Case Reports Commentary

The case report by Brander and colleagues diaphragm weakness due to one of the many causes listed by Brander and colleagues remain of severe diaphragm weakness due to phrenic nerve damage from radiotherapy given many undiagnosed despite diaphragm dysfunction contributing to symptoms of breathlessness and years earlier is of considerable interest. 1 It provides yet another cause of diaphragm dys-disability? This question can only be answered if we are prepared, when clinically appropriate, function to add to an already long list. The authors comment that the potential causes of to make specific measurements of respiratory muscle strength. diaphragm weakness include motor neurone disease, poliomyelitis, myasthenia, muscular Brander and co-workers treated their patient with nocturnal non-invasive ventilation with dystrophies, polyneuropathy, neuralgic amyo-trophy, malignant invasion of the phrenic good control of symptoms; for patients with severe orthopnoea the achievement of com-nerves, chest wall trauma, cardiothoracic surgery , connective tissue diseases, amyloid, and fortable sleep is most welcome. Such symptomatic control is a good indication for non-thyroid disease. There are other causes that could be added to this list and it is therefore invasive ventilation. A second indication would be established chronic ventilatory failure. This an important clinical point that diaphragm weakness is unusual, but it is not rare. Any did not occur in the case presented because the respiratory muscle weakness was largely respiratory physician with a busy clinical practice can expect to see patients with diaphragm confined to the diaphragm. 4 In patients with more widespread and severe respiratory muscle weakness, of varying severity, on an infrequent but regular basis. An important issue therefore weakness, ventilatory failure first develops at night (hence the importance of sleep studies) is how diaphragm weakness is diagnosed and how its severity is accurately assessed. and often occurs rather suddenly when the degree of weakness becomes sufficiently pro-When diaphragm weakness is severe the diagnosis – in a qualitative sense – is not a problem, found. Thus, patients may have a reduction of 30%, 40%, 50%, 60%, or even 70% in and the key features, as in this case presentation , are orthopnoea, paradoxical ab-respiratory muscle strength without developing ventilatory failure unless, in addition, there is dominal movement, and a fall in vital capacity when supine. However, these are late symptoms increased ventilatory load. At a relatively sharp cut off point, when inspiratory muscle strength and signs that only occur when diaphragm strength is reduced to approximately …