The main diagnostic sign of cardiac arrest is

Correct Answer: C

Rationale: Absence of a central pulse (carotid or femoral) confirms cardiac arrest. Peripheral pulses may be weak in shock, but loss of a central pulse requires immediate resuscitation efforts.

Correct Answer: A

Rationale: Intense pruritus is the hallmark of atopic dermatitis, often leading to scratching, lichenification, and secondary skin infections.

Correct Answer: D

Rationale: Calcium gluconate stabilizes cardiac membranes, preventing life-threatening arrhythmias without affecting serum potassium levels.

Correct Answer: A

Rationale: Edema is an early finding in systemic sclerosis.

Correct Answer: A

Rationale: Epinephrine is the first-line treatment for anaphylaxis, which is the most likely diagnosis given the symptoms.