In myxedema the significant ECG changes are:

Correct Answer: B

Rationale: Myxedema causes low voltage and flattened T-waves due to pericardial effusion and reduced cardiac activity.

Correct Answer: A

Rationale: Fanconi syndrome causes phosphaturia, lowering serum phosphorus.

Correct Answer: C

Rationale: Asthma is associated with eosinophilia from allergic inflammation.

Correct Answer: A

Rationale: Exophthalmos treatment (e.g., in Graves') uses steroids or surgery, not thyroid hormone, which worsens it.

Correct Answer: D

Rationale: All listed mechanisms "renal underexcretion, overproduction (PRPP), and HGPRT deficiency (Lesch-Nyhan) "cause hyperuricemia.