--- title: "Croup - Etiology, Pathology, Clinical Features, Investigations & Treatment" description: "ENT notes on Croup - etiology, pathology, clinical features, complications, management." source: "The ENT Resident" author: "Dr. Mausumi Das" canonical_url: "https://www.theentresident.com/ent-notes-lectures/croup-causes-symptoms-treatment-steeple-sign" categories: ["Larynx and Trachea"] video: "https://www.youtube.com/watch?v=Q-rEuZx2nbY" image: "https://media.theentresident.com/og-images/croup-causes-symptoms-treatment-steeple-sign.png" --- # Croup - Etiology, Pathology, Clinical Features, Investigations & Treatment ENT notes on Croup - etiology, pathology, clinical features, complications, management. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=Q-rEuZx2nbY ## 🗣️ Croup (Acute Laryngotracheobronchitis) Croup is an **acute inflammatory condition involving the larynx, trachea and bronchi**. #### 📌 Also Known As 👉 Acute Laryngotracheobronchitis ⭐ **Viral croup is the most common cause of airway obstruction in children.** (Important MCQ) Croup is **more common** than acute epiglottitis. Croup may be **viral** or **bacterial**. > What is pseudomembranous croup? --- ### Age Group Affected * Common age group: **6 months to 3 years** * Peak incidence: **2 years** * Annual incidence: **1.5 to 6%**. * More common in **winter**. > What is the sex prevalence of Croup? > What are the [differences between Croup and Acute Epiglottitis](https://www.theentresident.com/ent-notes-lectures/croup-vs-acute-epiglottitis-differences.md)? --- ### Etiology of Croup #### Viruses * Parainfluenza virus type 1 * Parainfluenza virus type 2 * Respiratory syncytial virus types A and B * Rhinovirus * Metapneumovirus * Coronavirus * Bocavirus > Which is the most common organism involved in causing Croup? #### Secondary Bacterial Infection * Streptococcus pyogenes * Staphylococcus * Hemolytic streptococci * Haemophilus influenzae --- ### Pathogenesis of Croup Viral infection → **Submucosal edema** of the larynx, trachea and bronchi → Two levels of obstruction: | Level of Obstruction | Mechanism | Resulting Feature | | --- | --- | --- | | **Subglottis** | Mechanical obstruction | **Inspiratory stridor** | | **Tracheobronchial tree** | Mechanical and secretional obstruction | **Prolonged inspiratory phase with wheeze** | → **Hypoxia** and restlessness → **Cyanosis, hypercapnia and acidosis** → Stuporous, quiet, glazed facial expression → Reduced air entry into the chest and reduced cough reflex → **Respiratory failure** > What are the Pathological Changes seen in Croup? > Why is the Subglottic Area crucial in Croup? > What are the [differences between the adult and pediatric larynx](https://www.theentresident.com/ent-notes-lectures/adult-vs-pediatric-larynx.md)? --- ### Clinical Features of Croup #### Symptoms of Croup ⭐ Symptoms occur because of **mucosal edema of the larynx and trachea** following the viral illness. * Preceding History of Upper respiratory tract infection * **Hoarseness of voice** * **Brassy, barking croupy cough** * Difficulty in breathing * Throat pain > What is the term used to describe the cough seen in Croup patients? > Which symptom helps in differentiating a case of Acute Epiglottitis from a case of Croup? > What are the factors which predispose to severe symptoms in Croup? --- #### Signs of Croup * Child is **restless and anxious** * ❌ Child is usually **not toxic** * May or may not be febrile * **Inspiratory or biphasic stridor** > What are the signs of Respiratory Failure in severe cases of Croup? > What are the Complications of Croup? --- ### ⭐ Westley Croup Score A scoring system based on **five clinical features** of croup. 👉 The total score correlates with the **diameter of the tracheal lumen**. ⭐ Maximum score: **17** | Clinical Feature | Finding | Score | | --- | --- | --- | | **Inspiratory stridor** | None | 0 | | | Audible with a stethoscope | 1 | | | Audible without a stethoscope | 2 | | **Retraction** | None | 0 | | | Mild | 1 | | | Moderate | 2 | | | Severe | 3 | | **Air entry** | Normal | 0 | | | Decreased | 1 | | | Severely decreased | 2 | | **Cyanosis** | None | 0 | | | With agitation | 4 | | | At rest | 5 | | **Level of consciousness** | Normal | 0 | | | Altered | 5 | > How will you classify the severity of Croup based on Westley Croup Score? --- ### Investigations of Croup ⭐ Croup is primarily a **clinical diagnosis**, made from the history and clinical features. Investigations are needed only in severe cases or when there is a diagnostic dilemma. **1- X-ray Thoracic Inlet / Neck (Anteroposterior View)** 👉 **Steeple Sign**, also known as the **Pencil Tip Sign** Narrowing of the **subglottis** produces an appearance resembling a **pencil tip** or the **steeple of a church**. > What are the [signs seen in Croup and Acute Epiglottitis](https://www.theentresident.com/ent-notes-lectures/steeple-croup-thumb-tripod-sign-epiglottitis.md)? **2- Flexible Fibreoptic Laryngoscopy** ⚠️ Performed only in the **operation theatre**, ready for intubation if necessary. > What are the findings seen in Flexible Fibreoptic Laryngoscopy in Croup? **3- X-ray Chest** To rule out: * Basal collapse * Mediastinal shift * Emphysema * Foreign body * Pulmonary edema **4- HRCT Neck and Mediastinum** > When is HRCT Neck and Mediastinum indicated in croup? --- ### Treatment of Croup ⭐ Croup is a **self-limiting disease**. * About **50%** of children improve within **24 hours** of onset of symptoms * Most recover within **4 days**, even without treatment * Rarely, airway symptoms become serious and life-threatening 👉 Mild cases need only **supportive treatment**, with reassurance of the child and caregiver, and monitoring of symptoms. **1- Hospitalization** The patient is kept under observation for worsening symptoms and impending airway obstruction. **2- Oxygen** Given at a flow rate of **3 to 5 litres per minute**. **3- Humidification of Inspired Air** 👉 Softens the thick tenacious secretions and crusts obstructing the airway. **4- IV Fluids** To combat dehydration. **5- Corticosteroids (Mainstay of Treatment)** > What is the Mechanism of Action of corticosteroids in treatment of Croup? > Which corticosteroids are used to treat Croup, and what are their doses? ⭐ Clinical benefit is assessed by improvement in the **Westley Croup Score**. **6- Nebulized Epinephrine** * Provides only **short symptomatic relief**, with no lasting effect beyond about **2 hours** * Does **not alter the natural course** of the disease * Only postpones or eliminates the need for an artificial airway such as intubation or tracheostomy * Usually given **at the same time as glucocorticoids** > What is the dosage of Nebulized Epinephrine in treatment of Croup? > What is the Mechanism of Action of Nebulized Epinephrine in treatment of Croup? **7- Heliox** > What is Heliox? > What is the Mechanism of Action of Heliox in treatment of Croup? **⚠️ Disadvantage** High **thermal conductivity**, so **humidification** must be used to avoid hypothermia. **8- Broad Spectrum Antibiotics** Given if there is a **secondary bacterial infection**. **9- Intubation and Tracheostomy** Required only in rare cases of **airway obstruction**. > What are the Indications for Intubation in Croup? > What are the Criteria for Extubation in Croup? **Tracheostomy** ⭐ A last-ditch measure, preferred only when intubation is expected to be needed for **longer than 72 hours**. > What is the Differential Diagnosis of Croup? --- ## 🦠 Bacterial Laryngotracheobronchitis A **severe form of laryngotracheobronchitis**, characterized by **profuse mucopurulent secretions with sloughing of the respiratory epithelium**. ⭐ Rare but **potentially life threatening** cause of upper airway obstruction in children. > What are the other names of Bacterial Laryngotracheobronchitis? ### Etiology of Bacterial Laryngotracheobronchitis * Staphylococcus aureus * Haemophilus influenzae * Moraxella catarrhalis * Pneumococcus * Pseudomonas aeruginosa > What are the Clinical Features of Bacterial Laryngotracheobronchitis? How is it different from Viral Laryngotracheobronchitis? ### Diagnosis of Bacterial Laryngotracheobronchitis ⭐ Requires a **high index of suspicion** for early diagnosis. > What are the findings seen on endoscopy of the larynx in a case of Bacterial Laryngotracheobronchitis? ⭐ It is often necessary to secure the airway by **intubation** for a couple of days. ### Treatment of Bacterial Laryngotracheobronchitis * **IV broad spectrum antibiotics** (mainstay) * Repeated **therapeutic tracheobronchoscopy** to clear secretions > What are the Complications of Bacterial Laryngotracheobronchitis? --- ### 🧠 Viva Pearls * Croup is also known as acute laryngotracheobronchitis. * Viral croup is the most common cause of airway obstruction in children. * Common age group is 6 months to 3 years, with a peak at 2 years. * The child in croup is not toxic, unlike in acute epiglottitis. * Stridor in croup is inspiratory or biphasic. * Westley Croup Score uses five clinical features, with a maximum score of 17. * Steeple sign or pencil tip sign is seen on an AP X-ray of the neck. * Croup is a self-limiting disease, with most children recovering within 4 days. * Corticosteroids are the mainstay of treatment. * Intramuscular dexamethasone is avoided due to the risk of muscle necrosis. * Nebulized epinephrine gives only short symptomatic relief and does not alter the course of the disease. * Tracheostomy is preferred only when intubation is expected for longer than 72 hours. * Pseudomembranous croup is the bacterial form, affecting older children aged 4 to 8 years. * Pseudomembranous croup fails to respond to steroids and nebulized epinephrine. --- ## About This Note This free ENT note on Croup - Etiology, Pathology, Clinical Features, Investigations & Treatment was written by Dr. Mausumi Das and is paired with a corresponding video lecture. 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