Epiglottitis, or infection and inflammation of the epiglottis, is mainly caused by Haemophilus influenza type b and commonly affects children between ages 2 and 7 and adults with a depressed immune system.
With the advent of vaccination against Hib there is a reduction in the incidence of this infection.
However, the condition may progress and worsen rapidly and often lead to life threatening complications and death if not identified and treated promptly.
Time is important in diagnosis of epiglottitis
Diagnosis relies on clinical judgement and examination primarily since time is of utmost importance.
Attempts to look at the inflamed epiglottis may be dangerous since it may precipitate complete airway obstruction and lead to death within minutes.
Bedside evaluation and certain diagnostic procedures are suggested. These are essential to rule out other conditions that may mimic epiglottitis.
This may include obstruction of the airway by an ingested foreign object, infection of the larynx (voice box) or trachea (windpipe) called croup in children, acute hypersentitivity or allergic reactions (e.g. allergy to peanuts etc.), injury of the throat due to chemicals or hot liquids and tumors. (1-5)
Tests for epiglottitis
Investigative procedures should be performed after airway is secured and patient is stable. Investigative procedures that confirm the diagnosis include (1-5):
- X ray of the neck. This shows the swollen and inflamed epiglottis when taken from the side. This method cannot be used to confirm diagnosis in 20% cases.
A swollen epiglottis is called a “thumb print” sign as the inflamed epiglottis appears like a thumb.
- Visualization of the inflamed epiglottis via nasopharyngoscopy or laryngoscopy. This is a tube like device made of fiber optic material with a camera it its tip. It is used to look at the epiglottis.
This may also be of use in the 44% patients in whom plain examination of the back of the mouth does not help in diagnosis.
- Chest X ray – this is performed to detect accompanying lung infection or pneumonia.
- Routine blood examination is usually prescribed. Hallmarks of infection include raised white blood cell count.
- Blood culture for Haemophilus influenza, H parainfluenzae, Streptococcus pneumoniae, and group A streptococci may be performed to confirm the organism causing the epiglottitis.
- A swab is used to swipe the mucus over the back of the neck. This is attempted only after ensuring that the airways are open and there is not obstruction in breathing.
This swab material is then placed over a glass slide. Using special stains and dyes the slide is examined under the microscope to detect the causative organism.
The samples collected from the epiglottis are also cultured in a petri dish in the laboratory. In specific nutrient medium and at appropriate environmental conditions the organisms are seen to grow. These can be identified under the microscope.
- Aspiration of abscess – in case of an abscess a long, thin and hollow needle may be used to collect samples of pus and infected material. This is done after securing adequate breathing. The samples are then tested for infecting organism detection.
- Computed tomography (CT) scanning of the neck in early or unusual cases may be prescribed.
However, a CT scan or MRI scan is more of use to exclude other conditions that mimic epiglottitis. These include an abscess within the neck, laryngeal infections or ingestion and obstruction due to a foreign object.
Further Reading