What Causes Locked in Syndrome LIS

Locked-in Syndrome

Abbreviation: LiS
Synonyms: pseudocoma, ventral pons syndrome, deefferent status, Monte Christo syndrome
English: locked-in syndrome

1 definition

The Locked-in Syndrome (LiS) is a rare neurological disease that occurs in a bilateral partial lesion of the cross-section of the brain stem. This results in tetraplegia involving the caudal cranial nerves. A complete inability to move while conscious is typical for the clinical picture. The affected person is only capable of vertical eye and eyelid movements. (Therefore the name locked-in: locked in)

2 epidemiology

So far, little has been statistically recorded on the incidence of locked-in syndrome in general. Although publications on this topic have increased in recent years, these are primarily descriptions of individual cases. Rough estimates assume that every hundredth to one thousandth stroke is associated with LiS.

Mortality can generally be classified as high. Many patients with LiS are not recognized as such. A mortality rate of 67% for vascular etiology and 41% for nonvascular causes was found.

Statistics from the years 1978-1988 from the University Clinic in Bern indicate the occurrence of LiS in 32 of approx. 100,000 patients.

3 causes / pathogenesis

3.1 vascular causes

The syndrome usually arises as a result of a thrombosis of the basilar artery, which leads to an extensive infarction in the foot of the bridge. There is a complete disruption of the ventrally located corticobulbar and corticospinal tract, possibly also part of the pontine reticular formation. The location of the vascular occlusion is decisive for the clinical symptoms and the likelihood of the development of LiS.

3.2 non-vascular causes

This umbrella term can be used to summarize all cases of LiS that are not directly attributable to a heart attack, bleeding or embolism. These can be:

Polyradiculitis cranialis, a severe crisis in myasthenia gravis, as well as neuromuscular blocking drugs can clinically produce a similar picture.

4 symptoms

The selective and complete damage to the motor nerve tracts while the rest of the tissue is preserved causes the unusual appearance of the LiS: Typically, vigilance and speech understanding are not impaired. The four extremities and the horizontal motor skills at pontine level are paralyzed, while the vertical turning of the gaze controlled by the rostral mesencephalon still works. The function of the caudal cranial nerves (swallowing, speaking and usually also facial functions) also fail. Therefore, the LiS must also be differentiated from the vegetative state.

5 diagnostics

Long-term, careful monitoring is necessary for reliable diagnosis of the LiS. EEG examinations, acoustic, somatosensory and motor evoked potentials (MEP) are particularly helpful.

Above all, it is important to distinguish the LiS from a number of other neurological disorders:

6 therapy

In the acute initial phase, therapeutic measures that are identical to the treatment of a stroke are indicated. In addition, it is important to create communication options for the patient as quickly as possible. Letter boards (to promote learning of vertical eye movements as a means of communication) and special computers can be used. Intensive combinations of physiotherapy, occupational therapy and speech therapy have proven effective in practice. Furthermore, the treatment includes the use of technical aids and psychological processing aids as well as social and professional integration.

Improvements can often be seen long after the onset of the illness.

7 links

LIS Locked-In-Syndrome e.V.