By Dr. Becker
Today we're going to discuss vestibular disease. The vestibular system is what gives most mammals balance and a sense of spatial orientation. Vestibular disease affects the body's balance systems. There is a peripheral form of the disease arising from outside the central nervous system which is caused by disorders affecting the inner ear. Central vestibular disease, which is a much less common and more serious form of the condition, originates inside the central nervous system.
Peripheral vestibular disease occurs when there's irritation to the nerves connecting the inner ear with the brain. The result is a loss of balance and other symptoms resulting from vertigo and dizziness. Peripheral vestibular disease can look and feel pretty dramatic to the dog owner, especially the first time it occurs. But fortunately, most cases improve quickly with supportive care and treatment, and of course addressing any underlying cause for the condition.
Causes of Vestibular Disease
The peripheral form of vestibular disease is much more common than the central form. Causes of the condition can include chronic and recurrent inner and middle ear infections, overzealous cleaning of the ears resulting in a perforated eardrum, trauma from head injury, stroke, tumors, polyps, meningoencephalitis, hypothyroidism, as well as certain drugs like the aminoglycoside antibiotics, including drugs like amikacin, gentamicin, neomycin, and tobramycin.
Loop diuretics and also certain ear cleaners that should not be used with ruptured eardrums but accidentally are used can all result in the condition. All of these things can irritate or damage the nerves of the inner ear and cause inflammation.
The disease can be present from birth as a congenital defect. It can also be idiopathic, meaning we haven't identified a root cause in elderly dogs. An infection of the middle ear is hands down the most common reason the disease occurs in younger dogs. In older dogs, we have to consider a brain tumor as a potential cause of the syndrome. Causes of central vestibular disease (the less common form) include inflammatory disease, infection, trauma or bleeding in the brain, loss of blood flow, and cancer.
Signs and Symptoms
Signs of vestibular disease include head tilting, loss of coordination, circling and stumbling, staggering, falling and rolling, as well as involuntary, rhythmic, jerking eye movements from side to side or up and down. The abnormal eye movement is called nystagmus.
Dizziness and loss of balance can cause excessive drooling, nausea and vomiting. If the disease affects only one ear, head tilting and circling will be in the direction of the affected ear. If only one side of the head is involved, only the eye on that side may develop nystagmus. Congenital vestibular disease is usually seen between birth and three months of age. Breeds predisposed to this condition include the German shepherd, Doberman pinscher, Akita, English cocker spaniel, beagle, smooth fox terrier, and the Tibetan terrier.
Vestibular disease in geriatric dogs is often mistaken for stroke. The vertigo caused by the disease can be particularly intense in older dogs with symptoms of nausea, difficulty or complete inability to stand up, head tilt, nystagmus, and circling. The disease in geriatric dogs can make eating and drinking or even going outside to potty very difficult or even impossible. Supportive therapy is often needed in the form of IV fluids and supplemental nutrition.
Many older dogs are really stressed by episodes of vestibular disorder, so natural calming agents like the amino acid L-theanine, as well as herbs such as passionflower, hops, skullcap, valerian, and chamomile can be given to senior dogs to help them cope. Other remedies such as tryptophan, GABA, flower essences, and homeopathics can also be very beneficial in calming overwhelmed dogs.
A physical examination including a neurological assessment will determine if the vestibular disease is peripheral or central. If the much more common peripheral form of the condition is identified, an otoscope will be used to look deep into your pet's ear. Sometimes X-rays are needed. Blood tests, culture and sensitivity, and cytology are all required to help eliminate other potential causes of specific symptoms.
Your vet may recommend a surgical biopsy for tumors and polyps that are found. If the condition is determined to be central vestibular disease, usually an MRI or CT scan, as well as spinal fluid taps, may be needed to identify the root cause. Obviously, if infection is the root cause, it must be resolved.
Treatment of Vestibular Disease
Nausea and vomiting can be alleviated with motion sickness medications. But there's no specific treatment that consistently manages congenital vestibular disease or the geriatric form of the condition. These pets require supportive therapy in the form of nursing care and confinement. I have used homeopathic remedies with some success and rehabilitation therapies to help these patients learn better body awareness and improve their physical stability.
Dizziness can prevent a dog from walking normally or at all, so food and water sometimes needs to be close by or even brought to the patient to encourage him to eat or drink. Some patients even need to be hand-fed until they're feeling better. Many dogs need assistance in getting back and forth from their potty spot.
The good news is puppies born with congenital vestibular disease issue often adapt and are less affected by the condition as they get older. In geriatric dogs, the condition usually resolves in one to two weeks, though the tendency to tilt the head can remain for a lifetime. If a middle or inner ear infection is present, sometimes antibiotics will be needed to improve the condition. If an underactive thyroid is the cause, the vestibular disease will resolve when the metabolic condition is managed correctly.
If a medication is the root cause, discontinuing the medication can bring complete resolution, but sometimes there can be some residual hearing loss. Removal of polyps can result in a complete cure, but if there are cancerous tumors, then the outcome is generally less positive. Central vestibular disease usually has a poorer prognosis than the more common peripheral form, primarily due to the potential damage to the brain stem, which can be overall quite devastating.
If an infection is identified it should be treated. If there is an inflammatory condition, it may respond to treatment initially, but it can progress to a point where it could be untreatable. I've had some success in managing these patients with acupuncture treatments. Fortunately, the most common form of canine vestibular disease – the peripheral form – in most cases improves quickly, once the underlying cause is addressed and symptoms of vertigo are managed with supportive care.