Diphtheria pseudomembrane formation

Introduction Pseudomembrane formation is a typical manifestation of diphtheria. The pseudomembrane is a membrane composed of necrotic white blood cells, bacteria and other substances, often located in the tonsils and other parts close to the throat. The pseudomembrane is thick and hard and is stained gray. If the pseudomembrane is forcibly removed, the mucous membrane below it will bleed. The pseudomembrane may reduce the passage of the airflow or suddenly block the airflow passage completely, hindering the child from breathing and causing an emergency. However, some of the milder diphtheria may not produce a pseudomembrane.

Cause

Diphtheria infection. Diphtheria bacilli multiply in the epithelial surface of the upper respiratory tract (usually the pharynx) of the susceptible person or in the surface skin to secrete exotoxin. Exotoxin infiltrates into local and surrounding tissues, causing tissue necrosis and acute pseudomembranous inflammation. The fluid exuded from the blood vessels contains fibrin which is easily coagulated to solidify inflammatory cells, mucosal necrotic tissue and diphtheria to form a pseudomembrane. The fake film is grayish white. The edges are neat. The pseudomembrane and the submucosal tissue are closely adhered and are not easily wiped off. A few patients' lesions can invade deep tissues and form ulcerated surface, throat, trachea and bronchial mucosa. The epithelium has cilia, and the formed pseudomembrane and mucous membrane adhesion are not tight, and it is easy to cut from the trachea. Squirting.

Diphtheria exotoxin is localized in the tissues and cells of the whole body through the lymph and blood after local absorption, causing lesions. Among them, the myocardial peripheral nerve is the most sensitive. Kidney and adrenal cortex and other lesions are also more significant. The amount of exotoxin absorbed is related to the location and extent of the pseudomembrane. The pharynx is most easily absorbed, the tonsils are the second, and the throat and trachea are the least. The wider the pseudomembrane, the greater the amount of toxin absorbed, and the combination of toxin and tissue begins to be fashionable and slack. The longer the combination, the stronger the combination, and it is not easy for the antitoxin to neutralize the diphtheria bacilli generally staying in the local lesions, not entering the blood line, even Reach the local lymph nodes.

an examination

Related inspection

Direct smear test

1. Epidemiological data: including age, season, history of diphtheria exposure, whether the whole process has been vaccinated in the past, and whether there is a diphtheria epidemic in the region.

2, clinical manifestations: the initial diagnosis of diphtheria must be based mainly on clinical manifestations.

(1) The onset is slow, fever and sore throat are not obvious, but the symptoms of systemic poisoning are heavier, and there is a typical diphtheria pseudomembrane in the pharynx.

(2) There are serous bloody secretions in the nasal cavity, swelling of the neck lymph nodes and symptoms of poisoning.

(3) Laboratory examination: positive bacterial culture can be diagnosed.

Differential diagnosis

Differential diagnosis of diphtheria pseudomembrane formation:

First, streptococcal tonsillitis: acute onset, high fever sore throat, a little yellowish exudate on the tonsils.

Second, Fen Sen's pharyngitis: necrosis, ulcers and pseudomembranes in the pharynx, accompanied by necrosis and inflammation of the gums.

Third, acute laryngitis: severe symptoms, difficulty breathing, periodicity, heavy day and night, no membranous pharyngeal membrane.

Fourth, allergic laryngeal edema, sudden onset, a history of allergies.

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