• a concentrated, frequently symmetric, noninflammatory demyelination within the central basis pontis. (see anatomy)close
• In at least 10% of patients demyelination also occurs in extrapontine regions, including the mid brain, thalamus, basal nuclei, and cerebellum.
• The exact mechanism that strips the myelin sheath is unknown.

• alcoholism
• liver disease
• malnutrition
• hyponatraemia
  • especially <120 for >48/24
  • especially with overly aggressive Rx such that Na+ rises too quickly
  • development of hypernatraemia during Rx

• confusion
• horizontal gaze paralysis
• initially flaccid, becoming spastic quadriplegia
• pseudobulbar palsy - H&N weakness, dysphagia, dysarthria
• Locked in Syndrome if lesion is large

• supportive only
• avoid over correction of Na+

• death is common
• chronic CNS deficits such as locked-in syndrome and quadriplegia
• secondary problems - infections, VTE etc

• identical pathological changes as in CPM
• Mutism, parkinsonism, dystonia, and catatonia have all been described.
• Notable that these movement disorders are treatable with dopaminergic Rx

• caused by damage to pons - damage to ventral brainstem and pyramidal bundles and corticobulbar tracts. Midbrain and therefore oculomotor N are usually spared.
• interruption of all motor fibres from grey matter via the brainstem and also centres in brainstem responsible for facial control and speaking
• cognition is unaffected
• usually due to infarct or haemorrhage, occasionally trauma. Most common = basilar art thrombosis
• Traditional classification -
  • Pure - loss of all voluntary movement except blinking and vertical eye movements
  • Incomplete - some other motor movements
  • Total - no movements of any voluntary muscle

• Gasperini syndrome - A lesion of the caudal pons tegmentum usually caused by an ischaemic stroke, usually due to occlusion of either pontine branches of the basilar artery or the long circumferential branch of the anterior inferior cerebellar artery 1,2, but can also be seen due to demyelination or haemorrhage
  • involvement of the CN V nucleus (sensory nucleus of the trigeminal nerve): ipsilateral facial sensory loss
  • involvement of the CN VI nucleus (abducens nucleus): ipsilateral impaired eye abduction
  • involvement of the CN VII nucleus (facial nucleus): ipsilateral facial palsy and hyperacusis
  • involvement of the CN VIII nucleus: vertigo and ipsilateral nystagmus
  • involvement of the spinothalamic tract: contralateral hemi-sensory impairment

• Brissaud-Sicard syndrome - very rare pontine stroke syndrome that involves the anterolateral and inferior pons.
  • Classically, presents as ipsilateral facial cramps and contralateral hemiparesis
  • postulated to be caused by damage to the pons involving the corticospinal tract and the CN VII nucleus or nerve root 2,3. It can be caused by a posterior circulation ischaemic stroke, as well as other lesions such as neoplasm eg brainstem glioma

• Lateral pontine syndrome, also known as Marie-Foix syndrome - one of the brainstem stroke syndromes of the lateral aspect of the pons - occlusion of perforating branches of the basilar and anterior inferior cerebellar (AICA) arteries
  • corticospinal tract: contralateral hemiplegia/hemiparesis
  • spinothalamic tracts: contralateral loss of pain and temperature sensation
  • cerebellar tracts: ipsilateral limb ataxia
  • facial nerve (CN VII) nucleus: ipsilateral facial paralysis
  • vestibulocochlear nerve (CN VIII) nuclei: ipsilateral hearing loss, vertigo and nystagmus

References include:
EMed CPM review
BMJ CPM and extrapontine myelinolysis syndromes 2004
Case study - Acute Psychosis as main manifestation of CPM 2016
Concepts in: Literature review 2016
Malacards search CPM
https://rarediseases.org/rare-diseases/locked-in-syndrome/
https://radiopaedia.org/articles/locked-in-syndrome-3?lang=gb