Workup for Worsening Tremor in Parkinson's Disease

Initial Assessment

The initial workup for worsening tremor in a patient with established Parkinson's disease should prioritize checking serum calcium levels and assessing for medication-related issues before attributing symptoms to disease progression, as recommended by the American Academy of Neurology 1
Checking serum calcium levels first is crucial, as hypocalcemia can induce or worsen tremors and other movement disorders in patients with Parkinson's disease, according to the Genetics in Medicine guidelines 2, 1

Additional metabolic screening should include parathyroid hormone (PTH) to evaluate for hypoparathyroidism, with a strength of evidence level of high, as per the Genetics in Medicine guidelines 2
Magnesium levels should also be checked, as hypomagnesemia can contribute to or worsen tremor, with a moderate level of evidence, as recommended by the Genetics in Medicine guidelines 2
Thyroid-stimulating hormone (TSH) should be evaluated to exclude thyroid dysfunction, with a high level of evidence, as per the Genetics in Medicine guidelines 2
Vitamin B12, folate, and vitamin D levels should be assessed, as deficiencies can impact neurological symptoms, with a moderate level of evidence, as recommended by the Praxis Medical Insights guidelines 1

The American Academy of Neurology recommends evaluating current dopaminergic therapy and assessing for "off" periods, where tremor worsens when medication effects wear off, although the strength of evidence for this is low 2
Drug-induced causes, including medications that may worsen tremor, should be reviewed, with a moderate level of evidence, as per the Genetics in Medicine guidelines 2

The American Academy of Neurology recommends determining tremor characteristics to distinguish progression from other causes, including evaluating for new postural or action tremor components in addition to resting tremor, with a high level of evidence 2
Screening for autonomic dysfunction, constipation, and other non-motor symptoms may indicate disease progression, with a moderate level of evidence, as recommended by the Praxis Medical Insights guidelines 1

The American College of Radiology recommends that neuroimaging is NOT routinely indicated if the patient meets diagnostic criteria for known Parkinson's disease and the clinical picture is consistent with disease progression or medication fluctuations, with a high level of evidence 3
However, MRI brain should be obtained if new focal neurological signs develop, atypical features suggest alternative diagnoses, or rapid progression or asymmetric findings raise concern for structural lesions, with a high level of evidence, as per the Journal of the American College of Radiology guidelines 4

The Journal of the American College of Radiology recommends that DaTscan (ioflupane SPECT) is NOT indicated in patients with established Parkinson's disease, as it is used to differentiate parkinsonian syndromes from essential tremor at initial diagnosis, not to evaluate progression, with a high level of evidence 4
Consider referral to movement disorders neurology if diagnostic uncertainty exists about whether symptoms represent PD progression versus another condition, with a moderate level of evidence, as recommended by the Genetics in Medicine guidelines 2

The American Academy of Otolaryngology-Head and Neck Surgery recommends not assuming worsening tremor equals disease progression without first correcting metabolic abnormalities, especially hypocalcemia, optimizing dopaminergic medication timing and dosing, and ruling out medication-induced worsening, with a high level of evidence 2, 1
Unnecessary vestibular testing should not be ordered unless vertigo or balance symptoms suggest a vestibular disorder rather than parkinsonian postural instability, with a moderate level of evidence, as per the Otolaryngology--head and neck surgery guidelines 3
Routine brain imaging should not be obtained in the absence of red flags, as this adds cost without changing management in typical PD progression, with a high level of evidence, as recommended by the Otolaryngology--head and neck surgery guidelines 3