**Question:** Distending media used in hysteroscopy are all except

A. Normal saline (sodium chloride solution)
B. Lactated Ringer's solution
C. Diluted potassium chloride solution
D. Diluted hydrochloric acid (HCl) solution

**Core Concept:**
Hysteroscopy is a diagnostic and therapeutic procedure that allows visualization and examination of the uterine cavity. Distending media are used to increase the intrauterine pressure, expand the cavity, and facilitate visualization. These solutions are isotonic (same osmolarity as plasma) to avoid tissue damage. They are also non-irritant and non-inflammatory to prevent complications.

**Why the Correct Answer is Right:**
Hysteroscopy distending media should be physiologic and non-irritant to minimize complications during the procedure. Distending media should also be isotonic to avoid tissue damage. Among the given options, diluted potassium chloride solution (C) is not suitable because potassium ions can cause tissue damage due to its high osmolarity and ionic strength. Diluted hydrochloric acid (D) is also incorrect as it is irritant and can cause inflammation, ulceration, and perforation of the uterine wall.

**Why Each Wrong Option is Incorrect:**

A. Normal saline (sodium chloride solution) is a suitable distending medium due to its isotonicity, non-irritant nature, and the presence of sodium ions that can help visualize the endometrial surface.

B. Lactated Ringer's solution is another suitable distending medium for hysteroscopy due to its isotonicity, non-irritant nature, and the presence of lactate ions.

Diluted potassium chloride solution (C) is unsuitable as mentioned above for its high osmolarity and ionic strength.

Diluted hydrochloric acid (D) is also unsuitable due to its irritant nature and potential to cause inflammation, ulceration, and perforation of the uterine wall.

**Clinical Pearl:**
Using appropriate distending media in hysteroscopy helps to ensure patient safety and optimal visualization of the endometrial surface. Sodium chloride solution and lactated Ringer's solution are commonly used options for distending media as they are isotonic, non-irritant, and contain essential ions for visualization. Avoiding potassium chloride and hydrochloric acid solutions is crucial to prevent complications and ensure safe and effective hysteroscopy.