Bilateral phrenic nerve palsy is caused by –
**Core Concept**
Bilateral phrenic nerve palsy refers to the paralysis of both phrenic nerves, which are responsible for controlling the diaphragm, the primary muscle involved in breathing. This condition can lead to impaired diaphragmatic function and respiratory distress.
**Why the Correct Answer is Right**
The correct answer is **C. Boerhaave syndrome**. Boerhaave syndrome is a rare condition characterized by a spontaneous rupture of the esophagus, which can cause bilateral phrenic nerve palsy due to the spread of mediastinal inflammation and irritation of the phrenic nerves. This condition often presents with severe chest pain, dysphagia, and respiratory distress.
**Why Each Wrong Option is Incorrect**
* **Option A:** **Tetanus** is a bacterial infection caused by Clostridium tetani, which can lead to muscle rigidity and spasms, but it does not typically cause bilateral phrenic nerve palsy.
* **Option B:** **Pulmonary embolism** is a blockage of an artery in the lung, which can cause respiratory distress, but it is not directly associated with bilateral phrenic nerve palsy.
* **Option D:** **Amyotrophic lateral sclerosis (ALS)** is a progressive neurological disease that affects motor neurons, but it is not typically associated with bilateral phrenic nerve palsy.
**Clinical Pearl / High-Yield Fact**
Boerhaave syndrome is often referred to as a "tear in the esophagus" and can be a medical emergency, requiring prompt surgical intervention to prevent complications such as mediastinitis and sepsis.
**Correct Answer: C. Boerhaave syndrome**