Editing Morvan's syndrome (section)

===Other symptoms===
Breathing difficulties can occur, resulting from neuromyotonic activity of the [[laryngeal muscles]].  Laryngeal spasm possibly resulting from neuromyotonia has been described previously, and this highlights that, in patients with unexplained [[laryngospasm]], neuromytonia should be added to the list of differential diagnoses.<ref name=clinical/>

Studies have shown subtly decreased metabolism on [[positron emission tomography]] (PET) and [[single photon emission computed tomography]] (SPECT) in the left inferior frontal and left [[temporal lobe]]s.<ref name=indian/> and or basal ganglia hypermetabolism.<ref name="Spinazzi"/> Ancillary laboratory tests including [[MRI]] and brain biopsy have confirmed temporal lobe involvement.  Cranial MRI shows increased signal in the [[hippocampus]].<ref name=thymoma/>

[[Cerebral spinal fluid]] (CSF) shows normal protein, [[glucose]], [[white blood cell]], and [[immunoglobulin G]] (IgG) levels, but there are weak [[oligoclonal bands]], which are absent in the [[Serum (blood)|blood serum]].  Marked changes in circadian serum levels of [[neurohormones]] and increased levels of peripheral neurotransmitters were also observed.  The absence of morphological alterations of the brain pathology, the suggestion of diffusion of IgG into the thalamus and striatum, more marked than in the cortex (consistent with effects on the thalamolimbic system) the oligoclonal bands in the CSF and the amelioration after PE all strongly support an antibody-mediated basis for the condition.<ref name=cardiac/> Raised CSF IgG concentrations and oligoclonal bands have been reported in patients with psychosis.  Anti-[[acetylcholine receptors]] (anti-AChR) antibodies have also been detected in patients with thymoma, but without clinical manifestations of [[myasthenia gravis]].<ref name=paraneoplastic/>  There have also been reports of non-paraneoplastic limbic encephalitis associated with raised serum VGKC suggesting that these antibodies may give rise to a spectrum of neurological disease presenting with symptoms arising peripherally, centrally, or both.  Yet, in two cases, oligoclonal bands were absent in the CSF and serum, and CSF immunoglobulin profiles were unremarkable.<ref name=sub-acute/>