**Question:** In Conn's syndrome, the following are true: a) Diastolic HTN without oedema, b) Systolic HTN without oedema, c) Pseudotetany, d) Hyper Na+ and e) Hyper K+

**Core Concept:** Conn's syndrome, also known as primary aldosteronism, is a hormonal disorder characterized by excessive production of aldosterone by the adrenal cortex. Aldosterone is a mineralocorticoid hormone that plays a crucial role in maintaining electrolyte balance and fluid homeostasis in the body.

**Why the Correct Answer is Right:** In Conn's syndrome, aldosterone overproduction leads to the following characteristics:

a) Diastolic hypertension (HTN) without oedema: Conn's syndrome primarily affects the arterial smooth muscle, causing vasoconstriction, which results in a decrease in peripheral vascular resistance and subsequently leads to diastolic hypertension.
b) Systolic hypertension without oedema: As diastolic hypertension prevails, systolic blood pressure remains relatively normal or elevated due to the increased peripheral vascular resistance.
c) Pseudotetany: Aldosterone's role in increasing calcium absorption in the intestines and promoting calcium reabsorption in the kidneys contributes to the development of pseudotetany, a condition with clinical symptoms resembling tetany but caused by other factors.
d) Hypernatremia (Hyper Na+): Aldosterone promotes sodium reabsorption in the distal renal tubules, leading to an increase in blood sodium levels (hypernatremia).
e) Hyperkalemia (Hyper K+): Aldosterone reduces potassium excretion in the distal renal tubules, resulting in elevated serum potassium levels (hyperkalemia).

**Why Each Wrong Option is Incorrect:**

a) Systolic HTN without oedema: Although Conn's syndrome may lead to systolic hypertension, the primary focus is on diastolic hypertension due to vasoconstriction, causing blood pressure to remain relatively normal or elevated.
b) Oedema: Oedema is not a common feature of Conn's syndrome, as the primary effect is on blood pressure regulation rather than fluid balance.
c) Tetany: Pseudotetany is a tetanic muscle spasm-like condition seen in Conn's syndrome, resembling tetany but caused by different factors.
d) Hyponatremia (Hypo Na+): Hypernatremia (Hyper Na+) is the characteristic feature of Conn's syndrome due to increased sodium reabsorption in the distal renal tubules.
e) Hypokalaemia (Hypo K+): Hyperkalemia (Hyper K+) is the main feature of Conn's syndrome caused by reduced potassium excretion in the distal renal tubules.

**Clinical Pearl:**

Conn's syndrome is an essential aspect to understand for medical students, residents, and practicing physicians, as it represents a crucial aspect of renal physiology and pathophysiology, particularly for endocrinologists, nephrologists, and primary care physicians. It is essential for diagnosing, treating, and managing patients with hypertension and electrolyte imbalances.