Mrs. X had a femur fracture following A. On day 3, suddenly she developed tachypnea, dyspnea, and tachycardia and progressed to delirium and coma. Diagnosis is
**Core Concept**
Acute respiratory distress syndrome (ARDS) is a life-threatening condition characterized by rapid onset of non-cardiogenic pulmonary edema leading to hypoxemic respiratory failure. This condition often results from severe injury, infection, or systemic inflammation.
**Why the Correct Answer is Right**
Mrs. X's sudden development of tachypnea, dyspnea, and tachycardia on day 3 following a femur fracture suggests the onset of ARDS. The femur fracture is likely leading to fat embolism syndrome (FES), a condition characterized by the release of fat globules into the bloodstream, which can cause pulmonary edema, neurological symptoms, and hypoxemia. In FES, the fat globules can activate the complement system, leading to the release of pro-inflammatory cytokines and the activation of coagulation pathways, resulting in the formation of microthrombi in the pulmonary vasculature.
**Why Each Wrong Option is Incorrect**
* **Option A:** While acute kidney injury (AKI) can occur following a femur fracture, it does not typically present with respiratory symptoms such as tachypnea and dyspnea.
* **Option B:** Sepsis can cause ARDS, but in this case, there is no indication of infection.
* **Option C:** Cardiac arrest would likely present with more immediate and severe symptoms, such as loss of consciousness and cessation of breathing.
**Clinical Pearl / High-Yield Fact**
In patients with severe trauma, particularly those with long bone fractures, be aware of the possibility of fat embolism syndrome, which can present with respiratory and neurological symptoms.
**Correct Answer:** D. Fat Embolism Syndrome