Encephalopathy work-up
Screening tests
Serum
glucose, electrolytes, calcium/phosphorus, uric acid, lactate and pyruvate, liver,
renal and thyroid
function tests
Prolactin levels (10 to 20 min after suspected seizure, diagnosis seizure vs. psychogenic nonepileptic seizure)
Serum CK
ANA, ENA, ANCA, RF, complement, ACE, anti-thyroglobulin and anti-thyroperoxidase antibodies (Hashimoto disease), autoantibody panel (thyroid antimicrosomal, antiparietal), immunoglobulins
Serum
ceruloplasmin and copper, 24h urinary copper, slit lamp, liver biopsy (WD)
CBC, ESR, CRP, plasma fibrinogen
Coagulation profile (protein C and S, ATIII, Factor Leiden V, APLS, anticardiolipin)
Serum vitamin B12 and folic acid
RPR,
TPHA
Serum cortisol, PTH and osmolality.
Serology: HIV, HSV, adenovirus, CMV, Coxsackie, polio, echovirus, hepatitis (A,B,C), parvovirus B19, mycoplasma, toxoplasma, VDRL, cysticercosis
Blood and urine organic acids and carnitine
Chest X-ray
PPD
Echocardiogram
EEG (non-convulsive status epilepticus), VEP, EMG/NCVs
Brain MRI, MRA
Conventional angiogram (CNS vasculitis)
CSF
Besides routine analysis (chemistry, cell count, smear and stainings): lactate and pyruvate (mitochondrial disease), oligoclonal bands, IgG index, VDRL, viral (measles titer), fungal, PCR (T. Whippleii, JC virus, HSV, CMV, VZV), Ziehl staining, repeated cytology,
anti-thyroglobulin and anti-thyroperoxidase antibodies (Hashimoto disease).
Specific investigations
Blood/serum
14-3-3 protein (CJD) (stable at room temperature and can be sent by regular mail)
Aminolevulinic acid, porphobilinogen, uroporphyrins, coproporphyrin
Antineural nuclear antibodies (ANNA-1(=Anti-Hu), ANNA-2 (=anti-Ri), ANNA-3, Purkinje cell cytoplasmic antibodies (PCCA-1 (=anti-Yo), PCCA-2, PCCA-Tr and mGluR1), plasma membrane cation channel antibodies (CV2/CRMP-5, Ma1, Ma2/Ta, amphiphysin, striational, voltage gated calcium channels (VGCC) and voltage gated potassium channels (VGKC), anti-NMDA-R (NR1 and NR2) antibodies.
Methylmalonic acid, VLCFA, arylsulphatase, homocysteine
Biopsy
Conjunctiva (sarcoidosis),
Small bowel (Whipple disease)
Skin (SLE, vasculitis, CADASIL)
Brain biopsy