Neuronal Autoantibody Confidence Scale (NACS) in a Patient with Autoimmune Encephalitis

Description

The Neuronal Autoantibody Confidence Scale (NACS) can help decide if autoantibodies to neuronal antigens in a patient blood or CSF are significant for explaining a neurological disorder. The authors are from Case Western Reserve University, University Hospitals of Cleveland, Alexandria University (Egypt), Akron Children's Hospital, Johns Hopkins University and Cleveland Clinic.

Patient selection: presence of neuronal autoantibodies

Parameters:

(1) antibody against intracellular antigen or voltage-gated potassium channel (VGKC)

(2) movement disorder and/or stiff person syndrome

(3) cancer and/or smoking history

(4) inflammatory CSF (high white cell count; positive IgG index; positive oligoclonal bands)

(5) hyponatremia

(6) duration in months

Parameter	Finding	Points
antibody target	no	0
	yes	1
movement disorder or stiff person syndrome	no	0
	yes	1
cancer or smoking history	no	0
	yes	1
inflammaotry CSF	no	0
	yes	1
hyponatremia	no	0
	yes	1
duration	<= 3 months	0
	> 3 months	-1

total score =

= SUM(points for all of the parameters)

Interpretation:

• minimum score: -1

• maximum score: 5

• A score > 1is an OR of 50.4 for clinically relevant autoantibody.

• A score of -1 or 0 indicates a clinically irrelevant autoantibody, while a score of 1 is indeterminate.

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