Bilateral (B/I) recurrent laryngeal nerve palsy is/ are caused by -a) Thyroid surgeryb) Thyroid malignancyc) Aneurysm of arch of aortad) Viral infectione) Mitral valve surgery
**Core Concept**
Bilateral recurrent laryngeal nerve palsy is a condition characterized by the paralysis of both recurrent laryngeal nerves, leading to impaired vocal cord mobility and function. This condition often results from compression or damage to the nerves during surgical procedures or due to anatomical abnormalities.
**Why the Correct Answer is Right**
Bilateral recurrent laryngeal nerve palsy is commonly caused by thyroid surgery, particularly total thyroidectomy, where the nerves are at risk of injury during the procedure. The recurrent laryngeal nerves are closely associated with the thyroid gland and are often damaged during dissection or removal of the gland. This can lead to bilateral vocal cord paralysis, resulting in respiratory and speaking difficulties.
**Why Each Wrong Option is Incorrect**
**Option A:** Thyroid malignancy can cause vocal cord paralysis, but it is less likely to result in bilateral recurrent laryngeal nerve palsy compared to thyroid surgery.
**Option B:** Thyroid malignancy can cause vocal cord paralysis, but it is less likely to result in bilateral recurrent laryngeal nerve palsy compared to thyroid surgery.
**Option C:** Aneurysm of the arch of the aorta can cause vocal cord paralysis due to compression of the left recurrent laryngeal nerve, but it is less likely to result in bilateral recurrent laryngeal nerve palsy.
**Option D:** Viral infection is a common cause of unilateral vocal cord paralysis, but it is less likely to result in bilateral recurrent laryngeal nerve palsy.
**Option E:** Mitral valve surgery is not typically associated with bilateral recurrent laryngeal nerve palsy.
**Clinical Pearl / High-Yield Fact**
Recurrent laryngeal nerve palsy can be caused by a variety of factors, including thyroid surgery, malignancies, and anatomical abnormalities. It is essential to identify the underlying cause to provide appropriate treatment and management.
**Correct Answer:** A. Thyroid surgery.