Acute subglottic laryngitis (ASL) is an inflammatory condition of the larynx, which causes narrowing of the latter. It predominantly occurs in children and presents with difficulty in breathing, voice changes, and a barking cough.
Presentation
Acute subglottic laryngitis (ASL), sometimes called pseudo-croup, is an infection that is usually seen in children and has a higher prevalence in boys. Most cases are reported at around one and a half years of age. In some literature, infection is only considered to be ASL if the causative organism is a virus [1]. ASL can, however, be bacterial or fungal. Furthermore, other sources of literature distinguish pseudo-croup from croup based on the causative organism, with croup being caused by the Corynebacterium diphtheriae.
The most frequently implicated virus is the parainfluenza virus. Initial viral infection can be followed by bacterial superinfection [2] [3]. The rate of occurrence of ASL may be higher in certain seasons, namely autumn and winter [1]. There are several modes of infection, for example, through airborne organisms, blood or trauma [4]. Some cases of ASL are preceded by other respiratory tract infections. Precipitating factors of ASL include infections, both local and systemic, hypersensitivity reactions, air pollution, cigarette smoke, and foreign bodies.
Symptoms are mainly due to the primary characteristic of ASL, which is narrowing of the trachea in the subglottic region due to inflammation resulting in edema. The extent to which the trachea narrows determines the severity of symptoms. Narrowing of the trachea is made more likely if there is a history of asthma, gastroesophageal reflux disease (GERD), trauma, or preexisting scarring or stenosis [2]. The onset of ASL is rapid and often occurs at night. It is also acute and self-limiting; thus treatment given is supportive.
Respiratory manifestations of the condition include dyspnea, cough, stridor, and hoarseness. Constitutional symptoms may be present, such as fever, cervical lymphadenopathy, loss of appetite, weakness, and restlessness. Cyanosis may also occur due to lack of oxygen. In a few cases, the condition may be life-threatening.
Workup
The diagnosis of acute subglottic laryngitis is made via a clinical examination, taking into account both history and physical examination. Laboratory studies are not routinely carried out. If there is pus, this can be cultured, and sensitivity determined before antibiotics are administered [5]. Nose and throat swabs may also be taken. A complete blood count (CBC) may be requested if the infection is thought to be bacterial in origin. Other possible laboratory tests are PCR (polymerase chain reaction), lateral flow tests, and immunoprecipitation.
Imaging modalities include laryngoscopy, although this is not mandatory. Laryngoscopy allows visualization of the inflamed airways and may reveal distortion in the symmetry and movement of the same [6]. Laryngoscopy is often done by a specialist. General practitioners may use indirect laryngoscopy. An additional imaging method is videostroboscopy [7]. This is used when presenting symptoms and laryngoscopic results are mismatched [8].
Treatment
The treatment of Acute Subglottic Laryngitis focuses on relieving symptoms and ensuring adequate oxygenation. Key management strategies include:
- Humidified air: Breathing in moist air can help soothe the inflamed airways.
- Corticosteroids: Medications like dexamethasone can reduce airway swelling and improve symptoms.
- Nebulized epinephrine: In severe cases, this can provide rapid relief of airway obstruction.
- Oxygen therapy: Administered if the child is experiencing significant respiratory distress.
Hospitalization may be necessary for severe cases or if there is a risk of airway obstruction.
Prognosis
The prognosis for Acute Subglottic Laryngitis is generally excellent, with most children recovering fully within a few days. The condition is self-limiting, and complications are rare. However, recurrent episodes can occur, especially in children with a history of croup.
Etiology
Acute Subglottic Laryngitis is most commonly caused by viral infections, with the parainfluenza virus being the most frequent culprit. Other viruses that can cause croup include respiratory syncytial virus (RSV), adenovirus, and influenza. The infection leads to inflammation and swelling of the subglottic region, resulting in the characteristic symptoms.
Epidemiology
Croup is a common condition, particularly affecting children between the ages of 6 months and 3 years. It is more prevalent in boys than girls and tends to occur more frequently during the fall and winter months. While it can affect older children and adults, it is less common and usually presents with milder symptoms in these age groups.
Pathophysiology
The pathophysiology of Acute Subglottic Laryngitis involves viral infection of the upper respiratory tract, leading to inflammation and edema (swelling) of the subglottic region of the larynx. This swelling narrows the airway, causing the characteristic symptoms of croup. The subglottic region is particularly susceptible to swelling due to its small diameter, especially in young children.
Prevention
Preventive measures for Acute Subglottic Laryngitis focus on reducing the risk of viral infections. These include:
- Good hygiene practices: Regular handwashing and avoiding close contact with individuals who have respiratory infections.
- Vaccination: Ensuring children are up-to-date with vaccinations, including the influenza vaccine, can help prevent some of the viral infections that cause croup.
Summary
Acute Subglottic Laryngitis, or croup, is a common respiratory condition in young children characterized by a barking cough, hoarseness, and stridor. It is usually caused by viral infections and is self-limiting, with most children recovering fully within a few days. Diagnosis is primarily clinical, and treatment focuses on symptom relief and ensuring adequate oxygenation. Preventive measures include good hygiene practices and vaccination.
Patient Information
For parents and caregivers, it is important to recognize the symptoms of croup, such as a barking cough and stridor, and to seek medical attention if the child is experiencing difficulty breathing. Most cases can be managed at home with humidified air and medications prescribed by a healthcare provider. In severe cases, hospitalization may be necessary. With appropriate care, children with croup typically recover quickly and without complications.
References
- Pucher B, Jonczyk-Potoczna K, Buraczynska-Andrzejewska B, et al. Environmental pollution and parental smoking influence on the appearance of pseudocroup in children. Ann Agric Environ Med. 2013;20(3):580-582.
- Cherry JD. Croup. N Engl J Med. 2008;358(4):384–391.
- Rosekrans JA. Viral croup: current diagnosis and treatment. Mayo Clin Proc. 1998;73(11):1102–1107.
- Wood JM, Athanasiadis T, Allen J. Laryngitis. BMJ. 2014;349:g5827.
- Vaughan CW. Current concepts in otolaryngology: diagnosis and treatment of organic voice disorders. N Engl J Med. 1982;307(14):863-866.
- Ng ML, Gilbert HR, Lerman JW. Some aerodynamic and acoustic characteristics of acute laryngitis. J Voice. 1997;11(3):356-363.
- Shohet JA, Courey MS, Scott MA, Ossoff RH. Value of videostroboscopic parameters in differentiating true vocal fold cysts from polyps. Laryngoscope. 1996;106(1 Pt 1):19-26.
- Schwartz SR, Cohen SM, Dailey SH, et al. Clinical practice guideline: hoarseness (dysphonia). Otolaryngol Head Neck Surg. 2009;141(3 suppl 2):S1-S31.