Panic Attacks: Causes, Symptoms and Which Tests to Take

A panic attack is a sudden episode of intense fear with physical symptoms: palpitations, shortness of breath, tremor, sweating, the sense of "I'm about to die." In most cases panic attacks are psychogenic — but not always. In 20–30% of patients the cause is somatic or endocrine: hyperthyroidism, pheochromocytoma, hypoglycemia, severe iron deficiency, HPA-axis dysregulation. Prescribing tranquilizers without excluding these causes is closing the eyes to potential organic disease.

What a Panic Attack Is: Symptoms and Manifestations

A panic attack unfolds over 5–10 minutes, peaks, then gradually subsides. Typical duration is 15–60 minutes. Symptoms:

• Palpitations, the sensation of a "pounding" heart
• Sudden intense fear, fear of dying or going insane
• Shortness of breath, "air hunger"
• Tremor, shakiness, sweating
• Chest pain, abdominal discomfort
• Dizziness, derealization
• Tingling and numbness in extremities

A diagnosis of "panic disorder" requires recurring attacks and persistent anticipatory anxiety. A single attack under heavy stress is not a diagnosis.

Important sign: in a "typical" panic attack, physical symptoms appear together with fear. In somatic causes (pheochromocytoma, hypoglycemia) the physical symptoms come first, with fear and anxiety joining secondarily — patients describe "first my heart started racing, then I got scared."

Psychogenic vs Somatic Causes of Panic Attacks

Psychogenic:

• Anxiety disorder, chronic stress
• Post-traumatic stress disorder (PTSD)
• Anticipatory anxiety
• Depression with anxious component
• Social phobia

Somatic / endocrine:

• Hyperthyroidism (overt or subclinical)
• Pheochromocytoma and paraganglioma
• Hypoglycemia (often after rapid carbs or in insulin-treated diabetics)
• Arrhythmias (PVCs, sinus tachycardia)
• Iron deficiency with significantly reduced ferritin
• Vestibular dysfunction
• Carcinoid (rare)

Some cases combine psychogenic and somatic factors. For example, a person with low ferritin and a tendency toward anxiety has more panic attacks than the same person after iron repletion.

Which Tests to Take for Panic Attacks

Minimum set to exclude somatic causes:

Thyroid hormones: TSH + free T4 — mandatory. TSH < 0.4 in panic attacks is a high priority for endocrinology referral. Conveniently drawn as a thyroid panel.

Morning (8:00–10:00) and evening (4:00–6:00 PM) cortisol. Cortisol is often modestly elevated in panic disorder; evening cortisol shows whether the circadian rhythm is preserved.

Ferritin — target > 50 ng/mL. Low ferritin is found in 30–40% of patients with panic attacks, especially women.

Fasting glucose + insulin — to assess hypoglycemic tendencies.

For attacks with strong cardiovascular features:

• 24-hour urinary or plasma metanephrines and normetanephrines (to exclude pheochromocytoma)
• ECG, ideally with Holter monitoring
• Magnesium, potassium

Vitamin D, B12, folate, magnesium — to exclude nutrient causes of hyperexcitability.

The stress block is conveniently combined into one adrenal stress panel.

Hyperthyroidism and Panic Attacks

Hyperthyroidism is the most common endocrine cause of "panic-like" symptoms. Excess thyroid hormones make β-adrenergic receptors hypersensitive to catecholamines, subjectively felt as tachycardia, tremor, fear. Additional features:

• Weight loss with preserved or increased appetite
• Heat intolerance, sweating
• Fine finger tremor
• Frequent stools
• Insomnia and "always irritable"
• Sometimes — eye proptosis (in Graves' disease)

With panic attacks plus these features, a TSH test is mandatory first. Paradoxically, a patient may be treated for "anxiety" with antidepressants for years while the real cause is thyroid hyperfunction.

Pheochromocytoma: A Rare but Dangerous Cause

Pheochromocytoma is a tumor of the adrenal medulla or extra-adrenal chromaffin tissue secreting catecholamines (epinephrine, norepinephrine). It is rare but extremely important to exclude — "classic" panic attacks in pheochromocytoma can occur with hypertensive crises and stroke risk.

Key features distinguishing pheochromocytoma crises:

• Sharp BP rises > 180/110 during attacks
• Symptoms emerge "from outside in" — first physical, then fear
• Attacks are often triggered by exertion, bending, or abdominal palpation
• Severe headache at the peak of the attack
• Pale (not flushed) skin
• Increased urination after the attack

Lab work: urinary or plasma metanephrines and normetanephrines elevated 3–10-fold. Confirmation — adrenal CT or MRI. With suspicion — urgent endocrinology consult; "self-managed BP control" is dangerous.

Hypoglycemia and Panic Attacks

A sharp glucose drop (< 3.5 mmol/L) triggers a powerful adrenergic response — sweating, tremor, palpitations, fear. These symptoms are biochemically identical to a panic attack.

At-risk groups:

• Diabetics on insulin or sulfonylureas
• Reactive hypoglycemia after rapid carbs (the "sugar swing")
• Long fasting (more than 14–16 hours)
• Alcohol on an empty stomach
• Rare causes — insulinoma, post-bariatric syndromes

If attacks happen 2–4 hours after meals and resolve with eating — high probability of a hypoglycemic component. The strategy is sugar stabilization through regular protein-containing meals and avoiding rapid carbs on an empty stomach.

Cortisol and Anxiety: The Link to Panic Attacks

Chronic HPA-axis activation does not cause panic attacks directly but creates an "anxious background" on which attacks happen more often. Patients with panic disorder frequently have:

• Elevated evening cortisol
• Flattened circadian rhythm
• Reduced DHEA-S (especially when combined with burnout)

Lowering baseline cortisol through lifestyle (sleep, caffeine restriction, regular exercise) reduces attack frequency, even when attacks are psychogenic. For more, see anxiety: which lab tests and how to lower cortisol.

When to See a Doctor

To a psychotherapist/psychiatrist first:

• Recurrent attacks with anticipatory anxiety
• Clear psychological context
• Normal lab values

To an endocrinologist first:

• TSH < 0.4 or > 4.0
• Elevated metanephrines (suspected pheochromocytoma)
• Symptoms emerging "from outside in" (physical → fear)

To a cardiologist/neurologist:

• Attacks with arrhythmias, syncope, or marked rhythm disturbance
• Suspicion of epileptic equivalents with autonomic symptoms

Emergency care — if an attack is accompanied by loss of consciousness, severe arrhythmia, neurological symptoms (facial asymmetry, speech disturbance, paresis), or BP > 200/120.

This article is for informational purposes only and does not replace professional medical advice. With first panic attacks, clinical evaluation to exclude somatic causes is mandatory.