What causes ivdd in dogs

Overview

Intervertebral Disc Disease (IVDD) is a common and often debilitating condition affecting the spine of dogs. It occurs when the intervertebral discs, which act as shock absorbers between the vertebrae, degenerate and lose their cushioning ability. This degeneration can lead to the discs bulging or rupturing, and the material within the disc can then press on the spinal cord. The pressure on the spinal cord can cause pain, nerve damage, and in severe cases, paralysis.

Understanding Intervertebral Discs

A dog's spine is made up of a series of bones called vertebrae, with soft, gel-like discs situated between each pair. These discs have two main parts: a tough outer fibrous ring (annulus fibrosus) and a soft, jelly-like center (nucleus pulposus). Their primary role is to absorb shock and allow for flexibility of the spine.

Causes of IVDD

The causes of IVDD in dogs are multifactorial, involving a combination of genetic, age-related, and environmental factors.

1. Genetic Predisposition and Breed

The most significant contributing factor to IVDD is genetics, particularly in certain breeds known as chondrodystrophic breeds. These breeds have genetic mutations that affect cartilage and bone development, leading to premature degeneration of their intervertebral discs. The nucleus pulposus within the disc can harden and calcify, losing its elasticity. This makes the disc more prone to bulging or rupturing under normal stress.

Common chondrodystrophic breeds include:

• Dachshunds (all varieties)
• Basset Hounds
• Beagles
• Corgis (Pembroke Welsh and Cardigan Welsh)
• Shih Tzus
• Pugs
• Pekingese
• Chihuahuas

While these breeds are at the highest risk, IVDD can occur in any breed of dog, including larger breeds that are not chondrodystrophic. In non-chondrodystrophic breeds, the degeneration tends to occur later in life and is often referred to as Type II IVDD, which involves gradual bulging of the annulus fibrosus.

2. Age

IVDD is more common in middle-aged dogs, typically between 3 and 8 years old. As dogs age, the intervertebral discs naturally undergo degenerative changes, becoming less hydrated and less flexible. This age-related degeneration can increase the likelihood of disc rupture, especially in predisposed breeds.

3. Trauma and Physical Activity

While discs in healthy dogs can withstand significant forces, trauma or excessive physical activity can trigger a disc rupture, especially in dogs with already degenerated discs. Activities that involve high impact, sudden twists, or excessive strain on the spine can be problematic. These include:

• Jumping off furniture (especially for small breeds)
• Jumping to catch balls or toys
• Rough play with other dogs
• Falls
• Repetitive strenuous movements

It's important to note that often, a specific traumatic event isn't identifiable, and the disc rupture can occur during normal activity due to the underlying degeneration.

4. Obesity

Excess body weight places additional stress on the intervertebral discs and the spine as a whole. An overweight dog is more susceptible to disc degeneration and rupture. Maintaining a healthy weight is crucial for spinal health, especially in breeds prone to IVDD.

5. Genetics vs. Environment

It's a complex interplay. For chondrodystrophic breeds, the genetic component is very strong, predisposing them to a specific type of disc degeneration (Type I). For other breeds, or even within chondrodystrophic breeds, environmental factors like obesity, activity level, and age can exacerbate or trigger the condition.

Types of IVDD

There are generally two types of IVDD recognized:

• Type I IVDD: This is the most common type, primarily affecting chondrodystrophic breeds. It involves acute degeneration and rupture of the nucleus pulposus, leading to sudden onset of symptoms.
• Type II IVDD: This type is more common in older, non-chondrodystrophic breeds. It involves chronic, progressive degeneration of the annulus fibrosus, leading to bulging of the disc and gradual onset of neurological signs.

Symptoms of IVDD

Symptoms can vary widely depending on the severity of the disc herniation and the location along the spine. Common signs include:

• Reluctance to jump or climb stairs
• Pain (whining, yelping, guarding the neck or back)
• Stiffness
• Weakness in the hind limbs
• Knuckling over of the paws (walking on the top of the foot)
• Loss of coordination (ataxia)
• Inability to stand or walk
• Loss of bladder or bowel control

Diagnosis and Treatment

Diagnosis typically involves a thorough physical and neurological examination, often followed by advanced imaging techniques such as X-rays, CT scans, or MRI to pinpoint the affected disc(s). Treatment options range from conservative medical management (rest, pain medication, anti-inflammatories) to surgical intervention, depending on the severity.

Prevention

While IVDD cannot always be prevented, especially in genetically predisposed breeds, owners can take steps to reduce the risk. These include maintaining a healthy weight, avoiding activities that put excessive strain on the spine, and providing appropriate nutrition. For breeds at high risk, consulting with a veterinarian about preventative measures and early detection is highly recommended.