Avoid Diagnostic Pitfalls For Parkinson's Disease

BALTIMORE — Be sure to reevaluate a diagnosis of Parkinson's disease in a patient at every visit, Dr. Stephen G. Reich advised at a meeting sponsored by the American Geriatrics Society and Johns Hopkins University.

The false-positive rate for a Parkinson's disease (PD) diagnosis is about 35% at the initial diagnosis and 24% at final diagnosis, according to data from several autopsy studies. Autopsy results remain the preferred method for confirming a diagnosis of PD, noted Dr. Reich, professor of neurology at the University of Maryland and codirector of its Maryland Parkinson's Disease and Movement Disorders Center.

In a study of more than 470,000 U.S. nursing-home residents, the three best predictors of PD were the presence of a resting tremor, a unilateral onset of symptoms, and a beneficial and sustained response to levodopa, the investigators noted (Pharmacotherapy 1999;19:1321–7).

Not everyone with PD has a resting tremor, but many do, and this tremor improves with movement. Classic PD starts on one side of the body, unrelated to right- or left-handedness. Some patients with Parkinson's-like syndromes (rather than Parkinson's disease) have an initial response to levodopa, but it won't be sustained.

Based on his research and experience, Dr. Reich listed the top 10 pitfalls of PD diagnosis. The first six are false positives:

▸ Essential tremor (ET). This is the condition most often misdiagnosed as PD. “The best way to distinguish ET from PD is the history and physical,” Dr. Reich said. Patients presenting with ET usually report that the tremor has been present for years. But most tremor patients with PD present to a primary care physician within about 6 months of the initiation of symptoms.

Also, ask tremor patients about their responses to alcohol. About 60% or more of patients with ET notice that a little alcohol temporarily alleviates the problem, he said.

When conducting the physical exam, remember that PD is a resting tremor and thus tends to improve with movement, but essential tremor worsens with movement. A strictly unilateral tremor is probably PD. “Essential tremor, although it might be asymmetrical, is almost always bilateral,” he said. Tremor of the head or voice is usually an essential tremor, he added.

Handwriting in patients with PD tends to be micrographic but is not tremulous, even if patients have tremor at rest. Patients with ET have full-sized handwriting, but it looks shaky. Patients with PD also may have cogwheel rigidity, a masked face, and trouble rising from a chair.

▸ Lower-half Parkinsonism. “These are the patients geriatricians see day in and day out. They are disproportionately fine from the waist up,” Dr. Reich said. This is not PD. It appears clinically as a shuffling, broad-based gait, difficulty rising from a seated position, with impaired posture and balance. Most patients with this condition present at an age older than 70 years, and the symptoms occur below the waist.

Some of these patients respond well to shunts for normal-pressure hydrocephalus, he noted.

▸ Drug-induced Parkinsonism. This condition often goes unrecognized because it might take up to 1 year to resolve after taking a particular drug. “You have to ask what medicines patients have taken in the past,” Dr. Reich said.

Check hospital records to confirm medications, and be cautious about diagnosing PD—especially if patients have taken antipsychotics, metoclopramide, or dopamine depleters such as reserpine, because the PD symptoms might resolve with time.

▸ Parkinson's disease vs. Parkinson's syndrome. Red flags that differentiate a Parkinson's syndrome (such as progressive supranuclear palsy or multiple system atrophy) from PD include impaired downward gaze, little or no response to levodopa, early hallucinations, early dementia, and falls early in the course, as well as symmetric onset and absence of tremor.

▸ Alzheimer's disease presenting as Parkinsonism. “The physical symptoms of Parkinsonism, such as lack of balance, may bring the patient to your office, but if it is accompanied by dementia, it is probably Parkinsonism rather than clinical PD,” Dr. Reich said.

▸ Parkinsonism of “normal aging.” PD tends to peak at about 60 years of age, so be cautious about diagnosing it after age 75 years, he said.

The last four pitfalls of PD diagnoses are false negatives:

▸ Sensory or pain presentation of PD. Dr. Reich said he often sees patients who have recovered from a frozen shoulder, for example, but they still have trouble moving one hand. Foot pain, particularly in young-onset PD patients, as well as tingling or numbness, fibromyalgia, or restless legs syndrome, can be symptoms of PD.

▸ Young-onset PD. PD is often not recognized in patients in their 30s and 40s. “You can be too old for PD but not too young,” Dr. Reich said. “It is uncommon, but it is out there,” he said.

▸ Unilateral lower extremity presentation. “When a patient presents with one lower-extremity symptom, even if he or she complains of pain or weakness, don't discount PD,” Dr. Reich said.

▸ Atremulous PD. Patients with atremulous PD are most often misdiagnosed with stroke, but the fact that only half the body is affected by stiffness or balance problems is a tip-off that the problem might be PD instead, Dr. Reich said.

BALTIMORE — Be sure to reevaluate a diagnosis of Parkinson's disease in a patient at every visit, Dr. Stephen G. Reich advised at a meeting sponsored by the American Geriatrics Society and Johns Hopkins University.

The false-positive rate for a Parkinson's disease (PD) diagnosis is about 35% at the initial diagnosis and 24% at final diagnosis, according to data from several autopsy studies. Autopsy results remain the preferred method for confirming a diagnosis of PD, noted Dr. Reich, professor of neurology at the University of Maryland and codirector of its Maryland Parkinson's Disease and Movement Disorders Center.

In a study of more than 470,000 U.S. nursing-home residents, the three best predictors of PD were the presence of a resting tremor, a unilateral onset of symptoms, and a beneficial and sustained response to levodopa, the investigators noted (Pharmacotherapy 1999;19:1321–7).

Not everyone with PD has a resting tremor, but many do, and this tremor improves with movement. Classic PD starts on one side of the body, unrelated to right- or left-handedness. Some patients with Parkinson's-like syndromes (rather than Parkinson's disease) have an initial response to levodopa, but it won't be sustained.

Based on his research and experience, Dr. Reich listed the top 10 pitfalls of PD diagnosis. The first six are false positives:

▸ Essential tremor (ET). This is the condition most often misdiagnosed as PD. “The best way to distinguish ET from PD is the history and physical,” Dr. Reich said. Patients presenting with ET usually report that the tremor has been present for years. But most tremor patients with PD present to a primary care physician within about 6 months of the initiation of symptoms.

Also, ask tremor patients about their responses to alcohol. About 60% or more of patients with ET notice that a little alcohol temporarily alleviates the problem, he said.

When conducting the physical exam, remember that PD is a resting tremor and thus tends to improve with movement, but essential tremor worsens with movement. A strictly unilateral tremor is probably PD. “Essential tremor, although it might be asymmetrical, is almost always bilateral,” he said. Tremor of the head or voice is usually an essential tremor, he added.

Handwriting in patients with PD tends to be micrographic but is not tremulous, even if patients have tremor at rest. Patients with ET have full-sized handwriting, but it looks shaky. Patients with PD also may have cogwheel rigidity, a masked face, and trouble rising from a chair.

▸ Lower-half Parkinsonism. “These are the patients geriatricians see day in and day out. They are disproportionately fine from the waist up,” Dr. Reich said. This is not PD. It appears clinically as a shuffling, broad-based gait, difficulty rising from a seated position, with impaired posture and balance. Most patients with this condition present at an age older than 70 years, and the symptoms occur below the waist.

Some of these patients respond well to shunts for normal-pressure hydrocephalus, he noted.

▸ Drug-induced Parkinsonism. This condition often goes unrecognized because it might take up to 1 year to resolve after taking a particular drug. “You have to ask what medicines patients have taken in the past,” Dr. Reich said.

Check hospital records to confirm medications, and be cautious about diagnosing PD—especially if patients have taken antipsychotics, metoclopramide, or dopamine depleters such as reserpine, because the PD symptoms might resolve with time.

▸ Parkinson's disease vs. Parkinson's syndrome. Red flags that differentiate a Parkinson's syndrome (such as progressive supranuclear palsy or multiple system atrophy) from PD include impaired downward gaze, little or no response to levodopa, early hallucinations, early dementia, and falls early in the course, as well as symmetric onset and absence of tremor.

▸ Alzheimer's disease presenting as Parkinsonism. “The physical symptoms of Parkinsonism, such as lack of balance, may bring the patient to your office, but if it is accompanied by dementia, it is probably Parkinsonism rather than clinical PD,” Dr. Reich said.

▸ Parkinsonism of “normal aging.” PD tends to peak at about 60 years of age, so be cautious about diagnosing it after age 75 years, he said.

The last four pitfalls of PD diagnoses are false negatives:

▸ Sensory or pain presentation of PD. Dr. Reich said he often sees patients who have recovered from a frozen shoulder, for example, but they still have trouble moving one hand. Foot pain, particularly in young-onset PD patients, as well as tingling or numbness, fibromyalgia, or restless legs syndrome, can be symptoms of PD.

▸ Young-onset PD. PD is often not recognized in patients in their 30s and 40s. “You can be too old for PD but not too young,” Dr. Reich said. “It is uncommon, but it is out there,” he said.

▸ Unilateral lower extremity presentation. “When a patient presents with one lower-extremity symptom, even if he or she complains of pain or weakness, don't discount PD,” Dr. Reich said.

▸ Atremulous PD. Patients with atremulous PD are most often misdiagnosed with stroke, but the fact that only half the body is affected by stiffness or balance problems is a tip-off that the problem might be PD instead, Dr. Reich said.

BALTIMORE — Be sure to reevaluate a diagnosis of Parkinson's disease in a patient at every visit, Dr. Stephen G. Reich advised at a meeting sponsored by the American Geriatrics Society and Johns Hopkins University.

The false-positive rate for a Parkinson's disease (PD) diagnosis is about 35% at the initial diagnosis and 24% at final diagnosis, according to data from several autopsy studies. Autopsy results remain the preferred method for confirming a diagnosis of PD, noted Dr. Reich, professor of neurology at the University of Maryland and codirector of its Maryland Parkinson's Disease and Movement Disorders Center.

In a study of more than 470,000 U.S. nursing-home residents, the three best predictors of PD were the presence of a resting tremor, a unilateral onset of symptoms, and a beneficial and sustained response to levodopa, the investigators noted (Pharmacotherapy 1999;19:1321–7).

Not everyone with PD has a resting tremor, but many do, and this tremor improves with movement. Classic PD starts on one side of the body, unrelated to right- or left-handedness. Some patients with Parkinson's-like syndromes (rather than Parkinson's disease) have an initial response to levodopa, but it won't be sustained.

Based on his research and experience, Dr. Reich listed the top 10 pitfalls of PD diagnosis. The first six are false positives:

▸ Essential tremor (ET). This is the condition most often misdiagnosed as PD. “The best way to distinguish ET from PD is the history and physical,” Dr. Reich said. Patients presenting with ET usually report that the tremor has been present for years. But most tremor patients with PD present to a primary care physician within about 6 months of the initiation of symptoms.

Also, ask tremor patients about their responses to alcohol. About 60% or more of patients with ET notice that a little alcohol temporarily alleviates the problem, he said.

When conducting the physical exam, remember that PD is a resting tremor and thus tends to improve with movement, but essential tremor worsens with movement. A strictly unilateral tremor is probably PD. “Essential tremor, although it might be asymmetrical, is almost always bilateral,” he said. Tremor of the head or voice is usually an essential tremor, he added.

Handwriting in patients with PD tends to be micrographic but is not tremulous, even if patients have tremor at rest. Patients with ET have full-sized handwriting, but it looks shaky. Patients with PD also may have cogwheel rigidity, a masked face, and trouble rising from a chair.

▸ Lower-half Parkinsonism. “These are the patients geriatricians see day in and day out. They are disproportionately fine from the waist up,” Dr. Reich said. This is not PD. It appears clinically as a shuffling, broad-based gait, difficulty rising from a seated position, with impaired posture and balance. Most patients with this condition present at an age older than 70 years, and the symptoms occur below the waist.

Some of these patients respond well to shunts for normal-pressure hydrocephalus, he noted.

▸ Drug-induced Parkinsonism. This condition often goes unrecognized because it might take up to 1 year to resolve after taking a particular drug. “You have to ask what medicines patients have taken in the past,” Dr. Reich said.

Check hospital records to confirm medications, and be cautious about diagnosing PD—especially if patients have taken antipsychotics, metoclopramide, or dopamine depleters such as reserpine, because the PD symptoms might resolve with time.

▸ Parkinson's disease vs. Parkinson's syndrome. Red flags that differentiate a Parkinson's syndrome (such as progressive supranuclear palsy or multiple system atrophy) from PD include impaired downward gaze, little or no response to levodopa, early hallucinations, early dementia, and falls early in the course, as well as symmetric onset and absence of tremor.

▸ Alzheimer's disease presenting as Parkinsonism. “The physical symptoms of Parkinsonism, such as lack of balance, may bring the patient to your office, but if it is accompanied by dementia, it is probably Parkinsonism rather than clinical PD,” Dr. Reich said.

▸ Parkinsonism of “normal aging.” PD tends to peak at about 60 years of age, so be cautious about diagnosing it after age 75 years, he said.

The last four pitfalls of PD diagnoses are false negatives:

▸ Sensory or pain presentation of PD. Dr. Reich said he often sees patients who have recovered from a frozen shoulder, for example, but they still have trouble moving one hand. Foot pain, particularly in young-onset PD patients, as well as tingling or numbness, fibromyalgia, or restless legs syndrome, can be symptoms of PD.

▸ Young-onset PD. PD is often not recognized in patients in their 30s and 40s. “You can be too old for PD but not too young,” Dr. Reich said. “It is uncommon, but it is out there,” he said.

▸ Unilateral lower extremity presentation. “When a patient presents with one lower-extremity symptom, even if he or she complains of pain or weakness, don't discount PD,” Dr. Reich said.

▸ Atremulous PD. Patients with atremulous PD are most often misdiagnosed with stroke, but the fact that only half the body is affected by stiffness or balance problems is a tip-off that the problem might be PD instead, Dr. Reich said.