The crisis of sickle cell anemia may be confused with:

Correct Answer: B

Rationale: Sickle cell crisis mimics acute appendicitis (B) vaso-occlusive pain (e.g., RLQ) overlaps with peritoneal irritation, confusing diagnosis. Rheumatic fever (A) causes arthritis, carditis. Leukemia (C) brings fatigue, bleeding. Appendicitis's acute abdomen is key, guiding nursing for imaging (e.g., US) and pain differentiation.

Correct Answer: A

Rationale: Pulmonary fibrosis is a restrictive lung disease characterized by the deposition of excessive collagen in the lung interstitium, leading to stiff, non-compliant lungs. This stiffness results in decreased lung compliance, making it difficult for the lungs to expand during inspiration. Additionally, the fibrotic tissue compresses pulmonary blood vessels, increasing pulmonary vascular resistance. The forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) are both reduced due to the restricted lung expansion, but the FEV1/FVC ratio remains normal or above normal because the reduction is proportional, distinguishing it from obstructive diseases where the ratio decreases. Residual volume (RV), however, is the amount of air remaining in the lungs after a maximal expiration. In pulmonary fibrosis, RV is typically decreased because the stiff lungs cannot hold as much air at the end of expiration, unlike in obstructive diseases like COPD where air trapping increases RV. Therefore, increased residual volume is not consistent with pulmonary fibrosis and stands out as the exception among the listed values, which align with the pathophysiology of this condition.

Correct Answer: D

Rationale: Residual volume (RV) is the air remaining in the lungs after a maximal expiration, preventing complete collapse and maintaining alveolar stability. It's not just after tidal expiration (that's FRC), so that statement is imprecise. In COPD, an obstructive disease, air trapping increases RV due to impaired expiration from narrowed airways or loss of elastic recoil, not decreases it. In pulmonary fibrosis, a restrictive disease, RV decreases because stiff lungs limit all volumes, including the amount left after maximal effort. However, RV remains relatively constant throughout a healthy person's life, unaffected by aging alone in the absence of disease, as lung elasticity and structure don't drastically alter RV without pathology. While lung volumes like vital capacity may shift with age, RV's stability reflects its role as a fixed baseline, measured indirectly (e.g., helium dilution), and isn't subject to significant physiological variation over time in health. Thus, its consistency across a lifetime is the correct statement, distinguishing it from disease-specific changes.

Correct Answer: A

Rationale: Total lung capacity (TLC) is the maximum volume of air the lungs can hold after a maximal inspiration, encompassing all lung volumes: residual volume (RV, ~1-1.5 L), expiratory reserve volume (ERV, ~1-1.5 L), tidal volume (VT, ~0.5 L), and inspiratory reserve volume (IRV, ~2-3 L). In a normal adult, TLC averages around 6 liters (5-7 L, varying by age, sex, and size), widely accepted in physiology (e.g., Guyton, West). The 2 L option might confuse with FRC (~2.5-3 L), the resting volume after normal expiration. Four liters approximates vital capacity (VC, ~4-5 L), excluding RV. Nine liters exceeds typical human capacity, possibly a misestimate, and 15 L is implausible without pathology (e.g., hyperinflation). The 6 L value aligns with standard measurements (e.g., spirometry plus RV via helium dilution), reflecting the full extent of lung expansion in a healthy individual, making it the most accurate approximation.

Correct Answer: C

Rationale: Surfactant, from type II alveolar cells, reduces alveolar surface tension, aiding lung function. It causes hysteresis the difference in lung inflation vs. deflation pressure-volume curves by lowering tension more effectively as alveoli expand, a true property. It decreases, not increases, pulmonary resistance by easing expansion and reducing collapse tendency, so that's incorrect but not the queried option. Surfactant deficiency is common in preterm neonates (<37 weeks), causing respiratory distress syndrome (RDS), but in term neonates (≥37 weeks), surfactant production is typically mature, making commonly deficient in term-neonates' incorrect RDS is rare at term unless congenital defects exist. Surfactant prevents pulmonary edema indirectly by maintaining alveolar stability, reducing transudation pressure, though not its primary role. The term-neonate statement is the incorrect one, misaligning with developmental physiology where surfactant sufficiency is expected at full gestation.