How to manage tremor in an older adult patient with a history of Polycythemia Vera (PV)?

Management of Tremor in Polycythemia Vera

Tremor in a patient with polycythemia vera (PV) is not a recognized manifestation of the disease itself and requires evaluation for alternative etiologies, as PV-specific guidelines do not address tremor as a disease-related symptom.

Tremor is Not a Characteristic Feature of PV

The available PV guidelines and comprehensive reviews consistently describe the characteristic clinical manifestations of polycythemia vera, which include:

• Microvascular symptoms: headache, light-headedness, transient neurologic or ocular disturbances, tinnitus, atypical chest discomfort, paresthesias, and erythromelalgia 1
• Pruritus: generalized itching exacerbated by hot baths, affecting approximately 48% of patients 1
• Thrombotic and hemorrhagic complications: arterial thrombosis (16% prior to or at diagnosis) and venous thrombotic events (7%) 2
• Constitutional symptoms: splenomegaly (36%), abdominal discomfort 2

Tremor is notably absent from the documented symptom profile of PV across all major guidelines and comprehensive reviews 1, 2, 3, 4, 5.

Evaluate for Alternative Causes

Since tremor is not a PV-related symptom, the evaluation should focus on:

Neurological Causes

• Essential tremor: most common movement disorder in older adults
• Parkinson's disease: particularly in older patients
• Cerebellar dysfunction: assess for ataxia, dysmetria, and other cerebellar signs
• Peripheral neuropathy: which can occur with various etiologies

Medication-Induced Tremor

Review the patient's current medications, particularly:

• Hydroxyurea: the first-line cytoreductive agent for high-risk PV patients 1
• Interferon-alpha: used as alternative first-line therapy, particularly in younger patients 1
• Ruxolitinib: JAK1/JAK2 inhibitor for hydroxyurea-resistant or intolerant patients 1, 2

Metabolic and Systemic Causes

• Hyperviscosity syndrome: though typically presents with headache, visual changes, and neurologic disturbances rather than tremor 1
• Thyroid dysfunction
• Electrolyte abnormalities
• Vitamin deficiencies: particularly B12 deficiency

Assess for Hyperviscosity-Related Neurologic Symptoms

While tremor itself is not typical, ensure the patient's hematocrit is adequately controlled:

• Target hematocrit <45%: the CYTO-PV trial demonstrated that maintaining hematocrit strictly below 45% efficiently reduces thrombotic events 1
• Phlebotomy remains cornerstone therapy: all patients require therapeutic phlebotomy regardless of risk category 1, 2
• Evaluate for transient neurologic disturbances: which are recognized PV manifestations that could be mischaracterized as tremor 1

Consider Age-Related Vestibular Dysfunction

In older adults with PV presenting with what appears to be tremor or unsteadiness:

• Screen for fall risk: using the CDC's three-question assessment (history of falls, feeling unsteady, worry about falling) 6
• Exclude benign paroxysmal positional vertigo (BPPV): affects 9% of elderly patients and can present as instability brought on by position changes 1, 6
• Assess for presbyvestibulopathy: which can manifest as unsteadiness and may be confused with tremor in older adults 6

Management Algorithm

1. Confirm adequate PV control: verify hematocrit <45%, review cytoreductive therapy if indicated 1, 2
2. Comprehensive neurological examination: distinguish tremor type (resting, postural, intention) and assess for associated neurological signs
3. Medication review: evaluate all current medications for tremor-inducing potential
4. Laboratory assessment: thyroid function, electrolytes, vitamin B12, complete metabolic panel
5. Consider neurology referral: if tremor persists despite adequate PV control and no obvious reversible cause is identified

Critical Pitfalls to Avoid

• Do not attribute tremor to PV without thorough evaluation: this may delay diagnosis of treatable conditions like essential tremor, Parkinson's disease, or medication side effects
• Do not overlook medication-induced tremor: particularly with interferon-alpha therapy, which can cause neurological side effects
• Do not neglect fall risk assessment: older adults with both PV and tremor have compounded fall risk requiring safety interventions 6
• Ensure thrombotic risk is adequately managed: all patients should receive low-dose aspirin (if no contraindications) and appropriate cytoreductive therapy based on risk stratification 1, 2