This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid, Subject name: Medicine
Non pitting edema is seen in? 
Select and explain. 
A. Congestive cardiac failure, B. Myxedema, C. Liver failure, D. Renal failure
B: Myxedema
Answer: B: Myxedema 
Explanation: ANSWER: (B) MyxedemaREF: Harrison's 18th ed chapter 36"The edema is non pitting in myxedema because of deposition of hyaluronic acid"Causes of non pitting pedal edema:MyxedemaHyperthyroidism (pretibial myxedema secondary to Graves' disease),FilarisasisLymphedemaLipoedema