Neurology: Day 11

As I finish with my time in Outpatient Neurology, it seems a good time to explore a little bit more about another common neurological disease which I saw frequently in clinic - Parkinson's Disease. Actually, when I was in my mid-clerkship review with the director, she made a comment on the fact that I've seen 13 Parkinson's patients in the past 2 weeks - "I think we know the main points you'll be taking away from Neurology!" First of all, I love these patients. As you may remember, Mike's granddad had Parkinson's Disease, so the patients always make me think of him. This is also what Michael J. Fox suffers from. Secondly, we have some amazing Movement Disorder specialists at my university who absolutely LOVE what they do and they are passionately committed to their patients. That enthusiasm has an infectious way of spreading interest in Parkinson's Disease. While I am in no way a specialist in Parkinson's Disease, I would still like to take the time to blog a little bit about what this disease is and what we do to help the patients cope with their degenerative disease.

A fun blog with daily cartoons added from a man with Parkinson's Disease can be found by clicking here. It's funny, and it might help to better empathize with these patients.

Clinical Correlation: A 64-year old man presented to our clinic with a chief complaint (CC) of a "tremor". Upon taking a history of present illness (HPI), it was discovered that this tremor was in his right hand, worse at rest, relieved when moving. It had been present for the past year or so, but has worsened to the point of frustrating him when he tries to work on his farm. He has also had some trouble with balance, especially when walking on an incline. He also admitted to some constipation, which has been a recent change in his bowel function. He has had some sleep disturbances, admits to feeling restless legs at night and his wife states that he sometimes yells and kicks while he is asleep.  He has otherwise been healthy his entire life, does not smoke or drink alcohol. Upon physical exam, a fine tremor was noticed at rest of his right hand. There was slight cogwheel rigidity in his right upper extremity. His gait was normal. He did have a slightly diminished movement of his muscles of facial expression, although the movements were symmetric and equal in strength bilaterally. Mini Mental Status exam was 30/30. The rest of the examination was unmarkable. He was started on a low-dose of a dopamine agonist, Pramipexole, and is to follow up in our clinic in 2-3months and to call us with any changes in condition and we will check on how he is doing in regards to the medication.

Parkinson's Disease: results from a loss of dopamine-containing neurons in the substantia nigra and the locus ceruleus of the midbrain (Lewy Bodies in neurons). Onset is typically after age 50. Patients with tremor as the major symptom tend to have a better prognosis than those who have bradykinesia as the main symptom.

Clinical Features:

1. Pill-rolling tremor at rest, worsens with emotional stress. Tremor remits with volitional movement.
1. Appears more like a supination-pronation tremor (Essential tremor is more up-down)
2. Bradykinesia
3. Cogwheel or Lead-Pipe Rigidity
4. Poor postural reflexes; Difficulty initiating first step, and walking with small shuffling steps; stooped posture
5. Masked Facies (expressionless face); Decreased Blinking
6. Dysarthria and Dysphagia, Micrographia (difficult speaking, swallowing, and small handwriting)
7. Impaired cognitive function (dementia) in advanced disease
8. Dysautonomia (orthostatic hypotension, constipation, increased sweating, oily skin)
9. Personality changes in early stages (depression is extremely common)
10. REM sleep disorders often predate the diagnosis of Parkinson's. 
11. Follows progressive course - significant disability usually presents within 5-10 years of onset.

Treatment:

1. There is no cure; goal is to delay disease progression and to relieve symptoms
2. Dopamine-receptor agonists (Pergolid, Bromocriptine, Pramipexole)
1. First line therapy; may delay need for Carbidopa-Levodopa for several years
2. Can be particularly useful for sudden episodes of hesitancy or immobility ("freezing")
3. Carbidopa-Levodopa (Sinemet): the most effective of all parkinson's medications
1. Side Effects: Dyskinesias (involuntary, often choreic movements) can occur after 5-7 years of therapy. Because of this, we try to keep away from Sinemet until it is absolutely needed.
2. "On-Off" Phenomenon: over the course of the day, there is a fluctuation in symptoms due to dose-response relationships. Often, this occurs in advanced disease.
4. Selegiline: Inhibits Monoamine Oxidase B activity (increases Dopamine activity and reduces the metabolism of levodopa.
1. Adjuvent medication often used in early disease
5. Amantadine: increases the availability of endogenous dopamine with few side effects
1. Only transiently improves symptoms
2. Can be used with or without levodopa
6. Anticholinergic Drugs (Trihexyphenidyl and Benztropine)
1. May be particularly helpful in patients with tremor as a major finding
7. Amitriptyline - an anticholinergic as well as antidepressant
8. Surgery - Deep Brain Stimulation - if patient does not respond to medications or in patients who develop severe disease before the age of 40.

Certain medications can cause Parkinsonian Symptoms, such as Neuroleptic drugs, Metclopramide (anti-nausea), and Reserpine.

"Shy-Drager Syndrome" - parkinsonian symptoms plus autonomic insufficiency.

A similar syndrome is known as Progressive Supranuclear Palsy (PSP): a degenerative disease of the brainstem, basal ganglia, and cerebellum, most commonly affecting middle-aged and elderly men.

   Causes: Bradykinesia, Limb Rigidity, Cognitive Decline, and follows a progressive course

   **Unlike Parkinson's: Does NOT cause tremor but DOES cause ophthalmoplegia.

References: 

Step Up to Medicine, 2008.

Case Files for Neurology, 2008.

http://www.knowabouthealth.com/harvard-study-ibuprofen-can-reduce-risk-for-parkinsons-disease/8037/