A 65-year-old patient presents to the emergency department with sudden onset of flashes of light, a shadow over the visual field, and floaters in their right eye. What is the most likely diagnosis?

Choice A Reason:

Diabetes Insipidus (DI) is characterized by excessive urination and thirst due to a deficiency of antidiuretic hormone (ADH) or a renal insensitivity to ADH. Patients with DI typically present with hypernatremia (high serum sodium) and low urine osmolality, which contrasts with the findings of low serum sodium and high urine osmolality in this patient.

Choice B Reason:

Adrenal insufficiency can cause hyponatremia and hyperkalemia due to a deficiency in aldosterone and cortisol. However, it usually presents with low serum osmolality and low urine sodium, which does not align with the patient’s laboratory results of high urine osmolality and elevated urine sodium.

Choice C Reason:

Hyperaldosteronism leads to increased sodium reabsorption and potassium excretion, resulting in hypernatremia and hypokalemia. This condition does not match the patient’s findings of hyponatremia and high urine osmolality.

Choice D Reason:

Syndrome of inappropriate Antidiuretic Hormone (SIADH) is characterized by excessive release of ADH, leading to water retention, hyponatremia, and concentrated urine. The patient’s laboratory results of low serum sodium, low serum osmolality, high urine osmolality, and elevated urine sodium are consistent with SIADH. This condition causes the kidneys to reabsorb water, diluting the blood and concentrating the urine.

Choice A: Instruct the patient to elevate the arm above the heart immediately after the procedure

Elevating the arm above the heart can help reduce blood flow to the area, potentially minimizing bleeding. However, this method alone is not sufficient to ensure proper hemostasis, especially in patients with thrombocytopenia. Applying direct pressure to the puncture site is more effective in stopping bleeding and preventing hematoma formation.

Choice B: Apply firm pressure to the site for at least 10 minutes after the procedure

Applying firm pressure to the venipuncture site is crucial in patients with thrombocytopenia to ensure proper clotting and prevent bleeding. This method helps in forming a stable clot at the puncture site, reducing the risk of prolonged bleeding and hematoma formation. Given the patient’s low platelet count, maintaining pressure for an extended period is essential to achieve hemostasis.

Choice C: Avoid using a tourniquet during the procedure

While avoiding a tourniquet might seem beneficial to reduce pressure on the veins, it is not a standard practice to minimize bleeding risk in thrombocytopenic patients. Tourniquets are typically used to make veins more prominent for easier access during venipuncture. The key to minimizing bleeding is proper post-procedure care, such as applying firm pressure to the site.

Choice D: Use a larger gauge needle to ensure quicker blood flow

Using a larger gauge needle is not advisable for patients with thrombocytopenia. Larger needles can cause more trauma to the vein, increasing the risk of bleeding and hematoma formation. Instead, using the smallest gauge needle that can effectively draw blood is recommended to minimize vein damage.