Movement disorders: Pathology review

In the neurology ward, there’s a mother with her child, named Justin, who is 2 years old. Justin’s mother is worried because she palpated a mass in his abdomen while bathing him. Justin also has been having episodes of rapid, dancing eye movements as well as shocklike, jerky movements of his extremities. Next, there’s a 42 year old male, named Oliver. For the past few months, Oliver has been acting strangely according to his sister. He forgets important information and is very aggressive with his family. He also has bursts of wild, dance-like movements of his arms. His sister is very anxious because their father died at age 50 after having similar symptoms. Okay, now next to Oliver, there’s a 58 year old male, named Ashton. His wife has noticed that her husband’s face has become inexpressive and he has been having hand tremor at rest for the past few months. Also, his movements have become slower, and he had frequent falls. His medical history is otherwise insignificant.

Okay, so all of them have movement disorders. The cerebrum, cerebellum, and basal ganglia all help coordinate movements, so movement disorders can be traced back to these structures. Movement disorders can be broadly grouped into 2 categories, hypokinetic disorders, which cause slowness of movement, and hyperkinetic disorders, which cause excessive involuntary movement.

Alright, when it comes to hypokinetic disorders, a lot of their symptoms are grouped together under the term “parkinsonism.” This can appear in many conditions including Parkinson’s disease itself, and other syndromes called “parkinson-plus” syndromes. These cause parkinsonism, plus other clinical features. Some Parkinson-plus syndromes include Lewy body dementia, multiple system atrophy, and progressive supranuclear palsy.

Okay, the four cardinal symptoms of parkinsonism can be remembered with the mnemonic “TRAP”. “T” for tremor, which is classically described as a resting, pill-rolling tremor, because it looks like someone is rolling a pill between their thumb and index finger. “R” stands for rigidity, which is often described as a cogwheel-like rigidity. This means that when attempting to passively move a limb, there are a series of stops or stalls, kind of like a cog on a wheel. There’s also lead-pipe rigidity, which is when a limb is rigid throughout the entire passive movement, kind of like trying to move a lead-pipe. “A” stands for akinesia, which is the absence of movement, and is a severe form of the more common finding of bradykinesia, which is slowness of movement. This can manifest as a narrow-based shuffling gait or a decreased facial expression, almost to the point where the individual’s face looks like they’re wearing a mask. “P” stands for postural instability, which causes a stooped posture, problems with balance, and an increased frequency of falls. Usually, these symptoms are asymmetric, with the exception of medication-induced parkinsonism, which usually causes symmetric symptoms.