Mucopurulent Discharge

Mucopurulent discharge is a pathological secretion consisting of a mixture of mucus and pus. It forms on the surface of mucous membranes as a result of an inflammatory process, usually caused by bacterial infection. It appears as a viscous, opaque fluid of yellowish, greenish, or grayish color.

Once such discharge is observed, it becomes an important clinical sign, often indicating a secondary bacterial infection that has developed following an initial viral or allergic inflammation. It reflects the active phase of the immune system’s response against pathogenic bacteria.

Aetiology and Pathophysiology

Mucopurulent exudate forms in two stages: Initially, in response to an irritant (e.g., a virus), goblet cells of the mucosa increase mucus production. This viscous secretion has a protective function. At this stage, the discharge is purely mucous.

The second phase is marked by secondary bacterial infection. The immune system recruits large numbers of neutrophils to the site of inflammation. These blood cells engulf and destroy bacteria. The massive death of neutrophils, bacteria, and damaged tissue cells results in pus formation. The original mucus mixed with newly formed pus produces mucopurulent discharge.

Clinical significance

The nature of the discharge is an important diagnostic criterion, helping the physician determine the etiology of the disease and select appropriate treatment strategies. Mucopurulent exudate is often the basis for initiating antibacterial therapy.

This symptom may be observed in various conditions:

• Otolaryngology (ENT): bacterial rhinitis, sinusitis (maxillary sinusitis, frontal sinusitis), adenoiditis.
• Ophthalmology: a classic sign of bacterial conjunctivitis.
• Pulmonology: mucopurulent sputum is characteristic of bacterial bronchitis, pneumonia, and bronchiectasis.
• Gynecology and urology: bacterial cervicitis, urethritis, including those caused by sexually transmitted infections (e.g., gonorrhea).

Differential Diagnosis

Mucopurulent discharge should be distinguished from other types of pathological secretions. Serous exudate: thin, watery, and transparent, unlike the thick, colored mucopurulent secretion. Purely mucous secretion: whitish or clear, without the yellow or green tint imparted by pus. Hemorrhagic discharge: contains blood, which differentiates it from mucopurulent exudate.