Respiratory illnesses associated with neuromuscular disorders
Neuromuscular disorders (NMD) encompass a wide variety of illnesses in which the muscle function is impaired either directly or indirectly by affecting the neuromuscular junctions or the peripheral nervous system. Disease of the brain or spinal cord that lead to muscle weakness are not considered as neuromuscular diseases. Examples of NMD are:
- Muscular dystrophies [e.g. Duchenne’s muscular dystrophy (DMD)]
- Myesthenia gravis
- Guillian-Barre´ syndrome
- Spinal muscular atrophy
- Amyptrophic lateral sclerosis
- Multiple sclerosis
Many of these disorders are inherited or genetic as in muscular dystrophies. Sometimes it could result from an immunological cause as in myasthenia gravis.
Symptoms:
Patients with NMD have muscular weakness, loss of muscle bulk, twitching of muscles, cramps, tingling. Those with neuromuscular junction anomalies can have droopy eyelids, double vision and weakness worsening with progressive activity. Other symptoms are:
- Rigidity
- Loss of muscle control
- Myoclonus with twitching, spasms, cramps
- Muscle pain
- Breathing difficulty
- Fatigue
- Swallowing problems
- Visual disturbances
- Sleep disordered breathing
- The respiratory involvement eventually worsens, with impaired airway clearance, pooling of secretions, and subsequent infections.
- Respiratory muscle weakness, eventually leads to abnormal breathing pattern and ventilatory drive and results in nocturnal desaturation and sleep disruption, and further progresses to daytime ventilatory failure.
Investigations:
- Lung function tests – Serial estimations help in prognosticating the child
- Overnight monitoring by detailed polysomnography (PSG) or simple oximetry
Interventions:
The basic aim for treating these children is to produce effective mucus clearing and having effective ventilation. The most important point is to start these interventions at the appropriate time, in order to improve the quality of life, reduce hospitalizations as well as the frequency of lower respiratory tract infections. The following interventions are used for these children:
- Antibiotics in case of respiratory tract infections
- Airway clearance therapies
- Noninvasive positive pressure ventilation (NIV) improves sleep-disordered breathing, quality of sleep and ultimately improves the quality of life and survival.
- NIV at night, in case of sleep disordered breathing to maintain nocturnal oxygenation
Hence in neuromuscular diseases it is best to discuss and plan a management for your child at the earliest so that lung functions are preserved and there is a good quality of life.