**Question:** Most common complication of myelography is

A. Subarachnoid hemorrhage
B. Infection
C. Cerebrospinal fluid leak
D. Allergic reaction

**Correct Answer:** D. Allergic reaction

**Core Concept:** Myelography is a diagnostic radiological procedure that involves injecting a contrast material into the subarachnoid space to visualize the spinal cord and spinal nerves.

**Why the Correct Answer is Right:** The most common complication of myelography is an allergic reaction to the contrast medium or local anesthesia used during the procedure. Allergic reactions can manifest as immediate reactions (anaphylaxis) or delayed reactions. Immediate reactions are life-threatening and can lead to severe symptoms like hypotension, respiratory distress, and cardiac arrhythmias. Delayed reactions, while less severe, can cause skin rashes, fever, and gastrointestinal symptoms.

**Why Each Wrong Option is Incorrect:**

A. Subarachnoid hemorrhage is a rare and severe complication of myelography, typically caused by iatrogenic injury from needle placement or contrast extravasation into the subarachnoid space.

B. Infection is not the most common complication. Although infection is a risk, it is less common than allergic reactions, subarachnoid hemorrhage, or neurological complications like radiculitis or myelitis.

C. Cerebrospinal fluid (CSF) leak is uncommon but can occur due to damage to the dura mater during needle placement or contrast extravasation.

D. Allergic reactions are the most common complication of myelography. Allergic reactions can be immediate or delayed and are a significant concern due to their potential severity.

**Clinical Pearl:** Myelography is a valuable diagnostic tool for evaluating spinal disorders, but it carries risks. Healthcare professionals should be vigilant for complications and have appropriate treatment strategies at hand to manage them effectively.

**Explanation of the Question:** The question is asking which complication is the most common in myelography out of the given options.

**Core Concept:** Myelography is a diagnostic radiological procedure involving the injection of contrast medium into the subarachnoid space to visualize the spinal cord and spinal nerves.

**Why the Correct Answer is Right:** Allergic reactions are the most common complication of myelography due to the presence of foreign substances in the contrast medium and local anesthetic agents used during the procedure. These reactions can occur immediately or delayed (hypersensitivity). Immediate reactions can lead to severe symptoms like hypotension, respiratory distress, and cardiac arrhythmias, which can be life-threatening. Delayed reactions manifest as skin rashes, fever, and meningitis.

**Why Each Wrong Option is Incorrect:**

A. Subarachnoid hemorrhage is an uncommon complication of myelography, usually caused by iatrogenic injury to the dura mater during the needle placement or contrast extravasation.

B. Infection is less common than allergic reactions but can still occur due to the introduction of pathogens into the subarachnoid space.

C. Cerebrospinal fluid (