Changes in TgAb and TPOAb titers are greater in thyrotoxicosis than isolated hypothyroidism induced by PD-1 blockade.

Anti-thyroglobulin antibodies (TgAb) and/or anti-thyroid peroxidase antibodies (TPOAb) positivity at baseline is a risk marker for thyroid immune-related adverse events (thyroid-irAEs) in anti-programmed cell death-1 antibody (PD-1-Ab) treatment; however, it is unknown if TgAb and TPOAb titers are associated with clinical characteristics of thyroid-irAEs. Among 586 patients treated with PD-1-Ab at Nagoya University Hospital between 2 November 2015 and 30 September 2021, 57 patients developed thyroid-irAEs (thyrotoxicosis [n = 38]; hypothyroidism without prior thyrotoxicosis {isolated hypothyroidism} [n = 19]) in whom thyroid function, and TgAb and TPOAb titers were determined at baseline and at the onset. The changes in TgAb (median, 54.8 vs. 0.2 IU/mL; p = 0.002) and TPOAb titers (31.6 vs. 0 IU/mL; p = 0.032) from baseline to onset of developing thyroid-irAEs were greater in patients with thyrotoxicosis than patients with isolated hypothyroidism. Higher TgAb and TPOAb titers, and the TgAb titer at baseline were associated with an earlier onset of thyrotoxicosis and higher peak free thyroxine levels, respectively. Twenty-eight patients who developed hypothyroidism after thyrotoxicosis had higher TgAb (54.5 vs. 10.7 IU/mL; p = 0.011) and TPOAb titers at baseline (46.1 vs. 9.0 IU/mL; p < 0.001) and greater changes in TgAb (61.7 vs. 7.8 IU/mL; p = 0.025) and TPOAb titers (52.8 vs. -0.8 IU/mL; p < 0.001) than patients who did not develop hypothyroidism. The TgAb titer at baseline and changes in the TgAb and TPOAb titers were greater in patients with thyrotoxicosis than patients with isolated hypothyroidism, suggesting that the magnitude of the thyroid autoimmune response reflects the clinical types of thyroid-irAEs.

Impact of coronavirus disease 2019 on medical practice in endocrine and metabolic diseases in Japan: a nationwide surveillance study conducted by the Japan Endocrine Society.

We investigated the impact of the Coronavirus disease 2019 (COVID-19) pandemic on the management of endocrine and metabolic disorders in Japan. We conducted a cross-sectional nationwide questionnaire survey targeting board-certified endocrinologists under the auspices of the Japan Endocrine Society. The questionnaire consisted of multiple-choice questions and open-ended responses. Out of approximately 2,700 specialists, 528 (19.5%) opted to participate, suggesting a high level of interest in COVID-19 management among endocrinologists. The study found that almost half of participants had encountered cases of endocrine and metabolic disorders following COVID-19 infection or vaccination. Conditions related to thyroid diseases, glucose metabolism disorders/diabetes, and hypothalamic-pituitary disorders were particularly prevalent. Diabetes and obesity were identified as having high rates of severe cases or fatalities due to COVID-19. The study also highlighted challenges in routine diagnosis and treatment, emphasizing the potential benefits of combining remote consultations with in-person visits to optimize the frequency of examinations and check-ups during infectious disease outbreak which disrupts access to healthcare providers. The insights obtained from this survey are expected to contribute to ensuring appropriate healthcare provision for patients with endocrine and metabolic disorders by using flexible consultation formats, particularly even in the conditions where medical access may be limited due to future outbreaks of emerging or re-emerging infectious diseases.

A machine learning approach for predicting treatment response of hyponatremia.

Hyponatremia leads to severe central nervous system disorders and requires immediate treatment in some cases. However, a rapid increase in serum sodium (s-Na) concentration could cause osmotic demyelination syndrome. To achieve a safety hyponatremia treatment, we develop a prediction model of s-Na concentration using a machine learning. Among the 341 and 47 patients admitted to two tertiary hospitals for hyponatremia treatment (s-Na <130 mEq/L), those who were admitted to the general unit with urine sodium <20 mEq/L or treated with desmopressin were excluded. Ultimately, 74 and 15 patients (342 and 146 6-hourly datasets) were included in the learning and validation data, respectively. We trained the prediction model using three regression algorithms for shallow machine learning to predict s-Na every 6 h during treatment with the data of patients with hyponatremia (median s-Na: 112.5 mEq/L; range: 110.0-116.8 mEq/L) from one hospital. The model was validated externally using the data of patients with hyponatremia (median s-Na: 117.0 mEq/L; range: 112.9-120.0 mEq/L) from another hospital. Using 5-7 predictors (water intake, sodium intake, potassium intake, urine volume, s-Na concentration, serum potassium concentration, serum chloride concentration), the support vector regression model showed the best performance overall (root mean square error = 0.05396; R2 = 0.92), followed by the linear regression and regression tree models. The predicted s-Na levels, using explainable machine learning algorithms and clinically accessible parameters, correlated well with the actual levels. Thus, our model could be applied to the treatment of hyponatremia in clinical practice.

Rapidly progressive interstitial lung disease with positive anti-MDA5 antibody as an immune-related complication of nivolumab: A case report.

Clinically amyopathic dermatomyositis (CADM) with a positive anti-MDA5 antibody titer is often associated with lethal rapidly progressive interstitial lung disease (RP-ILD). Despite the widespread use of immune checkpoint inhibitors (ICIs) in practice, there is no report of CADM with positive anti-MDA5 antibodies as their immune-related complication. We present a case of malignant mesothelioma who developed RP-ILD accompanied by distinct skin manifestations following the administration of nivolumab. Postmortem assessment of stored samples revealed a pre-existing positive titer of anti-MDA5 antibody, further augmented following ICI use, suggesting the possible value of serum screening for better risk stratification of this lethal complication.

Effects of Digitization of Self-Monitoring of Blood Glucose Records Using a Mobile App and the Cloud System on Outpatient Management of Diabetes: Single-Armed Prospective Study.

BACKGROUND: In recent years, technologies promoting the digitization of self-monitoring of blood glucose (SMBG) records including app-cloud cooperation systems have emerged. Studies combining these technological interventions with support from remote health care professionals have reported improvements in glycemic control. OBJECTIVE: To assess the use of an app-cloud cooperation system linked with SMBG devices in clinical settings, we evaluated its effects on outpatient management of diabetes without remote health care professional support. METHODS: In this multicenter, open-label, and single-armed prospective study, 48 patients with diabetes (including type 1 and type 2) at 3 hospitals in Japan treated with insulin or glucagon-like peptide 1 receptor agonists and performing SMBG used the app-cloud cooperation system for 24 weeks. The SMBG data were automatically uploaded to the cloud via the app. The patients could check their data, and their attending physicians reviewed the data through the cloud prior to the patients' regular visits. The primary outcome was changes in glycated hemoglobin (HbA1c) levels. RESULTS: Although HbA1c levels did not significantly change in all patients, the frequency of daily SMBG following applying the system was significantly increased before induction at 12 (0.60 per day, 95% CI 0.19-1.00; P=.002) and 24 weeks (0.43 per day, 95% CI 0.02-0.84; P=.04). In the subset of 21 patients whose antidiabetic medication had not been adjusted during the intervention period, a decrease in HbA1c level was observed at 12 weeks (P=.02); however, this significant change disappeared at 24 weeks (P=.49). The Diabetes Treatment Satisfaction Questionnaire total score and "Q4: convenience" and "Q5: flexibility" scores significantly improved after using the system (all P<.05), and 72% (33/46) patients and 76% (35/46) physicians reported that the app-cloud cooperation system helped them adjust insulin doses. CONCLUSIONS: The digitization of SMBG records and sharing of the data by patients and attending physicians during face-to-face visits improved self-management in patients with diabetes. TRIAL REGISTRATION: Japan Registry of Clinical Trials (jRCT) jRCTs042190057; https://jrct.niph.go.jp/en-latest-detail/jRCTs042190057.

Simplified drug efficacy evaluation system for vasopressin neurodegenerative disease using mouse disease-specific induced pluripotent stem cells.

Familial neurohypophyseal diabetes insipidus (FNDI) is a degenerative disorder in which vasopressin-secreting neurons degenerate over time due to the production of mutant proteins. We have demonstrated therapeutic effects of chemical chaperones in an FNDI mouse model, but the complexity and length of this evaluation were problematic. In this study, we established disease-specific mouse induced pluripotent stem cells (iPSCs) from FNDI-model mice and differentiated vasopressin neurons that produced mutant proteins. Fluorescence immunostaining showed that chemical chaperones appeared to protect vasopressin neurons generated from iPSCs derived from FNDI-model mice. Although KCL stimulation released vasopressin hormone from vasopressin neurons generated from FNDI-derived iPSCs, vasopressin hormone levels did not differ significantly between baseline and chaperone-added culture. Semi-quantification of vasopressin carrier protein and mutant protein volumes in vasopressin neurons confirmed that chaperones exerted a therapeutic effect. This research provides fundamental technology for creating in vitro disease models using human iPSCs and can be applied to therapeutic evaluation of various degenerative diseases that produce abnormal proteins.

Clinical characteristics and potential biomarkers of thyroid and pituitary immune-related adverse events.

Immune checkpoint inhibitors (ICIs) can cause immune-related adverse events (irAEs) in several organs including endocrine glands. Among endocrine irAEs, thyroid and pituitary irAEs are frequently observed, followed by primary adrenal insufficiency, insulin-dependent diabetes mellitus, and hypoparathyroidism. These conditions could lead to life-threatening consequences, such as adrenal crisis and diabetic ketoacidosis. On the other hand, several types of irAEs including thyroid and pituitary irAEs are reported to be associated with better overall survival. Therefore, it is important to understand and manage endocrine irAEs, which differ depending on the ICI regimen used. In this review, we describe the clinical features, potential biomarkers, management strategies, and possible mechanisms of thyroid and pituitary irAEs.

A retrospective study on tolvaptan prescription in clinical practice in patients with syndrome of inappropriate secretion of antidiuretic hormone (SIADH) using the Japanese claims database.

We aimed to survey the status of tolvaptan administration in routine clinical practice since the approval of a novel indication for treating syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in Japan. Data from a population of 3,152 patients aged ≥18 years and diagnosed with SIADH between July 1, 2020 and June 30, 2021 were extracted from a Japanese database. Tolvaptan was administered to 586 patients while 2,566 patients were followed up without tolvaptan. In the tolvaptan-treated group, the standard initial doses were 3.75 mg and 7.5 mg in 290 (49.5%) and 250 (42.7%) patients, respectively. The dose was increased in 112 (38.6%) and 71 (28.4%) and decreased in 8 (2.8%) and 46 (18.4%) of patients with 3.75 and 7.5 mg initial doses, respectively. Of the total 586 SIADH patients treated with tolvaptan, serum sodium concentrations were analyzed in 60 patients. In both treatment groups of 3.75 and 7.5 mg initial doses, the serum sodium concentration was elevated from the second day of treatment and reached 135 mEq/L on the fourth day, which was maintained for 2 weeks. Rapid correction of hyponatremia (>10 mEq/L increase in serum sodium concentration over 1 day or >18 mEq/L increase over 2 days) occurred in 26.7% patients with a 7.5 mg initial dose (4 of 15 patients) but not in the patients with a 3.75 mg initial dose (n = 16), suggesting that an initial dose of 3.75 mg of tolvaptan may be a better choice for the safe and proper correction of hyponatremia.

Improved glycemic control after the use of flash glucose monitoring accompanied by improved treatment satisfaction in patients with non-insulin-treated type 2 diabetes: A post-hoc analysis of a randomized controlled trial.

AIMS: In our previously reported randomized controlled trial in patients with noninsulin-treated type 2 diabetes, the use of flash glucose monitoring (FGM) improved glycated hemoglobin (HbA1c), and the improvement was sustained after the cessation of glucose monitoring. In this post-hoc analysis, we examined data from our trial to identify the factors that influenced FGM efficacy. METHODS: We analyzed data for 48 of 49 participants of the FGM group who completed the trial to clarify the changes in various parameters and factors related to HbA1c improvement with the use of FGM. RESULTS: Analyses of the FGM data during the 12-week FGM provision period showed that the weekly mean blood glucose levels considerably decreased as early as at 1 week compared with the baseline values, and this decline continued for 12 weeks. An enhancement in the Diabetes Treatment Satisfaction Questionnaire regarding "willingness to continue the current treatment" score was significantly associated with the improvement in HbA1c at 12 (p = 0.009) and 24 weeks (p = 0.012). CONCLUSIONS: Glycemic control was improved soon after FGM initiation, accompanied by improved satisfaction with continuation of the current treatment in patients with noninsulin-treated type 2 diabetes.

Generation and purification of ACTH-secreting hPSC-derived pituitary cells for effective transplantation.

Pituitary organoids are promising graft sources for transplantation in treatment of hypopituitarism. Building on development of self-organizing culture to generate pituitary-hypothalamic organoids (PHOs) using human pluripotent stem cells (hPSCs), we established techniques to generate PHOs using feeder-free hPSCs and to purify pituitary cells. The PHOs were uniformly and reliably generated through preconditioning of undifferentiated hPSCs and modulation of Wnt and TGF-ß signaling after differentiation. Cell sorting using EpCAM, a pituitary cell-surface marker, successfully purified pituitary cells, reducing off-target cell numbers. EpCAM-expressing purified pituitary cells reaggregated to form three-dimensional pituitary spheres (3D-pituitaries). These exhibited high adrenocorticotropic hormone (ACTH) secretory capacity and responded to both positive and negative regulators. When transplanted into hypopituitary mice, the 3D-pituitaries engrafted, improved ACTH levels, and responded to in vivo stimuli. This method of generating purified pituitary tissue opens new avenues of research for pituitary regenerative medicine.

Concurrent development of small lymphocytic lymphoma and lung cancer: A report of two cases and a review of the literature.

Small lymphocytic lymphoma (SLL) is a rare disease subtype which has the same morphological and immunophenotypic features as chronic lymphocytic leukemia (CLL) but does not demonstrate lymphocytosis and grows mainly in the lymph nodes and spleen. As with CLL, SLL patients tend to present with immune abnormalities, and are associated with an increased risk for developing second primary malignancies. We report here two cases of SLL who developed lung cancer concurrently. The biological and clinical features of these two patients were very similar to each other; they both developed SLL with trisomy 12 and lacked lymphocytosis or cytopenia. SLL cells involved nodal areas adjacent to lung adenocarcinoma which expressed PD-L1. One patient received immunochemotherapy including nivolumab and ipilimumab against lung cancer, and notably, transient deterioration of SLL occurred after the second cycle of immunochemotherapy along with the development of immune related adverse events. Immunohistochemical analysis of the SLL samples of the patient revealed that the tumor cells were positive for CTLA-4, suggesting that ipilimumab might have potentially induced the activation of SLL cells by blocking the inhibitory signal mediated by CTLA-4. These clinical findings indicate the potential biological relationship between SLL and lung cancer. According to these observations, we would like to draw attention to the possibility of deterioration of SLL when immune checkpoint inhibitors are used for the treatment of malignancies developed in SLL patients.

Response to endoplasmic reticulum stress in arginine vasopressin neurons.

Arginine vasopressin (AVP) is an antidiuretic hormone synthesized principally in the hypothalamic supraoptic and paraventricular nuclei. The immunoglobulin heavy chain binding protein (BiP), one of the most abundant endoplasmic reticulum (ER) chaperones, is highly expressed in AVP neurons, even under basal conditions. Moreover, its expression is upregulated in proportion to the increase in AVP expression under dehydration. These data suggest that AVP neurons are constantly exposed to ER stress. BiP knockdown in AVP neurons induces ER stress and autophagy, resulting in AVP neuronal loss, indicating that BiP is pivotal in maintaining the AVP neuron system. Furthermore, inhibition of autophagy after BiP knockdown exacerbates AVP neuronal loss, suggesting that autophagy induced under ER stress is a protective cellular mechanism by which AVP neurons cope with ER stress. Familial neurohypophysial diabetes insipidus (FNDI) is an autosomal dominant disorder caused by mutations in the AVP gene. It is characterized by delayed-onset progressive polyuria and eventual AVP neuronal loss. In AVP neurons of FNDI model mice, mutant protein aggregates are confined to a specific compartment of the ER, called the ER-associated compartment (ERAC). The formation of ERACs contributes to maintaining the function of the remaining intact ER, and mutant protein aggregates in ERACs undergo autophagic-lysosomal degradation without isolation or translocation from the ER, representing a novel protein degradation system in the ER.

Amino acid polymorphisms in human histocompatibility leukocyte antigen class II and proinsulin epitope have impacts on type 1 diabetes mellitus induced by immune-checkpoint inhibitors.

Introduction: Immune-checkpoint inhibitors are effective in various advanced cancers. Type 1 diabetes mellitus induced by them (ICI-T1DM) is a serious complication requiring prompt insulin treatment, but the immunological mechanism behind it is unclear. Methods: We examined amino acid polymorphisms in human histocompatibility leukocyte antigen (HLA) molecules and investigated proinsulin epitope binding affinities to HLA molecules. Results and Discussion: Twelve patients with ICI-T1DM and 35 patients in a control group without ICI-T1DM were enrolled in the study. Allele and haplotype frequencies of HLA-DRB1*04:05, DQB1*04:01, and most importantly DPB1*05:01 were significantly increased in patients with ICI-T1DM. In addition, novel amino acid polymorphisms in HLA-DR (4 polymorphisms), in DQ (12 polymorphisms), and in DP molecules (9 polymorphisms) were identified. These amino acid polymorphisms might be associated with the development of ICI-T1DM. Moreover, novel human proinsulin epitope clusters in insulin A and B chains were discovered in silico and in vitro peptide binding assays to HLA-DP5. In conclusion, significant amino acid polymorphisms in HLA-class II molecules, and conformational alterations in the peptide-binding groove of the HLA-DP molecules were considered likely to influence the immunogenicity of proinsulin epitopes in ICI-T1DM. These amino acid polymorphisms and HLA-DP5 may be predictive genetic factors for ICI-T1DM.

Anti-tumor effects of anti-programmed cell death-1 antibody treatment are attenuated in streptozotocin-induced diabetic mice.

Hyperglycemia impairs immune response; however, it remains unknown whether the anti-tumor effects of anti-programmed cell death-1 antibody (PD-1-Ab) treatment are changed in hyperglycemic conditions. We analyzed the effect of PD-1-Ab on tumor growth in streptozotocin-induced diabetic mice (STZ-mice) subcutaneously inoculated with MC38 (a colon carcinoma cell line). Furthermore, we assessed the expression of chemokines by polymerase chain reaction (PCR) array in tumor-draining lymph nodes (dLNs) of these mice and MC38 cells cultured in different glucose concentrations. The suppressive effect of PD-1-Ab on tumor growth was attenuated. This was accompanied by fewer tumor-infiltrating CD8+ T cells, and STZ-mice had fewer tumor-infiltrating CD11c+ dendritic cells (DCs) than normoglycemic mice. mRNA expression levels of CXCL9, a chemokine recruiting CD8+ T cells, were lower in dLNs of STZ-mice than in normoglycemic mice after PD-1-Ab treatment, and its protein was expressed in DCs. In MC38 cells cultured with 25 mM glucose, mRNA expression of CCL7, a chemokine recruiting DCs, was decreased compared to cells cultured with 5 mM glucose. These results suggest that the STZ-induced hyperglycemia impairs the effect of PD-1-Ab treatment on MC38 tumor growth, and is accompanied by reduced infiltration of DCs and CD8+ T cells and decreased expression of CCL7 and CXCL9.

Risk of Thyroid Dysfunction in PD-1 Blockade Is Stratified by the Pattern of TgAb and TPOAb Positivity at Baseline.

CONTEXT: Positive antithyroglobulin (TgAb) and/or antithyroid peroxidase antibodies (TPOAb) at baseline indicate a high risk of thyroid immune-related adverse events (irAEs) induced by antiprogrammed cell death-1 antibodies (anti-PD-1-Ab). However, whether the positivity patterns of both antibodies are associated with the risk of thyroid irAEs is unknown. OBJECTIVE: The aim of the present study was to clarify the association of the pattern of TgAb and TPOAb positivity at baseline with the risk of thyroid irAEs induced by anti-PD-1-Ab. METHODS: Patients (n = 516) were evaluated for TgAb and TPOAb at baseline and prospectively for thyroid function every 6 weeks for 24 weeks after initiating anti-PD-1-Ab. RESULTS: Fifty-one (9.9%) patients developed thyroid irAEs (thyrotoxicosis in 34, hypothyroidism without prior thyrotoxicosis in 17). Twenty-five patients subsequently developed hypothyroidism following thyrotoxicosis. The cumulative incidence of thyroid irAEs differed among 4 groups classified by the presence of TgAb/TPOAb at baseline (group 1: TgAb-(-)/TPOAb-(-), 4.6% [19/415]; group 2: TgAb-(-)/TPOAb-(+), 15.8% [9/57]; group 3: TgAb-(+)/TPOAb-(-), 42.1% [8/19]; group 4: TgAb-(+)/TPOAb-(+), 60.0% [15/25]) as follows: groups 1 vs 2-4 (P ≤ .001) and groups 2 vs 3 (P = .008) and 4 (P < .001). There were different incidences of thyrotoxicosis (groups 1-4, 3.1%, 5.3%, 31.6%, 48.0%, respectively; P < .001) in groups 1 vs 3 and 4, and groups 2 vs 3 and 4, and of hypothyroidism (groups 1-4: 2.9%, 15.8%, 31.6%, 60.0%, respectively; P < .001) in groups 1 vs 2 to 4, and groups 2 vs 4. CONCLUSION: The risk of thyroid irAEs was affected by the pattern of TgAb and TPOAb positivity at baseline; there were high risks of thyrotoxicosis in patients with TgAb-(+) and of hypothyroidism in patients with TgAb-(+) and those with TPOAb-(+).

Subcutaneous transplantation of human embryonic stem cells-derived pituitary organoids.

Introduction: The pituitary gland, regulating various hormones, is central in the endocrine system. As spontaneous recovery from hypopituitarism is rare, and exogenous-hormone substitution is clumsy, pituitary replacement via regenerative medicine, using pluripotent stem cells, is desirable. We have developed a differentiation method that in mice yields pituitary organoids (POs) derived from human embryonic stem cells (hESC). Efficacy of these POs, transplanted subcutaneously into hypopituitary mice, in reversing hypopituitarism was studied. Methods: hESC-derived POs were transplanted into inguinal subcutaneous white adipose tissue (ISWAT) and beneath dorsal skin, a relatively avascular region (AR), of hypophysectomized severe combined immunodeficient (SCID) mice. Pituitary function was evaluated thereafter for ¾ 6mo, assaying basal plasma ACTH and ACTH response to corticotropin-releasing hormone (CRH) stimulation. Histopathologic examination of organoids 150d after transplantation assessed engraftment. Some mice received an inhibitor of vascular endothelial growth factor (VEGF) to permit assessment of how angiogenesis contributed to subcutaneous engraftment. Results: During follow-up, both basal and CRH-stimulated plasma ACTH levels were significantly higher in the ISWAT group (p < 0.001 - 0.05 and 0.001 - 0.005, respectively) than in a sham-operated group. ACTH secretion also was higher in the ISWAT group than in the AR group. Histopathologic study found ACTH-producing human pituitary-cell clusters in both groups of allografts, which had acquired a microvasculature. POs qPCR showed expression of angiogenetic factors. Plasma ACTH levels decreased with VEGF-inhibitor administration. Conclusions: Subcutaneous transplantation of hESC-derived POs into hypopituitary SCID mice efficaciously renders recipients ACTH-sufficient.

Generation of hypothalamic neural stem cell-like cells in vitro from human pluripotent stem cells.

When damaged, restoring the function of the hypothalamus is currently impossible. It is unclear whether neural stem cells exist in the hypothalamus. Studies have reported that adult rodent tanycytes around the third ventricle function as hypothalamic neural stem cell-like cells. However, it is currently impossible to collect periventricular cells from humans. We attempted to generate hypothalamic neural stem cell-like cells from human embryonic stem cells (ESCs). We focused on retina and anterior neural fold homeobox (RAX) because its expression is gradually restricted to tanycytes during the late embryonic stage. We differentiated RAX::VENUS knockin human ESCs (hESCs) into hypothalamic organoids and sorted RAX+ cells from mature organoids. The isolated RAX+ cells formed neurospheres and exhibited self-renewal and multipotency. Neurogenesis was observed when neurospheres were transplanted into the mouse hypothalamus. We isolated RAX+ hypothalamic neural stem cell-like cells from wild-type human ES organoids. This is the first study to differentiate human hypothalamic neural stem cell-like cells from pluripotent stem cells.

Pyogenic spondylitis due to Streptococcus agalactiae with paraspinal abscess and vertebral destruction in a diabetic patient: time course of imagings.

Summary: A 76-year-old female with type 2 diabetes mellitus presented with hematuria, low back pain, and intermittent fever for 7 days. She was admitted to our hospital and diagnosed with Streptococcus agalactiae (GBS) bacteremia. CT showed an air density within the right iliopsoas muscle, and an MRI of the spine revealed hyperintensity in the right half of the L1-L2 intervertebral disk, leading to the diagnosis of a paraspinal abscess and L1-L2 pyogenic spondylitis. Antibiotic therapy was started and the clinical symptoms, as well as serologic biomarkers and radiologic images of the paraspinal abscess, were improved. The therapy was stopped on day 72 despite vertebral destruction progression. Vertebral endplate ossification was observed on day 108, and further bone formation was noted on day 177. Our case study with radiologic findings over 6 months demonstrated how bone destruction with pyogenic spondylitis, which had been treated with antibiotic therapy, improved after cessation of antibiotics. Learning points: Although GBS is a rare cause of spondylitis, diabetic mellitus is a risk factor for the development of invasive GBS infections, especially under poor glycemic control. Bone destruction of pyogenic spondylitis can improve after discontinuation of antibiotic therapy. It may be important to decide the period of antibiotic therapy based on clinical conditions, serologic biomarkers, and soft tissue findings rather than bone findings. When elderly diabetic patients present with back pain and fever, spondylitis should be considered in the differential diagnosis to avoid potential diagnostic delays or misdiagnosis.