− | Myasthenia gravis is a disease of the neuromuscular junction that occurs due to a defect or absence of nicotinic acetylcholine receptors on the post-synaptic membrane (in the congenital form) or due to the presence of antibodies that bind to the receptors and prevent them from functioning normally (in the acquired form). The underlying cause of the immune response against the acetylcholine receptors is not known but an association with thymomas and other neoplasias has been documented. Additionally immune mediated endocrinopathies such as hypothyroidism and hypoadrenocorticism have also be associated with the disease. Acquired myasthenia Gravis is the most common form of the disease. The classical focal form of myasthenia gravis affects only the extraocular muscles, the cranial [[Oesophagus - Anatomy & Physiology|oesophagus]] and the muscles innervated by [[Cranial Nerves - Anatomy & Physiology|cranial nerves]] V, VII and IX. 90% of animals diagnosed with myasthenia gravis have [[Megaoesophagus|megaoesophagus]] at presentation. | + | Myasthenia gravis is a disease of the neuromuscular junction that occurs due to a defect or absence of nicotinic acetylcholine receptors on the post-synaptic membrane (in the congenital form) or due to the presence of antibodies that bind to the receptors and prevent them from functioning normally (in the acquired form). The underlying cause of the immune response against the acetylcholine receptors is not known but an association with thymomas and other neoplasias has been documented. Additionally immune mediated endocrinopathies such as hypothyroidism and hypoadrenocorticism have also be associated with the disease. Acquired myasthenia Gravis is the most common form of the disease and cases present with generalized muscle weakness which is accentuated by mild exercise.. The classical focal form of myasthenia gravis affects only the extraocular muscles, the cranial [[Oesophagus - Anatomy & Physiology|oesophagus]] and the muscles innervated by [[Cranial Nerves - Anatomy & Physiology|cranial nerves]] V, VII and IX. 90% of animals diagnosed with myasthenia gravis have [[Megaoesophagus|megaoesophagus]] at presentation. |