If your dog has suddenly started stumbling, listing to one side and tilting their head, they are suffering from vertigo or vestibular dysfunction. Vestibular dysfunction arises from a problem within the brain (central vestibular disease) or within the inner ear. The most common causes of vestibular dysfunction in dogs are idiopathic (old dog) vestibular disease and middle/inner ear infections.
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The vestibular system in your dog
The vestibular system is what controls balance and posture. It is divided into the peripheral and central vestibular systems. The peripheral portion of your dog’s balance mechanism lies within the inner ear and the central portion lies within the brain. The inner ear is where the receptor organ for the vestibular system lies. Changes in head position and visual cues from the eyes will be detected by this receptor and relayed to the brain. If there is interruption of any part of the pathway there can be a loss of balance and incoordination of movements called vertigo.
Symptoms of vertigo in the dog
When dog’s are suffering from vertigo, one of the cardinal signs is a head tilt. By tilting their head, they are trying to compensate for their suddenly crooked perception of the world. Other signs that accompany symptoms of vestibular disease in dogs can include nystagmus (which is when the eyes flicker back and forth repeatedly), leaning of the body and a head tilt. Dogs can have varying degrees of imbalance ranging from just a mild head tilt and slight incoordination to more severe signs of falling over and even rolling.
Peripheral vestibular disease in the dog
If your dog suddenly develops staggering, a head tilt, and generalized incoordination consistent with vestibular disease, the good news is that it is most likely due to peripheral vestibular dysfunction. Peripheral vestibular disease is far more commonly seen in practice than brain disease as the cause of vertigo. The top two most common causes of peripheral vestibular disease are inner/middle ear infections and a spontaneous vertigo in old dogs that is coined “old dog vestibular disease”. This form of vestibular disease is treated with supportive care: managing nausea with anti-nausea medication, assisting with food and water and eliminations. Occasionally assistance may require hospitalization depending on how severe the symptoms may be. Old dog vestibular disease is self resolving within 1 to 3 weeks. If symptoms are not improving or worsen, then the diagnosis of peripheral vestibular disease may be incorrect.
Peripheral vestibular disease affects the balance organ located within the inner ear. It is typically diagnosed by physical exam features, the age and history of the patient and by ruling out hypertension and serious systemic disease such as liver dysfunction. Most of the acute vestibular diseases I’ve seen in emergency practice are older dogs that present with acute onset of incoordination, wobbling, head tilt and sometimes inappetence or vomiting. On exam, they are normally alert with normal or expected neurologic reflexes.
Physical exam signs in dogs with peripheral vestibular disease
Dogs with peripheral vestibular disease are more likely to veer to one side and have a fast resting nystagmus (versus nystagmus that occurs only with a certain head position). A resting nystagmus rate of over 66 beats per minute is considered highly specific and sensitive for peripheral vestibular disease. The median rate of nystagmus in peripheral vestibular disease is typically 90 beats per minute versus a much slower rate noted in dogs with central vestibular disease.
This is the typical patient with presumptive “old dog or idiopathic vestibular disease” is 12-1 3 years of age. Their vertigo generally improves a lot within 72 hours and completely resolves on its own in 1-3 weeks. Some dogs will have a mildly persistent head tilt following recovery.
Ear disease causing balance trouble in dogs
Middle/inner ear infections in dogs causing imbalance
Although the majority of patients I’ve seen with acute onset of vestibular disease have been due to old dog vestibular disease, 50% or more dogs with peripheral vestibular disease will have a middle/inner ear infection. The structure of the ear is divided into the external ear, middle ear and inner ear. The external ear is where the majority of ear infections are located. The external ear starts at the ear flap and extends down the ear canal to the eardrum. Behind the eardrum lies the middle and inner ear. Surprisingly, there does not need to be infection present in the external ear canal to have middle or inner ear infection (otitis media/interna). Long standing or severe external ear infections can rupture through the eardrum and lead to middle/inner ear infections. Middle/inner ear infections can also occur from blood borne infections.
Although otitis media/interna can occur in any breed, one study showed that French bulldogs, cavalier King Charles spaniels , cocker spaniels and West Highland white terriers were overrepresented.
Diagnosis is based on examination of the ear drug with an otoscopic exam, imaging with a CT and culture via myringotomy. Given that CT requires anesthesia and specialty radiology services and myringotomy (rupture of the eardrum to obtain a middle ear culture) are invasive and costly, the majority of dogs who present with a suspicion for middle/inner ear infections will go home with an antibiotic trial . The recommended treatment course for antibiotic therapy for a deep ear infection is 6-8 weeks. The recommended antibiotics are enrofloxacin or amoxicillin-clavulanate.
Middle/inner ear disease from ototoxic drugs causing a head tilt and wobbliness
Peripheral vestibular signs can develop if the eardrum is accidentally ruptured and an ear solution such as an ear wash or an ear medication that is ototoxic is instilled in the ear . Some ear medications can be toxic to the middle /inner ear and can cause signs of vertigo if they are used in a dog that has a ruptured eardrum. These drugs are classified as “ototoxic” ( toxic to the ear) such as aminoglycoside antibiotics The brain can compensate for the damage to the inner ear vestibular system within a few days to weeks, but a partial head tilt may be permanent. Antibiotics like neomycin and gentamicin can injure the auditory system. Hearing may improve again if these drugs are quickly discontinued when the hearing loss is detected.
Hypothyroidism causing incoordination/imbalance in the dog
In addition to a physical examination of any dog that presents with acute imbalance, the typical work up on emergency will include blood work to screen for any underlying illness. An inactive thyroid function can cause vestibular disease by affecting nervous tissue function. Thyroid supplementation typically improves function within a few months.
Central vestibular disease in the dog causing imbalance
Central vestibular disease is acute onset of head tilt and wobbliness secondary to a problem arising within the brain. A stroke (cerebrovascular event) is considered with acute onset, non progressive signs of central vestibular disease. The diagnosis of a cerebrovascular event in the brain is made by imaging the brain with an MRI. The most common underlying diseases that can predispose a dog to having a stroke are high blood pressure, chronic kidney disease, and Cushing’s disease.
Metronidazole toxicity causing wobbliness in the dog
Drug toxicity can affect the balance center of the brain. The most commonly implicated drug that can lead to acute onset of vertigo is metronidazole when given in doses that exceed 60mg/kg in a day. Luckily for dogs suffering from metronidazole toxicity, Valium administration (0.5mg/kg orally every 8 hours for 3 days) significantly improves recovery time.
Immune diseases and cancer causing central vestibular dysfunction in the dog
Immune mediated disease such as granulomatous meningoencephalitis and brain infections (encephalitis) are more rare causes of imbalance in dogs. However, these brain diseases tend to have more global effects.
Of course, cancer is commonly a cause of acute onset of central vestibular signs in the older dog. Brain tumors are diagnosed by imaging of the brain with an MRI
Physical exam signs that can distinguish central vestibular disease from peripheral vestibular disease in the dog
- Signs of dysfunction of the cerebellum (part of the brain that coordinates movement) can cause an intention tremor. This is most obvious when a patient is reaching for something like a food or water bowl, their head will bob.
- Nystagmus that is vertical in direction is a sign of central vestibular disease. Central lesions are more likely to have positional nystagmus too. This means their nystagmus will only occur if their head turned in a certain position.
- Proprioceptive deficits: when the dog’s paws are flipped over, so they are sending on the top of their paw, they will not properly right the paw or they high step when they are walking
- Changes in their level of awareness or mentation . Dogs with central vestibular disease can be dull and unaware. They may have seizures, a head turn, uneven pupil sizes and blindness.
- A slow resting rate of nystagmus is also characteristic for central vestibular disease.
How to take care of your dog at home when they are wobbly and falling over
If your dog is diagnosed with peripheral vestibular disease then you will have to assist them at home until they have recovered enough function to walk around without assistance. Therapy for these dogs relies on supportive care. You should find a space in your home where they can be kept in a more confined area. They should be away from stairs and kept on bedding on the ground so they can’t fall off furniture. Your dog might require regular assistance to eat and drink if they are too wobbly to properly reach into their food and water bowls. Some dogs will feel dizzy and this can lead to nausea. Over the counter motion sickness medications can help them. Meclizine (trade names: Antivert, Bonine) is a motion sickness medication for people that can be used for your dog. The typical doses are 12.5mg (1/2 of a 25mg tablet) up to 25mg (1 tablet) once daily. If your dog is still nauseated, you can ask your veterinarian about maropitant.
Summary of vestibular disease in dogs
Although it is scary to see your dog suddenly struggle to walk, the good news is that the majority of dogs will improve with the right treatment. If your dog does not have any serious underlying disease evident from blood work interpretation and they are not suffering from other signs of neurologic dysfunction (dull, blind, having seizures or suffering other nervous system deficits). You can give your dog some time and care and many times their symptoms will improve.