Idiopathic Parkinson Disease: Clinical Presentation and Diagnosis

00:01 What about symptoms how to patients with idiopathic PD present? Well, first we think about the motor symptoms and this presents as a typical Parkinsonism.

00:11 with bradykinesia, rigidity, postural instability, and typically for idiopathic PD with tremor.

00:18 But there are also a number of non-motor symptoms that we can also see that are very characteristic of idiopathic PD, including anosmia (loss of smell), REM behavior disorder, where patients will act out their dreams or caregivers will describe acting out the dreams.

00:33 Typically, patients are flaccid, there is a loss of tone, atonia during REM sleep.

00:39 But in Parkinson's disease, we can see a loss of atonia, patients develop tone during REM sleep.

00:46 REM sleep is when we dream.

00:47 So these patients have the ability to act out dreams as they're happening.

00:51 And this may predate the motor symptoms and being very early feature of subsequent development of Parkinson's disease.

01:03 Now let's talk about the diagnosis.

01:05 How do we diagnose idiopathic Parkinson's disease.

01:08 And I'd like for you to think about this in four categories.

01:11 I want you to think about the motor symptoms and motor Parkinsonism, which is really how we have established the diagnosis, in the vast majority of patients over the years, I want you to think about two supportive criteria having to be fulfilled.

01:25 I want you to know the exclusion criteria to think about and then also some red flags to consider when evaluating these patients.

01:33 So let's start with the motor symptoms.

01:35 What motor symptoms do we evaluate? Well, here we're looking for a Parkinsonism.

01:39 So we're looking for evidence of bradykinesia, rigidity, postural instability and tremor.

01:45 For bradykinesia we're looking at the speed and rhythm of finger taps or opening and closing of the hand or tapping of the foot.

01:53 We're looking for the speed of movement, and bradykinesia is evidence of reduced speed of movements.

01:59 Often patients with idiopathic PD present asymmetrically, and so we can see the differences from one side to the other.

02:06 When we evaluate rigidity, we're looking for increased resistance to passive movement, And again often in idiopathic PD, this is asymmetric.

02:15 Postural instability is evaluated by the pull test and rest tremor.

02:18 We're evaluating by observing the patient.

02:23 When we think about motor symptoms, it is important to differentiate pyramidal tract of dysfunction from extrapyramidal dysfunction.

02:31 We can go back to the origin of these tracts.

02:33 The pyramidal tracts begin in the cerebral cortex, the key tracts of the corticospinal and corticobulbar.

02:38 And here, patients have difficulty with voluntary muscle control, upper motor neuron symptoms, including hyperreflexia.

02:46 That's different from the extra pyramidal tracts.

02:49 So those four cardinal features, motor features of Parkinsonism result from dysfunction of these tracts, and this system.

02:56 The extrapyramidal system begins in the brainstem, descending tracts that carry information, for modulation of movement, or the vestibulospinal, reticulospinal, rubrospinal and tectospinal.

03:10 They're keeping the axial skeleton upright.

03:12 They're modulating movement while it's occurring, and dysfunction and problem in those tracts result in the development of Parkinsonian symptoms.

03:21 These tracts are involved in involuntary and automatic control of musculature, and that's why we see problems with those functions in patients.

03:29 Importantly, motor Parkinsonism comes from dysfunction of this extrapyramidal symptom.

03:35 It is an extrapyramidal disorder.

03:39 So let's look a little bit at the tracts and understand what what they are and how they work.

03:44 First, let's begin with the pyramidal system and this is one we know well.

03:49 The pyramidal system is composed of two tracts - the corticospinal tract, which controls voluntary muscle movement and control.

03:55 There's the lateral corticospinal tract which contains about 85% of the motor neurons from the primary motor cortex and the anterior corticospinal tract which carries the other 15%.

04:08 There's also the corticobulbar tract which carries information about voluntary control of muscles of the face and bulbar fibers.

04:16 This is different from the extrapyramidal system.

04:18 Here we're dealing with four tracts and four pathways.

04:22 The first is the rubrospinal tract which controls fine motor control.

04:27 The reticulospinal tract, there is a medial, the reticulospinal tract which is involved in in contraction and increasing axial tone and a lateral reticular spinal tract, which is involved in relaxation and decreasing axial tone to keep us upright, and our bodies moving in an upright posture.

04:50 The vestibulospinal system is involved in modulation of balance and posture and so we see importance in balance and posture in this tract And dysfunction of this tract can lead to the postural instability that we see in Parkinsonism.

05:06 And then finally, the tectospinal or colliculospinal tract is involved in head coordination, keeping the head above the body and moving along with the rest of the body and maintaining posture.

05:22 So the next criteria that we think about in establishing a diagnosis of idiopathic PD is looking for exclusion criteria and making sure there are no absolute exclusions for this diagnosis.

05:33 There are a number of red flags that could come up that would point towards an alternative diagnosis that's not idiopathic PD.

05:40 And in general, these are things that suggest an alternative neurodegenerative Parkinsonism so these patients may have Parkinsonian signs - bradykinesia, rigidity, postural instability, but also something else that points us away from idiopathic PD towards some some other etiology.

05:57 A prominent cerebellar abnormalities would be uncommon in a patient with idiopathic PD, and may suggest a diagnosis of multiple system atrophy.

06:06 Problems with downward supranuclear gaze palsy, reduced a vertical down gaze, or reduced vertical downward saccades, goal-directed downward eye movements is uncommon in idiopathic PD and may suggest a diagnosis of progressive supranuclear palsy.

06:24 An early diagnosis of frontotemporal dementia within the first 5 years of onset of Parkinsonian signs would be atypical of Parkinsons disease and may suggest a diagnosis of Lewy Body disease.

06:37 PD patients, idiopathic PD patients can develop dementia, but it's often late in the course.

06:43 Parkinsonian features that are restricted to the lower limbs for more than 3 years is uncommon in idiopathic PD and should prompt an evaluation for spinal cord pathology.

06:55 And then finally, treatment in the past year with a dopamine receptor blocker should warrant a workup for drug-induced Parkinsonism.

07:03 Drug-induced Parkinsonism can be seen with a number of agents including Metoclopramide and other dopamine antagonists.

07:11 Stopping of those agents can often result in improvement of the symptoms, and drug induced Parkinsonism is often more symmetric than idiopathic PD.

07:22 In addition, absence of observable responses to high dose levodopa should question the diagnosis of idiopathic PD.

07:30 PD, Parkinson's disease is often responsive to levodopa whereas many of the Parkinson's plus disorders are not, And the lack of response to leave a dopa should warrant a workup of alternative diagnoses.

07:43 Unequivocal cortical sensory loss, things like agraphesthesia, astereognosis, Alien Hand Syndrome, ideomotor apraxias, or progressive aphasias, should suggest an early cortical problem such as corticobasal degeneration, and these are uncommon early in the course of idiopathic PD.

08:03 The next area I'd like us to focus on is supportive criteria, things that help to establish a diagnosis of idiopathic PD, but are not definitive when present outright.

08:14 So what are some of those supportive criteria? Well, one is a dramatic improvement of symptoms with dopaminergic drugs.

08:20 This should strongly suggest an underlying diagnosis of idiopathic PD.

08:26 Asymmetry at onset is commonly seen in Parkinson's disease.

08:29 Rest tremor of limbs, particularly unilateral and then ultimately progressing to bilateral is common and supportive of that diagnosis.

08:38 And a history of anosmia or REM behavior disorder is also suggestive and supportive of a diagnosis of PD.

08:48 Finally, we want to think about red flags things that would suggest an alternative diagnosis.

08:53 A number of red flags can be considered rapid progression of gait impairment should warrant evaluation for structural problems, or alternative diagnoses.

09:03 Absence of progressive motor symptoms or signs for five years is also inconsistent and should warrant alternative workup.

09:11 Early bulbar dysfunction, severe dysphonia, dysarthria, dysphasia is uncommon in PD It can be seen late but is uncommon early and would be more likely to occur and progress to supranuclear palsy.

09:23 Inspiratory stridor, dyspnea, spasmodic dysphonia also should suggest evaluation for brainstem pathology or PSP.

09:33 Severe autonomic failure in the first five years of the disease is uncommon in PD.

09:38 We can see autonomic failure late, but early autonomic dysfunction, early orthostasis, early erectile dysfunction, early urinary retention should warrant structural evaluation for a brainstem pathology or can be seen with multiple system atrophy.

09:54 And then recurrent falls due to impaired balance within the first three years should warrant workup for cerebellar pathology or progressive supranuclear palsy.

10:02 Falls can be seen in idiopathic PD but are more common late in the disease.

10:06 So here we're talking about symptoms not only about whether they're occurring, but the timing in which they're occurring that can help us with establishing this diagnosis.

10:16 Involuntary flexion of the neck or contraction of the hands and feet should warrant alternative workup, Absence of common non-motor symptoms, anosmia, REM behavior disorder should prompt a consideration for alternative diagnoses.

10:31 Unexplained pyramidal tract signs, hyperreflexia, or spasticity is a red flag and really should prompt neuroimaging.

10:39 And bilateral symmetric Parkinsonism should warrant a careful evaluation of medication history as this would be more common in drug induced Parkinsonism.

10:51 And then, lastly, we can use imaging.

10:53 Structural brain imaging with CTs and MRIs are really not helpful in evaluating patients with Parkinson's disease.

11:00 They don't establish the diagnosis, but they can help exclude other causes.

11:05 The scan we can do to help establish the diagnosis is the DAT scan or the dopamine transporter scan.

11:12 This is a nuclear medicine scan.

11:14 Patients are given a radiolabeled dopamine agent this traffic's through the body and up into the brain, where it has a predilection for for appearing in the substantia nigra and the deep basal ganglia structures.

11:27 Here we're looking at a series of DAT scans, on the far left you see the normal DATscan.

11:32 They're symmetric uptake and adequate uptake in both basal ganglia bilaterally.

11:38 On the right, we see two abnormal DATt scans.

11:42 The left image or in the middle shows mildly reduced right putamen uptake of the tracer and that asymmetry is common.

11:49 This patient may have asymmetric symptoms which is consistent with idiopathic PD, and we see that also on the DAT scan.

11:57 On the far right, we see markedly reduced right putamen uptake of the dopamine transporter tracer and this is consistent with more severe moderate to severe disease and would be consistent with a diagnosis of a Parkinsonism, and specifically for idiopathic PD.

13:01 Parkinson's patients also fall, often fall backwards early, whereas PSP patients often fall forward early as a result of that vertical down gaze.