A 68-year-old man undergoing hemodialysis is being evaluated due to "difficulty breathing and chest tightness." He has not had any chest pain. The patient was feeling well when he arrived at his hemodialysis appointment. He was started on hemodialysis 15 minutes ago after a heparin flush; an intravenous iron infusion was started 5 minutes ago for iron deficiency anemia. Medical history is significant for end-stage renal disease due to uncontrolled hypertension, a small pericardial effusion, and small, bilateral pleural effusions. He has been on hemodialysis treatment for the past year. Temperature is 35.6 C (96.1 F), blood pressure is 90/60 mm Hg, pulse is 112/min, and respirations are 24/min. Pulse oximetry is 93% on room air. The patient is alert but in mild distress. Conjunctivae are pale. Lungs sounds are decreased at both bases. Bilateral wheezing is noted on auscultation of the lungs. Heart sounds are slightly muffled and rapid but without murmurs or rubs. Abdomen is soft and nontender. Skin is flushed. Mild, bilateral pitting pedal edema is present. What is the most likely cause of this patient's symptoms?

Question

A 68-year-old man undergoing hemodialysis is being evaluated due to "difficulty breathing and chest tightness."  He has not had any chest pain.  The patient was feeling well when he arrived at his hemodialysis appointment.  He was started on hemodialysis 15 minutes ago after a heparin flush; an intravenous iron infusion was started 5 minutes ago for iron deficiency anemia.  Medical history is significant for end-stage renal disease due to uncontrolled hypertension, a small pericardial effusion, and small, bilateral pleural effusions.  He has been on hemodialysis treatment for the past year.  Temperature is 35.6 C (96.1 F), blood pressure is 90/60 mm Hg, pulse is 112/min, and respirations are 24/min.  Pulse oximetry is 93% on room air.  The patient is alert but in mild distress.  Conjunctivae are pale.  Lungs sounds are decreased at both bases.  Bilateral wheezing is noted on auscultation of the lungs.  Heart sounds are slightly muffled and rapid but without murmurs or rubs.  Abdomen is soft and nontender.  Skin is flushed.  Mild, bilateral pitting pedal edema is present.  What is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bdd1_db52_8f63_d3ad9f67a307_MD0005_00 Determining the cause of dyspnea during hemodialysis can be challenging, in part because large, physiologic shifts (eg, fluid shifts) are occurring, but also because hemodialysis patients often have multiple comorbidities (eg, cardiovascular disease) that can manifest with dyspnea. Dyspnea prior to initiation of hemodialysis often results from volume overload and is common. However, dyspnea that begins after initiation of hemodialysis may reflect another medical condition (eg, acute coronary syndrome, anaphylaxis) that warrants further workup. This patient developed dyspnea with wheezing, hypotension, and flushing shortly after intravenous (IV) iron infusion. This is concerning for anaphylaxis, which may be diagnosed when cutaneous symptoms (eg, flushing) and either hypotension or respiratory distress (this patient has both) occur after exposure to a possible allergen (eg, IV iron). Allergic symptoms in ≥2 systems (eg, skin, respiratory, cardiovascular) after possible allergen exposure is another diagnostic criterion for anaphylaxis. IV iron is a recognized allergen. Although anaphylaxis is rare, IV iron infusions are common as the preferred treatment for anemia in hemodialysis patients (~70% of patients). Anaphylaxis may also be triggered by other medications (eg, antibiotics) administered during hemodialysis or by the dialysate itself. Early recognition and treatment with epinephrine can be lifesaving. (Choice A) Hemodialysis patients have an increased incidence of coronary artery disease and can develop acute myocardial infarction (AMI), causing chest tightness and dyspnea. However, AMI causing hypotension (eg, cardiogenic shock) would likely lead to pale skin (vs flushing) due to hypoperfusion and crackles (vs wheezing) due to acute pulmonary edema. This patient's lack of chest pain and his symptom onset after IV iron infusion make anaphylaxis more likely. (Choice B) Venous air embolism can cause dyspnea and hypotension, particularly if the air embolus travels to pulmonary circulation. However, flushing and wheezing would be unexpected. (Choice D) Dialysis patients can have small pericardial effusions (eg, slightly muffled heart sounds) due to volume overload. Large uremic effusions can lead to cardiac tamponade presenting with symptoms of cardiogenic shock (eg, dyspnea, hypotension) and impaired venous return (eg, peripheral edema). However, distended neck veins are also frequently present, and skin flushing and wheezing are not expected. (Choice E) Pulmonary embolism can cause dyspnea, chest tightness, hypotension, and tachycardia; however, flushing and bilateral wheezing are more suggestive of anaphylaxis. Educational objective: Although anaphylaxis can be difficult to recognize in hemodialysis patients due to large fluid shifts and confounding patient comorbidities, it should be considered as a potential cause of dyspnea in patients receiving intravenous iron infusions or other medications during hemodialysis. References: 84-year-old woman with hemodialysis-associated shortness of breath. (http://www.ncbi.nlm.nih.gov/pubmed/19181653) Diagnosis, treatment, and prevention of hemodialysis emergencies. (http://www.ncbi.nlm.nih.gov/pubmed/27831511) Safety of intravenous iron in hemodialysis patients. (http://www.ncbi.nlm.nih.gov/pubmed/28370957)

A 68-Year-Old Man Undergoing Hemodialysis Is Being Evaluated Due to "Difficulty