Source / episode info
- **Episode:**601
- **Title:**DIP Ep 601: USMLE Step 2/3 Rapid Review Series 122
- **Published:**2025-05-09
- Source:Episode page
One-liner
This rapid review series covers critical high-yield topics including the management of giant cell arteritis and iatrogenic Cushing syndrome, the workup of SIADH, the pathophysiology of George syndrome, and the differentiation between primary hyperparathyroidism and familial hypocalciuric hypercalcemia.
High-yield summary
- Giant Cell Arteritis (GCA): Initial management requires immediate, high-dose systemic corticosteroids to prevent irreversible vision loss; temporal artery biopsy is confirmatory but can be delayed by weeks.
- Steroid Complications: Prolonged corticosteroid use mandates prophylactic treatment with phosphonate therapy for osteoporosis and proton pump inhibitors (PPIs) for peptic ulcer disease.
- SIADH Workup: Characterized by euvolemic hyponatremia, low serum sodium, and inappropriately high urine osmolarity (>100 mOsm/kg). Common causes include SSRIs, carbamazepine, chlorpropamide (sulfonylurea), SCLC, or pulmonary/CNS pathology.
- George Syndrome: Caused by the absence of the 3rd and 4th aortic arch arteries, leading to thymic aplasia -> T-cell deficiency -> hypocalcemia -> tetany. A classic exam clue is "reduced supermedia spinal radio density" (indicating absent thymus).
- Hypercalcemia Differentiation: Primary Hyperparathyroidism (PHPT) presents with high PTH, high serum calcium, and high urinary calcium excretion; Familial Hypocalciuric Hypercalcemia (FHH) presents with high PTH, high serum calcium, but low urinary calcium excretion.
Learning objectives
- Differentiate the metabolic derangements and diagnostic criteria for primary vs. familial hypocalciuric hypercalcemia.
- Recognize the clinical presentation and underlying pathophysiology of George syndrome (thymic aplasia/hypoparathyroidism).
- Identify common drug associations and risk factors leading to SIADH, including sulfonylureas and SSRIs.
- Understand the necessary prophylactic management strategies for patients on long-term corticosteroid therapy.
- Correlate classic radiographic findings (e.g., subperiosteal resorption) with hyperparathyroidism.
Board exam buzzwords