What is the best description of Addison's disease?

Choice A reason: Decreased hydrostatic pressure reduces fluid movement out of capillaries, favoring fluid return to the intravascular space. Low plasma proteins affect oncotic, not hydrostatic, pressure, causing fluid to leak into tissues, not return to vessels, making this incorrect.

Choice B reason: Increased hydrostatic pressure, as in heart failure, pushes fluid into the interstitial space. Low plasma proteins reduce oncotic pressure, not hydrostatic, leading to edema via a different mechanism, making this choice incorrect for the described scenario.

Choice C reason: Low plasma proteins, like albumin, decrease oncotic (osmotic) pressure, reducing the force pulling fluid into capillaries. This causes fluid to move from the intravascular to the interstitial space, leading to edema, making this the correct choice.

Choice D reason: Increased osmotic pressure would pull fluid into the intravascular space, as with high plasma protein levels. Low plasma proteins decrease oncotic pressure, causing fluid to leak into tissues, not return to vessels, making this choice incorrect.

A. Opiate drugs cause respiratory acidosis by depressing the central nervous system, specifically the respiratory centers in the brainstem, leading to reduced ventilation and accumulation of carbon dioxide. This increases arterial PCO2, lowering blood pH. The patient’s exposure to opiates aligns with this mechanism, as it impairs the physiological need for adequate respiration, a key component of Maslow’s hierarchy.

B. Atelectasis results in respiratory acidosis due to collapsed alveoli, which reduces effective gas exchange and causes carbon dioxide retention. This elevates PCO2, decreasing pH. The patient’s condition of atelectasis directly contributes to hypoventilation, supporting this classification.

C. Hypoventilation leads to respiratory acidosis by decreasing alveolar ventilation, causing carbon dioxide buildup. Elevated PCO2 lowers blood pH. The patient’s hypoventilation directly correlates with this mechanism, as it disrupts the respiratory system’s ability to maintain acid-base balance.

D. Renal failure causes metabolic acidosis by impairing the kidneys’ ability to excrete hydrogen ions and reabsorb bicarbonate, leading to acid accumulation and reduced serum bicarbonate. This aligns with the patient’s renal failure, as it disrupts the renal regulation of acid-base homeostasis, a critical physiological need.

E. Airway obstruction results in respiratory acidosis by preventing adequate ventilation, leading to carbon dioxide retention and increased PCO2, which lowers pH. The patient’s airway obstruction directly causes this imbalance, impairing respiratory function.

F. Diarrhea causes metabolic acidosis due to excessive loss of bicarbonate-rich intestinal fluids, reducing serum bicarbonate and lowering pH. The patient’s diarrhea aligns with this mechanism, as it leads to a direct loss of base, disrupting acid-base equilibrium.