Tremor and movement disorders

Sadly, this young man suffered terribly from movement disorders, leading to literally millions of people laughing at his poor, crippled, "moon" walk. Partly as a result of this cruelty, he is now dead, which is another type of involuntary disorder that affects your ability to produce and control movement.

Definition

Movement disorders are conditions and syndromes that affect your ability to produce and control movement.
Tremor is an involuntary movement disorder of a limb in a to-and-fro manner.

Epidemiology

At some point in their lives, most people will have some type of tic, tremor or disorder. The majority are temporary and benign, but do worsen with age.

Pathophysiology

There is only one real cause: Neurological. Either there is a problem in the brain, the central nervous system or the peripheral nervous system.

That problem is usually either something worrying and degenerative, something longstanding and static, or something temporary, like alcohol use.

Clinical and Associated Features

Hyperkinetic (loads of movement!)

• Dystonia - muscle contractions, causing weird twisting, or repetitive moevement. Can affect anywhere in the body. Ranges all the way from mild cramp, to crazy upper body limb flailing. Can be painful.
• Tremor - Uncontrollable shaking of a body part. Can occur when relaxed, or during an action (intention tremor).
• Tics - Involuntary, rapid, nonrhythmic movement or sound. Tics can be controlled briefly.
• Myoclonus - A sudden, shock-like muscle contraction. Myoclonic jerks may occur singly or repetitively. Unlike tics, myoclonus cannot be controlled even briefly.
• Chorea - Rapid, nonrhythmic, usually jerky movements, most often in the arms and legs - seen in Huntingdons.

Hypokinetic (lack of movement)

• Bradykinesia - Slowness of movement.
• Freezing - Inability to begin a movement or involuntary stopping of a movement before it is completed.
• Rigidity - An increase in muscle tension when an arm or leg is moved by an outside force.
• Postural instability - Loss of ability to maintain upright posture caused by slow or absent righting reflexes.

Differential Diagnosis

Something worrying and degenerative

• Huntingons's disease - commonly causes chorea. Genetically inherited, leads to death.
• Parkinson's disease - more commonly hits in old age. Causes the parkinsonism features. Generally doesn't kill people, but can massively restrict lifestyle.
• Multiple sclerosis - can cause random issues from individual muscle weaknesses, to losing control or sensation in a leg. Takes a few years but eventually kills you.
• Other stuff - mainly brain problems - especially ones in the cerebellum, such a brain tumour or infection; or Wilson's disease.

Something longstanding and static

• Tourette's syndrome - Tourette's, well known for having people shout out "AARDVARK!", is actually mostly a cause of tics and spasms, and rarely has the vocal component.
• Essential tremor - The biggest cause in the UK population of tremor, this is a (usually) mild tremor, noted mostly in the hands, present all the time. Whilst generally benign, it can be very frustrating to the individual.

Something temporary

• Alcohol abuse - can make you walk funny, as can drug abuse.
• Infection - This is serious. Not sure I know much about it though.
• Receiving a Stone Cold Stunner - this will KNOCK YOU DOWWWWWWWWWWN!

Investigations

Depends how it presents. If you have a sudden onset loss of sight, you definitely want to screen for MS.

• Head CT wouldn't hurt either.