Background: Shrinking lung syndrome (SLS) is an uncommon complication of systemic lupus
erythematosus (SLE) that has also been seen in other autoimmune diseases and is linked with a
high risk of acute or chronic respiratory failure. Alveolar hypoventilation in the presence of
obesity-hypoventilation syndrome, systemic lupus erythematosus (SLE), and myasthenia gravis
(MG) is uncommon and poses a diagnostic and therapeutic challenge.

Case report: We reported a 33-year-old female patient from Saudi Arabia who suffered from obesity,
bronchial asthma, newly diagnosed essential hypertension, type 2 diabetes mellitus, with
recurrent acute alveolar hypoventilation, secondary to obesity hypoventilation syndrome and
mixed autoimmune disease (systemic lupus erythematosus and myasthenia gravis), based on the
correct constellation of clinical findings and laboratory evidence.

Conclusion: The interesting aspect of this case report: is the presentation of the overlap of obesity
hypoventilation syndrome and shrinking lung syndrome due to systemic lupus erythematosus
with generalized and respiratory muscle dysfunction due to myasthenia gravis with good outcomes
after therapy.