Q

What is 14-3-3 protein in the CSF suggestive of?

A

Creutzfeldt-Jakob disease

5
Q

What is the most common complication of LPs?

A

Low-pressure HA. Treated by having patient lie flat and drink lots of fluids and caffeine

6
Q

When should a CT be ordered before an LP?

A

Always, except in the setting of suspected bacterial meningitis (don’t want to wait).

7
Q

When should an LP not be performed?

A

When CT indicates closure of the 4th ventricle and quadrigeminal cistern, increased ICP

8
Q

What are evoked potentials?

A

Electrical potentials that are recorded from the brain, spinal cord, or peripheral nervous system in response to stimulus

9
Q

How are visual evoked potentials (VEPs) elicited and what do they help diagnose?

A

A visual target is presented to the patient and the surface potentials are recorded over the occipital lobe. A delay in the P100 potential suggests dysfunction in the optic nerve (helpful for the diagnosis of optic neuritis and MS)

10
Q

What do different electromyography (EMG) results indicate?

A

Reduced muscle activation is seen in CNS disease, reduced recruitment suggests PNS disease, early recruitment indicates myopathic disease

11
Q

What labs should be done before administering tPA?

A

A CBC, blood glucose, and coagulation profile - to check that the patient is not at increased risk for hemorrhage or does not have an abnormal glucose level which may be causing their symptoms

12
Q

What are lab findings of Wilson disease?

A

Increased serum copper and decreased serum ceruloplasmin. Increased 24-hour urinary copper excretion is the most sensitive screening test

13
Q

What is normal ICP?

A

<15 mm Hg

14
Q

What is the cerebral perfusion pressure (CPP)?

A

The difference between the MAP and ICP. A goal CPP is between 60 and 75 mm Hg

15
Q

What is a normal opening pressure?

A

6-15 cm H2O

16
Q

What is the CSF profile of a postictal patient?

A

Normal

17
Q

What is the CSF profile of a patient with normal pressure hydrocephalus?

A

Normal