Whenever dogs have to get up, run, jump or make any other movement, their brain will send a signal to the muscle to communicate that precise command. The transmission of the message comes through an electrical impulse, just in the same way that the current propagates.
A fascinating and extremely efficient biological mechanism, which in the myasthenia gravis in dogs is compromised. Let’s see in detail what it is and how to treat this autoimmune disease.
What is myasthenia gravis in dogs?
Myasthenia gravis in dogs is one neuromuscular disease which prevents the correct transmission of the signal that is sent from the brain to the muscles.
It causes a condition in dogs (but also in cats) weakness, muscle wasting, generalized reduction or loss of strength, with easy fatigue and insufficient response to stimuli.
This disease predisposes dogs to further diseases, such as megaesophagus and thymoma.
What is it caused by?
Myasthenia gravis in dogs is caused by the absence or, more frequently, by the destruction by the immune system of acetylcholine receptors, a chemical messenger essential in the transmission of the electrical impulse.
L’acetylcholine in fact it accompanies the signal along the neuromuscular junction, a small space between nerves and muscles. Acetylcholine receptors are found on the muscles and its bond with them generates muscle contractions.
How many types of myasthenia gravis are there in dogs?
There are two types of myasthenia gravis in dogs: congenital and acquired. The second is the most frequent and is one of the main ones autoimmune diseases dogs.
Congenital
The congenital form indicates that the dog was born with this disease. His body non produce a sufficient number of receptors acetylcholine so that the signal can be transmitted correctly, causing the typical symptoms.
Acquired
The acquired form is much more frequent and the dog can develop it at any time in life.
Here the receptors are not lacking, but they are recognized by the immune system as non-self.
Consequently these receptor cells are destroyed even if they are essential for the organism. It can be induced by thymus tumor (timo).
Symptoms of myasthenia gravis in dogs
A few minutes of exercise are enough to generate a powerful and immediate weakness in the dog with myasthenia gravis.
After rest the condition improves, but the autonomy of movement of the four-legged will always be very reduced: in the most serious cases, Fido will not even be able to keep his head straight.
Usually i symptoms main occur in the 4 limbs or hind limbs:
Other symptoms associated with myasthenia gravis in dogs concern the difficulty in carrying out some physiological functions in which the muscles play a key role, such as digestion.
This pathology is often predisposing to megaesofagocharacterized by regurgitation, difficulty in ingesting and assimilating nutrients.
Diagnosis
Myasthenia gravis has several symptoms in common with other dog neurological diseases.
A blood test will reveal the massive presence of antibodies directed to the acetylcholine receptor (anti-AChR antibody titer). Other methods are:
- Tensilon Test,
- Electromyography
- Chest X-ray.
- Muscle biopsy
Treatment of myasthenia gravis in dogs
If the pet suffers from this condition he will have to follow a lifetime therapy, which will still allow him to be happy and live in decent conditions.
The treatment to this provides for the administration of:
- Acetylcholinesterase inhibitor drugs, which is the enzyme that causes the destruction of acetylcholine.
- cortisone drugs: lower the immune defenses by preventing the body from attacking the receptors
- antibiotic medications, to treat any lung forms or secondary infections.
Life expectation
The life expectancy of a dog with myasthenia gravis depends on many factors, such as
- general health conditions,
- the age
- the severity of the disease.
In case the dog has developed megaesophagus, thelife expectancy is reduced: 40-60% of dogs with this complication do not survive more than one year.
To improve Fido’s quality of life and prolong it while respecting his well-being, symptomatic therapy is essential: it consists in the use of a Bailey chair that allows the four-legged person to eat uprightstemming part of the negative effects of this pathology.
If you suspect that your dog may be suffering from myasthenia gravis, contact your veterinarian immediately: he will be able to give you useful advice on this disease, which unfortunately will forever characterize your friend’s life. Face it to the fullest!