How is diphtheria diagnosed?

Diphtheria is diagnosed based on clinical symptoms, laboratory tests, and throat cultures. Here's an overview of the diagnostic process:

1. Clinical Symptoms:

- Healthcare professionals consider a diagnosis of diphtheria based on symptoms such as sore throat, difficulty swallowing, hoarseness, and a thick grayish membrane covering the back of the throat (pseudomembrane).

2. Throat Culture:

- A throat swab is taken to collect a sample of secretions from the back of the throat.

- The sample is then sent to a laboratory for culture and analysis.

3. Laboratory Tests:

- The throat culture is incubated and examined for the presence of Corynebacterium diphtheriae, the bacteria that causes diphtheria.

- Specific laboratory tests, such as Gram staining and culture, are used to identify the bacteria.

4. Toxin Testing:

- If C. diphtheriae is identified in the throat culture, further testing is done to determine if the bacteria is producing the diphtheria toxin.

- This is done through a toxin neutralization test or polymerase chain reaction (PCR) to detect the toxin gene.

5. Additional Tests:

- In some cases, additional tests may be performed, such as:

- Blood tests to check for antibodies against the diphtheria toxin (serology).

- Chest X-ray to evaluate the extent of the infection and look for complications such as pneumonia.

It's important to note that diphtheria can be confused with other illnesses that cause similar symptoms, such as tonsillitis or strep throat. Therefore, accurate diagnosis requires clinical judgment, laboratory testing, and sometimes consultation with infectious disease specialists.