A 56-year-old woman with a history of hypertension is brought to the emergency department due to 3 days of dysuria and back pain. Temperature is 39.2 C (102.6 F), blood pressure is 70/40 mm Hg, pulse is 130/min, and respirations are 28/min. The patient is confused and has suprapubic and costovertebral angle tenderness. The skin is diffusely warm but there are no rashes or edema. Complete blood count demonstrates leukocytosis with increased neutrophils but is otherwise normal. Coagulation studies are normal. Urinalysis is positive for leukocyte esterase and nitrites, and microscopy shows numerous bacteria. Several hours later, the patient becomes increasingly hypoxic and requires mechanical ventilation. This patient's respiratory symptoms are most likely due to which of the following pathologic conditions?

Question

A 56-year-old woman with a history of hypertension is brought to the emergency department due to 3 days of dysuria and back pain.  Temperature is 39.2 C (102.6 F), blood pressure is 70/40 mm Hg, pulse is 130/min, and respirations are 28/min.  The patient is confused and has suprapubic and costovertebral angle tenderness.  The skin is diffusely warm but there are no rashes or edema.  Complete blood count demonstrates leukocytosis with increased neutrophils but is otherwise normal.  Coagulation studies are normal.  Urinalysis is positive for leukocyte esterase and nitrites, and microscopy shows numerous bacteria.  Several hours later, the patient becomes increasingly hypoxic and requires mechanical ventilation.  This patient's respiratory symptoms are most likely due to which of the following pathologic conditions?

Quizplus · Accepted Answer

11ec160b_3a04_b11a_9249_75273bbcd1aa_MD0001_00 This patient has a urinary tract infection complicated by fever and hemodynamic instability consistent with sepsis. Her rapid-onset respiratory failure is suggestive of acute respiratory distress syndrome (ARDS). ARDS is characterized by bilateral pulmonary infiltrates and hypoxemia in the absence of heart failure. It can occur due to direct pulmonary trauma (eg, pulmonary contusions, inhaled irritants) or indirect nonpulmonary insults (eg, sepsis, burns, pancreatitis) that result in pulmonary epithelial and/or endothelial injury. The 3 phases of ARDS follow the disease's progression: Exudative phase: Inflammatory cytokines (eg, tumor necrosis factor, IL-1, IL-6) activate the pulmonary endothelium and recruit neutrophils to the lung tissue. Resultant endothelial damage leads to increased capillary permeability and leakage of protein-rich fluid into the alveolar space. Organization of the edema and cellular debris leads to the formation of hyaline membranes. Proliferative phase: One to two weeks later, endothelial cells, pneumocytes, and fibroblasts proliferate in attempts to repair the damaged lung; collagen is deposited and scarring may occur. Edema is reabsorbed. Fibrotic phase: In a minority of patients, excessive collagen deposition leads to irreversible pulmonary fibrosis and pulmonary hypertension. (Choice B) Necrotizing inflammation and pulmonary hemorrhage are commonly associated with granulomatosis with polyangiitis, which involves both the lungs and the kidneys. However, this condition normally presents subacutely with cough, hemoptysis, and nephritic syndrome; this patient's acute respiratory decline in the setting of sepsis is more consistent with ARDS. (Choice C) Noncaseating granulomas are found in sarcoidosis, which typically presents more chronically with cough, skin findings, or uveitis. Hemodynamic instability and acute respiratory failure would be unexpected. (Choice D) Mucus plugging typically occurs in patients with underlying lung disease (eg, cystic fibrosis, chronic obstructive pulmonary disease). Mucus plugs can cause hypoxemia but would not be expected to cause hypotension and fevers, and acute respiratory deterioration in the setting of sepsis is more likely due to ARDS. (Choice E) Wedge-shaped areas of hemorrhagic necrosis can be seen with pulmonary embolism, which can cause acute respiratory failure, hypotension, and tachycardia. However, patients often have chest pain, and in general, decompensation occurs suddenly (not progressively over a course of hours). In addition, urinary symptoms, confusion, and high fevers are unexpected in this condition. Educational objective: Acute respiratory distress syndrome is caused by injury of the pulmonary epithelium and/or endothelium, and occurs most often due to sepsis or pneumonia. Cytokines recruit neutrophils to the lung tissue, which cause capillary damage and leakage of protein-rich fluid into the alveoli. Later, cellular proliferation and collagen deposition occurs, and in some patients, this leads to irreversible pulmonary fibrosis.

A 56-Year-Old Woman with a History of Hypertension Is Brought