A man with a history of T6 paraplegia came to the emergency department with delirium, hypotension, and fever. Laboratory results revealed a high white blood cell count and mild elevation of bilirubin and liver enzymes. A stat abdominal CT showed a mildly thickened gallbladder. The patient was admitted to the intensive care unit with a provisional diagnosis of septic shock and treated with broad-spectrum antibiotics and intravenous fluids. He was transferred to the medical ward on hospital day 2, where the receiving hospitalist realized the diagnosis was still unclear.

An elderly man had iron deficiency anemia with progressively falling hemoglobin levels for nearly 2 years. Although during that time he underwent an upper endoscopy, capsule endoscopy, and repeat upper endoscopy and received multiple infusions of iron and blood, his primary physician maintained that he didn't need a repeat colonoscopy despite his anemia because his previous colonoscopy was negative. The patient ultimately presented to the emergency department with a bowel obstruction, was diagnosed with colon cancer, and underwent surgery to resect the mass.

A woman with a history of prior spine surgery presented to the emergency department with progressive low back pain. An MRI scan of T11–S1 showed lumbar degenerative joint disease and a small L5–S1 disc herniation. She was referred for physical therapy and prescribed muscle relaxant, non-steroidal anti-inflammatories, and pain relievers. Ten days later, she presented to a community hospital with fever, inability to walk, and numbness from the waist down. Her white blood cell count was greater than 30,000 and she was found to be in acute renal and liver failure.

Admitted with generalized weakness, nausea, and low blood pressure, an elderly man was given IV fluids and broad spectrum antibiotics. Laboratory test results revealed a mildly elevated white count, acute kidney injury, and elevated liver function tests. The patient was admitted to the medical ICU with a presumed diagnosis of septic shock. His blood pressure continued to trend downward. While reviewing the emergency department test results, the ICU resident noticed the patient's troponin level was markedly elevated and his initial ECG revealed T-wave inversions.

An older man with multiple medical conditions and an extensive smoking history was admitted to the hospital with worsening shortness of breath. He underwent transthoracic echocardiogram, which demonstrated severe aortic stenosis. The cardiology team recommended cardiac catheterization, but the interventional cardiologist could not advance the catheter and an aortogram revealed an abdominal aortic aneurysm (AAA) measuring 9 cm in diameter. Despite annual visits to his primary care physician, he had never undergone screening ultrasound to assess for presence of an AAA.

Brought to the emergency department from a nursing facility with confusion and generalized weakness, an older woman was found to have an elevated troponin level but no evidence of ischemia on her ECG. A consulting cardiologist recommended treating the patient with three anticoagulants. The next evening, she became acutely confused and a CT scan revealed a large intraparenchymal hemorrhage with a midline shift.

An elderly man with early dementia fractured his leg and was admitted to a skilled nursing facility for physical therapy. On his third day there, he became delirious and agitated and was taken to the emergency department and hospitalized. A few days later, doctors involuntarily committed him and administered risperidone, which worsened his delirium.

Admitted with bruising from a fall and persistent pain on his left side, a patient was kept in the emergency department overnight due to crowding. After being reevaluated by the surgical service the next day, the patient was urgently taken to the operating room for probable necrotizing fasciitis and pyomysitis.

Despite new back pain and worsening symptoms of tingling, pain, and weakness bilaterally, in both hands and feet, a man recently diagnosed with peripheral neuropathy was not sent for further testing after repeated visits to a primary care clinic. By the time neurologists saw him, they diagnosed critical cervical cord compression, which placed the patient at risk for permanent paralysis.

Following delivery and successful phototherapy for hyperbilirubinemia, an infant developed anemia over the next few weeks. Found to have Rh hemolytic disease, the infant was admitted to the hospital for blood transfusion and close monitoring.

A woman with coronary artery disease, diabetes, and hypertension was admitted for a myocardial infarction. Following percutaneous coronary intervention, the patient had several runs of non-sustained ventricular tachycardia (NSVT) and later experienced a cardiac arrest secondary to sustained VT.

An elderly woman with severe abdominal pain was admitted for an emergency laparotomy for presumed small bowel obstruction. Shortly after induction of anesthesia, her heart stopped. She was resuscitated and transferred to the intensive care unit, where she died the next morning. The review committee felt this case represented a diagnostic error, which led to unnecessary surgery and a preventable death.

Admitted to the hospital with headache and word-finding difficulties, a man was given a preliminary diagnosis of vasculitis. Although serial imaging studies seemed to indicate progression of his brain lesions, these were not biopsied and discovered to be glioblastoma multiforme until 4 months later. The delay in diagnosis contributed to his rapid clinical decline.

A woman with abdominal pain, bloating, and weight loss went to her primary physician, who ordered imaging and a biopsy. Lymph node pathology was reported as Castleman disease. A specialist felt the presentation and test results were atypical for this diagnosis. Further testing revealed adult-onset celiac disease.

Following an emergency department (ED) evaluation for chest pain, a patient was discharged with a presumptive diagnosis of gastroesophageal reflux disease. Two days later, he returned to the ED in severe distress, now with an acute myocardial infarction and a large pericardial effusion.

At his first visit with a new physician, a man with a "spot" on his lung reported being followed with CT scans every 6–12 months for 8 years. In total, the patient had more than 20 CT scans.

A 32-year-old man went to the emergency department with fever and pleuritic chest pain. Following an extensive work-up, he was discharged with "fever, pleural effusion, and chest wall pain", but no clear diagnosis. He returned to the ED 3 days later with worsening pain, continued fever, a new cough, and dyspnea. The patient was started on antibiotics and admitted for pneumonia with effusion.

A woman presented to the emergency department with an eyelid laceration, which was sutured without complication. Her visual acuity was not formally tested and ophthalmology was not consulted. Ten days later, she presented with eye pain and poor vision. Ophthalmologist evaluation revealed a ruptured globe requiring surgical repair.

A woman undergoing chemotherapy for breast cancer developed fulminant liver failure after clinicians failed to check whether she had a history of hepatitis.