Respir Med. 2015 Feb 12. pii: S0954-6111(15)00021-9. doi: 10.1016/j.rmed.2015.01.018. [Epub ahead of print]
Respiratory dysfunction in multiple sclerosis.
AbstractRespiratory dysfunction frequently occurs in patients with advanced multiple sclerosis (MS), and may manifest as acute or chronic respiratory failure, disordered control of breathing, respiratory muscle weakness, sleep disordered breathing, or neurogenic pulmonary edema. The underlying pathophysiology is related to demyelinating plaques involving the brain stem or spinal cord. Respiratory complications such as aspiration, lung infections and respiratory failure are typically seen in patients with long-standing MS. Acute respiratory failure is uncommon and due to newly appearing demyelinating plaques extensively involving areas of the brain stem or spinal cord. Early recognition of MS patients at risk for respiratory complications allows for the timely implementation of care and measures to decrease disease associated morbidity and mortality.
An MS plaque (arrows) in the medulla, the breathing center of the brain can lead to acute breathing difficulties
In general breathing problems occur in MSers with advanced stage of disease. It is thankfully rare in ambulatory/walking MSers. Rarly, it occurs acutely in RRMS, caused by MS plaques in the cervical cord or medulla (see above picture).
Over the past year, I looked after two MSers with breathing difficulties, both heavily disabled (EDSS 8.5-9.0), but requiring in-patient care primarily because of their breathing. First MSer would go silent mid conversation, turning blue around the lips - after momentary panic our initial thoughts were that it was a seizure, but his O2 probe showed that his SATS (O2 saturation) had dropped to 40% - this was Cheyne-Stokes breathing. Second MSer in fact had epilepsy but worsening seizure control due to recurrent aspiration pneumonia (chest infections resulting from breathing in secretions from the mouth or stomach into the lungs).
It is therefore not surprising that breathing problems account for 47% of all deaths in MS. The standardized mortality ratio is 2.79 (95% CI 2.44 - 3.18) i.e. almost three times more likely die prematurely due to breathing difficulties.
It is therefore critical to recognize those at greater risk and initiate appropriate measures in a timely manner. Pointers to potential breathing problems:
- a weak cough
- swallowing difficulties
- difficulty controlling breathing
- shortness of breath and excessive daytime sleepiness
- shortness of breath on lying flat
- sleep disordered breathing (obstructive/central sleep apnoea)
And general considerations in management include:
- prompt treatment of chest infections
- influenza and streptococcal pneumonia vaccinations
- smoking cessation
- avoidance of sedatives
Specific measures include:
- chest physiotherapy and cough assist devices in those with a weak cough
- non-invasive ventilation for acute failure in breathing or those with nocturnal sleep difficulties for long-term support of symptoms
- targeted respiratory muscle training exercises to boost strength and endurance (can be administered over 4-12 weeks)