What is the initial management for polyradiculoneuropathies (such as Guillain-Barré Syndrome) presenting with sinus tachycardia and moderately reduced ejection fraction (EF)?

Management of Polyradiculoneuropathies Presenting with Sinus Tachycardia and Reduced Ejection Fraction

In patients with Guillain-Barré syndrome (GBS) or other polyradiculoneuropathies presenting with sinus tachycardia and moderately reduced ejection fraction, the primary focus must be on treating the underlying polyradiculoneuropathy with immunotherapy while simultaneously managing the cardiac manifestations as secondary autonomic dysfunction, not as primary cardiac disease requiring rate suppression. 1, 2

Immediate Recognition and Diagnosis

Identify the Polyradiculoneuropathy

• GBS is the most common acute polyradiculoneuropathy and typically presents with ascending weakness, sensory disturbances, and autonomic dysfunction including cardiac arrhythmias. 1, 3
• Diagnosis requires clinical features supported by CSF examination (albuminocytologic dissociation) and electrophysiological studies to distinguish between acute inflammatory demyelinating polyradiculoneuropathy (AIDP), acute motor axonal neuropathy (AMAN), and acute motor sensory axonal neuropathy (AMSAN). 1, 2
• Autonomic involvement occurs in approximately 20% of GBS patients and can manifest as sinus tachycardia, blood pressure instability, and cardiac arrhythmias. 1

Assess Cardiac Involvement

• The sinus tachycardia in this context represents autonomic nervous system dysfunction secondary to the polyradiculoneuropathy, not a primary cardiac arrhythmia. 1
• The moderately reduced ejection fraction may represent tachycardia-induced cardiomyopathy if the heart rate has been persistently elevated (>100 bpm) for weeks to months. 1
• Obtain 12-lead ECG, continuous cardiac monitoring, echocardiography to assess EF, and evaluate for other reversible causes of cardiomyopathy. 1, 4

Primary Treatment: Immunotherapy for the Polyradiculoneuropathy

Definitive Immunotherapy

• Administer intravenous immunoglobulin (IVIg) 0.4 g/kg daily for 5 days in patients within 2 weeks of weakness onset who cannot walk unaided. 2
• Alternatively, plasma exchange (PE) 12-15 L in 4-5 exchanges over 1-2 weeks can be used within 4 weeks of onset if the patient cannot walk unaided. 2, 5
• Do not combine PE followed immediately by IVIg as this provides no additional benefit. 2
• The electrophysiological subtype (demyelinating vs. axonal) does not change treatment selection—both IVIg and PE are effective regardless of subtype. 3

Critical Monitoring

• Approximately 20% of GBS patients require mechanical ventilation due to respiratory muscle weakness. 1
• Use the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess risk of requiring artificial ventilation. 2
• Admit to intensive care unit if respiratory compromise is anticipated or if severe autonomic instability is present. 1, 2

Secondary Management: Cardiac Manifestations

Approach to Sinus Tachycardia

• Do not aggressively suppress the sinus tachycardia with rate-controlling medications as this represents compensatory autonomic dysfunction, not a primary arrhythmia requiring treatment. 1, 6
• The mainstay of managing sinus tachycardia is identifying and treating the underlying cause—in this case, the polyradiculoneuropathy itself. 1, 4
• Beta-blockers should be used with extreme caution in GBS patients with autonomic dysfunction, as they may worsen blood pressure instability and mask compensatory tachycardia. 1

Management of Reduced Ejection Fraction

• Initiate standard heart failure therapy to attenuate adverse remodeling: ACE inhibitors or angiotensin receptor blockers, beta-blockers (if tolerated given autonomic dysfunction), and diuretics as needed for volume management. 1
• If tachycardia-induced cardiomyopathy is suspected, maintenance of sinus rhythm or control of ventricular rate is indicated, but this must be balanced against the autonomic instability from GBS. 1
• The ejection fraction may improve substantially once the underlying polyradiculoneuropathy is treated and the autonomic dysfunction resolves. 1

Critical Pitfalls to Avoid

Do Not Suppress Compensatory Mechanisms

• Never suppress sinus tachycardia before identifying the underlying cause, as the elevated heart rate may be maintaining cardiac output in the setting of reduced EF. 6
• In GBS with autonomic dysfunction, aggressive rate control can precipitate severe hypotension or cardiovascular collapse. 1

Do Not Delay Immunotherapy

• Time to treatment is critical—immunotherapy (IVIg or PE) should be initiated as soon as the diagnosis of GBS is confirmed in patients unable to walk unaided. 2, 5
• Waiting for complete diagnostic workup or attempting to optimize cardiac function first will delay definitive treatment and worsen neurological outcomes. 1

Recognize Treatment-Related Fluctuations

• 2-5% of GBS patients experience treatment-related fluctuations (TRF), where they deteriorate after initial stabilization or improvement on therapy. 1
• However, do not administer a second course of IVIg in patients with poor prognosis, as this is not recommended. 2
• If progression continues beyond 8 weeks from onset, consider changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP), which occurs in approximately 5% of initially diagnosed GBS patients. 2

Prognosis and Long-Term Considerations

Expected Outcomes

• 60-80% of GBS patients can walk independently 6 months after onset with appropriate treatment. 1
• Mortality remains 3-10% even with optimal care, largely due to autonomic complications and respiratory failure. 1
• The ejection fraction may normalize once the tachycardia is controlled and the underlying polyradiculoneuropathy resolves, though persistent ultrastructural cardiac changes may remain. 1

Prognostic Assessment

• Use the modified Erasmus GBS Outcome Score (mEGOS) to assess individual patient outcomes. 2
• Patients with axonal variants (AMAN, AMSAN) may have higher mortality rates compared to demyelinating forms. 7