When a patient complains of dizziness, diagnosticians must establish whether it is vertigo.
HEALTH Vertigo is the sensation of spinning. It can be caused by nystagmus or disorders within the ear canal. Certain head movements or even vapors can trigger it. Fundamentally, the patient presents with periodic difficulty standing or keeping head erect. For lack of a better word, the admitting nurse may be told the reason for visiting is "dizziness." Dizziness is a term used to describe everything from feeling faint or lightheaded to feeling weak or unsteady. 
“Easy Diagnosis. Let Me Get You That Referral.”
The structure of today's healthcare system with its typical 5-minute patient consultation leaves doctors and patients at a disadvantage. For a patient presenting "dizziness," the primary care physician (PCP) generally attempts to gather enough information to funnel the "vertigo" patient to an otolaryngologist, neurologist or psychologist. Efficiency necessitates predictive responses. Dizziness complaints are frequently diagnosed as Benign Paroxysmal Positional Vertigo (BPPV). BPPV is characterized by brief episodes of mild to intense dizziness associated with specific changes in the position of the head. With a quick review of the chart, the PCP begins to formulate opinions about where the consult might head.
Stepping into the exam room (with stopwatch ticking), the doctor may immerse the patient with common questions: "How often does it occur? Do you feel like you're spinning clockwise or counterclockwise? Is the room rotating around you, or are you moving around your environment? How long does the dizziness last? Do you feel headaches? Is there any nausea?" Just thinking about responses could make a normal person dizzy.
"About 5 to 10 times a year. No directional spinning. Yes, there's 'stomach discomfort' and the episodes last several hours," replies the patient. The physician may conclude that BPPV is improbable. After all, BPPV is a frequent but momentary condition lasting several seconds — less than a minute — not hours.  Instead of forcing a statistically popular diagnosis, more skillful questioning is required.
Unanticipated Responses Increase Possibilities
At this critical junction, patients are generally referred to an otolaryngologist or ENT specialist for comprehensive evaluation. There are many equilibrium testing devices available to induce vertigo without establishing a cause. Once an episode is replicated, an otolaryngologist pretty much has license to prescribe treatment. Being a specialist in hearing and balance, there may be real or imagined pressure to diagnose and treat the patient. I have seen three separate otolaryngologist offer a different diagnosis and treatment program for the same patient. Ineffective medication prolongs suffering and delays accurate diagnosis.
What "dizziness" could last for hours? Perhaps a migraine variation — stomach, vertiginous or vestibular — should be investigated. Migraine causes more vertigo than any other medical condition.  Approximately 27 to 42% of migraine patients suffer from associated vertigo.
Stress or anxiety disorders can trigger vertigo.  Mental rumination over real or imagined fears can upset the sense of balance. Because of the stigma associated with mental health, the PCP may visit this option after others are exhausted.
During the remaining minutes of the consultation, the PCP may wish to ascertain what the patient does during a vertigo attack and when the episodes generally occur. It might be discovered that the patient awakens from a full night's sleep with non-spinning disequilibrium, lightheadedness, headache and fatigue with sensation of pins and needles in the legs and feet. After several hours recuperation in bed, the patient complains of stomach cramps, photophobia, phonaphobia or olfactophobia. By the tenth hour of bed rest, stomach cramps subside but fatigue and malaise continue through the next day or two.
Cardiologist or Otolaryngologist?
Presynscope involves lightheadedness, muscular weakness, and feeling faint. Presyncope does not result from primary central nervous system pathology, nor does it originate in the inner ear, but is most often cardiovascular in etiology. In many patients, lightheadedness is a symptom of orthostatic hypotension. This occurs when blood pressure drops significantly when the patient stands from a supine or sitting position. If loss of consciousness (fainting) occurs in this situation, it is termed syncope. 
The diagnostician must rule out transient ischemic attack (TIA), and paroxysmal vestibular disorder accompanied by headache. TIA is essentially a mini stroke — a change in the blood supply to a particular area of the brain resulting in brief neurologic dysfunction.
Central nervous system ischaemia response is triggered by an insufficient level of oxygenated blood in the brain. An ischaemic episode increases oxygen supplied to the brain and reduces the delivery to and use of oxygen in other parts of the body. The weakness of the legs causes most sufferers to sit or lie down if there is time to do so.
Orthostatic hypotension is primarily caused by gravity-induced blood pooling in the lower extremities, which in turn compromises venous return, resulting in decreased cardiac output and subsequent lowering of arterial pressure. For example, if a person changes from a lying position to standing, he or she will lose about 700 ml of blood from the thorax. It can also be noted that there is a decreased systolic (contracting) blood pressure and a decreased diastolic (resting) blood pressure.  The overall effect is an insufficient blood perfusion in the upper part of the body.
Sometimes, one may be asked to wear a Holter monitor. This is a portable ECG device that can record the wearer's heart rhythms during daily activities over an extended period of time.  Since fainting usually does not occur upon command, a Holter monitor can provide a better understanding of the heart's activity during fainting episodes. Tilt table test is perhaps the most common test performed for syncope. Though it can be helpful, the purpose is to induce a fainting episode, and thus, is not necessarily conclusive in why this occurs.
Vasoconstriction can be caused by diet. Caffeine, smoking or certain medications can play a significant factor. Diet can pair with syncope or orthostatic hypotension producing a unique trigger that is difficult to pinpoint.
Better Responses Result in More Accurate Diagnosis
This discussion points out several different causes for vertigo beyond BPPV. Frequency and duration are key diagnostic indicators. Unlike most illnesses, a patient is often only able to visit the doctor after an episode subsides — possibly when appearing perfectly healthy. Responses rely on patient recollection of sensations during a time when powers of concentration were diminished. Sometimes what the patient may recall as "vertigo" or "dizziness" is actually a feeling of faintness or lightheadedness that may require investigation by a cardiologist. Cardiologists tasked with assisting with a diagnosis should be prepared to do more than a standard treadmill test or single-position ECG.
On the front line, the diagnostician is tasked with obtaining an accurate description of symptoms from the patient. An extra 5 minutes during the initial visit to complete a systematic evaluation could eliminate years of uncertainty and suffering.  This may necessitate a carefully worded questionnaire and more deliberately paced verbal questioning possibly with multiple-choice responses offered after the patient says as symptom as vaguely as "dizzy." If the PCP decides to defer comprehensive evaluation to an otolaryngologist, the latter should consider other medical professionals. In the end, a proper diagnosis may be achieved with cooperation of several specialists. Dizziness is a symptom. Often, it is not advantageous to settle on treatment without diagnosis.
- Dizziness. MayoClinic.com
- Benign paroxysmal positional vertigo (BPPV): Symptoms. MayoClinic.com
- Migraine-associated vertigo. Wikipedia
- Dizziness: Causes. MayoClinic.com
- Syncope. Wikipedia
- Idiopathic Orthostatic Hypotension and other Autonomic Failure Syndromes. Jeffery Tam Sing, MD, eMedicine by WebMD
- Syncope. Timothy C. Hain, M.D, Dizziness-and-Balance.com
- Ten-Minute Examination of the Dizzy Patient. Joel A. Goebel, M.D., F.A.C.S., Medscape Today by WebMD