Why does the patient cough up rust-colored sputum?

Patients coughing up rust-colored sputum is primarily caused by Streptococcus pneumoniae infection, rupture of pulmonary capillaries, oxidative breakdown of hemoglobin, inflammatory exudates in the lungs, and mixing of airway secretions. It is often associated with severe lung infections. If rust-colored sputum is accompanied by high fever, chest pain, or difficulty breathing, immediate medical attention is recommended.

1. Streptococcus pneumoniae infection: This is the most common cause. The bacteria invade the lungs and trigger inflammation, stimulating the alveoli to produce large amounts of exudate, creating the basis for rust-colored sputum.

2. Rupture of alveolar capillaries: Worsening lung inflammation damages the capillaries surrounding the alveoli, causing red blood cells to leak out and mix with secretions in the alveoli.

3. Oxidative breakdown of hemoglobin: Leaked red blood cells rupture and release hemoglobin, which undergoes oxidation in the lungs to form hemosiderin, giving the sputum its characteristic rust color.

4. Pulmonary inflammatory exudate: Inflammation stimulates the production of abundant inflammatory exudates in the lungs, which mix with hemosiderin and necrotic tissue, further shaping the color and consistency of the sputum.

5. Mixing with airway secretions: The airway mucosa, irritated by inflammation, secretes mucus that envelops hemosiderin and inflammatory substances. This mixture is expelled through coughing, forming the typical rust-colored sputum.

Treatment should follow medical guidance, including use of appropriate antibiotics to control infection and expectorants or antitussives to relieve symptoms. For care, ensure adequate rest, drink plenty of water to thin the sputum, maintain a light diet to support nutrition, keep indoor air well-ventilated, and avoid smoke or dust exposure that may irritate the respiratory tract.