Tuesday, 27 September 2011

L'hermitte's sign

Level 1: In response to a query in outpatients today regarding L'hermitte's sign.

Spinal cord disease: L'hermitte's sign is the electric shock-like sensation that runs down the back and into the limbs on flexion of the neck. It is non-specific and simply indicates pathology of the posterior columns* of the spinal cord. In young adults it usually occurs in association with demyelination and other inflammatory myelopathies. However, it can occur as a result of compressive myelopathy, radiation myelopathy, subacute combined degeneration of the spinal cord (vB12 deficiency), copper deficiency, tumours, etc. Reverse L'hermitte's sign is when the shock-like sensation radiates up the spine; this is due to involvement of the posterior columns lower down the spinal cord.

*"Please note that posterior columns, not dorsal columns, is the correct anatomical term used to describe human anatomy. Dorsal and ventral terms should be restricted to describe veterinary anatomy; spot the error in the labelling of the diagram below. Unfortunately, dorsal is so entrenched in the human anatomy jargon that it is unlikely to be replace sometime soon by the exclusive use of posterior."

Frontal lobe disease:

Another eponymous sign that is also sometimes called L'hermitte's sign, or preferably L'hermitte's frontal lobe sign, is utilisation behaviour. Patients inappropriately grab objects, but use them appropriately. This occurs as a result of unilateral or bilateral frontal lobe lesions. Utilisation behaviour often occurs in association with imitation behavior; the inappropriate imitation of certain task or posture.

Utilisation behaviour: (A) Bilateral infarction of the territory of Huebner's artery; old haematoma of the medial part of the corpus callosum; bilateral demyelination of the white matter. (B) Smoking behaviour. (C) Putting glasses on the nose. (Compston Brain (2005) 128(1): 3-4 doi:10.1093/brain/awh361)

History of Neurology: Jean L'hermitte (1877 - 1959) was born in Mont-Saint-Père, studied in Paris and graduated in medicine in 1907. He specialised in neurology and became Chef-de-clinique (resident) for nervous diseases in 1908, Chef de laboratoire in 1910, and professeur agrégé for psychiatry1922. He later became Médecin des Hôpitaux at the "Hospice Paul Brousse", head of the foundation "Dejerine", and clinical director at the Salpêtrière Hospital.

1 comment:

  1. Nice blog! But I'm compelled to point out that Terminologia Anatomica lists dorsal and ventral on an equal footing with posterior and anterior for the structures in the spinal cord that take these adjectives. This makes sense in the spine, since these axes more or less coincide there. As you move into the cranium, however, dorsal-ventral becomes very distinct from anterior-posterior because dorsal-ventral is relative to the tortuous neuraxis while anterior-posterior is always relative to anatomic position. If you maintain that they're equivalent orientation terms but differ only in that one pair is for humans and the other for other animals, what name would you propose for what is presently known as the anteroventral nucleus of thalamus?

    -An atomist