Table 2.

Comparison of patients with PCR-confirmed herpes encephalitis, PCR-negative possible viral encephalitis, or an alternative diagnosis

Parameter	Etiology			p
	PCR-confirmed Herpes encephalitis (n=7)	PCR-negative viral encephalitis (n=48)	Alternative diagnosis (n=13)
Demographic
Female	5 (71)	25 (52)	6 (46)	0.545
Age, median years (range)	(26–75)	(14–89)	(25–78)	0.245
Prodrome
Upper respiratory tract infection	2 (29)	11 (23)	1 (8)	0.416
Tonsillectomy	1 (14)	0	0	0.012
Spinal cord stimulation operation	0	1 (2)	0	0.809
Dental infection	0	1 (2)	0	0.809
Clinical presentation
Altered behavior	6 (86)	30 (63)	10 (77)	0.344
Headache	0	5 (10)	1 (8)	0.654
Seizure	0	1 (2)	2 (15)	0.098
Loss of strength	0	1 (2)	0	0.809
Altered behavior + headache	1 (14)	11 (23)	0	0.153
Neurological examination
Altered consciousness (AC)	5 (71)	31 (65)	6 (46)	0.411
Normal	0	8 (17)	2 (15)	0.507
Minor hemiparesis + AC	1 (14)	4 (8)	1 (8)	0.863
Neck stiffness + AC	1 (14)	2 (4)	3 (23)	0.089
Papilledema + AC	0	3 (6)	0	0.520
Fever (≥38.0°C)	5 (71)	32 (66)	5 (39)	0.056
MRIa
Temporal T2 hyperintensity	6 (86)	13 (27)	1 (8)	0.001
Non-temporal lesion	0	5 (10)	9 (69)	0.000
Normal	1 (14)	30 (63)	3 (23)	0.006
EEG findings				0.635
Normal		12 (25)	1 (8)
Diffuse BEDb	2 (29)	13 (27)	3 (23)
Focal BED
Left	3 (43)	11(23)	3(23)
Right		4 (8)
Neuronal hyperexcitability	1 (14)	1 (2)	1 (8)
Generalized discharges	(-)	(-)	1 (8)
PLEDc	(-)	(-)	2 (15)
Not performed	1 (14)	7 (15)	2 (15)
CSF analysis
Neutrophilic pleocytosis	3 (43)	12 (25)	5 (39)	0.456
Lymphocytic pleocytosis	4 (57)	27 (56)	4 (31)	0.252
No cells	0	9 (19)	4 (31)	0.247
Elevated protein count (>50 mg/dL)	6 (86)	25 (52)	8 (62)	0.230

^aMRI: magnetic resonance imaging

^bBED: bioelectrical disorganization

^cPLED: Periodic lateralized epileptiform discharges.