On Respiratory Crisis and Other Respiratory Curiosities in the Aftermath of Encephalitis Lethargica: "Like Asthma".

Pandemics in the early 20 th century (and now with SARS-CoV-2) have been dominated by respiratory viruses damaging lungs. Less is known about abnormal respiratory patterns from brain inflammation. One of the first descriptions of respiratory rhythm abnormalities was seen with an acute attack of epidemic encephalitis (encephalitis lethargica), and reports appeared soon after the original description in 1921. We reviewed these ill-remembered disorders of the respiration rate, respiratory patterns and respiratory "tics." Most commonly, dysregulations occurred during the phase when ocular signs appeared. The early symptoms were an unrelenting tachypnea without air hunger and an inspiratory hold ( fixés en inspiration forcée ). Initially regarded as "hysterical" in nature, the later bizarre disorders of respiration were considered equally serious with attacks of gasping, panting, puffing, inspiratory breath holding, coughs, giggles, sighing, grunting, and moaning. These respiratory disorders were seen exclusively as part of a parkinsonian syndrome. Most remarkably, these attacks could be provoked by oxygen administration.These respiratory abnormalities with encephalitis lethargica are not well remembered. One purpose of recalling these episodes is to call attention to central causes of respiratory illness even in pandemics with respiratory viruses.