Vestibular syndrome in dogs. A brief review | Vets & Clinics

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Vestibular syndrome in dogs. A brief review

The vestibular system serves to orientate dogs with respect to space and gravity, harmonising their movements. It maintains the position of the eyes, body and limbs in relation to the head. The system functions as a reflex arc; therefore, the syndrome is a neurological problem arising from damage to the VIII cranial nerve or inner ear (peripheral vestibular disorders) or a brainstem injury (central disorders) (1). It is essential to determine the location of the injury in order to identify the disease causing the syndrome.

Veterinary medicine and care

Visible clinical signs

Four main signs can be observed:

  • Tilted head: the patient tilts or turns its head to one side. The vestibular lesion is usually on the side the dog tilts its head towards.

  • Nystagmus: horizontal, rotating or vertical movements of the eyes. These movements usually involve two phases: a slow phase towards the site of the lesion and a rapid phase in the opposite direction.

  • Strabismus: the eyes assume an abnormal position, mainly when the head is tilted or the animal is lying on its side.

  • Ataxia: vestibular ataxia can be distinguished from other forms of ataxia because it is asymmetric. The animal maintains a wide base stance, that is, with its legs well apart. Its head and body sway and it may even fall or roll sideways when it tries to get up.

How to differentiate between peripheral and central vestibular disorders

It is fundamental to determine whether the originating lesion is peripheral or central to make a full diagnosis and reveal the underlying disease.

Specific signs can be observed in central vestibular disorder. For example, vertical nystagmus is typical of a central injury; similarly, impaired consciousness and neurological signs representative of lesions in other cranial nerves are other clear indications (2).

Causes of vestibular syndrome in dogs

Vestibular syndrome in dogs is often the manifestation of an underlying disease. The most common causes are:

In peripheral vestibular syndrome:

  • Infectious otitis affecting the inner ear. This is the most common cause of the syndrome.

  • Traumatic injuries to the tympanic bulla.

  • Neoplasms in the nerve or bone structure.

  • Idiopathic causes.

In central vestibular syndrome:

  • Neoplasms.

  • Inflammatory processes such as distemper or granulomatous meningoencephalitis.

  • Ischaemic brainstem haemorrhages affecting the vestibular nucleus.

Idiopathic vestibular syndrome in dogs

The term idiopathic vestibular syndrome is applied to cases where the origin of the vestibular signs is unknown and there are no other neurological signs. It usually manifests in an acute form and is the second most common cause after otitis interna.

Some purebred dogs are prone to a form of idiopathic vestibular syndrome that appears in puppies from birth to about 12 weeks old. In this case, the disorder usually resolves by itself by the age of 2 to 4 months.

Recommended treatment and prognosis

Antibiotics are required if there is an infection, but an antibiogram is always advisable to ensure the most effective one is prescribed. Surgical drainage should be considered if there is exudate and thickening of the tympanic bulla. The prognosis will depend on the patient’s response to these treatments.

The prognosis for idiopathic vestibular syndrome is good, and no treatment is necessary as it usually subsides on its own after 3 to 21 days. However, it is a good idea to stop the animal from moving around too much during the acute period to avoid other injuries, and antiemetics (anticholinergics ) can be prescribed if necessary.

When the vestibular syndrome is due to a central lesion, the most uncomfortable signs for the dog can be treated with calcium channel blockers or anticholinergics to alleviate any dizziness or vomiting. In this case, the prognosis depends on the underlying cause.

(1) BOSCO VIDAL, ENZO. ASPECTOS BÁSICOS DEL SÍNDROME VESTIBULAR EN PERROS Y GATOS. REVISTA VETERINARIA ARGENTINA.
(2) LOWRIE, MARK. VESTIBULAR DISEASE: ANATOMY, PHYSIOLOGY AND CLINICAL SIGNS. COMPEND CONTIN EDUC VET. 2012 JUL;34(7):E1


 

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