Table 2.
Differential Diagnosis of Limbic Encephalitis
| HSV-1 Encephalitis |
HHV6 | VZV | SLE | Sjögren Syndrome | PACNS | |
|---|---|---|---|---|---|---|
| Clinical syndrome | Seizures, headache, personality changes, confusion and fever | Confusion, agitation, short-term memory loss, seizures, tremor, ataxia, focal signs, headache, fever | Headache, confusion, fever, meningeal signs (20–30 %). Seizures are rare. Dermatomal rash in 50% | Anxiety, mood disorders, psychosis, seizures, headache | Seizures, meningeal signs, cognitive dysfunction, long tract signs | Headache, cognitive dysfunction, focal signs |
| MRI: uni- or bilateral temporomesial T2/FLAIR hyperintensities | Very frequent 90 % | Frequent | Less frequent 40–70 % | Very rare | Very rare | Very rare |
| CSF | Pleocytosis, moderate protein increase. Red blood cells frequent | Lymphocytic pleocytosis, moderate protein increase | Pleocytosis, moderate protein increase. Red blood cells uncommon | Sometimes increased protein, pleocytosis rare | Pleocytosis, increased protein | Increased protein, sometimes pleocytosis |
| EEG | 80 % abnormal, paroxysmal sharp waves and spikes. Temporal bi- and triphasic waves and PLEDs | Diffuse slowing, occasionally spikes and sharp waves | Paroxysmal sharp waves and spikes. | Diffuse slowing, spikes and sharp waves | Diffuse slowing, spikes and sharp waves | Focal and diffuse slowing |
| Diagnostic tests and distinctive features | HSV-PCR in CSF Seizures very common | HHV6-PCR in CSF Immunocompromised patients | VZV-PCR in CSF Herpes zoster rash 50 % Immunocompromised patients | dsDNA-antibodies Systemic SLE features | SS-A, SS-B antibodies salivary gland imaging and biopsy | Biopsy Angiography |
| Therapy | Aciclovir, neurological sequelae common, high morbidity and mortality | Foscarnet, cidofovir, ganciclovir | Aciclovir, neurologic sequelae common. | Steroids, azathioprinecyclophosphamide, rituximab | Steroids, immunosuppressants | Steroids, cyclophosphamide |
CSF = cerebrospinal fluid; EEG = electroencephalograph; FLAIR = fluid attenuated inversion recovery; HHV-6 = human herpes virus 6; HIV = human immunodeficiency virus; HSV-1 = herpes simplex virus 1; ocb = oligoclonal bands; MRI = magnetic resonance image; PACNS = primary angiitis of the central nervous system; PLEDS = periodic lateralised epileptiform discharges; SLE = systemic lupus erythematosus; VZV = varicella zoster virus.