Source / episode info

• **Episode:**210
• **Title:**Divine Intervention Episode 210 – USMLE Step 2CK Rapid Review Series 31.
• **Published:**2020-02-11
• Source:Episode page

One-liner

This episode provides high-yield rapid reviews covering the menstrual cycle phases and amenorrhea workup, differentiating medial longitudinal fasciculus (MLF) vs paramedian pontine reticular formation (PPRF) lesions in gaze palsies, managing blunt force trauma to the kidneys, recognizing metabolic links like heart-noble disease, and distinguishing pulmonary from myocardial contusions.

High-yield summary

• Menstrual Cycle: The follicular phase is characterized by estrogen production from the dominant follicle, leading to endometrial proliferation; progesterone (from the corpus luteum) stabilizes this into a secretory endometrium.
• Gaze Palsies: An MLF lesion affects only the adducting eye and results in an abnormal horizontal conjugate gaze but preserves the convergence response. A PPRF lesion affects both eyes and causes deviation away from the side of the lesion.
• Kidney Trauma Workup: For blunt force trauma to the kidneys, the initial diagnostic step is always obtaining a urinalysis; CT scan is only necessary if hematuria is present.
• Metabolic Links: Heart-noble disease (defect in neutral amino acid reabsorption) impairs tryptophan absorption, leading to reduced serotonin synthesis and increasing the risk of depression due to monoamine deficiency.
• ALP Elevation Workup: If ALP is elevated, checking the Gamma-Glutamyl Transferase (GGT) is critical; an elevated GGT strongly suggests a biliary or hepatic source, while normal GGT makes a biliary cause less likely.

Learning objectives

• Differentiate the clinical presentation of MLF lesions versus PPRF lesions using specific ocular motility tests (conjugate gaze vs convergence).
• Outline the sequential diagnostic workup for blunt force trauma to the kidneys.
• Correlate amino acid transport defects (e.g., tryptophan) with potential secondary metabolic and psychiatric complications.
• Differentiate between pulmonary and myocardial contusions based on clinical signs following blunt chest trauma.
• Interpret laboratory findings (ALP/GGT ratio) to localize the source of elevated alkaline phosphatase.

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