Definition

Respiratory alkalosis is a condition marked by a low level of carbon dioxide in the blood due to breathing excessively.

Alternative Names

Alkalosis - respiratory

Causes

Common causes include:

• Anxiety or panic
• Fever
• Overbreathing (hyperventilation)
• Pregnancy (this is normal)
• Pain
• Tumor
• Trauma
• Severe anemia
• Liver disease
• Central nervous system (brain) abnormalities
• Overdose of certain medicines, such as salicylates, progesterone

Any lung disease that leads to shortness of breath can also cause respiratory alkalosis (such as pulmonary embolism and asthma).

Symptoms

The symptoms may include:

• Dizziness
• Lightheadedness
• Numbness of the hands and feet
• Breathlessness
• Confusion
• Chest discomfort

Exams and Tests

Your health care provider will perform a physical exam. Tests that may be done include:

• Arterial blood gas, which measures oxygen and carbon dioxide levels in the blood
• Basic metabolic panel
• Chest x-ray
• CT scan of the chest 
  
• Pulmonary function tests to measure breathing and how well the lungs are functioning

Treatment

Treatment is aimed at the condition that causes respiratory alkalosis. Breathing into a paper bag -- or using a mask that causes you to re-breathe carbon dioxide -- sometimes helps reduce symptoms when anxiety is the main cause of the condition.

Outlook (Prognosis)

Outlook depends on the condition that is causing the respiratory alkalosis.

Possible Complications

Seizures may occur if the alkalosis is extremely severe. This is very rare and more likely to happen if the alkalosis is due to increased ventilation from a breathing machine.

When to Contact a Medical Professional

Contact your provider if you have any symptoms of lung disease, such as long-term (chronic) cough or shortness of breath.

References

McCoin NS, Self WH. Acid-base disorders. In: Walls RM, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 113.

Sanghavi S, Albert TJ. Acid-base balance. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 12.

Seifter JL. Acid-base disorders. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 110.