RM, a 38-year-old woman who is attending graduate school and is very sedentary, comes to a community outpatient clinic. Her chief complaint is overwhelming fatigue that is not relieved by rest. She is so exhausted that she has difficulty walking to classes and trouble concentrating when studying. She reports a recent weight gain of 15 pounds (6.8 kg) over 2 months without clear changes in her dietary habits. Her face looks puffy, she has experienced excessive hair loss, and her skin is dry and pale. She says she has general body aches and pains with frequent muscle cramps and constipation. You note she is dressed inappropriately warmly for the weather. The physician orders lab work. The lab results are as follows:

WBC - WNL

HGB - WNL

Glucose - WNL

Amylase - WNL

Cholesterol - WNL

T4 (thyroxine) -↓

T3 (triiodothyronine) -↓

Thyroid-stimulating hormone (TSH) -↑

The physician diagnoses RM with an endocrine disorder. The assessment findings and lab work are consistent with which endocrine problem?

Choice A reason: This statement is incorrect because the combination of heparin and warfarin does not dissolve the blood clot faster. Instead, these medications have different mechanisms of action. Heparin works quickly to prevent further clot formation, while warfarin takes several days to reach therapeutic levels and maintain anticoagulation over the long term.
Choice B reason: While the risk of a blood clot in the lungs (pulmonary embolism) is a concern, the necessity of using both heparin and warfarin is not because of the need for multiple blood thinners but rather due to their complementary pharmacokinetics. Heparin provides immediate anticoagulation, whereas warfarin requires time to become effective.
Choice C reason: This statement is also incorrect. Heparin does not dissolve clots but works to prevent the extension of existing clots and the formation of new ones. Warfarin, likewise, does not dissolve clots but prevents further clot formation by inhibiting vitamin K-dependent clotting factors.
Choice D reason: This is the accurate response. Heparin works immediately, providing rapid anticoagulation, which is essential for acute management of venous thromboembolism. On the other hand, warfarin takes several days to achieve its anticoagulant effect because it works by inhibiting the synthesis of vitamin K-dependent clotting factors. Therefore, the patient is initially placed on heparin to provide immediate protection against clotting while warfarin is started simultaneously. Once warfarin reaches a therapeutic level, heparin can be discontinued, and warfarin can maintain long-term anticoagulation.

Choice A reason: Addison's Disease is characterized by insufficient production of adrenal hormones, leading to symptoms like weight loss, hyperpigmentation, low blood pressure, and severe fatigue. The lab findings would typically show low sodium, high potassium, and low cortisol levels. RM's lab results and symptoms are not consistent with Addison's Disease, making this an unlikely diagnosis.
Choice B reason: Cushing syndrome results from excess cortisol production, often causing weight gain, particularly around the abdomen and face, thinning skin, and hypertension. RM's symptoms of fatigue, dry skin, hair loss, and weight gain without dietary changes do not align with Cushing syndrome, and her lab results do not indicate elevated cortisol levels.
Choice C reason: Hyperthyroidism is characterized by excessive thyroid hormone production, leading to symptoms like weight loss, anxiety, palpitations, and heat intolerance. RM's symptoms of weight gain, fatigue, and cold intolerance, along with her lab results showing low T4 and T3 and elevated TSH, are not consistent with hyperthyroidism.
Choice D reason: Hypothyroidism occurs due to an underactive thyroid gland producing insufficient thyroid hormones. This leads to symptoms such as fatigue, weight gain, cold intolerance, dry skin, hair loss, and constipation. RM's lab results showing low T4 and T3 levels and elevated TSH align with the diagnosis of hypothyroidism. The body's response to low thyroid hormone levels is to increase TSH production in an attempt to stimulate the thyroid gland. The clinical presentation and lab findings point towards hypothyroidism as the correct diagnosis.