Source / episode info

• **Episode:**607
• **Title:**DIP Ep 607: USMLE Step 2/3 Rapid Review Series 124
• **Published:**2025-06-02
• Source:Episode page

One-liner

Episode 607 provides a rapid review emphasizing AKI workup (pre-renal vs. intrinsic), CKD management including mineral bone disorder and anemia, common nephrotic syndromes (FSGS), and complex coagulation disorders like Factor V Leiden and hemophilia.

High-yield summary

• AKI Workup: Intrinsic AKI is often caused by nephrotoxins (Vancomycin, iodinated contrast, myoglobin/hemoglobinuria) and presents with low urine specific gravity and low urine osmolality (unlike pre-renal AKI).
• CKD Mineral Bone Disorder: In CKD, the kidney fails to convert 25-hydroxyvitamin D to active Calcitriol (1,25-dihydroxyvitamin D), leading to hypocalcemia, secondary hyperparathyroidism, and hyperphosphatemia. Treatment requires administering Calcitriol directly.
• Nephrotic Syndrome/FSGS: FSGS is the most common nephrotic syndrome in HIV patients; it causes edema due to both volume overload and critically, a decrease in plasma oncotic pressure (due to urinary protein loss).
• Thrombophilia Diagnosis: Factor V Leiden is diagnosed by an Activated Protein C Resistance Assay, which shows no change in clotting time after adding activated Protein C.
• Coagulation Workup: Hemophilia A (Factor VIII deficiency) presents with deep tissue/joint bleeds and elevated PTT; the diagnosis is confirmed by a mixing study where the PTT normalizes upon administration of Factor VIII concentrate.

Learning objectives

• Differentiate the laboratory findings (urine specific gravity, osmolality, UNa+) between pre-renal and intrinsic AKI.
• Outline the pathophysiology and management of CKD-Mineral Bone Disorder, including appropriate vitamin D replacement therapy.
• Recognize the clinical presentation and diagnostic testing for common nephrotic syndromes (e.g., FSGS in HIV).
• Interpret results from specialized coagulation assays, specifically the Activated Protein C Resistance Assay and mixing studies.
• Identify key risk factors for thrombosis associated with chronic kidney disease or nephrotic syndrome.

Board exam buzzwords