Experience The Root & Route™ Method

Interactive Demo: Hover over the highlighted phrases to discover the logical thread. Follow the Root & Route to find the diagnosis.
A 35-year-old African American woman presents for a routine check-up. She reports a persistent dry cough and mild shortness of breath for the past three months. She denies fever, chills, or weight loss. She works as a history professor. A chest x-ray is performed, which reveals bilateral hilar lymphadenopathy. A subsequent lab workup is notable for a serum calcium level of 11.2 mg/dL.
🌱 ROOT
This is our anchor. For a young African American woman with vague pulmonary symptoms, granulomatous diseases like sarcoidosis should always be on our chronic differential.
🌱 ROOT
This is the foundational symptom. A non-productive cough points us towards an interstitial or inflammatory process, rather than a typical bacterial infection.
🗺️ ROUTE
This is a major pathway sign. This classic X-ray finding dramatically narrows our differential. It's the hallmark of sarcoidosis and makes other possibilities far less likely.
🗺️ ROUTE
This is our final confirmation. Hypercalcemia is a key feature of sarcoidosis, caused by unregulated Vitamin D production by the granulomas themselves. This clue locks in our diagnosis.

What enzyme is responsible for the laboratory abnormality in this patient?

(A) 21-hydroxylase
(B) 11β-hydroxylase
(C) 1α-hydroxylase
(D) 25-hydroxylase
🧵 Correct! You found the thread.
The Thread Statement: In this young African American woman with chronic dry cough, the thread flows from demographic risk → pulmonary symptoms → bilateral hilar lymphadenopathy → hypercalcemia → sarcoidosis diagnosis, with 1α-hydroxylase being the enzyme responsible for unregulated vitamin D production.

Key Takeaway: The hypercalcemia in sarcoidosis is caused by macrophage-mediated production of 1α-hydroxylase, creating a classic biochemical signature.

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