Severe form of hypothyroidism, where accumulation of a mucus-like substance under skin and other tissues causes swelling, in addition to life threatening symptoms.

• A. Thyrotoxicosis.
• B. Hypothyroidism.
• C. Myxedema.
• D. Thyroiditis.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the key terms in the problem. The question describes a severe form of hypothyroidism characterized by the accumulation of a mucus-like substance under the skin and other tissues, causing swelling and life-threatening symptoms.
2. Step 2: Review the definitions of the options provided: Thyrotoxicosis refers to excess thyroid hormone in the body; Hypothyroidism is a condition of low thyroid hormone levels; Thyroiditis is inflammation of the thyroid gland; Myxedema is a severe form of hypothyroidism with characteristic swelling due to mucopolysaccharide deposits.
3. Step 3: Identify the condition that matches the description of severe hypothyroidism with mucus-like substance accumulation and swelling. This points to Myxedema, which is known for these symptoms.
4. Step 4: Differentiate Myxedema from other options by noting that Thyrotoxicosis involves excess hormone (opposite of hypothyroidism), Hypothyroidism is a general term without specifying severity or symptoms, and Thyroiditis is inflammation rather than mucus accumulation.
5. Step 5: Conclude that the correct term for the described condition is Myxedema, based on the clinical features and terminology.