Giant cell arteritis (GCA) is a chronic vasculitis that primarily affects the elderly, and can cause visual impairment, requiring prompt diagnosis and treatment. The global impact of the coronavirus disease 2019 (COVID-19) pandemic has been substantial. Although vaccination programs have been a key defense strategy, concerns have arisen regarding post-vaccination immune-mediated disorders and related risks. We present a case of GCA after COVID-19 vaccination with 2 years of follow-up. A 69-year-old woman experienced fever, headaches, and local muscle pain two days after receiving the COVID-19 vaccine. Elevated inflammatory markers were observed, and positron emission tomography (PET) revealed abnormal uptake in the major arteries, including the aorta and subclavian and iliac arteries. Temporal artery biopsy confirmed the diagnosis of GCA. Treatment consisted of pulse therapy with methylprednisolone, followed by prednisolone (PSL) and tocilizumab. Immediately after the initiation of treatment, the fever and headaches disappeared, and the inflammation markers normalized. The PSL dosage was gradually reduced, and one year later, a PET scan showed that the inflammation had resolved. After two years, the PSL dosage was reduced to 3 mg. Fourteen reported cases of GCA after COVID-19 vaccination was reviewed to reveal a diverse clinical picture and treatment response. The time from onset of symptoms to GCA diagnosis varied from two weeks to four months, highlighting the challenge of early detection. The effectiveness of treatment varied, but was generally effective similarly to that of conventional GCA. This report emphasizes the need for clinical vigilance and encourages further data collection in post-vaccination GCA cases.

In some cases, differentiating thrombotic thrombocytopenic purpura (TTP) from septic disseminated intravascular coagulation (DIC) without measuring ADAMTS13 activity is critical for urgent lifesaving plasma exchange. To investigate whether PLASMIC score without identifying the presence of schistocytes, D-dimer, fibrin/fibrinogen degradation products (FDP), FDP/D-dimer ratio, prothrombin time-international normalized ratio (PT-INR), lactate dehydrogenase (LD), hemoglobin (Hb), and LD/Hb ratio are useful in differentiating patients with TTP from those with septic DIC. Retrospective analysis was conducted on the medical records of the patients with septic DIC (32 patients) or TTP (16 patients). The PLASMIC score and other laboratory measurements all were helpful in differentiating TTP from septic DIC. When dichotomized between high risk (scores 6–7) and intermediate–low risk (scores 0–5), the PLASMIC score predicted TTP with a sensitivity of 75.0% and a specificity of 100%. However, 4 of 16 patients with TTP and 19 of 32 patients with septic DIC showed comparable PLASMIC scores of 4 or 5, making it difficult to distinguish between the two by PLASMIC score alone. Among the measurements examined, the LDH/Hb ratio was the most useful for differentiation. Receiver operating characteristic analysis of the LD/Hb ratio for predicting TTP revealed a cutoff of 53.7 (IU/10 g) (sensitivity 0.94, specificity 0.91). If the LD/Hb ratio was less than 53.7, it was unlikely that the patient had TTP. A combination of the LD/Hb ratio and the PLASMIC score may be useful for distinguishing between TTP and DIC and identifying patients who need rapid plasma exchange or caplacizumab administration.

Mycoplasma pneumoniae is a self-propagating microorganism that commonly causes respiratory tract infections. It can also cause a variety of extrapulmonary symptoms with or independently of respiratory symptoms, such as skin lesions, arthralgia, myalgia, hemolysis, cardiac lesions, gastrointestinal symptoms, and central nervous system lesions, which are rare manifestations reported in approximately 0.1% of cases. In this study, we present a unique case of Mycoplasma-related abducens nerve palsy, polyarthritis, and erythema multiforme without respiratory disease. The patient was a 69-year-old woman who presented to our hospital with a skin rash, fever, arthralgia, and diplopia without respiratory symptoms. Brain magnetic resonance imaging showed optic neuritis on the right side, suggesting the diplopia was caused by right abducens nerve palsy. However, the etiologies of abducens nerve palsy were not revealed by the physical examination, blood biochemistry tests, or bacteriological examinations, including the cerebrospinal fluid examination obtained at admission. Mycoplasma infection was suspected from erythema multiforme revealed by a skin biopsy and polyarthralgia, and it was finally diagnosed according to elevated Mycoplasma particle agglutination (PA) antibodies in paired serum. Though minocycline did not improve her diplopia, the daily administration of 30 mg of prednisolone gradually improved her symptoms, and the Mycoplasma PA antibody titer, which was regularly measured in the clinical course, also decreased, suggesting a relationship between Mycoplasma infection and abducens nerve palsy. This is the first case of isolated abducens nerve palsy, which was reported as the only central neurological symptom in an adult patient with Mycoplasma infection. The mechanism or pathogenesis of CNS manifestations caused by Mycoplasma pneumoniae remains to be elucidated, and further investigation is needed. Hence, Mycoplasma infection is a common disease. Clinicians should be aware of the diverse manifestations, including abducens nerve palsy, of Mycoplasma infection and should consider Mycoplasma infection even in the absence of typical respiratory symptoms.

Neuro-Behçet’s disease (NB) is a rare complication of Behçet’s disease (BD) characterised by central nervous system involvement. While NB typically presents with brainstem lesions, we report an unusual case of NB in a 27-year-old male with multiple subcortical nodular brain lesions but without brainstem, thalamic, or basal ganglia involvement, making this presentation exceptionally rare. The patient had a prior diagnosis of BD and was HLA-B51 positive. He presented with a sudden loss of consciousness, which was attributed to a seizure. Imaging studies showed low-density areas in the white matter of the bilateral temporal lobes and the right frontoparietal lobe on brain CT. Cerebrospinal fluid examination indicated elevated initial pressure and protein concentration, along with increased interleukin-6. Despite presenting with nodular brain lesions, distinguishing between NB and infectious diseases such as tuberculosis (TB) was challenging, and required brain biopsy revealing vasculitis. However, even with this biopsy result, TB could not be ruled out, so TB was treated at the same time. Treatment with anti-TB drugs and standard steroid therapy initially failed to improve the patient’s condition. However, increasing the steroid dosage considering the increased steroid degradation by rifampicin, including pulse therapy with 2 g of methylprednisolone, followed by 18 mg of betamethasone, led to remission of the nodular brain lesions and resolution of the nasopharyngeal ulcer. This case highlights the diagnostic challenge of differentiating between NB and TB based on imaging alone and the potential efficacy of high-dose steroid therapy in cases of steroid-resistant NB with subcortical nodular brain lesions.

Purpose: This study aims to investigate the characteristics of Epstein–Barr virus associated-hemophagocytic lymphohistiocytosis (EBV-HLH) and HLH caused by a severe form of infectious mononucleosis (IM-HLH) compared to IM by EBV, and thus also to assist in early diagnosis and providing appropriate treatment. Methods: Data for this analysis were collected from patients at the Department of General Medicine, Nara Medical University, between April 1, 2012, and August 1, 2020. EBV infection was diagnosed using clinical presentation and laboratory tests. HLH diagnosis followed the HLH-2004 protocol, supplemented by plasma EBV DNA detection. A range of clinical and laboratory parameters were collected, including age, sex, clinical outcomes, blood cell counts, hemoglobin, platelets, and various serum values. Plasma EBV DNA levels and flow cytometric analysis (FCM) of bone marrow were performed for HLH cases. Results: Among 1850 hospitalized patients, 14 cases were identified, including 2 HLH cases and 12 IM cases. Comparative analysis revealed distinctive features of HLH, including lower lymphocyte and platelet counts and higher levels of ferritin, soluble interleukin 2 receptor (sIL-2R), and D dimer compared to IM. Notably, one HLH case responded well to corticosteroid monotherapy, while the other case did not, resulting in a fatal outcome. Detection of a cluster of CD5-CD7 lymphocytes in bone marrow is a hallmark of EBV-HLH and useful to distinguish from IM-HLH. Conclusion: This study underscores the importance of early differentiation among EBV-HLH, IM-HLH, and IM in adults to guide appropriate treatment strategies. While specific laboratory markers help distinguish HLH from IM, a more detailed analysis of FCM is crucial for precise diagnosis of HLH cases and tailored therapeutic interventions.