Neuromyelitis optica spectrum disorder (NMOSD) associated with rheumatoid arthritis (RA) is an uncommon inflammatory demyelinating condition that presents a diagnostic challenge. We report the case of a woman with a 10-year history of RA and a six-year progressive paraparesis. Magnetic resonance imaging revealed longitudinally extensive transverse myelitis from T4 to the filum terminale. Cerebrospinal fluid analysis showed negative oligoclonal bands and hyperproteinorachia without pleocytosis. The immunological profile confirmed positivity for anti-aquaporin-4 antibodies (62 UI/mL), along with markedly elevated rheumatoid factor and anti-CCP. Following intravenous methylprednisolone, a partial motor recovery to 3/5 was achieved. The patient voluntarily discontinued medical follow-up, preventing the initiation of maintenance immunosuppressive therapy. The onset of atypical neurological symptoms in patients with systemic autoimmunity requires a high clinical suspicion of NMOSD, regardless of the stability of the underlying arthropathy. Early diagnosis and strict treatment adherence are critical to prevent cumulative structural damage and permanent disability.

Antineutrophil cytoplasmic antibodies (ANCA)-negative pauci-immune necrotizing glomerulonephritis (PING) is a rare entity, representing a distinct subset of small-vessel vasculitis. The absence of ANCA does not exclude the diagnosis, and clinical suspicion should remain high in the presence of compatible systemic and renal findings. We present the case of a 22-year-old woman with recurrent, non-specific cutaneous manifestations since early childhood, who was hospitalized for an exacerbation of skin lesions. Laboratory results revealed nephrotic-range proteinuria of 17 g/d [N < 150 mg/d] and a reduced estimated glomerular filtration rate (eGFR) of 47 mL/min/1.73 m² [N > 90 mL/min/1.73 m²]. Renal biopsy results demonstrated cellular crescents, focal segmental tubular necrosis, intense mononuclear inflammatory infiltrates, and segmental proliferation of Bowman's capsule epithelial cells. Direct immunofluorescence yielded negative results for IgG, IgA, IgM, C3, or C1q deposits. Electron microscopy confirmed segmental podocyte foot process effacement and microvillous transformation. Serologic testing was comprehensively negative, specifically confirming the absence of PR3-ANCA, MPO-ANCA, anti-glomerular basement membrane (GBM) antibodies, and serum cryoglobulins. Based on the clinical, histologic, and immunopathologic findings, a definitive diagnosis of isolated ANCA-negative PING was established, although atypical features prompted the consideration of secondary podocytopathy. Methylprednisolone therapy was initiated, but progressive renal deterioration following a substantial loss to follow-up period necessitated renal replacement therapy. This report underscores the diagnostic challenge of ANCA-negative PING, given its absent serologic markers and overlapping features with other glomerular diseases, highlighting the crucial role of renal biopsy in reaching a timely diagnosis.

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening hyperinflammatory syndrome that can occur as an immune-related adverse event following immune checkpoint inhibitor therapy. Early diagnosis is challenging because its clinical features frequently overlap with severe sepsis, particularly in oncology patients who have recently received marrow-suppressing cytotoxic regimens. We report the case of a 39-year-old woman with triple-negative breast cancer who underwent neoadjuvant chemo-immunotherapy with carboplatin, paclitaxel, epirubicin, cyclophosphamide, and pembrolizumab. Two weeks after her last cycle, she presented with fever, a generalized rash, and purulent discharge from a peripherally inserted central catheter site, with blood cultures initially positive for Gram-positive bacteria. Despite prompt microbiological clearance with broad-spectrum antimicrobials, she developed persistent daily pyrexia, progressive liver function derangement, severe anemia, bilateral pleural effusions, and stage 3 acute kidney injury requiring continuous renal replacement therapy. Serial assessments revealed marked hyperferritinemia, hypertriglyceridemia, elevated aspartate aminotransferase, and an increasing HScore. Bone marrow biopsy showed treatment-related dyspoiesis without overt hemophagocytosis, which did not preclude the diagnosis of pembrolizumab-associated secondary HLH and concurrent immune-mediated nephritis. Targeted treatment with high-dose methylprednisolone, anakinra, and subsequently mycophenolate mofetil led to clinical recovery. The patient was successfully liberated from continuous renal replacement therapy; her cytopenias and kidney function improved, and her hyperinflammatory markers and HScore normalized. Anakinra was discontinued, and she was discharged on oral mycophenolate mofetil and prednisolone. This case underscores the complexity of distinguishing checkpoint inhibitor-associated HLH from persistent infection. Serial clinical scoring, multidisciplinary input, and substituting conventional cytotoxic HLH protocols with targeted biological therapies and organ-preserving immunosuppressants are essential to resolve the hyperinflammatory cascade while preserving renal function.

An information technology worker of South Asian heritage in his 30s presented with haematemesis and central chest pain. Initial evaluation, including oesophagogastroduodenoscopy, was unremarkable. Subsequent imaging revealed multiple pulmonary artery aneurysms. Blood tests showed a negative autoimmune profile and raised inflammatory markers. Infectious, thromboembolic and connective-tissue differentials were excluded. A history of oral ulcers with genital ulceration, together with vascular involvement, fulfilled International Criteria for Behçet's Disease (ICBD). Given the life-threatening risk, we initiated intravenous methylprednisolone followed by cyclophosphamide, later transitioning to azathioprine with a structured steroid taper. Haemoptysis ceased promptly, and follow-up imaging showed aneurysm resolution. This case illustrates how haemoptysis can masquerade as gastrointestinal bleeding and emphasises the need to consider pulmonary artery aneurysms in young patients with compatible systemic features, where early imaging and rapid immunosuppression may be lifesaving.

Bronchiectasis in ANCA-associated vasculitis (AAV) is usually attributed to structural damage from established disease. We report a 74-year-old woman with 7 years of culture-negative bronchiectasis, incompletely responsive to corticosteroids, in whom AAV was diagnosed after she developed palpable purpura, haemoptysis, hematuria and acute kidney injury. MPO-ANCA was markedly elevated (250.2 U/mL; reference < 1.0 U/mL) with PR3-ANCA negative. Renal biopsy showed pauci-immune crescentic glomerulonephritis, Berden focal class (one of 14 glomeruli with a cellular crescent). Induction with intravenous methylprednisolone and rituximab produced substantial renal recovery (eGFR nadir 23, stabilizing at 60 mL/min/1.73 m[2] at 15 months) and near-complete resolution of the pulmonary consolidations. This case describes an airway-first AAV phenotype. She met none of the trigger features that current guidelines use to prompt autoimmune screening, identifying a diagnostic blind spot in progressive culture-negative bronchiectasis without systemic features.

The coexistence of antibody-mediated rejection (AMR) and BK polyomavirus-associated nephropathy (BKPyVAN) represents a major therapeutic challenge after kidney transplantation. Whereas treatment of AMR typically requires intensification of immunosuppression, management of BKPyVAN relies on reduction of immunosuppressive therapy to restore antiviral immune control. We report a kidney transplant recipient who developed active AMR with de novo donor-specific antibodies and concurrent BKPyVAN 12 weeks after transplantation. Given ongoing BKPyV replication, recent infectious complications, and concerns regarding further escalation of conventional immunosuppressive therapy, the patient was treated with pulse methylprednisolone followed by anti-CD38 therapy using daratumumab. Treatment resulted in recovery of allograft function, disappearance of donor-specific antibodies, and complete histological resolution of AMR. BKPyV replication subsequently declined and ultimately resolved without recurrent rejection. This case highlights CD38 blockade as a potential therapeutic option in selected patients with concomitant AMR and BKPyVAN. However, given the concurrent administration of corticosteroids and optimization of maintenance immunosuppression, these findings should be regarded as hypothesis-generating.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare form of vasculitis characterized by late-onset asthma, eosinophilia, and systemic manifestations involving small- and medium-sized vessels. We report a severe case of EGPA occurring during treatment with omalizumab in a patient diagnosed with chronic urticaria. A 67-year-old woman presented with acute dyspnea, epistaxis, hemoptysis, and fatigue. Her medical history included late-onset asthma and chronic urticaria with persistent eosinophilia and elevated IgE levels, under treatment with omalizumab. Laboratory investigation revealed eosinophilia and elevated inflammatory markers, while chest computed tomography demonstrated bilateral ground-glass opacities. Bronchoalveolar lavage showed marked eosinophilia and progressively hemorrhagic sequential aliquots, confirming diffuse alveolar hemorrhage. Autoimmune panel was positive for MPO-p-ANCA, supporting the diagnosis of EGPA. The patient was initially treated with high-dose intravenous methylprednisolone, followed by rituximab. Despite treatment initiation, the patient rapidly deteriorated, requiring endotracheal intubation and admission to the intensive care unit. Treatment was escalated with therapeutic plasma exchange and intravenous cyclophosphamide. After a prolonged hospitalization, the patient gradually recovered and was transferred for rehabilitation. This case report highlights the diagnostic challenges of EGPA and the importance of early recognition. Whether omalizumab unmasked, coincided with, or induced EGPA remains uncertain. Clinicians should investigate unexplained, persistent eosinophilia as it could be an expression of a systemic disease.

Herpes zoster-associated voiding dysfunction is an uncommon complication but may occur when the sacral dermatomes are involved. In immunocompromised patients, including kidney transplant recipients receiving immunosuppressive therapy, urinary retention may predispose patients to secondary urinary tract infections such as pyelonephritis. Prompt recognition and appropriate management are therefore essential. We report the case of a woman with a history of living-donor kidney transplantation who developed urinary retention and pyelonephritis following herpes zoster involving the buttock. She had been receiving maintenance immunosuppressive therapy with methylprednisolone, mizoribine, and cyclosporine. After the diagnosis of herpes zoster, antiviral therapy was initiated. Several days later, she developed dysuria caused by urinary retention, which was successfully managed with corticosteroid therapy and temporary urinary catheterization. However, she subsequently developed fever and was diagnosed with acute pyelonephritis on hospital day 7. Intravenous antibiotic therapy resulted in gradual clinical improvement, and inflammatory markers and urinary findings normalized by hospital day 15. This case highlights that sacral herpes zoster can cause neurogenic bladder dysfunction, resulting in urinary retention and subsequent pyelonephritis, particularly in immunocompromised patients. Careful monitoring of urinary symptoms and early intervention may help prevent serious infectious complications in this high-risk population.

Anti-N-methyl-D-aspartate receptor encephalitis frequently presents with isolated psychiatric symptoms indistinguishable from primary psychosis, delaying diagnosis. The authors have described a previously healthy 35-year-old woman admitted with abrupt first-episode psychosis, who (within 48 hours and without seizures, movement disorder, or altered consciousness) developed a true aphasic syndrome, fluctuating output with semantic and phonemic paraphasias and intermittent mutism, distinct from the disorganized speech of primary psychosis. The emergence of focal language disturbance prompted neurologic evaluation. Brain magnetic resonance imaging was unremarkable; cerebrospinal fluid showed lymphocytic pleocytosis, elevated protein, and a raised immunoglobulin G index, with anti-N-methyl-D-aspartate receptor immunoglobulin G strongly positive in cerebrospinal fluid. Pelvic imaging identified an ovarian teratoma, which was resected. First-line immunotherapy (intravenous methylprednisolone and immunoglobulin) followed by plasma exchange, with short-term antipsychotic treatment, achieved sustained remission. Serial neuropsychological assessment over 18 months documented a heterogeneous recovery trajectory: early, near-complete recovery of graphomotor speed and verbal consolidation, slower recovery of associative and working-memory functions, and verbal working memory persisting as the most stable residual deficit. This case showed that rapidly evolving aphasia, distinguished at the bedside from schizophasia, can localize an autoimmune process beyond any primary psychiatric differential and trigger the workup that secures the diagnosis.