Recommended Surveillance for Limb Girdle Muscular Dystrophy
Regular cardiac and respiratory monitoring is essential for all patients with limb girdle muscular dystrophy (LGMD), even when asymptomatic, as cardiac involvement and respiratory compromise are significant causes of morbidity and mortality that can be addressed with timely intervention.
Cardiac Surveillance
Initial Evaluation
- Complete cardiac assessment at diagnosis including:
- Detailed cardiac history and examination
- 12-lead ECG
- Echocardiogram
Follow-up Monitoring
- For LGMD with progressive cardiac involvement (especially Emery-Dreifuss and limb-girdle type IB):
- Annual cardiac evaluation with ECG and echocardiogram
- More frequent monitoring if abnormalities detected
Cardiac Red Flags
- Monitor for:
- Conduction defects (PR interval >240 ms, left bundle-branch block)
- Non-sustained ventricular tachycardia (NSVT)
- Reduced left ventricular ejection fraction (LVEF <45%)
- Symptoms of cardiac dysfunction (palpitations, syncope, dyspnea)
Cardiac Interventions
- Consider ICD placement for:
Respiratory Surveillance
Initial Evaluation
- Baseline pulmonary function tests (PFTs) including:
- Forced vital capacity (FVC)
- Maximum inspiratory and expiratory pressures (MIP/MEP)
- Peak cough flow
Follow-up Monitoring
- Annual pulmonary function testing while ambulatory
- Every 6 months after loss of ambulation or when FVC <80% predicted
- Overnight oximetry or polysomnography when:
- FVC <60% predicted
- Signs/symptoms of sleep-disordered breathing (morning headaches, daytime sleepiness, fatigue)
Respiratory Red Flags
- Monitor for:
- Declining FVC (especially <50% predicted)
- Ineffective cough (peak cough flow <270 L/min)
- Symptoms of nocturnal hypoventilation
- Recurrent respiratory infections
Respiratory Interventions
- Airway clearance techniques when cough becomes ineffective
- Nocturnal non-invasive ventilation when indicated by:
- Symptoms of nocturnal hypoventilation
- Abnormal overnight oximetry/sleep study
- FVC <50% predicted
Neuromuscular Surveillance
- Strength assessment every 6-12 months using standardized measures
- Functional assessments to track disease progression
- Monitoring for contractures and scoliosis
- Evaluation of mobility aids and adaptive equipment needs
Multidisciplinary Care Components
- Neurology: Every 6-12 months to assess disease progression
- Physical therapy: Every 6 months for range of motion, strength, and functional assessment
- Orthopedics: As needed for scoliosis, contractures, and fracture risk
- Nutrition: Annual assessment of weight, swallowing function, and nutritional status
- Pain management: Regular assessment and treatment of musculoskeletal pain
Special Considerations
Genetic Testing and Counseling
- Genetic testing for specific LGMD subtype to guide surveillance
- Family screening and genetic counseling
Perioperative Management
- Comprehensive cardiac and respiratory assessment before any surgery
- Careful anesthetic planning due to risk of malignant hyperthermia in some subtypes
Common Pitfalls to Avoid
- Delayed cardiac surveillance: Cardiac involvement can be clinically silent until advanced
- Overlooking respiratory decline: Respiratory failure is a major cause of morbidity and mortality
- Missing early signs of nocturnal hypoventilation: Can present subtly as morning headaches, fatigue
- Inadequate monitoring frequency: Disease progression can accelerate, requiring adjustment of monitoring schedule
- Failure to consider ICD placement: Particularly in LGMD subtypes with high risk of sudden cardiac death
By implementing this comprehensive surveillance approach, clinicians can identify complications early and intervene appropriately to improve quality of life and potentially extend survival in patients with LGMD.