Parkinson’s disease: A treatment guide

Dx seldom requires testing, but may take time to come into focus

Motor symptoms. The key diagnostic criterium for PD is bradykinesia with at least one of the following: muscular rigidity, resting tremor (particularly a pill-rolling tremor) that improves with purposeful function, or postural instability.² Other physical findings may include masking of facies and speech changes, such as becoming quiet, stuttering, or speaking monotonously without inflection.¹ Cogwheeling, stooped posture, and a shuffling gait or difficulty initiating gait (freezing) are all neurologic signs that point toward a PD diagnosis.²

A systematic review found that the clinical features most strongly associated with a diagnosis of Parkinson's Disease were trouble turning in bed, a shuffling gait, tremor, difficulty opening jars, micrographia, and loss of balance.

A systematic review found that the clinical features most strongly associated with a diagnosis of PD were trouble turning in bed, a shuffling gait, tremor, difficulty opening jars, micrographia, and loss of balance.¹⁰ Typically these symptoms are asymmetric.¹

Symptoms that point to other causes. Falling within the first year of symptoms is strongly associated with movement disorders other than PD—notably progressive supranuclear palsy.¹¹ Other symptoms that point toward an alternate diagnosis include a poor response to levodopa, symmetry at the onset of symptoms, rapid progression of disease, and the absence of a tremor.¹¹ It is important to ensure that the patient is not experiencing drug-induced symptoms as can occur with some antipsychotics and antiemetics.

Nonmotor symptoms. Neuropsychiatric symptoms are common in patients with PD. Up to 58% of patients experience depression, and 49% complain of anxiety.¹² Hallucinations are present in many patients and are more commonly visual than auditory in nature.¹³ Patients experience fatigue, daytime sleepiness, and inner restlessness at higher rates than do age-matched controls.³ Research also shows that symptoms such as constipation, mood disorders, erectile dysfunction, and hyposmia may predate the onset of motor symptoms.⁵

Insomnia is a common symptom that is likely multifactorial in etiology. Causes to consider include motor disturbance, nocturia, reversal of sleep patterns, and reemergence of PD symptoms after a period of quiescence.¹⁴ Additionally, hypersalivation and PD dementia can develop as complications of PD.

Symptoms, such as constipation, mood disorders, erectile dysfunction, and hyposmia, may predate the onset of motor symptoms in Parkinson's disease.

A clinical diagnosis. Although PD can be difficult to diagnose in the early stages, the diagnosis seldom requires testing.² A recent systematic review concluded that a clinical diagnosis of PD, when compared with pathology, was correct 74% of the time when the diagnosis was made by nonexperts and correct 84% of the time when the diagnosis was made by movement disorder experts.¹⁵

Imaging. Computed tomography and magnetic resonance imaging can be useful in ruling out other diagnoses in the differential, including vascular disease and normal pressure hydrocephalus,² but will not reveal findings suggestive of PD.

Other diagnostic tests. A levodopa challenge can confirm PD if the diagnosis is unclear.¹¹ In addition, an olfactory test (presenting various odors to the patient for identification) can differentiate PD from progressive supranuclear palsy and corticobasal degeneration; however, it will not distinguish PD from multiple system atrophy.¹¹ If the diagnosis remains unclear, consider a consultation with a neurologist.