DIP Episode 330 - USMLE Step 2CK Rapid Review Series 61

Source / episode info

• Episode: 330
• Title: Divine Intervention Episode 330 – USMLE Step 2 CK Rapid Review Series 61.
• Published: 2021-08-02
• Source: Episode page

One-liner

Episode 330 is a comprehensive review covering vascular lesions (hemangiomas), genetic syndromes associated with neurocutaneous findings (VHL, TSC, Prader-Willi/Angelman), critical care management of ARDS and CLABSI, and high-yield topics like HIV prophylaxis and family therapy.

High-yield summary

• Hepatic Hemangioma Imaging: Classically shows peripheral enhancement in the arterial phase, followed by centripetal filling in later phases on CT/MRI.
• ARDS Pathophysiology: Characterized by non-cardiogenic pulmonary edema; thus, the Pulmonary Capillary Wedge Pressure (PCWP) is typically normal (<18 mm Hg), but Central Venous Pressure (CVP) and right heart pressures are elevated due to increased systemic inflammation.
• Tuberous Sclerosis Complex (TSC): Associated with seizures (West Syndrome/Infantile Spasms, diagnosed by Hypsarrhythmia on EEG); characteristic skin findings include hypopigmented macules ("ashy spots"). The drug of choice for infantile spasms is ACTH.
• VHL Syndrome: Presents with posterior fossa hemangioblastomas and polycythemia; patients are at high risk for developing Renal Cell Carcinoma (RCC) and Pancreatic Cancer.
• CLABSI Workup: Requires obtaining two blood cultures: one from the catheter lumen and one from a peripheral vein. A differential growth rate (higher growth in the catheter sample) strongly suggests CLABSI. Treatment involves removing the catheter and administering incontamining.
• Genetic Syndromes & Autism: Prader-Willi Syndrome is linked to paternal deletion of chromosome 15; Angelman Syndrome is linked to maternal deletion of chromosome 15.

Learning objectives

• Differentiate the clinical presentation and management of various neurocutaneous syndromes (TSC, NF1).
• Interpret chest imaging findings in ARDS to distinguish between cardiogenic and non-cardiogenic pulmonary edema.
• Recognize the diagnostic criteria and workup protocol for central line associated bloodstream infections (CLABSI).
• Understand the genetic basis and clinical manifestations of chromosome 15 deletions (Prader-Willi vs Angelman).
• Apply knowledge of critical care management principles in ARDS, including ventilator strategies and positioning.

Board exam buzzwords

Rapid review table

Board-speak -> diagnosis

Differential diagnosis / distinguishing features

Genetic Syndromes: Prader-Willi vs Angelman

Pneumonia Etiology

Management pearls

• ARDS Management: Implement low tidal volume ventilation and high PEEP settings to minimize ventilator-induced lung injury. Consider prone positioning for improved oxygenation.
• CLABSI Workup: Always obtain two blood cultures: one from the catheter lumen/site, and one from a peripheral vein. If differential growth is noted, suspect CLABSI.
• TSC Seizure Management: For suspected West Syndrome (Infantile Spasms), the drug of choice is ACTH or an ACTH analog (e.g., cabergoline).
• HIV Prophylaxis in Labor: Administer Zidovudine (AZT) to both mother and newborn during labor/delivery to reduce vertical transmission risk.

Don't miss

Integration & clinical reasoning

• Vascular Lesions (Hemangiomas): The imaging pattern of peripheral enhancement followed by centripetal filling is a classic, high-yield radiological sign that must be recalled for board exams.
• Genetic Syndromes & Development: Understanding the imprinting mechanism of chromosome 15 deletions (Prader-Willi vs Angelman) highlights how parental origin dictates phenotype and disease presentation.
• Critical Care Hemodynamics: Recognizing that systemic inflammation in ARDS elevates right heart pressures (elevated CVP/CVP) despite a normal PCWP is critical for accurate hemodynamic assessment.

OMM / COMLEX integration

• For any acute/unstable patient (e.g., septic shock leading to ARDS or suspected CLABSI), standard emergency management takes absolute priority over OMT. Stabilization measures (fluid resuscitation, source control, mechanical ventilation) must be initiated first.
• The principles of systemic inflammation and vascular permeability seen in ARDS are relevant to understanding the pathophysiology of sepsis and multi-organ failure, which can be addressed with supportive care protocols.

Concept connections / cross-references

• For detailed information on the pathophysiology of pulmonary edema and cardiac function, review [Episode 12].
• For comprehensive coverage of infectious disease workups, including sepsis and central line care, see [Episode 45].
• For general genetic disorder reviews, consult [Episode 78].

High-yield association table

Key terms glossary

Study optimization

Question pattern recognition

• Pattern: Posterior fossa mass + Polycythemia: Points strongly to Von Hippel-Lindau Syndrome (VHL) due to hemangioblastoma formation and EPO excess.
• Pattern: Hypopigmented macules + Seizures/West Syndrome: Highly suggestive of Tuberous Sclerosis Complex (TSC). Next step is ACTH therapy.
• Pattern: Central line fever + Differential growth in cultures: Diagnostic hallmark for CLABSI, requiring immediate removal and incontamining.

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