Hyaline membrane is seen in: September 2011
## Core Concept
The hyaline membrane is a layer of fibrin and cellular debris that forms in certain pathological conditions. It is most commonly associated with **acute respiratory distress syndrome (ARDS)** and **diffuse alveolar damage**. The formation of the hyaline membrane is a hallmark of this type of lung injury.
## Why the Correct Answer is Right
The hyaline membrane is characteristic of **hyaline membrane disease**, also known as **neonatal respiratory distress syndrome (NRDS)**, which primarily affects premature infants. This condition arises due to a deficiency of **surfactant**, a substance that reduces surface tension within the lungs, allowing them to expand more easily during breathing. In NRDS, the lack of surfactant leads to increased surface tension, causing the alveoli to collapse and resulting in the formation of the hyaline membrane. This membrane lines the alveoli and prevents gas exchange, leading to respiratory distress.
## Why Each Wrong Option is Incorrect
- **Option A:** While certain types of **pneumonia** can cause severe lung injury, the hyaline membrane is not a defining characteristic of this condition.
- **Option B:** **Chronic bronchitis** is a form of chronic obstructive pulmonary disease (COPD) characterized by inflammation and irritation of the bronchial tubes, not typically associated with hyaline membrane formation.
- **Option D:** **Asthma** is a chronic inflammatory disease of the airways that causes recurring episodes of wheezing, breathlessness, chest tightness, and coughing. It does not typically involve the formation of a hyaline membrane.
## Clinical Pearl / High-Yield Fact
A key clinical pearl is that the hyaline membrane is a diagnostic feature of **neonatal respiratory distress syndrome (NRDS)**, and its presence can be confirmed by histopathological examination of lung tissue. Surfactant replacement therapy is a mainstay of treatment for NRDS, aimed at reducing surface tension and preventing further lung injury.
## Correct Answer Line
**Correct Answer: C. Hyaline membrane disease (Neonatal Respiratory Distress Syndrome).**