Blog | Monday, March 12, 2012

Diagnosing dizziness


Dizziness has been a chief complaint that up until recently I've had difficulty with. We've been taught, and teach to others, that there is a long differential to consider when working up a differential for dizziness. Having a succinct framework to approach a dizzy patient and a cost-effective work up is essential.

I've recently been introduced to the work of Dr. Martin Samuels and his approach to vertigo and dizziness. He defines an approach categorizing the dizzy patient into those suffering from syncope or near-syncope, disequilibrium, anxiety and/or depression, or vertigo.

Syncope or near-syncope suggests a cardiovascular disorder. Patients may complain of a feeling of fainting. Orthostatic hypotension, vaso-vagal, arrhythmia's, outflow obstruction, and hypersensitive carotid sinus are possibilities. Work up of syncope or near-syncope includes obtaining orthostatic vital signs, auscultating for a murmur, an EKG and possibly a Holter monitor if symptoms are suggestive of an arrhythmia.

Disequilibrium, or feeling as if one might fall, can be caused by multiple sensory deficits syndrome (MSDS) or cerebellar ataxia. MSDS can be seen in elderly patients who may have poor vision, poor hearing and decreased peripheral sensation from neuropathy, especially in situations with poor environmental clues such as dark rooms at night. The combination of poor proprioceptive input leads to feeling as if one may fall. Cerebellar ataxia will have associated gait or side-to-side intention tremor. Evaluation and management of disequilibrium will include treating the underlying sensory deficit or evaluating for the cause of the ataxia.

Anxiety and/or depression can be associated with complaints of ill-defined dizziness.

Vertigo will give a patient the subjective experience of being pulled or moving through space or that their environment is moving around them. Vertigo can be from peripheral-cochlear disease, peripheral-retrocochlear disease, or central disease.

Peripheral cochlear lesions can be from labyrinthitis, vestibular neurtits, cochlear neuritis, Meniere disease, or BPPV. Peripheral retrocochlear syndrome can be caused by vestibular schwannoma. Central lesions can be caused by drugs, demyelinating illness, vascular disease such as vertebrobasillar insufficiency, temporal lobe seizures, or migraine.

Symptoms of vertigo should be evaluated by examining the patient for hearing loss using finger rub or using a ticking watch as well as the Weber and Rhine test. Look for nystagmus with eyes at 45 degrees from midline. When nystagmus is present note which direction the eyes rapidly beat toward and which direction they slowly move toward. Perform the Dix-halpike maneuver.

Peripheral vertigo needs to meet 4 criteria: rapid-phase nystagmus away from the lesion, slow-phase nystagmus toward the lesion, environment spinning away from the lesion, and Romberg's sign toward the lesion. Therefore when evaluating the patient note the direction of the slow-phase (toward the lesion), the rapid-phase (away from the lesion), and the direction of perceived external movement (toward the side of the lesion), the feeling of falling or movement will be away from the lesion or toward the slow phase of nystagmus.

Dizziness is a common symptom and having this frame work is very helpful in easily approaching the dizzy patient.

Justin Penn, MD, ACP Associate Member, attended medical school at the University of Washington School of Medicine and trained in internal medicine at the University of Rochester, where he is serving as Chief Resident. This post originally appeared at his blog, Musings of an Internist.