Neurobites – Myelomalacia in dogs

Every week, the BVNS neurologists, residents and interns convene to discuss a human or veterinary neurology/neurosurgery article.

NeuroBites is a digestible synopsis written by Dr. Bush of the article covered in journal club.

Welcome to NeuroBites.


Castel A, et al. Clinical Characteristics of Dogs with Progressive Myelomalacia
Following Acute Intervertebral Disc Extrusion.

J Vet Intern Med 2017;31:1782–1789

Click HERE for the full article.

Dr. Stallings picked a very good article and did an excellent job with her presentation at journal club. Here it goes….

What is myelomalacia?

Myelomalacia is when there is severe hemorrhage and clogging of blood vessels (thrombosis) of the spinal cord.

Is myelomalacia a bad thing?

Well, imagine a patient that has had spinal surgery and was maybe even able to move their back legs and feel a deep pain stimulus to the back tail that several days later stops eating, develops a fever, loses feeling and tone in the back legs and abdomen and then is euthanized in the next 12-24 hours. If you can easily think of a worse case scenario then more power to you – you are a sick person. Myelomalacia sucks.

Can myelomalacia be predicted?

MRI can suggest myelomalacia but is only correct in identifying it in 45-85% of the cases.

What do you see on MRI to know there is myelomalacia?

When you look at a MRI, the spinal cord is outlined on the top and bottom by 2 white lines such that it looks like train tracks. The white line disappears when there is pressure within the spinal cord, like with myelomalacia. If the loss of the white lines exceeds 7.4 times the length of the L2 vertebrae, there is an 85% chance of myelomalacia. If there are white spots on the T2 sagittal MRI exceeding 6 times L2, there is a 45% chance of myelomalacia.

Why is it a massive problem that tests to determine myelomalacia are not very good?

VERY CONCERNING is that these parameters fail to identify the disease so we might go to surgery and then in the next few days post-operation myelomalacia sets in and the patient is euthanized.

How common is myelomalacia?

Among dogs in the worst neurological grade (no motor, no feeling) 11-17% of the dogs could have myelomalacia. French Bulldogs may get it up to 33% of the time in this circumstance. Also very worrisome is that the process of myelomalacia can still develop in dogs that can move their legs and feel deep pain.

When I am monitoring a patient – what might I see on physical exam that could tell me myelomalacia could be present?

·        Absent deep pain

·        Hypothermia (30%), Hyperthermia (15%), Very painful (20%)

·        Cranial movement of the cutaneous trunci muscle reflex

·        Absent patella reflex

·        Absent perineal reflex and poor anal tone

·        Decreased to absent abdominal tone

·        Abnormal respiratory pattern

·        Difficulty maintaining sternal recumbency

·        Thoracic limb weakness or postural deficit

·        Altered mentation, stupor and seizure-like episodes

Do all cases of myelomalcia progress? Is there a treatment?

About 10% can have a cessation to the progression of myelomalacia and then go on to get better. Why? Nobody knows because there is no known treatment for myelomalacia. Bad stuff.

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