A 79-year-old woman is hospitalized after a fall that resulted in a left femoral neck fracture. She tripped over her dog while cleaning her home, hit her head on a bookshelf, and landed on her left side. Prior to this she had been in her usual state of health; her other medical issues include obesity, type 2 diabetes mellitus, hypertension, chronic kidney disease, and hypothyroidism. The patient lives at home by herself. She has smoked a pack of cigarettes daily for 38 years. She drinks alcohol every weekend. Results of the patient's initial workup in the emergency department demonstrated the left femoral neck fracture, creatinine of 2.0 mg/dL, and a negative noncontrast head CT. She was admitted to the hospital and the following day underwent surgical repair. The procedure was uncomplicated. However, on postoperative day 3 the patient is noted to be uncomfortable and mildly agitated. She is unable to coherently explain her symptoms. Current medications include prophylactic subcutaneous heparin, insulin glargine, omeprazole, hydrocodone, and levothyroxine. Temperature is 37.7 C (99.9 F), blood pressure is 104/68 mm Hg, pulse is 114/min, and respirations are 28/min. Pulse oximetry is 86% on room air. Examination shows equal round and reactive pupils. Lung examination demonstrates decreased breath sounds at the bilateral bases. Heart rhythm is regular with normal S1 and S2. The surgical incision shows no surrounding erythema or purulent drainage. The patient follows commands and moves all extremities except the left leg. Laboratory results are as follows:
Troponin I is undetectable. Chest x-ray shows slight bibasilar atelectasis without focal consolidation, pleural effusion, or pulmonary edema. ECG shows sinus tachycardia but is otherwise unremarkable.
Which of the following is the most appropriate next step in management of this patient?

Question

A 79-year-old woman is hospitalized after a fall that resulted in a left femoral neck fracture.  She tripped over her dog while cleaning her home, hit her head on a bookshelf, and landed on her left side.  Prior to this she had been in her usual state of health; her other medical issues include obesity, type 2 diabetes mellitus, hypertension, chronic kidney disease, and hypothyroidism.  The patient lives at home by herself.  She has smoked a pack of cigarettes daily for 38 years.  She drinks alcohol every weekend.  Results of the patient's initial workup in the emergency department demonstrated the left femoral neck fracture, creatinine of 2.0 mg/dL, and a negative noncontrast head CT.  She was admitted to the hospital and the following day underwent surgical repair.  The procedure was uncomplicated.  However, on postoperative day 3 the patient is noted to be uncomfortable and mildly agitated.  She is unable to coherently explain her symptoms.  Current medications include prophylactic subcutaneous heparin, insulin glargine, omeprazole, hydrocodone, and levothyroxine.  Temperature is 37.7 C (99.9 F), blood pressure is 104/68 mm Hg, pulse is 114/min, and respirations are 28/min.  Pulse oximetry is 86% on room air.  Examination shows equal round and reactive pupils.  Lung examination demonstrates decreased breath sounds at the bilateral bases.  Heart rhythm is regular with normal S1 and S2.  The surgical incision shows no surrounding erythema or purulent drainage.  The patient follows commands and moves all extremities except the left leg.  Laboratory results are as follows:
 Troponin I is undetectable.  Chest x-ray shows slight bibasilar atelectasis without focal consolidation, pleural effusion, or pulmonary edema.  ECG shows sinus tachycardia but is otherwise unremarkable.
Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Explanation: This patient likely has an acute pulmonary embolism (PE). Recent surgery and immobilization, tachycardia, and absence of a more likely alternate diagnosis give her a modified Wells score >4, which indicates likely pretest probability of PE. Hypoxemia that is out of proportion to chest x-ray findings and active smoking further increases the probability of an acute PE. Although receipt of prophylactic heparin reduces the risk of acute PE, it does not preclude the diagnosis. modified Wells score CT angiogram of the chest is typically preferred for diagnostic confirmation of acute PE; however, due to impaired renal function, intravenous contrast should be avoided. Therefore, ventilation-perfusion scan is most appropriate. In the setting of likely pretest probability for acute PE, a high-probability ventilation-perfusion scan confirms the diagnosis. (Choice A) Intravenous antibiotics, preceded by the collection of appropriate cultures, are appropriate for management of suspected sepsis. This patient's lack of fever, absence of consolidation on chest x-ray, and several risk factors for PE make sepsis less likely. (Choice B) Benzodiazepines (eg, lorazepam) are appropriate treatment for suspected alcohol withdrawal. Patients typically have a history of heavy alcohol use and present with signs of sympathetic nervous system activation (eg, agitation, tachycardia, hypertension) 48-96 hours following hospital admission. This patient's risk factors for PE and lack of hypertension make alcohol withdrawal less likely. (Choice C) Naloxone is an opiate receptor antagonist used to reverse the effects of opioid (eg, hydrocodone) overdose. Opioid overdose can cause hypoxemia due to hypoventilation; however, patients should be somnolent with decreased respiratory rate and pinpoint pupils. This patient's tachypnea and round and reactive pupils are not consistent with opioid overdose. (Choice D) CT scan of the head would be appropriate if intracranial hemorrhage were suspected. This elderly patient is at risk for developing a subdural hematoma following her fall; however, subdural hematoma would not explain her hypoxemia and tachycardia, and the initial negative head CT makes the diagnosis less likely. Educational objective: Hip fracture, recent surgery or immobilization, and smoking increase the risk of acute pulmonary embolism (PE), and PE can occur despite treatment with prophylactic heparin. In patients with impaired renal function, ventilation-perfusion scan is most appropriate to evaluate for acute PE; in the setting of likely pretest probability, a high-probability ventilation-perfusion scan confirms the diagnosis. References: Radionuclide diagnosis of pulmonary embolism. (http://www.ncbi.nlm.nih.gov/pubmed/27620309)

A 79-Year-Old Woman Is Hospitalized After a Fall That Resulted