Variation in coagulation factor activity levels cause discrepancies between activated partial thromboplastin time and anti-Xa activity for heparin monitoring: a retrospective observational study.

BACKGROUND: Unfractionated heparin (UFH) is primarily monitored using activated partial thromboplastin time (APTT). However, the recent introduction of anti-activated factor X (anti-Xa) activity testing has provided a direct evaluation of Xa inhibition by anticoagulants. This study aimed to investigate discrepancies between APTT and anti-Xa activity during UFH monitoring in critically ill patients and explore their underlying causes. METHODS: This study analyzed 271 pairs of laboratory test results from blood samples of 99 critically ill patients receiving continuous intravenous UFH. Theoretical APTT values were calculated using fitted curve equations from spiked sample measurements with anti-Xa activity. Samples were categorized into three groups based on the measurement of the APTT/theoretical APTT ratio: the lower group (< 80%), the concordant group (80-120%), and the upper group (> 120%). RESULTS: The overall concordance rate between APTT and anti-Xa activity was 45%, with a 55% discrepancy rate. The lower group frequently showed apparent heparin overdoses, while coagulation factor activities in the lower and upper groups were higher and lower, respectively, than those in the concordant group. Particularly, the lower group exhibited higher factor VIII activity levels than the upper and concordant groups. CONCLUSIONS: Discrepancies between APTT and anti-Xa activity were frequently observed, influenced by changes in coagulation factors activity levels. The lower and upper groups were classified as pseudo-heparin-resistant and coagulopathy types, respectively. Accurate monitoring of heparin in critically ill patients is crucial, especially in cases of pseudo-heparin resistance, where APTT values may wrongly indicate inadequate heparin dosing despite sufficient anti-Xa activity. Understanding these discrepancies is important for managing heparin therapy in critically ill patients. TRIAL REGISTRATION: Not applicable.

Multiple Retroperitoneal Abscesses Caused by Citrobacter koseri are Associated with a Poor Prognosis: A Case Report.

Citrobacter koseri causes opportunistic infections in various organs. We herein report an 84-year-old man with diabetes mellitus who presented to our hospital with left hip pain and walking difficulty. Computed tomography showed an extensive abscess with gas production, mainly in the left retroperitoneal space, caused by C. koseri infection. Despite daily cleaning of the wound and antimicrobial therapy (with surgical drainage), the patient developed repeated pneumonia and small bowel hemorrhaging caused by disseminated intravascular coagulation and died on day 65 of hospitalization. Overall, retroperitoneal abscesses caused by C. koseri are rare, and multiple abscesses may show a poor prognosis.

A case of plastic bronchitis with a remarkable response to steroids.

Plastic bronchitis can cause fatal airway obstruction. An 85-year-old woman with no medical history presented to the emergency department of our hospital with progressing respiratory failure and hemoptysis. Bronchoscopy revealed a fibrin-type cast thrombus in the trachea, and plastic bronchitis was diagnosed. Initial treatment involved airway thrombus removal, and the patient survived. However, bleeding persisted for 6 days, and respiratory status showed slight improvement despite ventilatory management. Steroids were administered for concomitant acute respiratory distress syndrome, and there was marked improvement in both airway hemorrhage and respiratory failure. The patient was extubated, the steroid dose was reduced, and no rebleeding was observed. The patient was discharged from the hospital 1 month after the onset of symptoms. Blood tests were positive for the myeloperoxidase-anti-neutrophil cytoplasmic antibody; however, no biopsy was performed, and no specific symptoms were observed. A definitive diagnosis was therefore not reached. The causes of plastic bronchitis are numerous, and there are no standardized diagnostic criteria or treatment guidelines for this condition. The present case suggests that steroids may be effective in some patients with plastic bronchitis.

Subacute thyroiditis associated with thyrotoxic periodic paralysis after COVID-19 vaccination: a case report.

Summary: We report a 26-year-old Japanese man who visited our outpatient clinic presenting fever immediately after i.m. injection of the second dose of a coronavirus disease 2019 (COVID-19) vaccine (Moderna®). At the first visit, the patient had a fever of 37.7°C and a swollen thyroid gland with mild tenderness. He was diagnosed with subacute thyroiditis (SAT) based on the presence of thyrotoxicosis (free tri-iodothyronine, 32.3 pg/mL; free thyroxine, >7.77 ng/dL; and thyroid-stimulating hormone (TSH) < 0.01 µIU/mL), high C-reactive protein level (7.40 mg/dL), negative TSH receptor antibody, and characteristic ultrasound findings. His HLA types were A*02:01/24:02, B*15:11/35:01, Cw*03:03, DRB1*09:01/12:01, DQB1*03:03, and DPB1*05: 01/41:01. He was initially administered prednisolone 15 mg/day, following which the fever subsided. After 10 days, he developed limb weakness and could not walk. The serum potassium level decreased to 1.8 mEq/L, which confirmed the diagnosis of thyrotoxic periodic paralysis (TPP). Potassium supplementation was initiated. The muscle weakness gradually decreased. Prednisolone therapy was terminated 6 weeks after the first visit. His thyroid function returned to normal 5 months after the first visit, through a hypothyroid state. To our knowledge, this is the first reported case of TPP-associated SAT following COVID-19 vaccination. Persistent fever following vaccination should be suspected of SAT. Additionally, TPP may be associated with SAT in Asian male patients. Learning points: Following coronavirus disease 2019 (COVID-19) vaccination, subacute thyroiditis may develop regardless of the vaccine type. If persistent fever, anterior neck pain, swelling and tenderness of thyroid gland, and symptoms of thyrotoxicosis are observed immediately after the COVID-19 vaccination, examination in consideration of the onset of subacute thyroiditis is recommended. HLA-B35 may be associated with the onset of subacute thyroiditis after the COVID-19 vaccination. Although rare, subacute thyroiditis can be associated with thyrotoxic periodic paralysis, especially in Asian men. Glucocorticoid therapy for subacute thyroiditis may induce thyrotoxic periodic paralysis through hypokalemia.