Immune system



USMLE® Step 1 questions

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USMLE® Step 1 style questions USMLE

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A 78-year-old female presents to the emergency department with altered mental status. She was found down by her neighbors, who immediately called EMS. Medical history is notable for multiple myeloma, for which she is currently undergoing treatment. Temperature is 38.9°C (102°F), pulse is 137/min, respirations are 26/min, blood pressure is 87/60 mmHg, and O2 saturation is 89% on room air. Physical exam reveals a cachectic, ill-appearing woman who is moaning and unable to provide further history. She has bilateral costovertebral angle tenderness to palpation as well as warm and perfused peripheral extremities. Subsequent blood cultures grow a Gram-negative rod. Which of the following is the most likely trigger of this patient’s clinical presentation?

External References

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Arthritis p. 476

septic p. 478


acute tubular necrosis p. 627


immunodeficient patients p. 116

lymphopenia with p. 431

neutropenia with p. 431

shock with p. 321

Streptococcus agalactiae as cause p. 135


Listeria monocytogenes p. , 137

readmissions with p. 277

Waterhouse-Friderichsen syndrome p. 355


Sepsis is a potentially life-threatening condition that occurs when an infection spreads through the bloodstream and triggers a widespread immune response. The body's normal immune response to infection can sometimes become overactive, leading to widespread inflammation, which can cause tissue damage and affect organ function.

Common signs and symptoms include fever, increased heart rate, increased breathing rate, and confusion. There may also be symptoms related to a specific infection, such as a cough with pneumonia, or painful urination with a kidney infection. In the very young, old, and people with a weakened immune system, there may be no symptoms of a specific infection and the body temperature may be low or normal rather than high.

Insufficient blood flow may be evident by low blood pressure, high blood lactate, or low urine output. Septic shock is low blood pressure due to sepsis that does not improve after reasonable amounts of intravenous fluids are given. Treatment for sepsis typically involves antibiotics to treat the underlying infection, as well as supportive care to address the symptoms and prevent complications.


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