Acquired myasthenia gravis (MG) is an autoimmune disease in which antibodies attack the acetylcholine receptors of the neuromuscular junction, so muscles tire quickly. It is uncommon in cats (MSD) and differs from the canine disease in two ways that matter for the NAVLE: many affected cats have a thymoma, and most develop generalized weakness without megaesophagus.
Key facts
Myasthenia gravis at a glance- Species and system: cat; neuromuscular junction.
- Cause: autoantibodies against the nicotinic acetylcholine receptor (AChR), reducing functional receptors; often paraneoplastic with thymoma.
- Cranial mediastinal mass: found in 52% (69 of 133 cats with thoracic radiographs) in the largest series of 235 cats, most commonly thymoma.
- Classic presentation: fatigable generalized weakness, ventroflexion of the neck, sometimes regurgitation and a reduced palpebral reflex.
- Definitive test: serum AChR antibody titer (above 0.3 nmol/L in the main feline study).
- Treatment: pyridostigmine, with immunosuppression (prednisolone) usually needed; resection of a thymoma.
- Zoonotic or reportable: no.
What's inside
12 sections in the full guide- Key facts
- How the NAVLE tests this
- Cause and pathophysiology
- Clinical signs
- Diagnosis
- Differential diagnoses
- Treatment and management
- A practical approach for the exam
- Prognosis
- Quick review
- Test yourself
- References
The full guide also has 4 tables, 1 figure, 3 self-test questions and 5 references, available to NAVLE members.
Read the full study guide
The full guide is part of every NAVLE plan, with diagnosis and treatment tables, figures, a quick review and self-test questions. Start a free trial to try the question bank, or log in if you are already a member.