Shortlived survival of severe hypercapnia from chronic respiratory failure in motor neuron disease

Introduction: Surviving extreme hypercapnia from muscular respiratory failure has been only rarely reported. Case Report: A 66­year­old male developed slowly progressive weakness of the lower limbs since one year resulting in recurrent falls and later dysarthria, weakness of the left intrinsic hand muscles, general wasting, brisk tendon reflexes, and symmetric stocking type pall­hypaesthesia. Electromyograms of various muscles were neurogenic. Cerebral MRI showed diffuse atrophy, leucaraiosis, spot­like hyperintensities subcortically and in the basal ganglia and a diffuse hypersignal in the pons. Probable amyotrophic lateral sclerosis (ALS) was diagnosed. Four months later he was admitted for respiratory insufficiency, impaired consciousness, exsiccosis, and cachexia. Blood pH was 6.9 and blood pCO2 was 235 mmHg (n, 35 ­ 45 mmHg). Within six hours under mechanical ventilation he recovered completely from hypercapnia and actively extubated himself two days after admission. Conclusion: This case shows that severe hypercapnia from weakness of the respiratory muscles may be survived if respiratory failure develops slowly, and if adequately treated.