Sleep hypoventilation syndrome and respiratory failure due to multifocal motor neuropathy with conduction block

Abstract

Sleep hypoventilation syndrome and respiratory failure have been reported in association with a diverse spectrum of neuromuscular disorders. We report a patient with multifocal motor neuropathy with conduction block who presented with sleep hypoventilation, presumably due to bilateral phrenic neuropathy and was initially diagnosed to have obstructive sleep apnea syndrome. Once the correct diagnosis was made the patient was treated successfully with a combination of regular immunoglobulin and bilevel nocturnal ventilation. Delay in the administration of intravenous immunoglobulin resulted in respiratory failure.

Multifocal motor neuropathy

“…27 There are isolated reports of diaphragmatic involvement with respiratory insufficiency and hypoventilation. 28 Cranial nerve involvement is also rare but hemiatrophy of the tongue has been noted in one patient. 29 Despite the fact that in most demyelinating disorders, symptoms worsen in heat, in MMN, 'cold paresis' with worsening of weakness in cold temperature has been reported.…”

Multifocal motor neuropathy: a review of pathogenesis, diagnosis, and treatment

“…There are, however, features that distinguish MMN from motor neuron disease (amyotrophic lateral sclerosis): 1) MMN affects predominantly (but not exclusively) the upper limbs; 2) MMN usually lacks bulbar or respiratory involvement; 3) muscle weakness in MMN is associated with less atrophy, unless it becomes severe or longstanding; 4) cramps and fasciculations can occur in motor neuron disease but are less prominent than in MMN, occurring in up to 50% of patients with MMN; 5) MMN has no upper motor neuron signs; and 6) MMN has a characteristic electrophysiological pattern of motor conduction block 11. Although typically associated with motor neuron disease, MMN can be associated with normal (20%) or even brisk (8%) deep tendon reflexes and, rarely, respiratory insufficiency due to phrenic nerve involvement 6,12–15. Therefore, care must be taken to consider the clinical picture as a whole.…”

“…Life expectancy in MMN is normal but conversely spontaneous remission has not been reported 1,5,40. Life-threatening respiratory weakness associated with hypoventilation and respiratory insufficiency due to phrenic nerve involvement with diaphragmatic paresis has been described but is thought to be a rare manifestation of MMN 13,15…”

A 54-Year-Old Man with Acute Onset Orthopnea and Sleep-Related Hypoxia

“…There was no evidence for other conditions which may rarely cause bilateral phrenic neuropathies, such as diabetes, 8 multifocal motor neuropathy with conduction block, 9 POEMS syndrome, 10 sarcoidosis, 11 arsenic poisoning, 12 prior irradiation, 13 or acid maltase deficiency. 14 BIPN presents as a painless paralysis of the diaphragm with relatively acute onset, and without antecedent factors such as infection or prior surgery.…”