Acute Laryngotracheitis - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Laryngotracheitis is a condition in which inflammation occurs in the larynx and the trachea resulting from acute infections of viral origin. In severe cases, the infection may even extend into the lower airway. This is most commonly seen in children with symptoms like hoarseness, cough, and onset of acute stridor (harsh or vibratory sound produced due to a narrow airway). This illness has been known for centuries and is also known as croup which derives its name from the Anglo-Saxon word, kropan, or an old Scottish word, roup, meaning to cry out in a hoarse voice.

What Is Laryngotracheitis?

Laryngotracheitis is an upper airway infection that makes breathing harder as the airway narrows. It can lead to a cough that sounds like barking and other signs and symptoms that may result from swelling and irritation around the larynx (voice box), trachea (windpipe), and bronchial tubes (bronchi). When a patient coughs, the air is forced through this narrow passage, which makes a sound like barking as the vocal cords are inflamed. Moreover, while breathing, a high-pitched sound is produced called a stridor. This infection most affects younger children and is usually non-serious and can be treated at home.

What Is the Pathophysiology of Acute Laryngotracheitis?

Viruses responsible for causing acute laryngotracheitis can spread through direct inhalation from cough or sneeze or by contamination of hands with fomites and touching the mucosa of eyes, nose, and mouth. The cause of infection can be understood by following steps -

• The primary entry points of the virus are through the nose and nasopharynx.

• Then the infection spreads and affects the larynx and trachea.

• After that, the inflammation and edema of the subglottic larynx and trachea can be seen near the cricoid cartilage.

• Under microscopic view, the involved areas can be seen edematous with cellular infiltration.

• The edema or inflammation leads to airway narrowing, barking cough, stridor, and chest wall retractions.

• The mobility of vocal cords also gets affected due to edema leading to hoarseness in the voice.

What Is the Epidemiology of Acute Laryngotracheitis?

Laryngotracheitis or croup is one of the most common pediatric illnesses. This is primarily seen in infants and toddlers from 6 to 36 months (3 years). In North America, the incidence rate is found to be high in the second year of life, with five to six cases per 100 toddlers. However, it is rarely seen after the age of six years or in adults.

The male-to-female ratio for this disease is approximately 1.4:1. The disease occurs mostly in the winter or late fall. However, it can occur at any time of the year.

What Are the Causes of Acute Laryngotracheitis?

Croup is caused due to an acute viral infection that can spread through either direct inhalation or contamination with fomites. One of the most common causative organisms is the parainfluenza virus. The parainfluenza viruses (types - 1,2, and 3) are responsible for around 80 percent of acute laryngotracheitis cases, with types 1 and 2 accounting for 66 % of cases. Other than that, Mycoplasma pneumoniae is also seen in some cases.

Some other causative organisms that can lead to acute laryngotracheitis include -

• Adenovirus.

• Respiratory syncytial virus (RSV).

• Human bocavirus.

• Coronavirus.

• Echovirus

• Enterovirus

• Rhinovirus.

• Reovirus.

• Metapneumovirus.

• Influenza A and B.

• Rarer causes such as measles virus, herpes simplex virus, varicella.

What Are the Types of Laryngotracheitis?

There are two types of croup, which include -

1. Viral Croup - This type is milder and generally results in continuous fever, nasal congestion, and cough in children of six months to three years of age. The virus, mainly parainfluenza, cause it. The symptoms can continue over three days which is the main difference between the two types.

2. Spasmodic Croup - This type usually occurs due to an infection caused by unknown genetic factors which run in the family. It can be found within the same age group as viral croup but can also be seen in older people. It causes sudden attacks of cough and hoarseness and generally occurs during the evening time over a period of two to four days.

What Are the Sign and Symptoms of Acute Laryngotracheitis?

Acute laryngotracheitis usually begins as an ordinary cold. If there is swelling and irritation, it can lead to the following:

• Loud barking cough that gets worse with crying and coughing.

• Fever.

• Hoarse voice.

• Noisy breathing.

The symptoms may last three to five days and worsen at night.

When to See the Doctor?

Parents should seek medical advice if symptoms get worse and last longer than three to five days and are not responding to the home treatment. Parents should immediately go to the doctor if their child -

• Makes noisy high-pitched breathing sounds, when and even sitting ideally.

• Begins drooling or has problems swallowing.

• Breathes at a faster rate than usual.

• Struggles to breathe.

• Shows anxiety, upset, restlessness, tiredness, or no energy.

• Have a blue or gray tint around the nose, in or around the mouth, or on fingernails.

How to Diagnose Acute Laryngotracheitis?

A healthcare provider usually diagnoses acute laryngotracheitis through clinical examination. The provider will -

• Observe the breathing of the child.

• Listen to the sounds by using a stethoscope on the chest of a child.

• Examine the throat.

• X-rays may also be advised to rule out other possible causes.

A special scoring system is used to check the severity of the illness, known as the Westley score. Although its clinical application has not been researched completely, it has been widely used for research purposes for evaluating a treatment plan. This system gives points based on the factors listed below, and the final score ranges from 0 to 17. The factors include -

Level of Consciousness -

• Normal - 0 points.

• Including Sleep - 0 points.

• Depressed - 5 points.

According to this the scoring has been given to different illnesses which include -

Cyanosis -

• None - 0 points.

• Upon Agitation - 4 points.

• At Rest - 5 points.

Inspiratory Stridor -

• None - 0 points.

• Upon Agitation - 1 point.

• At Rest - 2 points.

Air Entry -

• Normal - 0 points.

• Mild Decrease - 1 point.

• Marked Decrease - 2 points.

Retractions -

• None - 0 points.

• Mild - 1 point.

• Moderate - 2 points.

• Severe - 3 points.

Another scoring system was formulated by Alberta clinical practice guideline working group to clinically evaluate the severity of croup, which include -

• Mild (Score 0 to 2) - Occasional barky cough, no stridor, mild or no retractions.

• Moderate (Score 3 to 7) - Frequent barky cough, stridor at rest, and mild to moderate retractions but little or no distress or agitation.

• Severe (Score 8 to 11) - Frequent barky cough, stridor at rest, marked retractions, significant distress, and agitation.

• Impending Respiratory Failure (Score 12 to 17) - Depressed level of consciousness, stridor at rest, severe retractions, poor air entry, cyanosis (bluish discoloration of the skin), or pallor (paleness or loss of skin color).

What Is the Treatment of Acute Laryngotracheitis?

Most children with acute laryngotracheitis can be treated at home, and the treatment usually depends upon the severity of the symptoms. The most important aspect of treatment is to calm and comfort the child, as crying or getting anxious can worsen the condition. Along with that, it should be noted that the child should drink plenty of fluid to stay hydrated.

In cases where home treatment is not helpful, parents can seek medical advice. The healthcare provider may prescribe some of the following medicines to treat the condition -

• Corticosteroids - To reduce swelling, and the symptoms may improve within a few hours.

• Epinephrine - This is also effective in reducing swelling and is given in patients with more severe symptoms. This can be given in an inhaled form via a nebulizer. It is fast acting and the child is observed after administering the medicine if they need another dose.

Conclusion:

Acute laryngotracheitis is a common illness found in children which can be managed easily with home care and can be resolved within three to four days. Medical attention is only needed in cases where the condition gets severe and does not go away with home treatment.