Learning Objectives

“I’M DIZZY” David Horne, M.D. WEEK 7: 02/14 – 02/18/05

Learning Objectives:

1. To understand the approach to the symptom of dizziness 2. Know the most common causes of vertigo and etiologies that are more serious 3. Be aware of signs and symptoms that serve as red flags and should alert the clinician that further work-up is indicated 4. Be familiar with the Dix-Hallpike and otolith repositioning maneuvers

CASE ONE:

Scottie Ferguson is a 57-year-old man with hypertension, COPD and obesity, who complains of feeling “dizzy” for the past week. His current medications are HCTZ 25mg and ipratropium/albuterol (Combivent) MDI.

Questions:

1. How do we approach the patient with a complaint of dizziness? When eliciting patients’ symptoms of dizziness, why is it important to use open-ended questioning? What open-ended question(s) would you use? Dizziness is the third most common reason for outpatient visits and is the most common reason for visiting a doctor after the age of 75. A careful patient interview is especially important as this can clinch the diagnosis in 75% of patients. The first step involves classifying the dizziness in one of four categories: a. Vertigo: The sense of abnormal motion or spinning, either of the patient or the surroundings. b. Disequilibrium, a sensation of unsteadiness. This is caused by a combination of deficits in proprioception, vision, orthopedic problems and musculoskeletal problems. c. Pre-syncope, experienced as light-headedness or near fainting. This is generally due to decreased cerebral perfusion, as is seen in orthostatic hypotension. d. Non-specific. The primary symptom may be the sensation of “floating” or “swimming” or a state of disassociation. Frequently psychogenic in etiology (diagnosis of exclusion).

Although patients often have difficulty describing symptoms of dizziness, the first step is to distinguish vertigo from other causes of dizziness. The diagnosis is vertigo in 95% of patients who mention sensation of motion without prompting, but the specificity drops to about 75% for patients who answer affirmatively when asked about spinning or motion. So the first question should be to ask patients to describe the dizziness in their own words (e.g. “Try to describe your symptoms without using the word ‘dizzy.’”). Keep in mind that up to 40% of patients may have symptoms that are too diverse or vague to fit within a single category.

Once it is clear that the patient is describing vertigo, asking about the circumstances in which the dizziness occurs is more important than a description of the dizziness. Important goals in taking the history are to: a. Clarify the sensation including frequency, duration, and initial onset b. Identify positional effects (e.g. certain head positions, standing, sitting, walking) c. Associated symptoms- otologic symptoms, other neurologic symptoms d. Recent medication changes

2. How will you focus the physical exam? Important features of the physical include orthostatic vital signs, examination of the ears, heart, and CNS. A thorough neuro exam includes assessment of the cranial nerves, Romberg test (for proprioception), and observation of gait including turning around. Don’t forget to assess for nystagmus. Nystagmus that appears only on extreme lateral gaze is not pathologic and occurs in up to 60% of adults; however, nystagmus that occurs closer to midline is abnormal. The Dix-Hallpike maneuver is an important part of the examination of the vertiginous patient (more in next section).

CASE ONE CONTINUED:

On further questioning, you learn that the patient’s symptoms last for several seconds and usually occur in the morning. He notes that symptoms can come on with rolling over in bed and washing his hair. He has no problems with his hearing. His BP is 135/85 supine, 130/85 standing, and his pulses are 70 and 75 respectively. Ears, cardiac exam, and cranial nerves are normal. Gait, stance, and turning ability are normal. Romberg test is negative. Nystagmus occurs only at extreme lateral gazes. The Dix-Hallpike maneuver elicits temporary vertigo with rotatory nsytagmus pointing toward the right ear when the right ear is facing downwards. Cerebellar exam is within normal limits.

3. How do you interpret the results of the Dix-Hallpike maneuver? How can it help you in differentiating peripheral versus central causes of vertigo? The Dix-Hallpike maneuver can be used to establish the diagnosis of BPV. Please see the attached NEJM review article for instructions on performing this test. It explains the pattern of nystagmus that qualifies as a “positive” result. Failure to hyperextend the neck and movement from a seated to supine position that takes more than two seconds will decrease the sensitivity of the test. Interestingly, the sensitivity of the maneuver was only 60% in one study of 250 patients with BPV. Of initially negative tests, 30% were positive in later visits and once a positive test was documented it was not always present on subsequent visits for BPV.

This maneuver can also be used in differentiating peripheral from central causes of vertigo. In BPV: 1) there is latency of 2-20 seconds before onset of nystagmus, 2) maintaining the patient in the head hanging position will result in extinguishment of the nystagmus after 50 seconds, 3) repetition of the maneuver will result in briefer and weaker episodes of nystagmus. In central causes of vertigo, there is no latency to onset, extinguishment or fatigability (e.g. nystagmus will persist regardless of how many times the maneuver is performed).

4. What is your leading diagnosis? How would you treat Mr. Ferguson? The patient’s presentation is most consistent with BPV. An Epley maneuver should be performed on the patient. Again, please see the accompanying NEJM article. Success is achieved more often if the patient is fitted with a soft-collar after canalith repositioning is performed and instructed to not bend over, lie back, or move their head for the rest of the day. BPV recurs in 50% of patients. Patients can be instructed on how to perform the maneuver on themselves.

5. What aspects of patient history or exam may be concerning for serious (i.e. potentially fatal) etiologies? When would you refer a patient for further evaluation? Generally, serious central causes of vertigo are fairly rare (in one study, cerebrovascular disease was the cause of dizziness in 6% of patients.) Clearly, accompanying neurologic symptoms or vertical beating nystagmus raise concern for stroke or tumor. Unilateral hearing loss demands workup for an acoustic neuroma. Also, the above listed results of a Dix-Hallpike test that suggest a central cause require further workup.

Dizziness is a rare symptom of anterior circulation disease but affects 75-100% of patients with posterior circulation disease (basilar, AICA, PICA and vertebral arteries). In 75% of patients with dizziness and posterior circulation disease there were accompanying symptoms, especially dysarthria, numbness, diplopia and hemiparesis. In the other 25%, dizziness may be the only symptom, so consider risk factors for stroke and likelihood of other diagnosis. If the patient has had dizziness for more than six weeks, cerebrovascular disease is not the cause.

ENG (electronystagmographs) and MRI may be useful if the diagnosis remains unclear.

6. With the help of your preceptor and a volunteer, demonstrate the Dix-Hallpike maneuver and the Epley maneuvers. Assume that the right ear is affected.

Cultural literacy:

Who is Scottie Ferguson? The character played by Cary Grant in the Alfred Hitchcock film “Vertigo.”

References:

1. Furman J.M. and Cass S.P. Benign paroxysmal positional vertigo. New England Journal of Medicine. 1999; 341(21): 1590-96. 2. The Neurologist. 2004; 10(3): 154-64.

Additional References:

1. Southern Medical Journal. 2000: 93(2): 160-7. 2. Western Journal of Medicine. 1995; 162(1): 37-42. 3. JAMA. 1994; 271(5): 385-88.