A 65-year-old man is brought into the Emergency Department by his daughter, who reports that he is fatigued and short of breath. Several days ago he developed a fever with a productive cough, which has now progressed to dyspnea at rest. On examination, the patient’s temperature is 38.6°C, his blood pressure is 74/42 mmHg, his heart rate is 96 beats per minute, his respiratory rate is 24 breaths per minute, and his oxygen saturation is 94% on room air. He is lethargic, his neck veins are flat, and his extremities are warm and moist. There is dullness to percussion and decreased breath sounds over the right lung base. Serum blood work shows an elevated lactate.
What is the correct diagnosis?A. Cardiogenic shock
Severe sepsis. This patient has severe sepsis secondary to pneumonia. It is important to know the definitions related to the topic of sepsis. Systemic inflammatory response syndrome (SIRS) is defined by two or more of the following: (1) temperature >38°C or <36°C; (2) a heart rate >90 beats per minute; (3) a respiratory rate >20 breaths per minute or a PaCO2 <32 mmHg; and (4) a serum leukocyte count >12,000/mm3 or <4,000/mm3 or >10% bands. With a suspected source of infection, it is called sepsis. Severe sepsis is the definition for sepsis with end-organ dysfunction, signified by hypotension or hypoperfusion (e.g., oliguria, elevated serum lactate, elevated liver enzymes, etc.). Septic shock is severe sepsis that does not respond to adequate fluid resuscitation. This patient meets SIRS criteria with a suspected source of infection (pneumonia) and hypotension; (C) IV fluids have not been administered yet, so the definition of septic shock is not met.
Septic shock is one type of distributive shock, which is characterized by hypotension with flat neck veins and warm extremities (low systemic vascular resistance). (E) Anaphylaxis is another form of distributive shock, but is unlikely since there was no history of recent exposures mentioned in the vignette (e.g., bee sting, new medication, etc.). (A, B) Both cardiogenic shock and pulmonary embolism (a type of obstructive shock) are ruled out by flat neck veins (which indicate hypovolemic or distributive shock).Finally, hypovolemic shock would present with flat neck veins and cool extremities, since systemic vascular resistance increases in an attempt to maintain blood pressure.