Clinical spectrum of voltage gated potassium channel (VGKC) autoimmunity

Tan KM, Lennon et al. Neurology 2008; 70:1883-1890. 

80 patients were found, 71 with clinical information available.  Mean age 65.

Neurologic symptoms were subacute or chronic including

1.  cognitive impairment 71 %-- see below

2.  seizures 58 %-- several types

3.  dysautonomia 33 %

4.  myoclonus  29 %

5.  dyssomnia 26 %

6.  peripheral nerve dysfunction 25 %

7.  EPS 21 %

8.  brainstem/cranial nerve dysfunction 19 %-- vision loss/blurred vision, diplopia, dysarthria, hemifacial spasm, facial numbness, anosmia.

9.  hypothalamic involvement-- 38 %-- hyponatremia (36 %) , hyperphagia, (8%) 

Common misdiagnosis was CJD (14 %)..  Other misdiagnoses:  viral encephalitis, recurrent TGA, generalized anxiety disorder, conversion disorder.

Associated tumors (paraneoplastic) 33 % confirmed histologically

carcinoma 18, adenoma 5, thymoma1, hematologic 3.

Associations

hyponatremia  36 %

other organ specific autoantibodies 49 %

coexisting autoimmune disorder 33 % (thyroiditis, DM)

34/38 responded to immunotherapy, half "vigorously" so.

Classic reports of association:

1.  Morvan's syndrome

2,  acquired neuromyotonia

3.  epilepsy

4.  limbic encephalitis

5.  dysatuonomia

6.  lung carcinoma
7. FACIAL BRACHIAL DYSTONIC SEIZURE

Cognitive presentation:

1.  frontosubcortical (personaltiy change, disinhibition,  executive dysfunction) 13 %

2.  Visual hallucination (10 %)

3.  Depression or agitation (13 %)