What are the common causes of myasthenia gravis in dogs and cats?

Myasthenia gravis is most often linked to an immune-mediated attack on neuromuscular junction receptors. Some cases may be associated with an underlying tumour or other condition. Your vet will carry out further tests to determine the cause.

How does the vet confirm a diagnosis of myasthenia gravis?

Diagnosis typically combines a thorough history, physical and neurological examination, neuromuscular function tests, blood work, and imaging. Some cases require specialist testing for confirmation. Ask your vet about the appropriate workup for your pet.

What is the prognosis after treatment?

Prognosis depends on disease duration, concurrent conditions, and response to treatment. Some pets regain normal activity with appropriate treatment and supportive care. Regular follow-up as directed by your vet is essential.

What home care can help manage the condition?

Record your pet's breathing and feeding patterns, adjust food texture and feeding technique, prepare observation videos, and attend rechecks as directed by your vet. Contact your vet immediately if symptoms worsen.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Myasthenia Gravis in Dogs & Cats: Symptoms, Diagnosis & Care [2025]

Myasthenia gravis is a neuromuscular junction disorder causing exercise-induced muscle weakness, often accompanied by megaesophagus and aspiration pneumonia.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ACVIM, WSAVA, National Taiwan University Veterinary Teaching Hospital

When to See a Vet

Seek Emergency Care Immediately

•Breathing becomes shallow or visibly labored with changes in respiratory rate
•Sudden collapse or brief loss of consciousness
•Gums or oral mucous membranes turn purple or abnormally pale

Schedule a Clinic Visit Soon (Within 24–72 Hours)

•Persistent fatigue or noticeably reduced activity level
•Frequent choking or obvious difficulty swallowing while eating
•Repeated vomiting or frequent regurgitation after feeding

01What symptoms indicate something is wrong?

Myasthenia gravis primarily causes skeletal muscle weakness, often affecting mobility, swallowing, and breathing. Symptoms may persist or gradually worsen over time.

Persistent or progressive muscle weakness with reduced activity levels
Difficulty swallowing, frequent coughing or regurgitation when eating
Repeated vomiting or frequent regurgitation after feeding
Shallow or laboured breathing, or obvious respiratory effort
Lethargy, easy fatigue, or episodes of sudden collapse

Seek emergency care immediately if you notice the following symptoms:

⚠️ Breathing difficulty or noticeably weakened breathing — seek emergency care immediately
⚠️ Sudden collapse or sudden loss of consciousness
⚠️ Blue, purple, or abnormally pale gums or oral mucous membranes

02How can I assess the situation at home? Key observations and when to go to emergency

Key observations to record at home before your vet visit, helping your vet understand the progression of the condition more quickly.

Note the number of vomiting or regurgitation episodes, the timing, and contents
Observe and record your pet's breathing rate and whether breathing appears laboured
Note changes in alertness, activity level, and responsiveness to you
Monitor appetite, water intake, and how well your pet tolerates feeding
Record bowel and bladder habits and the timeline of symptom onset or changes
Bring all observation notes and videos to the appointment for your vet's reference

03How will the vet diagnose this? Common tests and examinations

The vet will conduct a thorough physical examination along with imaging and functional tests to assess muscle strength, swallowing, and breathing.

Detailed physical examination

assessing muscle strength, reflexes, and swallowing function

Chest X-ray

evaluating pulmonary and thoracic changes

Electrocardiogram (ECG)

checking heart rhythm and cardiopulmonary status

Blood tests

ruling out infection, metabolic disorders, or organ dysfunction

Advanced imaging (CT/MRI)

evaluating neuromuscular or thoracic lesions when necessary

Muscle or nerve-related tests and biopsy when indicated

Referral to a specialist hospital with neuromuscular diagnostic capability is recommended for follow-up

04How is the condition treated and managed? Medications, dietary adjustments, and care guide

Treatment focuses on supportive care and medications as directed by your vet. Regular follow-up is essential and the treatment plan may be adjusted based on your pet's condition.

IV fluids, nutritional support, and other supportive care may be needed during the acute phase
Oxygen therapy or respiratory support may be required if breathing is unstable
The vet will assess whether immunosuppressive or other medications are appropriate
Adjust feeding technique and food texture to minimise the risk of aspiration
Schedule regular rechecks and monitoring as directed by your vet
Referral to a specialist hospital is recommended for long-term follow-up and treatment planning

05What should I prepare before the vet visit? Key information to help your vet assess quickly

Record when symptoms first appeared, how they have fluctuated, and the key timeline

Note the number of vomiting or regurgitation episodes, feeding method, and food type

Prepare a list of current medications, past medical history, and any known allergies

Record videos of feeding, swallowing, or breathing (both front and side views)

If your pet is having difficulty breathing or has collapsed, call the clinic first to arrange emergency care

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.