How to manage new onset gait ataxia in an elderly female patient on Diltiazem, levothyroxine, metoprolol, and pravastatin?

Management of New-Onset Gait Ataxia in an Elderly Female on Diltiazem and Metoprolol

Immediately discontinue or reduce the dose of diltiazem and metoprolol, as the combination of these medications poses significant risk for bradycardia, AV conduction abnormalities, and hypotension—all of which can manifest as gait instability and falls in elderly patients. 1, 2

Urgent Medication Review and Deprescribing

The combination of diltiazem (a non-dihydropyridine calcium channel blocker) with metoprolol (a beta-blocker) is particularly hazardous and should be avoided due to potentially profound adverse effects on AV nodal conduction, heart rate, and cardiac contractility. 2 This combination can cause:

• Severe bradycardia leading to cerebral hypoperfusion and ataxia 1
• Orthostatic hypotension causing unsteady gait and fall risk 3
• Cardiac conduction abnormalities even in patients without pre-existing conduction defects 1

The prescribing cascade may have occurred here—an adverse drug event (the ataxia) could be erroneously perceived as a new neurological condition rather than a medication side effect. 3 Deprescribing is the critical first step: reduce or eliminate one of these negatively inotropic/chronotropic agents immediately. 3

Specific Action Steps:

• Check orthostatic vital signs (blood pressure and heart rate supine, sitting, and standing) 3
• Obtain 12-lead ECG to assess for bradycardia, AV block, or prolonged PR interval 1
• Measure serum creatinine as impaired renal function exacerbates drug accumulation and toxicity with this combination 1
• If blood pressure control is the indication: Consider switching to a single agent (either beta-blocker OR calcium channel blocker, not both) or use an alternative class such as ACE inhibitor or ARB 1

Comprehensive Fall Risk Assessment Using P-SCHEME

After addressing the medication issue, evaluate other fall risk factors using the P-SCHEME acronym: 3

• Pain (axial or lower extremity): Assess for arthritis, spinal stenosis, or neuropathy
• Shoes: Evaluate footwear for proper fit and non-slip soles
• Cognitive impairment: Screen with Mini-Cog or similar brief assessment 3
• Hypotension (orthostatic or iatrogenic): Already addressed above with medication review
• Eyesight: Check visual acuity and refer to ophthalmology if impaired 3
• Medications (centrally acting): Review levothyroxine dose (hypothyroidism can cause ataxia if undertreated) 4
• Environmental factors: Home safety evaluation 3

Functional Mobility Testing

Perform bedside assessment to quantify fall risk: 3

• Timed Up and Go (TUG) test: Time >12 seconds indicates increased fall risk 3
• 4-Stage Balance Test: Inability to hold tandem stand for 10 seconds warrants broader intervention 3
• Ask three key screening questions: "Have you fallen in the past year?", "Do you feel unsteady when standing or walking?", "Are you worried about falling?" 3

Any positive screening result mandates referral to physical therapy for gait training, balance exercises (tai chi, resistance training), and evaluation for assistive devices. 3

Thyroid Function Verification

Verify that levothyroxine dosing is adequate by checking TSH levels. 4 Hypothyroidism—even subclinical—can cause cerebellar-type ataxia, muscle weakness, and cognitive slowing that mimics neurological disease. 4 One case report documented rhabdomyolysis from atorvastatin-diltiazem combination that led to discovery of previously undiagnosed hypothyroidism with Hashimoto's encephalopathy presenting as ataxia and confusion. 4

Neurological Evaluation (If Ataxia Persists After Medication Adjustment)

Only if gait ataxia persists after discontinuing the diltiazem-metoprolol combination and optimizing thyroid function should you pursue neurological workup: 5, 6

• Brain MRI to exclude cerebellar stroke, mass, or degenerative disease
• Vitamin B12, folate, copper levels (nutritional ataxias)
• Paraneoplastic antibody panel if cancer risk factors present
• Consider genetic testing only if family history or early-onset features suggest hereditary ataxia 6

Critical Pitfalls to Avoid

• Do not assume new neurological disease without first addressing polypharmacy. The combination of diltiazem and metoprolol is a well-documented cause of bradycardia-induced cerebral hypoperfusion manifesting as gait instability. 1, 2
• Do not continue both agents while "monitoring." The risk of sudden cardiac arrest or complete heart block is unpredictable and may be enhanced by CYP2D6 poor metabolizer status. 2
• Do not overlook pravastatin interaction. While pravastatin has lower interaction potential than lipophilic statins, the combination with diltiazem still increases rhabdomyolysis risk, which can present with weakness mimicking ataxia. 4
• Do not delay physical therapy referral. Even if medications are the primary cause, deconditioning and fear of falling create a vicious cycle requiring active rehabilitation. 3