Evaluation of ChatGPT-Generated Differential Diagnosis for Common Diseases With Atypical Presentation: Descriptive Research.

Background: The persistence of diagnostic errors, despite advances in medical knowledge and diagnostics, highlights the importance of understanding atypical disease presentations and their contribution to mortality and morbidity. Artificial intelligence (AI), particularly generative pre-trained transformers like GPT-4, holds promise for improving diagnostic accuracy, but requires further exploration in handling atypical presentations. Objective: This study aimed to assess the diagnostic accuracy of ChatGPT in generating differential diagnoses for atypical presentations of common diseases, with a focus on the model's reliance on patient history during the diagnostic process. Methods: We used 25 clinical vignettes from the Journal of Generalist Medicine characterizing atypical manifestations of common diseases. Two general medicine physicians categorized the cases based on atypicality. ChatGPT was then used to generate differential diagnoses based on the clinical information provided. The concordance between AI-generated and final diagnoses was measured, with a focus on the top-ranked disease (top 1) and the top 5 differential diagnoses (top 5). Results: ChatGPT's diagnostic accuracy decreased with an increase in atypical presentation. For category 1 (C1) cases, the concordance rates were 17% (n=1) for the top 1 and 67% (n=4) for the top 5. Categories 3 (C3) and 4 (C4) showed a 0% concordance for top 1 and markedly lower rates for the top 5, indicating difficulties in handling highly atypical cases. The χ2 test revealed no significant difference in the top 1 differential diagnosis accuracy between less atypical (C1+C2) and more atypical (C3+C4) groups (χ²1=2.07; n=25; P=.13). However, a significant difference was found in the top 5 analyses, with less atypical cases showing higher accuracy (χ²1=4.01; n=25; P=.048). Conclusions: ChatGPT-4 demonstrates potential as an auxiliary tool for diagnosing typical and mildly atypical presentations of common diseases. However, its performance declines with greater atypicality. The study findings underscore the need for AI systems to encompass a broader range of linguistic capabilities, cultural understanding, and diverse clinical scenarios to improve diagnostic utility in real-world settings.

Age-related changes in the hematopoietic stem cell pool revealed via quantifying the balance of symmetric and asymmetric divisions.

Hematopoietic stem cells (HSCs) are somatic stem cells that continuously generate lifelong supply of blood cells through a balance of symmetric and asymmetric divisions. It is well established that the HSC pool increases with age. However, not much is known about the underlying cause for these observed changes. Here, using a novel method combining single-cell ex vivo HSC expansion with mathematical modeling, we quantify HSC division types (stem cell-stem cell (S-S) division, stem cell-progenitor cell (S-P) division, and progenitor cell-progenitor cell (P-P) division) as a function of the aging process. Our time-series experiments reveal how changes in these three modes of division can explain the increase in HSC numbers with age. Contrary to the popular notion that HSCs divide predominantly through S-P divisions, we show that S-S divisions are predominant throughout the lifespan of the animal, thereby expanding the HSC pool. We, therefore, provide a novel mathematical model-based experimental validation for reflecting HSC dynamics in vivo.

Clinical significance of high-dose chemotherapy with autologous stem cell transplantation in the era of novel agents in patients older than 65 years with multiple myeloma.

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is the standard treatment for symptomatic multiple myeloma (MM) in patients under 65 years of age. However, the performing of ASCT in older patients > 65 years without comorbidities or complications is controversial. Introduction of novel drugs, such as daratumumab, has improved the long-term survival of patients with MM who are ineligible for ASCT. This retrospective study aimed to evaluate the clinical significance of ASCT in older patients, even in the era of novel drugs. A total of 55 patients aged 65-74 years (15 ASCT recipients and 40 ASCT-ineligible patients) newly diagnosed with MM between March 2013 and October 2021 at our institution were analyzed in this study. There were no significant differences in the 3-year overall survival (84.6% vs. 90.6%, p = 0.72) and progression-free survival (PFS) (61.2% vs. 75.1%, p = 0.40) between ASCT recipients and ASCT-ineligible patients. There was also no significant difference in complete response (CR) with minimal residual disease (MRD)-negative rate between the two groups (27% vs. 33%, p = 1.0). Multivariate analysis showed that CR was an independent predictor of PFS (hazard ratio [HR], 0.26; 95% confidence interval, 0.08-0.76; p = 0.01). In this retrospective study, despite patients who were determined to be intolerant to ASCT, the non-ASCT group was non-inferior to the ASCT group in PFS and overall response rate. The results of this study confirm that the significance of ASCT is diminishing in patients 65 years of age and older because newer agents can achieve good responses without ASCT.

Missed Opportunities for Diagnosing Vertebral Osteomyelitis Caused by Influential Cognitive Biases.

BACKGROUND Vertebral osteomyelitis is a rare form of bone infection that requires prompt diagnosis and treatment; however, this is challenging because of the lack of specific symptoms and low sensitivity of diagnostic tests, especially in the early stages. Our case demonstrates the challenges in diagnosing vertebral osteomyelitis and provides relevant information for other physicians dealing with possible cases of vertebral osteomyelitis. CASE REPORT An 83-year-old man presented to the Emergency Department with severe low back pain of 2 weeks' duration. He had experienced occasional pain for several years, which was diagnosed as a compression fracture by an orthopedic surgeon at a local clinic. On arrival, he had a high-grade fever (40.2°C). The initial diagnosis was urinary tract infection, based on urinalysis results. However, after admission, vertebral osteomyelitis was diagnosed based on the results of magnetic resonance imaging of the spine and blood and urine cultures (both yielded methicillin-sensitive Staphylococcus aureus). He was immediately treated with the appropriate antibiotics and discharged on the 92nd day of admission without complications. CONCLUSIONS Our report highlights the difficulties in clinical diagnosis of vertebral osteomyelitis and identifies factors that can affect the diagnosis, including clinician bias, search satisficing, premature closure, anchoring bias, and diagnostic momentum. All patients with low back pain should be considered potential candidates for vertebral osteomyelitis.

Missed Diagnosis of Subarachnoid Haemorrhage.

A 79-year-old woman presented with left retro-orbital pain, headache and blurred vision. Based on negative radiological tests, life-threatening conditions like subarachnoid haemorrhage (SAH) were ruled out and outpatient follow-up was planned. However, the patient returned to the hospital that night because of progressively declining consciousness and was diagnosed with SAH by head computed tomography. The diagnosis of SAH is often challenging, especially in cases with negative radiological results. We describe some strategies, other than radiological examination, for ruling out SAH, such as performing a lumbar puncture and repeating tests to take account of disease progression, and describe biases which can affect clinical decision-making. LEARNING POINTS: A high diagnostic error rate highlights the difficulty in diagnosing subarachnoid haemorrhage (SAH).Headache together with oculomotor nerve palsy is an important symptom of SAH.If SAH is suspected, further diagnostic measures including lumber puncture are warranted.A strategy of repeating tests to take account of disease progression would also be effective.

Isolated Superior Mesenteric Artery Dissection Mimicking Impending Rupture of Abdominal Aortic Aneurysm.

BACKGROUND Isolated superior mesenteric artery dissection (SMAD) is a rare vascular disease that is difficult to diagnose. We report a case of SMAD in a patient with an abdominal aortic aneurysm (AAA) that mimicked an impending rupture of the AAA. In addition, we describe several clinical biases that contributed to the delayed diagnosis. CASE REPORT A 66-year-old man presented with a 3-day history of abdominal pain, without a history of trauma, that worsened gradually and caused him to visit our hospital. The patient's medical history included an AAA under observation. The patient was well oriented and initially remained hemodynamically stable, and the abdomen was soft and non-tender on palpation. An emergency contrast-enhanced computed tomography (CT) scan confirmed a 44-mm AAA without any leakage, but with an isolated SMAD. His previous physician confirmed there was no change in the AAA size since 3 months prior to hospital admission. Thus, the symptoms were caused by the isolated SMAD. The patient showed improvement with pain-relieving and antihypertensive management, without anticoagulation therapy or revascularization, and was discharged on day 25 of admission without any complications. CONCLUSIONS The misdiagnosis in this case was attributable to several clinical biases, including search satisfaction, Sutton's slip, and anchoring bias. Physicians should guard against presumptive diagnoses based on patient symptoms or initial plausible findings and instead pursue a thorough workup to reach a definitive diagnosis.

Angioimmunoblastic T-cell lymphoma accompanied by pure red cell aplasia: A case report.

BACKGROUND: Angioimmunoblastic T-cell lymphoma (AITL) is a peripheral T-cell lymphoma, which is a rare subtype of lymphoma. Patients with AITL often have skin lesions, which are observed in 50% of all cases; the chief complaint of this patient was palpable purpura. AITL often complicates autoimmune or hematological disorders; however, among these, pure red cell aplasia (PRCA) is a very rare complication of AITL. We herein report a case of AITL with PRCA. CASE SUMMARY: A 77-year-old Japanese man presented to our hospital with complaints of loss of appetite for 2 mo and a 10-d history of palpable purpura. On physical examination, the patient was afebrile but had bilateral multiple palpable purpuric lesions over the lower extremities, lower abdomen, and part of the upper extremities. Moreover, lymphadenopathy of the bilateral inguinal, cervical, and supraclavicular nodes was noted. Laboratory and imaging studies and skin biopsy were conducted but were inconclusive. Based on inguinal lymph node excisional biopsy, we diagnosed the patient with AITL. Subsequently, the patient developed progressive normocytic normochromic anemia that necessitated almost daily blood transfusion. The clinical presentations and results of bone marrow assessment were consistent with those of PRCA, which is associated with AITL. Chemotherapy was initiated but was not effective. The patient refused further chemotherapy and opted to continue receiving best supportive care. CONCLUSION: PRCA is an extremely rare complication of AITL. As the pathophysiology remains unclear, further research is warranted.

Intravascular lymphoma with hypopituitarism: A case report.

BACKGROUND: Intravascular lymphoma (IVL) is a rare subtype of lymphoma involving the growth of lymphoma cells within the vessel lumina without lymphadenopathy. Because of various modes of presentation and its rarity, IVL is often diagnosed postmortem. Herein, we report a case of intravascular B-cell lymphoma with hypopituitarism, an extremely rare complication, that was successfully treated with chemotherapy. CASE SUMMARY: An 80-year-old Japanese woman presented with a 7-mo history of a tingling sensation in the lower limbs. She also presented with various other symptoms such as pancytopenia, high fever daily, and unconsciousness with hypoglycemia. Although the doctor who previously treated her diagnosed hypoglycemia as being due to hypopituitarism, the cause of the other symptoms remained uncertain despite a 7-mo evaluation period. We performed bone marrow aspiration to evaluate pancytopenia and found that she had hemophagocytic lymphohistiocytosis (HLH). On the basis of a random skin biopsy for assessing the cause of HLH, she was diagnosed with intravascular B-cell lymphoma. HLH and hypopituitarism were considered secondary to IVL. All her clinical findings matched the presentations of IVL. She was immediately treated with chemotherapy and achieved complete response. She was relapse free two years after treatment. CONCLUSION: IVL should be included in the differential diagnosis of hypopituitarism, which although life-threatening, is treatable through prompt diagnosis and appropriate chemotherapy.

Metastatic spinal cord compression by gastric cancer: a case report.

Metastatic spinal cord compression (MSCC) is one of the serious complications of malignancy. Most cases of MSCC occur from breast or prostate cancer primaries; MSCC secondary to gastric cancer is rare. We herein report a case of a patient with gastric cancer with weakness of the lower limbs and urinary retention on initial presentation. This case demonstrates that although rare, bone metastases and MSCC may occur from gastric primaries. It also highlights the importance of prompt diagnosis and early treatment of MSCC.