Pathology Questions for the CDN Exam — Practice Free

This represents KDIGO Stage 2. Stage 2 is defined as a SCr increase of 2.0 to 2.9 times the baseline. Since the patient's SCr more than doubled (2.2x), it meets Stage 2 criteria. Exam Strategy: NNCC focuses on the three KDIGO stages: - Stage 1: 1.5–1.9x baseline or ≥0.3 mg/dL increase. - Stage 2: 2.0–2.9x baseline. - Stage 3: ≥3.0x baseline, SCr ≥4.0 mg/dL, or initiation of RRT. Note: Urine output (UO) criteria can also define these stages (e.g., UO <0.5 mL/kg/hr for 12+ hours for Stage 2).

Fibroblast Growth Factor 23 (FGF-23) is the primary phosphaturic hormone. It rises early in CKD to promote renal phosphorus excretion. CRITICAL EXAM POINT: FGF-23 inhibits the enzyme 1-alpha-hydroxylase, which converts 25(OH)D to active 1,25(OH)2D (Calcitriol). This leads to decreased intestinal calcium absorption and contributes to early hypocalcemia. NNCC emphasizes that elevated FGF-23 is an independent risk factor for left ventricular hypertrophy and mortality in dialysis patients.

LVH in dialysis patients is driven by: 1. Pressure Overload: Primarily caused by systemic hypertension and increased arterial stiffness (calcification), increasing afterload. 2. Volume Overload: Caused by chronic fluid expansion, sodium retention, and high-flow AV fistulas, increasing preload. Clinical Pearl: LVH is present in up to 75% of patients starting dialysis. NNCC Exam Tip: Distinguish between concentric (pressure) and eccentric (volume) remodeling. While both occur, hypertension is the most modifiable risk factor for preventing LVH progression.

Diagnosis: Type A First-Use Syndrome (Anaphylactic reaction). Immediate Priority: Stop the blood pump immediately and CLAMP the lines. DO NOT return the blood to the patient. Rationale: Type A reactions are IgE-mediated and often triggered by residual ethylene oxide (ETO). Returning the blood re-exposes the patient to a bolus of the allergen, which can lead to fatal cardiovascular collapse. Support with Epinephrine, antihistamines, and oxygen as ordered. NNCC exams frequently test the no blood return rule for Type A reactions.

Encapsulating Peritoneal Sclerosis (EPS). EPS is a life-threatening condition characterized by peritoneal fibrosis and cocooning of the bowel. Key Exam Points: 1. Risk increases significantly after 5–8 years of PD. 2. Hemorrhagic effluent is a late warning sign. 3. Ultrafiltration failure (often shifting to a high-transporter status) usually precedes bowel symptoms. Strategy Tip: The NNCC often tests the correlation between PD vintage (duration) and the sudden onset of bloody effluent as a trigger for EPS suspicion.