Vestibular syndrome describes any disease that affects a dog’s vestibular system, the body apparatus that keeps it balanced and upright. A problem with his vestibular system causes a dog to appear dizzy and disoriented.
Vestibular syndrome in a dog can be of two types: peripheral or central. Peripheral vestibular syndrome affects the components of the middle and inner ear. Central vestibular syndrome affects the parts of the brain responsible for coordinating movement of the eyes, head, and limbs.
Your vet will perform a complete physical and neurological exam on your dog to determine if his vestibular syndrome is peripheral or central (or if his symptoms are caused by a seizure or syncope; these conditions may be similar). Determining the type of vestibular syndrome narrows the list of possible causes. It also helps determine which diagnostics will be helpful in identifying the cause of your dog’s vestibular syndrome.
Do not administer Benadryl
Do not try to treat vestibular syndrome at home without first consulting your vet. Benadryl is sometimes suggested for dogs with vestibular syndrome, but while it has a good anti-nausea effect in dogs experiencing motion sickness, the drowsiness it induces can cause more difficulty for a dog already having trouble walking.
Causes of peripheral vestibular syndrome
There are a number of quite disparate causes of peripheral vestibular syndrome:
- Idiopathic vestibular disease. The most common cause of peripheral vestibular syndrome is also known as old dog vestibular syndrome. Idiopathic vestibular disease tends to affect older dogs and can affect any breed. Dogs with this condition have no mental status changes; they are still bright, alert and want to be with their people. They look like they are on a ship on the high seas!
Signs of idiopathic vestibular disease usually begin to subside after three days. It can take up to two weeks for an affected dog to return to normal, although it may have a persistent head tilt for two months or more. The cause and treatment of idiopathic vestibular disease is unknown. Your vet may prescribe medication to treat the nausea associated with his vertigo while he recovers.
You can help your dog during his recovery from idiopathic vestibular disease by keeping him off stairs or other places where he could fall and injure himself. You may need to support your dog while walking or taking a stance to urinate and defecate. You can provide support with bath towels slung under the chest and belly or an orthopedic harness (such as the Help ‘Em Up Harness).
— Middle ear infection (otitis media) or an inner ear infection (otitis interna). Collectively, these ear infections are the second most common cause of peripheral vestibular syndrome. These infections are different from the more common outer ear infections (otitis externa). External otitis affects the ear canal and sometimes the eardrum (eardrum); These are the parts that your vet can see when examining your dog’s ear with an otoscope. Otitis media and interna affect the part of the ear where the other eardrum side: the part that cannot be seen with an otoscope.
Diagnosis of otitis media/interna can sometimes performed by examining the eardrum with an otoscope. A bulging, discolored, or even ruptured eardrum is consistent with otitis media/interna. But a dog with otitis media/interna may have an intact and normal-appearing eardrum. If your vet suspects your dog has otitis media/interna but the eardrum appears normal, he may order x-rays or a skull CT scan to examine the middle and inner ear.
Treatment of otitis media/interna may require a 4-6 week course of antibiotics. Your vet can collect a sample of pus from your dog’s ear and send it to the lab for bacterial culture and sensitivity. This ensures that the correct antibiotic has been selected to treat your dog’s infection.
— Less common causes of peripheral vestibular syndrome. These include inner ear tumors, recent head trauma, and hypothyroidism (low thyroid hormone level). Recent administration of ototoxic drugs, such as the antibiotics gentamicin and amikacin, can also cause peripheral vestibular syndrome. A rare congenital condition seen in German Shepherds, English Cocker Spaniels, and Doberman Pinschers can cause peripheral vestibular syndrome in puppies.
Causes of central vestibular syndrome
Central vestibular syndrome is a rare condition in dogs. Dogs with this condition will have many of the same symptoms as Peripheral Vestibular Syndrome, but with a few key differences. There may also be blindness, facial paralysis, stiffness of the forelimbs or all limbs, flaccid paralysis of two or more limbs, or a recent change in behavior.
— Cerebral ischemic events (strokes) and intracranial masses (brain tumors) are the two most common causes of central vestibular syndrome.
Dogs that have suffered a stroke often begin to improve on their own within a few hours to a few weeks. The neurological changes that occur with a stroke have an acute onset. Strokes can come back and cause more damage each time they wreak havoc on the brain. Therefore, it is important to look for an underlying cause of the stroke to minimize the risk of recurrence.
Brain tumors can cause a sudden and rapid decline in a dog’s neurological status. Unlike a stroke, brain tumors can cause gradual changes in a dog’s behavior, including staring into space, walking into corners, unexplained barking, and aggression toward family members (both human and animal). Depending on the location of the tumor, there may also be gradual loss of vision, gradual and progressive loss of control of your limbs, and gradual and progressive facial paralysis.
If your vet suspects your dog has a brain tumor, he or she may order advanced imaging of his brain, such as an MRI or CT scan. Since brain tumors can be primary (originating in the brain) or secondary (metastasizing from other places in the body), he may also order chest X-rays, blood tests, and an abdominal ultrasound to look for cancer in other parts of the body. Treatments for a brain tumor include surgical removal of the mass, radiation therapy, chemotherapy, or palliative steroid therapy.
— Less common causes of central vestibular syndrome. These include infections that affect the brain, an inflammatory condition known as granulomatous meningoencephalitis, congenital malformations (such as hydrocephalus or Chiari-type malformation), prolonged use of high doses of metronidazole (an antibiotic), and recent head trauma. Infections that affect the brain can be viral (such as canine distemper), bacterial (such as tick-borne diseases), protozoal (such as toxoplasmosis or neosporosis), or fungal (including cryptococcosis, coccidiodomycosis, and blastomycosis).
Diagnosis of one of the less common causes of peripheral or central vestibular syndrome may require advanced imaging (such as CT or MRI), obtaining a sample of cerebrospinal fluid to look for infectious or inflammatory conditions, and thyroid function tests.
Prognosis for Dogs With Vestibular Syndrome
The prognosis for dogs with idiopathic vestibular syndrome is generally good, while the prognosis for other causes is variable depending on the underlying cause. This is one of the few times we welcome a syndrome without a specific cause!
