Diagnostic Errors Case Studies

This case describes a man in his 70s with a history of multiple myeloma and multiple healthcare encounters for diarrhea in the previous five years, which had always been attributed to viral or unknown causes, without any microbiologic or serologic testing. The patient was admitted to the hospital with gastrointestinal symptoms and diagnosed with cholecystitis and gangrenous gallbladder. Two months after his admission for cholecystitis, he was readmitted for severe vomiting and hypotension. An upper gastrointestinal endoscopy with biopsy unexpectedly showed that his duodenum was heavily infiltrated with a parasitic helminth (worm) called Strongyloides stercoralis. He was treated with the anti-parasitic drug ivermectin and eventually improved enough to be discharged from the hospital. The commentary summarizes factors contributing to the missed diagnosis of strongyloidiasis, potential consequences of a failure to diagnose this infection, and approaches to identify patients who should be tested for Strongyloides infection.

An 18-year-old man with a history of untreated depression and suicide attempts (but no history of psychiatric hospitalizations) was seen in the ED for suicidal ideation after recent gun purchase. Due to suicidal ideation, he was placed on safety hold and a psychiatric consultation was requested. The psychiatry team recommended discharge with outpatient therapy; he was discharged with outpatient resources, the crisis hotline phone number, and strict return precautions. After two encounters with his primary care provider and another visit to the ED for suicidal ideation, the patient was found with a loaded gun in a hotel room. He was taken to the ED for a third time, where has was evaluated and involuntarily admitted to an inpatient psychiatric hospital for five weeks.  He was ultimately discharged with a diagnosis of “Bipolar 1 – moderate-severe with mixed features.” The commentary discusses the challenges of screening for suicide risk and the importance of continuity of care for patients at risk of self-harm and suicide.

A 31-year-old woman presented to the ED with worsening shortness of breath and was unexpectedly found to have a moderate-sized left pneumothorax, which was treated via a thoracostomy tube. After additional work-up and computed tomography (CT) imaging, she was told that she had some blebs and mild emphysema, but was discharged without any specific follow-up instructions except to see her primary care physician. Three days later, the patient returned to the same ED with similar symptoms and again was found to have had a left pneumothorax that required chest tube placement, but the underlying cause was not established. After she was found two weeks later in severe respiratory distress, she was taken to another ED by paramedics where the consulting pulmonary physician diagnosed her with a rare cystic lung disease. The commentary discusses the importance of CT scans for evaluating spontaneous pneumothorax and educating providers to increase awareness of rare cystic lung diseases.

Beginning in her teenage years, a woman began "feeling woozy" after high school gym class. The symptoms were abrupt in onset, lasted between 5 to 15 minutes and then subsided after sitting down. Similar episodes occurred occasionally over the following decade, usually related to stress. When she was in her 30s, she experienced a more severe episode of palpitations and went to the emergency department (ED). An electrocardiogram (ECG) was normal and she was discharged with a diagnosis of stress or possible panic attack. She continued to experience these symptoms for two more years and her primary care physician (PCP) suggested that she see a psychiatrist for presumed panic attacks. At the patient’s request, the PCP ordered a 24-hour Holter monitor, which was normal. When she was 40 years old, the patient experienced another severe episode and went to the ED. During an exercise treadmill test, she experienced another “woozy” spell and the ECG showed an elevated heart rate with narrow QRS complexes. She was diagnosed with paraoxymal supraventricular tacycardia (PSVT). The commentary discusses the diagnostic challenges of PSVT and approaches to reduce diagnostic uncertainty, especially given gender bias in attributing palpitations to psychiatric rather than cardiac causes.

A pregnant patient was admitted for scheduled Cesarean delivery, before being tested according to a universal inpatient screening protocol for SARS-CoV-2. During surgery, the patient developed a fever and required oxygen supplementation. Due to suspicion for COVID-19, a specimen obtained via nasopharyngeal swab was sent to a commercial laboratory for reverse transcriptase polymerase chain reaction (RT-PCR) testing. However, due to delays in receiving those results, another sample was tested two days later with a newly developed in-house test, and a third sample was sent to the state public health laboratory. The in-house test returned as positive for SARS-CoV-2. The patient was discharged in stable clinical condition but was advised to quarantine for 14 days. Two days after the patient’s discharge, the commercial and state lab tests were both reported as negative. A root-cause analysis subsequently determined that the positive test run on the in-house platform was due to cross-contamination from a neighboring positive sample. The commentary discusses the challenges associated with SARS-CoV-2 testing, the unprecedented burden faced by health systems, and downstream consequences of false positive tests.

After a breast mass was identified by a physician assistant during a routine visit, a 60-year-old woman received a diagnostic mammogram and ultrasound. The radiology assessment was challenging due to dense breast tissue and ultimately interpreted as “probably benign” findings. When the patient returned for follow-up 5 months later, the mass had increased in size and she was referred for a biopsy. Confusion regarding biopsy scheduling led to delays and, 7 months after initial presentation, the patient was diagnosed with invasive breast cancer involving the axillary nodes and spine. The commentary discusses the diagnostic challenges of potentially discordant findings between imaging and physical exams and the importance of structured inter-professional handoffs and closed-loop referrals in reducing diagnostic delays and associated harm.