Vertigo

Vertigo is a sensation where an individual feels as though they or their surroundings are moving when they are not. This condition often presents as a spinning or swaying movement and can be accompanied by nausea, vomiting, and difficulty walking.

Causes

The most common causes of vertigo include benign paroxysmal positional vertigo (BPPV), Ménière's disease, and vestibular neuritis. Less frequent causes are stroke, brain tumours, brain injury, multiple sclerosis, migraines, trauma, and uneven pressures between the middle ears. Exposure to toxins such as carbon monoxide, alcohol, or aspirin can also result in vertigo. Physiologic vertigo may occur following prolonged motion exposure, such as being on a ship.

Classification

Vertigo can be classified as either peripheral or central, depending on the location of the dysfunction in the vestibular pathway. Peripheral vertigo originates from issues with the inner ear or vestibular system, while central vertigo arises from injury to the central nervous system, often involving the brainstem or cerebellum. Psychological factors can also contribute to vertigo.

Peripheral Vertigo

Peripheral vertigo is often caused by conditions like BPPV, Ménière's disease, and vestibular neuritis. People with peripheral vertigo typically experience mild to moderate imbalance, nausea, vomiting, hearing loss, tinnitus, and ear pain. The rapid compensation process usually results in improvement within days to weeks.

Central Vertigo

Central vertigo, resulting from central nervous system issues, is generally associated with less prominent movement illusion and nausea but may include neurologic deficits such as slurred speech and double vision. Conditions like strokes, tumours, epilepsy, cervical spine disorders, migraines, multiple sclerosis, and parkinsonism can lead to central vertigo. Recovery may be slower compared to peripheral vertigo.

Signs and Symptoms

Common symptoms of vertigo include a spinning sensation, nausea, vomiting, unsteadiness, and difficulties in walking. Vertigo may present as a persistent or episodic onset. Persistent vertigo, often seen with central vertigo, lasts longer than a day and is due to degenerative changes affecting balance. Episodic vertigo, common in BPPV, typically lasts only seconds to minutes. Blurred vision, difficulty speaking, and hearing loss may also occur.

Pathophysiology

The neurochemistry of vertigo involves six primary neurotransmitters in the vestibulo-ocular reflex (VOR) arc: glutamate, acetylcholine, gamma-aminobutyric acid (GABA), dopamine, norepinephrine, and histamine. These neurotransmitters play roles in maintaining central vestibular neuron discharge, modulating synaptic transmission, and compensating for vestibular disturbances.

Diagnosis

Diagnosing vertigo involves eliciting nystagmus and differentiating it from other causes of dizziness. Tests include electronystagmography (ENG), Dix-Hallpike manoeuvre, rotation tests, head-thrust test, caloric reflex test, and computerised dynamic posturography (CDP). The HINTS test, comprising the horizontal head impulse test, nystagmus observation, and skew test, helps differentiate central from peripheral causes. Imaging techniques like CT scans and MRIs can be useful.

Management

Treatment depends on the underlying cause. Ménière's disease treatments include a low-salt diet, intratympanic gentamicin injections, or surgical interventions. Medication options for vertigo include anticholinergics (e.g., hyoscine hydrobromide), anticonvulsants (e.g., topiramate), antihistamines (e.g., betahistine), beta blockers (e.g., metoprolol), and corticosteroids (e.g., methylprednisolone).

For decompression sickness-related vertigo, initial treatment with 100% oxygen followed by hyperbaric oxygen therapy is recommended. Repositioning manoeuvres like the Epley manoeuvre are effective for BPPV.

Vertigo, its causes, and management are multifaceted, requiring a comprehensive approach to diagnosis and treatment. Understanding the underlying pathophysiology and appropriate therapeutic interventions is very important for effective management.

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Self-assessment MCQs (single best answer)

Sure, here are the questions formatted in HTML and pseudocode:

What is vertigo?

Which of the following is NOT a common cause of vertigo?

Which neurotransmitter is NOT involved in the neurochemistry of vertigo?

What is the main differentiating factor between peripheral and central vertigo?

Which diagnostic test involves the observation of eye movement to diagnose vertigo?

Which of the following treatments is used specifically for BPPV?

What symptom is common in both peripheral and central vertigo?

Which condition is NOT typically associated with central vertigo?

In the management of Ménière's disease, which of the following is NOT a common treatment?

What does the HINTS test stand for?

Each question is now formatted as requested, with appropriate feedback for each choice.