Differential Diagnosis
The patient presents with severe fatigue, abnormal cortisol levels, and elevated ferritin. Here's a differential diagnosis based on the provided information:
- Single most likely diagnosis
- Adrenal insufficiency: The baseline cortisol level is low (8.5), and the response to cosyntropin is inadequate (24.2), suggesting adrenal insufficiency. The fasting cortisol level is also low (4.4), which further supports this diagnosis. The patient's severe fatigue is consistent with adrenal insufficiency.
- Other Likely diagnoses
- Anemia of chronic disease: The patient has elevated ferritin (692) and a transferrin saturation (TSAT) of 42%, which may indicate anemia of chronic disease. This could contribute to the patient's fatigue.
- Hypothyroidism: Although not directly supported by the provided lab results, hypothyroidism can cause fatigue and may be associated with abnormal cortisol levels. Further testing (e.g., TSH, free T4) would be necessary to confirm this diagnosis.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Hemochromatosis: The patient's elevated ferritin and TSAT levels could indicate hemochromatosis, a genetic disorder that can lead to iron overload and organ damage. Although less likely, this diagnosis is critical to consider due to its potential severity.
- Pituitary apoplexy or other pituitary disorders: The patient's abnormal cortisol levels and response to cosyntropin could indicate a pituitary disorder, such as pituitary apoplexy. This is a medical emergency that requires prompt attention.
- Rare diagnoses
- Familial hemophagocytic lymphohistiocytosis (FHLH): This rare genetic disorder can cause elevated ferritin levels and may be associated with adrenal insufficiency. However, it is a rare condition and would require further testing to confirm.
- Congenital adrenal hyperplasia (CAH): Although less likely in an adult patient, CAH can cause abnormal cortisol levels and may be associated with fatigue. Further testing (e.g., 17-hydroxyprogesterone) would be necessary to confirm this diagnosis.