Differential Diagnosis for Cushing Syndrome vs Simple Obesity

The question requires a sign that differentiates Cushing syndrome from simple obesity. Let's analyze the options given and categorize them based on their likelihood and clinical significance.

• Single most likely diagnosis:

  • A. Pink striae: This is the most specific sign among the options provided that differentiates Cushing syndrome from simple obesity. Pink striae, particularly when widespread and found on areas such as the abdomen, thighs, and buttocks, are a hallmark of Cushing syndrome due to the skin's inability to withstand the tension caused by rapid weight gain and the catabolic effects of excess cortisol.

• Other Likely diagnoses:

  • B. Proximal myopathy: While this can be a feature of Cushing syndrome due to muscle protein catabolism caused by excess cortisol, it is not as specific or as easily identifiable as pink striae in differentiating Cushing syndrome from simple obesity.
  • D. Hypertension: Hypertension is common in both Cushing syndrome and simple obesity, making it less useful as a differentiating sign.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):

  • None of the options directly fit into this category as they are all related to the differential diagnosis between Cushing syndrome and simple obesity. However, it's crucial to consider other life-threatening conditions that could mimic or coexist with these conditions, such as pheochromocytoma or primary aldosteronism, which can also present with hypertension.

• Rare diagnoses:

  • C. Central obesity: While central obesity is a common feature of Cushing syndrome, it is also very common in simple obesity, making it not useful for differentiation. Other rare conditions that could lead to similar presentations might include familial Cushing syndrome or other rare genetic disorders affecting cortisol metabolism or action, but these would not be directly suggested by the options provided.