The Diagnosis of Parkinsonism

 

Parkinsonism is simply a clincial syndrome

Cardinal Features: (Mnemonic = T-R-A-P)

T remor

R igidity 2 of the first 3 features for diagnosis of Parkinson's Disease (PD)

A kinesia / Bradykinesia

P ostural Instability

 

Tremor:

- classic 4- to 6-Hz resting tremor ("pill-rolling")

- may be absent in up to 25% of PD

- brought out when patient distracted (ask to close eyes & count backwards) or with stress / anxiety /fatigue

- can also have postural tremor (may be attenuated when actually moving to position)

- often begins in one hand and remains more severe on that side throughout

- may also affect chin / lips / tongue (but not usually head)

- often not a disabling feature (not interfere w/ purposeful movements)

 

NB: most common differential for tremor-dominant PD is essential tremor (ET)

- features useful to distinguish ET from PD tremor include:

1) Family History: autosomal dominant inheritance common w/ ET (uncommon in PD)

2) Postural tremor predominant in ET (but can occur at rest if severe, and PD can have postural component)

3) Bilateral: in ET, never unilateral, although often can be asymmetric

4) Associated head tremor in ET ('titubation') & vocal tremor

5) Absence of other features of parkinsonism: no true rigidity or bradykinesia

 

Rigidity:

- resistance to passive movement in both flexors & extensors throughout whole range of motion

- patients may complain of feeling of "muscle stiffness", weakness or fatigue

- reduction in arm swing during gait often early sign

- may also begin unilaterally (and remain asymmetric)

- may be brought out by augmentation maneuvers

(eg. Froment's - ask to open & close contralateral body hand)

 

Bradykinesia:

- slowness of movements

- speech becomes hypophonic & swallowing slowed (saliva pools, drooling)

- trouble with buttons & fine finger movements

- takes longer to get dressed or do ADLs

- micrographia

 

Akinesia:

- poverty of movement & trouble initiating movements

- facial = hypomimia / amimia (and decreased eye blinking) ddx depression

 

Posture & Gait:

- short, shuffling gait (bradykinesia & rigidity)

- stooped (simian) posture

- may appear to drag one leg if asymmetric

- decrease in arm swing

- hesitancy in initiating & freezing (e.g. going through a door)

- turning en bloc

- may festinate (centre of gravity forward so take short increasingly rapid steps to catch up)

- postural instability as disease progresses (falls, retropulsion)

Main Differential Diagnosis

 

Most of these diseases are diagnosed clinically

- no easily available, reliable, diagnostic tests for PD, PSP etc.- rely on careful history taking & clinical examination

- 15-25% of cases are misclassified when compared to pathology / autopsy

- 24% of cases of PD undiagnosed in community door-to-door studies

 

1) Neurodegenerative Diseases:

- Idiopathic PD - Progressive Supranuclear Palsy (PSP)

- Cortico-Basal Degeneration (CBD / CBGD) - Diffuse Lewy Body Disease (DLBD)

- Multiple System Atrophy (MSA-P) aka striatonigral degeneration

 

2) Drug-Induced: (incl. tardive syndrome)

- Neuroleptics (Dopamine receptor blockers), Metoclopramide / Prochlorperazine

- Valproate

- Lithium

 

3) Vascular Parkinsonism: multi infarct

 

4) Familial / Early onset cases:

- Wilson's disease - Huntington's disease (Westphal variant)

- Machado-Joseph disease - Familial PD (parkin, alpha-synucelin, unidentified?)

 

5) Structural Lesions: (usually hemiparkinsonsim)

- Neoplasms, Vascular, Traumatic

 

6) Toxic:

- Manganese -MPTP - Organophosphates - Carbon monoxide

- Methanol - Carbon disulfide - Cyanide

 

7) Infectious:

- CJD / Prion diseases - HIV encephalitis

- Postencephalitic (von Economo's) - SSPE

 

8) Other:

-          NPH

-          Trauma (pugilistic encephalopathy)

-          parathyroid abnormalities, hypothyroidism, hepatocerebral degeneration

-          brain tumor, paraneoplastic diseases

 

Features suggesting atypical Parkinsonism:

1) Early dementia (seen in PSP, DLBD, CBD, AD-PD)

2) Early age of onset (MSA, CBD in 40's-50's, not PSP, can occur in PD)

3) Rapid progression (over 3-4 yrs; in MSA, PSP, CBD)

4) Eye movement abN (loss of vertical saccades & OKN = PSP)

5) Autonomic dysfx (impotence, bladder n, orthostatic hypoTN, temp dysregulation, GI dysmotility) in MSA

6) Early postural instability (PSP, MSA)

7) Early dysarthria (PSP, MSA, Vascular)

8) Axial > Limb rigidity (PSP)

9) Pyramidal signs (PSP, MSA, CBD +/- structural lesions) or cerebellar findings (MSA / OCPA)

10) Lower body parkinsonism (shuffling gait, good arm swing = vascular, NPH)

11) Poor / non-sustained response to levo-dopa (MSA / PSP may respond initially)

12) Sensory dysfunction (especially parietal w/ apraxia, cortical sensory loss, stimulus-sensitive myoclonus, alien-limb phenomenon = CBD)

13) Hemibody involvement (asymmetry more common in PD; also seen in CBD & hemiparkinsonism hemiatrophy)

14) Prominent visual hallucinations (prior to treatment) in DLBD (also fluctuating cognitive state & sensitivity to neuroleptic medications)

 

Other Common Manifestations of Parkinson's Disease:

          Cognitive dysfuntion (Bradyphrenia - dementia in 30%)

          Depression (30-40%)

          Sleep disturbance (due to rigidity, tremor, dystonia [waking], restless legs, depression)

          Sexual dysfunction

          Sialorrhea (excessive salivation) ~ 75%

          Olfactory hypofunction

          Dysphagia / Dysarthria

          Autonomic dysfunction (constipation, orthostatic hypotension, satiety, nausea)

          Urinary dysfunction (detrusor hyperreflexia w/ urgency, frequency, nocturia)

          Sensory: pain, cramps

          Dystonia

          Seborrheic dermatitis

          Visual hallucinations / psychosis (especially due to dopaminergic Rx)

 

NB: many of these 'secondary' manifestations are not responsive to PD Rx

 

Hoehn and Yahr Scale:

Stage I - unilateral disease

Stage II - bilateral disease w/ preservation of postural reflexes

Stage III - bilateral disease w/ impaired postural reflexes but preserved ability to ambulate independently

Stage IV - severe disease, considerable assistance required

Stage V - end-stage disease (confined to bed or chair)

 

UPDRS (United Parkinson's Disease Rating Scale)

- validated tool for use in clinical trials to evaluate disease severity & response to treatment

- broken down into subsets: 1) cognitive; 2) ADLs; 3) motor exam; and 4) complications of Rx

 

References:

Med Clin N Am 1999; 83(2): 327-347

BMJ 1995; 310: 447-452.

NEJM 1998; 339: 1044-1053.

 

Thanks to Dr. Verity J. John for this page.