Frequent dizziness and what tests will help determine the cause

Dizziness is not a single condition, and its manifestations vary significantly. For one patient, it is a feeling as if the support is disappearing from under their feet, for another - the illusion of the room spinning, darkening in the eyes, unsteadiness, severe weakness, a pre-conscious state or nausea. Therefore, the primary task of diagnosis is not to prescribe a wide range of laboratory tests, but to clarify the nature of the sensations experienced by the patient as accurately as possible.

As MedlinePlus notes, the term dizziness in clinical practice, two different phenomena are often referred to: a feeling of lightheadedness or a pre-fainting state, actually, and dizziness — a condition in which a person feels as if they or nearby objects are spinning. The etiology of these conditions is multifactorial: from dehydration, hypoglycemia, and side effects of medications to pathology of the vestibular apparatus or hemodynamic disorders.

Laboratory testing is warranted in cases where dizziness is recurrent and accompanied by weakness, fatigue, tachycardia, pallor, paresthesias, glucose abnormalities, or when anemia or endocrine disorders are suspected. However, not every episode of dizziness has a laboratory-verified cause. Often, diagnostic workup requires measurement of blood pressure in various body positions, neurological examination, assessment of static and dynamic balance, otolaryngological examination, electrocardiography, or other instrumental methods.

First you need to distinguish the type of dizziness

The same description of «I feel dizzy» can mean different mechanisms. If the room seems to be spinning, the doctor is more likely to think of vestibular, inner ear, or neurological causes. If the vision darkens upon standing, blood pressure, pulse, dehydration, anemia, glucose, or cardiovascular factors are more important.

The Mayo Clinic notes that the nature of the sensation and the triggers of the dizziness can help determine the possible cause. Causes of dizziness can include inner ear disorders, medication side effects, anemia, low blood sugar, poor circulation, infections, or injuries.

It is worth paying attention to when the symptom occurs:

• after standing up abruptly;
• during hunger or after a long break from eating;
• after physical exertion;
• in transport;
• when turning the head;
• along with nausea or tinnitus;
• along with heartbeat;
• along with weakness, paleness, or shortness of breath;
• after infection;
• after starting a new medication.

These details often determine which tests will be truly useful and which will only create unnecessary anxiety.

When tests are especially appropriate

Laboratory testing makes the most sense when dizziness seems to be more than just a balance problem, but a manifestation of a general disturbance in the body. For example, if it is accompanied by weakness, pallor, cold sweat, palpitations, fatigue, thirst, weight loss, heavy menstruation, or numbness.

The AAFP, in its material on the evaluation of vertigo, notes that most patients with vertigo do not automatically require laboratory tests, but certain differential diagnoses require tests if there is clinical suspicion. Orthostatic pressure, examination for nystagmus, Dix-Hallpike test for positional vertigo, and other elements of the physical examination are important for evaluation.

You should discuss the tests with your doctor if you have:

• dizziness several times a week or more;
• darkening in the eyes when getting up;
• weakness and fatigue;
• shortness of breath during normal exercise;
• palpitation;
• pallor;
• heavy menstruation;
• thirst and frequent urination;
• sweating or trembling during attacks;
• numbness or tingling;
• tinnitus or hearing loss;
• weight loss;
• fever or night sweats;
• dizziness after infection;
• taking medications that can lower blood pressure or glucose.

If dizziness is accompanied by constant weakness, it is also useful to pay attention to the material about constant fatigue, because these symptoms often have common laboratory testing directions.

Anemia as a common cause of weakness and dizziness

Anemia can cause lightheadedness, weakness, shortness of breath, palpitations, paleness, and fatigue. Dizziness is often worse during exercise, after climbing stairs, when standing up quickly, or due to blood loss.

The Merck Manual, in its table of causes of dizziness, links anemia to paleness, weakness, or fatigue, and suggests blood tests to check for it. Low glucose levels, according to the same source, may be accompanied by sweating and require glucose testing during symptoms, if possible.

The following may indicate the benefit of testing for anemia:

• pale skin;
• constant weakness;
• dyspnea;
• palpitation;
• cold hands and feet;
• heavy menstruation;
• bleeding;
• black stools or blood in the stool;
• hair loss;
• brittle nails;
• low ferritin in the past.

In such a situation, the doctor may prescribe complete blood count, ferritin, iron, transferrin, vitamin B12, folic acid and other indicators as needed.

Glucose and attacks of weakness with tremors

Dizziness can occur when blood glucose levels drop or fluctuate dramatically. People often describe it as sudden weakness, shakiness, sweating, hunger, palpitations, anxiety, blackouts, or a feeling that "it's going to get bad.".

Low blood sugar can be a cause of dizziness, especially in people with diabetes who are taking medications to lower their blood sugar. The Mayo Clinic also lists low blood sugar as a possible cause of dizziness.

Glucose testing is appropriate if there is:

• attacks of weakness on an empty stomach;
• worsening after a long break from eating;
• trembling;
• cold sweat;
• severe hunger;
• palpitation;
• diabetes or suspicion of it;
• frequent urination;
• thirst;
• blurred vision;
• sudden weight change.

The doctor may recommend blood glucose, glycated hemoglobin, and in some cases, additional studies of carbohydrate metabolism.

Thyroid and hormonal causes

Thyroid disorders don't always just show up as weight or mood swings. They can affect your heart rate, body temperature, energy levels, and overall well-being. This can cause some people to feel weak, shaky, have palpitations, or feel unsteady.

The Merck Manual notes that hormonal changes, particularly those associated with thyroid disease, can cause dizziness. Its diagnostic chart lists thyroid function tests for suspected thyroid disorders.

TSH and free T4 may be appropriate if dizziness is accompanied by:

• constant fatigue;
• frostbite;
• drowsiness;
• dry skin;
• hair loss;
• weight gain;
• constipation;
• palpitation;
• trembling;
• sweating;
• weight loss for no apparent reason;
• menstrual cycle disorders.

If the form already has a TSH deviation, you can view the material about elevated TSH, which explains why this indicator should be evaluated along with free T4 and symptoms.

Dehydration, electrolytes and pressure

Frequent dizziness can be associated with dehydration, especially after vomiting, diarrhea, heat, heavy sweating, not drinking enough fluids, or taking diuretics. In such cases, a person may experience weakness, dry mouth, palpitations, and blurred vision upon standing up.

MedlinePlus lists dizziness or lightheadedness among the symptoms of dehydration, and blood tests, including electrolytes, and urine tests may be used to evaluate for dehydration and its cause.

The doctor may check:

• sodium;
• potassium;
• calcium;
• magnesium;
• creatinine;
• urea;
• general urine analysis;
• glucose;
• indicators of inflammation or infection as needed.

It is especially important to measure blood pressure, especially in the lying and standing positions. If dizziness occurs after standing up, the cause may be orthostatic hypotension or impaired vascular tone regulation.

Vitamin B12 and neurological symptoms

B12 deficiency can manifest itself not only in weakness. Sometimes dizziness is accompanied by numbness, tingling, burning in the feet, unsteadiness of gait, impaired concentration or memory. In such cases, it is important not to limit yourself to measuring blood pressure.

A B12 test may be appropriate if there is:

• numbness of the hands or feet;
• tingle;
• unsteadiness when walking;
• burning tongue;
• anemia;
• restrictions on animal products;
• chronic diseases of the stomach or intestines;
• taking medications that may affect absorption;
• prolonged weakness for no apparent reason.

B12 is usually evaluated along with a complete blood count, folate, ferritin, and other tests depending on symptoms.

When the cause may not be in the tests

It's important to be honest: tests don't always find the cause of dizziness. If the problem is related to the inner ear, positional vertigo, vestibular migraine, Meniere's disease, or neurological conditions, lab results may be normal.

MedlinePlus notes that causes of dizziness and vertigo can include inner ear problems, including benign positional vertigo, which is a common cause of vertigo, as well as other conditions. If your doctor suspects a stroke or head injury, imaging may be needed, in addition to tests.

That is why, when you experience dizziness, your doctor may recommend not only laboratory tests, but also:

• pressure measurement in different positions;
• ECG;
• examination by a neurologist;
• examination by an ENT doctor;
• vestibular tests;
• audiometry for tinnitus or hearing loss;
• MRI or CT scan as indicated;
• assessment of the medications the patient is taking.

The AAFP emphasizes that laboratory tests and imaging are not usually needed for all patients with vertigo, but may be helpful when a specific cause is suspected based on symptoms and examination.

What tests may be needed for frequent dizziness?

This is not a list for ordering all the tests at once. It shows how a doctor can move from a symptom to possible causes.

Dangerous signs that you shouldn't wait for tests

Sometimes dizziness requires emergency care rather than routine laboratory testing, especially if it comes on suddenly, is very severe, or is accompanied by neurological symptoms.

The Mayo Clinic advises seeking emergency care for new severe dizziness or vertigo along with a sudden severe headache, chest pain, difficulty breathing, numbness or paralysis of the arms or legs, fainting, double vision, fast or irregular heartbeat, confusion, or slurred speech.

Do not delay your application if you have:

• weakness in one arm or leg;
• speech disorders;
• facial asymmetry;
• double vision or sudden loss of vision;
• severe new headache;
• chest pain;
• dyspnea;
• faint;
• strong heartbeat or interruptions;
• dizziness after head injury;
• inability to stand or walk;
• black stools or significant bleeding;
• high fever with severe weakness.

In such cases, it is dangerous to wait for routine tests. A medical assessment of the condition is required first.

How to prepare for consultation and tests

To make the examination more accurate, it is a good idea to gather information about your seizures before your visit. This helps your doctor understand whether blood tests, vestibular tests, an ECG, or other methods are needed.

Write down:

• when dizziness occurs;
• how long does the attack last;
• is there a rotation of space;
• is there any darkening in the eyes;
• is it related to getting up;
• Is there nausea?;
• Is there tinnitus or hearing loss?;
• is there a heartbeat;
• whether there is weakness, shortness of breath, or pallor;
• what medications and supplements you take;
• whether there have been any recent infections;
• whether there is heavy menstruation or bleeding.

Some tests may require blood to be drawn in the morning or on an empty stomach, especially if they are testing glucose, biochemical parameters, or certain hormones. You should not stop taking medications on your own, but you should tell your doctor what you are taking.

What not to do yourself

With frequent dizziness, people often start taking «vascular» medications, iron, vitamins, iodine, or sedatives without a diagnosis. This may not help and sometimes hide the real cause.

It is not worth it:

• treat dizziness without understanding its type;
• take iron without a confirmed deficiency;
• starting hormonal or iodine-containing drugs without a doctor;
• ignore palpitations or fainting;
• blame everything solely on stress;
• independently cancel blood pressure or diabetes medications;
• delay treatment for neurological symptoms;
• to take random tests without a plan.

Frequent episodes of dizziness cannot be resolved with a single universal laboratory test - they require a step-by-step diagnostic strategy. If the symptom is associated with changes in blood composition, glucose levels, electrolyte balance, nutritional deficiencies or thyroid function, targeted laboratory studies can significantly narrow down the range of possible causes. If the primary source lies in the vestibular apparatus, cardiovascular system or central nervous system, instrumental and functional examination methods come to the fore. It is the combination of a carefully collected anamnesis, an objective clinical examination and a well-considered appointment of additional tests that allows you to translate an indefinite feeling of instability into the plane of a specific pathogenetic mechanism.

Author: Ulyana Anatolyivna Dzyuba

Director of Medi Lab Plus LLC, a doctor of the highest category. Has over 45 years of practical experience in medicine and laboratory diagnostics. Founder and head of the laboratory since 2007. More details…