T2 weighted magnetic resonance scan image showing bilaterally symmetrical hyperintensities in caudate nucleus (small, thin arrow), putamen (long arrow), with sparing of globus pallidus (broad arrow), suggestive of extrapontine<unk>  (osmotic demyelination syndrome) Symptoms depend on the regions of the brain involved. Prior to its onset, patients may present with the neurological signs and symptoms of hyponatraemic encephalopathy such as nausea and vomiting, confusion, headache and seizures. These symptoms may resolve with normalisation of the serum sodium concentration. Three to five days later, a second phase of neurological manifestations occurs correlating with the onset of<unk> . Observable immediate precursors may include seizures, disturbed consciousness, gait changes, and decrease or cessation of respiratory function. The classical clinical presentation is the progressive development of spastic quadriparesis, pseudobulbar palsy, and emotional lability (pseudobulbar affect), with other more variable neurological features associated with brainstem damage. These result from a rapid<unk>  of the corticobulbar and corticospinal tracts in the brainstem. In about ten per cent of people with<unk> , extrapontine<unk>  is also found. In these cases symptoms of Parkinson's disease may be generated.
Central pontine myelinolysis
Paraneoplastic cerebellar degeneration
Leukoencephalopathy
Bickerstaff brainstem encephalitis
Acute flaccid myelitis
Acute disseminated encephalomyelitis
Cerebellar stroke syndrome
Tropical neuropathy