Table 3

Respiratory features of neuromuscular diseases

ConditionRespiratory failureSecretion clearance difficultyRecurrent pneumoniaProgressionDisease-specific features
 Type 1All by 2 yearsMarkedAllRapidAll require full-time respiratory support
 Type 2∼40% in childhoodEarly∼25% in first 5 yearsSlow
 Type 3Rare in childhoodRare in childhoodRare in childhoodSlow
SMA with respiratory distress type 1All by 6 monthsMarkedAllRapid in first year, then slows.All require full-time respiratory support
DMD/severe childhood onset limb-girdle muscular dystrophyAfter loss of ambulationAfter loss of ambulationLate Cardiomyopathy usually occurs after respiratory problems but may precede them
Facioscapulohumeral muscular dystrophyWhen onset <20 yearsWith infantile onsetWith infantile onsetSlowSevere infantile onset type is frequently associated with sensorineural deafness
Congenital muscular dystrophy
 All typesAny age depending on severityAny age depending on severityAny age depending on severitySlow
 Ullrich70% in adolescenceMildInfrequent Proximal contractures with marked distal laxity
Rigid spine muscular dystrophyEarly while ambulation preservedMildInfrequent Hypoventilation may occur in ambulant children with relatively preserved vital capacity
Congenital myopathy
 Central coreUncommon except in severe recessive typeUncommonUncommonSlowSusceptible to malignant hyperthermia
 MinicoreEarly while ambulation preserved
 NemalineEarly in severe neonatal form, mild later onset form may develop early while ambulation preservedIn severe formIn severe formSlow
 Myotubular85% in severe X-linked formIn severe formIn severe formSlowOphthalmoplegia, rare coagulopathy and liver haemorrhage
Fibre type disproportionDepends on genotypeUncommonUncommon
Myotonic dystrophy
 Myotonic dystrophy 1Common in severe congenital onset, usually improvesCommon in severe congenital onsetCommon in severe congenital onsetInitial improvement, later slow deteriorationProminent learning difficulty, somnolence, central hypoventilation
 Myotonic dystrophy 2UncommonUncommonUncommon
Congenital myasthenic syndromesOften in neonatal period, may occur during inter-current illnessesEspecially during inter-current illnessesPossible if weakness severe and persistent Weakness may fluctuate, episodic apnoea in some. Congenital stridor in those with DOK7 mutations
Mitochondrial myopathyCommonPossiblePossibleAcute deterioration possible
Charcot–Marie–ToothWith severe early onset, especially with GDAP1 mutationWith severe early onsetWith severe early onset Stridor, especially with GDAP1 mutation
PompeInfantile onset, may be early in later onset while ambulation preservedInfantile onsetInfantile onsetInfantile rapid, late onset slowVariable relationship between motor and respiratory progression
  • DMD, Duchenne muscular dystrophy; SMA, spinal muscular atrophy.