This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diseases of Thyroid, Subject name: Medicine
The most common symptom of thyrotoxicosis is? 
Select and explain. 
A. Palpitation, B. Fatigue and weakness, C. Diarrhea, D. Hyperactivity and irritability
D: Hyperactivity and irritability
Answer: D: Hyperactivity and irritability 
Explanation: Clinical feature of thyrotoxicosis: Hyperactivity, Irritability and dysphoria ( m/c symptom) Heat intolerance Dairrhea Weight loss Tachycardia ( persists during sleep ) Hypeension Fine resting tremor Proptosis Warm sweaty skin Irregular menses Osteoporosis Proximal myopathy