Description

A non-smoking 71-year-old man had suffered myocardial infarction 6 years back. After a circumflex angioplasty, he remained asymptomatic with moderately impaired left ventricular function. This was unchanged when he presented with 6 months’ progressive breathlessness and orthopnoea, but no chest pain. There was insufficient evidence on CT to explain his restrictive spirometry. A diagnostic coronary angiography was arranged, but soon abandoned when he developed pulmonary oedema while recumbent. Frequent fasciculations were noted (video 1). The pulmonary oedema resolved with treatment, but his type II respiratory failure and orthopnoea persisted. Troponin was not raised.

Retaking the history revealed 3 months’ weight loss alongside general weakness. He had noticed he was not able to lift his arms. Over the last 4 months there had been progressive loss of speech articulation, cramps in hands and difficulty in arising from a chair. Ankle jerks were absent.

Clinical neurophysiology revealed sensory responses generally absent or reduced, as were the lower limb motor responses. Motor response in his right hand was not augmented after a 10 s maximal contraction (against Lambert-Eaton myasthenia). There was no decrement in repetitive nerve stimulation. A concentric needle electromyography (EMG) (table 1) identified an active denervation in upper and lower limbs, extending into the cranially innervated territory. Notwithstanding the axonal-type polyneuropathy, disproportionate diffuse motor axonal loss supported amyotrophic lateral sclerosis.

Symptoms improved with non-invasive ventilation, suggesting pulmonary oedema had arisen from insufficient respiratory excursion while recumbent. Dyspnoea–fasciculation syndrome is a presentation of Amyotrophic Lateral Sclerosis.1 Type II respiratory failure from weakness can underlie orthopnoea, in our case exacerbated when supine for cardiac catheterisation.