What is Croup?
Croup is a common breathing sickness that affects the windpipe, voice box, and air tubes in the lungs, leading to a harsh, barking cough and a high-pitched sound when breathing in. The condition generally includes three types: laryngotracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis. Usually, a virus known as the parainfluenza virus causes croup, but bacteria can also be responsible.
Diagnosing croup primarily involves observing the symptoms, but it’s important to first rule out other potentially dangerous conditions, like the presence of a foreign object in the airway or a swelling in the throat known as epiglottitis. To treat croup, corticosteroids, which help reduce inflammation, are usually given to patients. In more severe cases, epinephrine, a medication that opens up the airway, may be used.
What Causes Croup?
Croup, an illness that affects child’s airway, is typically caused by viruses, but bacteria can also be responsible in some cases.
For the viral category:
– The most common cause of viral croup, which results in the sudden onset of a barking cough or hoarse voice, is the Parainfluenza virus, especially types 1 and 2.
– Other viruses including influenza A and B, measles, adenovirus, and respiratory syncytial virus (RSV) can also lead to viral croup.
– Spasmodic croup, a type of croup that usually comes on suddenly and typically at night, is also caused by the same viruses, but without visible signs of infection.
On the bacterial side:
– Bacterial croup takes several forms: laryngeal diphtheria, bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis.
– Laryngeal diphtheria results from a bacteria called Corynebacterium diphtheriae. The other forms of bacterial croup initially begin as viral infections but get worse as additional bacteria grow.
– The usual types of bacteria that cause these forms of croup are Staphylococcus aureus, Streptococcus pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis.
Risk Factors and Frequency for Croup
Croup, a common respiratory condition among children, leads to hospitalization of about 7% of children under five years each year in the United States. It affects roughly 3% of children annually, particularly those aged 6 months to 3 years. The parainfluenza virus is responsible for over 75% of croup infections. The condition is more prevalent in boys than girls, with a ratio of 1.5 to 1. Most cases of croup (around 85%) are mild, with less than 1% being severe.
- Croup leads to 7% of hospitalizations among children under five each year in the US.
- About 3% of children are affected by croup each year, mainly those aged 6 months to 3 years.
- More than 75% of these cases are caused by the parainfluenza virus.
- The condition is slightly more common in boys than girls, with a ratio of 1.5 to 1.
- Approximately 85% of croup cases are mild, while less than 1% are considered severe.
Signs and Symptoms of Croup
Croup is a health condition that often comes with a distinctive cough that sounds like a seal’s bark. Alongside this, patients usually experience a hoarse voice, breathing difficulties, and stridor, a harsh, vibrating noise when breathing. These issues tend to become more noticeable during the nighttime, and agitation or stress can also make the stridor worse. Stridor can often be heard even when the patient is at rest. Additional symptoms can include a fever and shortness of breath, but some patients might not have any noticeable increase in body temperature. Therefore, a lack of fever should not lead to any reduction in the suspicion for croup. Moreover, the patient may also showcase an increased breathing and heart rate; the normal range for this is typically around 20 to 30 breaths per minute. Obvious signs such as nasal flaring, retractions, or in severe cases, cyanosis (bluish discoloration of the skin) may also be present, hinting at a higher likelihood for croup.
- Starts as a regular upper respiratory infection, then progresses to a barking cough and stridor within one to two days
- Mild fever
- No drooling or difficulty swallowing
- Duration of symptoms usually lasts between three to seven days, with the worst of them typically seen on day three or four
Testing for Croup
The severity of croup, a common respiratory condition in children, is usually measured using the Westley score system. The Westley score, which ranges from 0 to 17 points, evaluates five factors: breathing noises (stridor), skin pulling in between the ribs while breathing (retractions), bluish skin color due to lack of oxygen (cyanosis), the child’s awareness level or state of consciousness, and the ease of breathing or air entry.
Each category is given a score as follows:
- Inspiratory stridor: 0 (None), 1 (When upset), 2 (At rest)
- Retractions: 0 (None), 1 (Mild), 2 (Moderate), 3 (Severe)
- Air entry: 0 (Normal), 1 (Decreased), 2 (Significantly decreased)
- Cyanosis: 0 (None), 4 (When crying), 5 (At Rest)
- Level of consciousness: 0 (Alert), 5 (Disoriented)
A Westley score of 2 points or less means the croup is considered mild, a score between 3 to 5 points indicates moderate croup, and a score between 6 to 11 points is considered to show severe croup. If the score is more than 12, there is a risk of respiratory failure.
Most children, over 85%, will present with a mild form of croup, while severe cases are quite rare, less than 1%.
Typically, a diagnosis of croup is based on the child’s signs and symptoms. Tests can be done to identify specific viruses, though they aren’t usually required. Other conditions that obstruct the airway, such as swelling of the windpipe’s flap (epiglottitis), a blocked airway from foreign objects, airway narrowing (subglottic stenosis), skin swelling (angioedema), abscess in the neck (retropharyngeal abscess), and bacterial infection of the windpipe (bacterial tracheitis), should also be evaluated and ruled out.
An X-ray of the front of the neck may be considered, but it’s not usually done. This test can show a characteristic narrowing of the windpipe in about 50% of cases, a condition called subglottic stenosis, which looks like a pointed tower or steeple.
Blood tests and viral culture are not commonly suggested as they may cause unnecessary distress to the child, leading to possible swelling and blockage of the airway. Viral cultures can confirm the cause but are typically used in research settings only.
If a patient isn’t getting better with standard treatments, a bacterial infection should be considered.
Treatment Options for Croup
Treatment for croup in children is determined using the Westley croup score. For those with mild croup, meaning a score under 2, a single dose of dexamethasone is given. If the croup is moderate to severe, which is a score over 3, the child gets dexamethasone and nebulized epinephrine. Any patients with low oxygen levels will be given additional oxygen. Severe cases need to be observed for up to 4 hours and hospital admission is necessary if there are no signs of improvement.
Steroids
Steroids such as dexamethasone can help reduce symptoms quickly, lower the chances of needing further medical attention, and reduce the length of a hospital stay. Dexamethasone works better than budesonide at improving symptoms, but there is no difference in rates of readmission to the hospital. Various doses of dexamethasone work the same, but 0.6 mg/kg is used the most.
Epinephrine
For moderate to severe croup, nebulized racemic epinephrine can be administered which can improve symptoms after about 30 minutes. However, the effects may wear off after about 2 hours, which is why continued observation is recommended for anyone who gets this treatment. If the symptoms haven’t gotten worse after 4 hours, the patient can usually go home with a follow-up appointment. L-epinephrine delivered via nebulizer seems to be more effective than racemic epinephrine at the 2-hour mark due to its longer lasting effects.
Oxygen
Oxygen should be given using a method known as “blow-by” administration because it’s less distressing for the child compared to using a mask or nasal cannula.
Intubation
A very small percentage of children, around 0.2%, may require a procedure called endotracheal intubation which provides support for breathing. Normally, a tube that’s a half-size smaller than usual is used to account for any narrowing of the airway due to swelling and inflammation.
Hot Steam & Cough Medicine
Hot steam or humidified air treatments haven’t been shown to have significant improvement on symptoms. Cough medicines, typically containing dextromethorphan or guaifenesin, are usually not recommended.
Heliox
Heliox is a treatment that mixes helium and oxygen, but there isn’t much evidence supporting its routine use in treating croup.
Antibiotics
Croup is typically caused by a virus, so antibiotics are usually kept as an option only when a primary or secondary bacterial infection is suspected. In cases of a secondary bacterial infection, the antibiotics vancomycin and cefotaxime are recommended. If the croup is severe and linked to influenza A or B, antiviral drugs known as neuraminidase inhibitors can be used.
What else can Croup be?
When a doctor is trying to identify the cause of a patient’s symptoms, they might consider a variety of possibilities such as bacterial infection of the windpipe, inflammation of the flap at the base of the tongue, choking on a foreign object, blood vessel tumors, abscess around the tonsils or at the back of the throat, cancer, or even the effects of inhaling smoke.
It’s really crucial to be able to differentiate between a condition called croup and a serious condition known as epiglottitis, as the latter can quickly worsen. A cough is a very typical sign of croup, while drooling is a common indicator of epiglottitis. Other signs that a child may have epiglottitis include a sudden difficulty in swallowing, a painful throat, high temperature, and a muffled voice.
Kids with an abscess around their tonsils may have a sore throat, fever, and a distinctive muffled, ‘hot potato’ kind of voice. Kids with an abscess at the back of their throat might also have fever, drooling, difficulty swallowing, and a painful throat, but they might also have neck pain and a noticeable bulge in the back of their throat which can be detected on a neck X-ray.