Sputum, commonly known as phlegm, is mucus produced by the respiratory tract, including the lungs and throat. It functions as a natural defense mechanism, trapping inhaled foreign particles and microorganisms. Cilia then sweep these substances out of the lungs. When the respiratory system is irritated or infected, the body produces increased mucus, and changes in its color or consistency indicate underlying health issues.
Defining Purulent Sputum and Its Appearance
The term “purulent” indicates that the sputum contains pus, resulting from the body’s inflammatory response to an infection, usually bacterial. Purulent sputum is opaque, thick, and discolored, unlike the clear or white appearance of normal mucus.
Its coloring, ranging from yellow to dark green, is due to large quantities of inflammatory cells, primarily neutrophils. These white blood cells rush to the infection site to fight pathogens. As these cells break down, they release myeloperoxidase, a greenish enzyme that imparts the distinctive green hue. A rusty or brownish color can also be purulent, suggesting old blood or specific bacterial infections.
Common Medical Conditions That Cause Purulent Sputum
Purulent sputum strongly indicates an active respiratory tract infection, categorized as acute or chronic. Acute bacterial infections are the most common cause, with bacterial pneumonia being a frequent diagnosis. In pneumococcal pneumonia, the sputum may present as a rust color, reflecting the specific bacteria. Acute bronchitis, often viral, can produce purulent sputum if a secondary bacterial infection develops in the inflamed airways.
The initial viral infection damages the respiratory lining, making it susceptible to bacterial colonization. A lung abscess, a serious complication, produces a significant quantity of purulent and often foul-smelling sputum due to the localized collection of pus.
Among chronic respiratory illnesses, purulent sputum is a persistent or recurring symptom, often indicating bacterial colonization or an acute exacerbation. Individuals with Chronic Obstructive Pulmonary Disease (COPD) frequently experience worsening episodes characterized by increased volume and purulence of their sputum. This change guides the decision to administer antibiotics during an exacerbation.
Bronchiectasis, where airways are permanently damaged and widened, leads to chronic pooling of mucus that becomes easily infected. Patients often produce large amounts of purulent sputum daily because the compromised airways cannot effectively clear secretions. Cystic Fibrosis (CF) also causes thick, sticky mucus that clogs airways, resulting in chronic bacterial infections and persistent purulent phlegm.
Diagnostic Procedures and Treatment Approaches
Diagnosis begins with a thorough clinical evaluation and the collection of a high-quality sputum sample. Clinicians instruct patients to produce a deep-cough specimen, ideally collected early in the morning to minimize contamination. This sample is sent for a Sputum Culture and Sensitivity test. The culture identifies the specific microorganism causing the infection, and sensitivity testing determines the most effective antibiotics.
Imaging procedures, such as a chest X-ray, are utilized to look for signs of pneumonia or other structural abnormalities contributing to the symptom.
Treatment aims to eliminate the underlying cause and manage secretion accumulation. If a bacterial infection is confirmed, a course of antibiotics is the primary treatment, selected based on sensitivity results. For chronic conditions like COPD or Bronchiectasis, management includes supportive care and specialized airway clearance techniques.
Supportive measures focus on keeping airways hydrated to thin secretions, often involving humidification or increased fluid intake. Medications like bronchodilators may open the airways, and techniques such as chest physiotherapy help mobilize the thick, purulent sputum. Successful treatment is monitored by observing a reduction in volume and a return to a less purulent, clearer consistency.