A staff nurse is teaching a client who has secondary hypothyroidism about the disease process. The client asks the nurse what causes secondary hypothyroidism. Which of the following responses should the nurse make?

A. Atorvastatin is a statin used to lower cholesterol levels in the blood. Reducing cholesterol levels helps to prevent the progression of atherosclerosis (plaque buildup in the arteries), which is a major cause of chronic stable angina. Statins are commonly prescribed to manage the underlying condition that leads to angina by stabilizing plaques and reducing the risk of heart attacks and strokes.
B. Digoxin is a medication used to treat heart failure and certain types of abnormal heart rhythms (arrhythmias). It works by increasing the force of heart contractions and controlling heart rate. While it can be helpful in specific cases of heart failure or arrhythmias, it is not typically used for the management of chronic stable angina.
C. Furosemide is a diuretic used to treat conditions such as heart failure and edema by removing excess fluid from the body. It helps to reduce fluid buildup but does not address the underlying cause of chronic stable angina or improve coronary artery function. It is not a primary medication for managing angina.
D. Rituximab is a monoclonal antibody used primarily to treat certain types of cancer and autoimmune diseases by targeting specific immune cells. It is not used to treat chronic stable angina or related cardiovascular conditions. It does not play a role in managing cholesterol levels or improving coronary artery health.

A. Elevated potassium levels (hyperkalemia) can occur in chronic kidney disease, as the kidneys struggle to excrete potassium. However, hyperkalemia does not typically cause visible crystals on the skin. It is more associated with cardiac arrhythmias and muscle weakness rather than skin manifestations.
B. Sodium imbalance is common in chronic kidney disease, often leading to fluid retention and hypertension. However, excess sodium does not result in crystal formation on the skin. Sodium issues are more related to fluid balance and blood pressure, not external crystalline deposits.
C. Urea is a waste product formed from the breakdown of proteins and is normally excreted by the kidneys. In chronic kidney disease, urea accumulates in the blood (uremia) because the kidneys cannot effectively filter it out. Urea can be deposited on the skin and form crystals, leading to a condition known as "uremic frost." This is often observed on the forehead or other areas of the skin and is a direct result of excess urea in the body.

D. Creatinine is another waste product filtered by the kidneys. Elevated levels indicate impaired kidney function, but creatinine itself does not form visible crystals on the skin. Elevated creatinine levels are primarily used as an indicator of kidney function rather than a cause of external skin manifestations.