Final answer:
Hypoxemia in a Myasthenia Gravis patient with hypercapnia is typically caused by alveolar hypoventilation, which is a result of weakened respiratory muscles impeding proper gas exchange in the lungs.
Step-by-step explanation:
The correct option : a
The cause of hypoxemia in a patient with Myasthenia Gravis who develops hypoxemia along with hypercapnia is A. Alveolar hypoventilation. Myasthenia Gravis is an autoimmune neuromuscular disease which can weaken respiratory muscles, leading to insufficient ventilation. Alveolar hypoventilation occurs when there is inadequate air movement into the alveoli, causing a reduced gas exchange.
In such a patient, the weakened respiratory muscles are unable to maintain adequate ventilation. This results in a lower exchange of gases, with oxygen levels dropping (hypoxemia) and carbon dioxide levels rising (hypercapnia) in the blood. When the respiratory system fails to expel carbon dioxide efficiently due to hypoventilation, hypercapnia occurs, and when not enough oxygen enters the alveoli for transport into the bloodstream, hypoxemia ensues.