From the Guidelines
The best initial laboratory tests for evaluating dizziness include a complete blood count (CBC), comprehensive metabolic panel (CMP), thyroid function tests (TSH, T3, T4), hemoglobin A1C, vitamin B12 and folate levels, and electrolytes (particularly potassium, sodium, and calcium) 1. These tests help identify common causes of dizziness such as anemia, electrolyte imbalances, diabetes, thyroid dysfunction, and nutritional deficiencies. Additional specialized tests may be considered based on the patient's symptoms and physical examination findings, such as:
- Vestibular function tests like electronystagmography (ENG) or videonystagmography (VNG) to assess inner ear function
- Audiometry to evaluate hearing
- Brain imaging studies such as MRI if a central nervous system cause is suspected
- Blood pressure measurements in different positions (lying, sitting, standing) to check for orthostatic hypotension It is essential to note that radiographic imaging, such as CT or MRI, is not recommended for patients with suspected benign paroxysmal positional vertigo (BPPV) unless there are additional signs or symptoms that warrant imaging 1. Similarly, vestibular function testing is not recommended for patients who meet diagnostic criteria for BPPV without additional vestibular signs or symptoms 1. The specific combination of tests ordered should be tailored to the patient's symptoms, medical history, and physical examination findings, and should prioritize the most recent and highest quality evidence available 1.
From the Research
Diagnostic Approach
The diagnostic approach for dizziness involves a thorough evaluation of the patient's symptoms, medical history, and physical examination. The following steps can be taken:
- Identify the timing and triggers of dizziness to develop a differential diagnosis 2, 3, 4
- Perform a physical examination, including orthostatic blood pressure measurement, a full cardiac and neurologic examination, assessment for nystagmus, and the Dix-Hallpike maneuver 2, 3
- Use the HINTS (head-impulse, nystagmus, test of skew) examination to distinguish peripheral from central etiologies 2, 3
Laboratory Testing and Imaging
Laboratory testing and imaging are not always required and are usually not helpful in diagnosing dizziness 2, 5, 3. However, they may be ordered if the patient has abnormal findings on physical examination that may indicate a more serious cause of dizziness 6.
Treatment
The treatment for dizziness depends on the underlying cause. The following treatments may be effective:
- Canalith repositioning procedures (e.g., Epley maneuver) for benign paroxysmal positional vertigo 2, 3
- Vestibular rehabilitation for peripheral and central etiologies 2
- Pharmacologic intervention, although limited, may be used to treat specific causes of dizziness 2
- Salt restriction and diuretics for Meniere disease 3
- Vestibular suppressant medications and vestibular rehabilitation for vestibular neuritis 3
Common Causes of Dizziness
The most common causes of dizziness include: