From the Guidelines
Laboratory tests for dizziness are not always necessary and should be guided by the patient's specific symptoms, medical history, and physical examination findings. The most recent and highest quality study, 1, suggests that imaging evaluation in patients with brief episodic vertigo triggered by specific head movements, such as those with benign paroxysmal positional vertigo (BPPV), is unnecessary unless there are atypical features or additional neurologic symptoms.
Some key points to consider when evaluating dizziness include:
- A complete blood count (CBC), comprehensive metabolic panel (CMP), thyroid function tests, and vitamin B12 and vitamin D levels may be helpful in identifying potential causes of dizziness, such as anemia, electrolyte imbalances, thyroid disorders, or nutritional deficiencies.
- Additional specialized tests, such as hemoglobin A1c, cardiac enzymes, and vestibular function tests, may be necessary in certain cases, but should be guided by the patient's specific symptoms and medical history.
- Blood pressure measurements in different positions (lying, sitting, standing) are important to detect orthostatic hypotension.
- The results of laboratory evaluations should guide appropriate treatment, which may range from simple interventions like hydration and dietary changes to medication adjustments or specific therapies targeting the identified cause.
It's also important to note that, according to 1, clinicians should not obtain radiographic imaging in a patient who meets diagnostic criteria for BPPV in the absence of additional signs and/or symptoms inconsistent with BPPV that warrant imaging. Similarly, vestibular function testing is not necessary for patients who already meet clinical criteria for the diagnosis of Meniere's disease, as stated in 1.
Overall, a thorough medical history, physical examination, and targeted laboratory evaluations are essential in evaluating dizziness and guiding appropriate treatment. The decision to order laboratory tests should be based on the individual patient's presentation and medical history, rather than a routine or blanket approach.
From the Research
Lab Work for Dizziness
- The evaluation of dizziness does not typically require special tools or laboratory testing, as the physical examination and patient history are often sufficient for diagnosis 2.
- Laboratory testing and imaging are usually not required and are often not helpful in evaluating dizziness, unless there are abnormal findings on physical examination that suggest a more serious cause 3, 4.
- Diagnostic tests should be ordered for patients who have abnormal findings on physical examination that may indicate a more serious cause of dizziness, such as orthostatic hypotension or benign paroxysmal positional vertigo 5.
- A timing-and-triggers approach can be used to characterize the patient's vestibular symptoms and guide the evaluation of acute dizziness and vertigo 6.
Physical Examination
- The physical examination for dizziness includes orthostatic blood pressure measurement, a full cardiac and neurologic examination, assessment for nystagmus, and the Dix-Hallpike maneuver 3, 4.
- The HINTS (head-impulse, nystagmus, test of skew) examination can help distinguish peripheral from central etiologies of dizziness 3, 4.
Diagnostic Approach
- The differential diagnosis for dizziness is broad and includes peripheral and central causes, with peripheral etiologies generally being less concerning and central etiologies being more urgent 3, 4.
- Identifying common peripheral vestibular disorders, such as benign paroxysmal positional vertigo, is a priority in the evaluation of dizziness, as it can help exclude more serious central causes 2.