Anxiety attacks are a type of heightened anxiety that comes on gradually and involves feelings of increased anxiety or stress, along with physical symptoms. People who have anxiety attacks may have a baseline low level of anxiety that is increased with certain triggers.
An anxiety attack is not the same as a panic attack, which comes on suddenly and involves intense feelings of fear or an impending sense of doom that lasts for a short time, usually only a few minutes.
An anxiety attack feels like fear or worry, usually triggered by actual or perceived threats or potential dangers.
People having an anxiety attack may feel:
- Excessively worried
- “On edge”
- Irritable
- Restless
- Easily frightened/startled
- Fearful
- Distressed
- Panicked
- As if they need to escape
- Like their mind has gone blank
- As if they are out of control
Physical symptoms of an anxiety attack may include:
- Muscle tension
- Being easily fatigued
- Difficulty concentrating
- Sleep problems
- Increased heart rate
- Chest pain
- Shortness of breath
- Shaking or trembling
- Dizziness
- Hot flashes or chills
- Upset stomach
- Diarrhea
- Numbness or tingling in hands or feet
What Causes Anxiety Attacks?
Generalized anxiety disorder and anxiety attacks may be caused by:
- Genetic factors
- Environmental factors such as early childhood trauma
- Underlying medical conditions
- Use of certain substances, such as over-the-counter (OTC) medications, herbal preparations, and illicit drugs
Certain conditions can trigger anxiety attacks, such as:
- Stress
- Loss – of a loved one, pet, job
- Problems with relationships
- Heart problems
- Illness
- Caffeine
- Side effects from medications
- Low oxygen levels, due to:
- Being at high altitudes
- Lung disease such as chronic obstructive pulmonary disease (COPD, including emphysema or chronic bronchitis)
- Blood clot in the lung (pulmonary embolism, or PE)
How Are Anxiety Attacks Diagnosed?
Anxiety disorders are usually diagnosed with a psychological evaluation. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association, provides diagnostic criteria for an anxiety disorder.
Lab studies to help diagnose or exclude medical conditions that may cause anxiety disorders and anxiety attacks include:
- Blood tests
- Complete blood cell (CBC) count
- Chemistry profile
- Thyroid function tests
- Urine tests
- Urinalysis
- Urine drug screen
Tests to rule out central nervous system (CNS) disorders that can cause anxiety disorders and anxiety attacks include:
- Brain computed tomography (CT) scan
- Electroencephalography (EEG)
- Lumbar puncture
- Magnetic resonance imaging (MRI) of the brain
- Neurologic consultation
- Positron emission tomography (PET) scan
Tests to rule out heart conditions that can cause anxiety disorders and anxiety attacks include:
- Electrocardiography (ECG)
- Treadmill ECG
What Is the Treatment for Anxiety Attacks?
A combination of medication and/or psychotherapy is typically used to treat anxiety disorders and anxiety attacks.
Therapies used to treat anxiety disorders and anxiety attacks include:
- Behavioral therapy and cognitive behavioral therapy (CBT)
- Computerized CBT (FearFighter)
- Psychodynamic therapy
- Interpersonal psychotherapy
- Relaxation therapy
- Supportive psychotherapy
- Mindfulness therapy
Medications used to treat anxiety disorders and anxiety attacks include:
- Anti-anxiety drugs such as buspirone (BuSpar)
- Antidepressants
- Selective serotonin reuptake inhibitors (SSRIs) such as paroxetine (Paxil), escitalopram (Lexapro), sertraline (Zoloft), fluoxetine (Prozac), fluvoxamine (Luvox), and citalopram (Celexa)
- Serotonin and norepinephrine reuptake inhibitors (SNRIs) such as venlafaxine (Effexor and Effexor XR) and duloxetine (Cymbalta)
- Atypical antidepressants such as nefazodone (Serzone), mirtazapine (Remeron), and trazodone (Desyrel)
- Tricyclic antidepressants such as imipramine (Tofranil) and clomipramine (Anafranil)
- Monoamine oxidase inhibitors (MAOIs) such as phenelzine (Nardil), selegiline (Emsam), tranylcypromine (Parnate), and isocarboxazid (Marplan)
- Benzodiazepines, often used in emergency situations, such as lorazepam (Ativan), clonazepam (Klonopin), and alprazolam (Xanax)
- Anticonvulsants such as pregabalin (Lyrica), divalproex (Depakote), and gabapentin (Neurontin)
- Antihypertensive drugs such as clonidine (Catapres), propranolol (Inderal, Betachron E-R, InnoPran XL), nadolol (Corgard), and atenolol (Tenormin)
Other treatments used for anxiety disorders and anxiety attacks include:
- Cranial electrotherapy stimulator (CES)
In the following severe cases, anxiety attacks may need to be treated in the hospital:
- Severe functional impairment (cannot meet own daily needs)
- Suicide or homicide risk
- Deficits in social skills
Dietary changes that may help treat anxiety attacks include:
- Avoiding caffeine
- Taking over-the-counter preparations and herbal remedies with caution because ephedrine and some herbs can cause or worsen anxiety symptoms
From 
https://www.nimh.nih.gov/health/topics/anxiety-disorders/index.shtml#part_145333
https://www.calmclinic.com/anxiety/stop-anxiety-quickly