BACKGROUNDAcute diffuse glomerulonephritis is one of the most prevalent causes of glomerulonephritis worldwide. Children of preschool age are the most affected age group, being rare in adults over 40 years old. Treatment is symptomatic and the prognosis is favorable in most cases. CASE REPORTFemale patient, 42 years old, in 2019 started with a recurrent urinary infection. During the investigation, the presence of proteinuria was evidenced, an ANA was requested, which was reactive and a renal biopsy was indicated, but not performed at the time due to loss of follow-up. In January 2020, she developed malar rash, photosensitivity, alopecia, inflammatory rhythm arthralgia in metacarpophalangeal and proximal interphalangeal joints. After an irregular external follow-up period and with a report of shortterm use of hydroxychloroquine and methotrexate, in August 2021 she was referred to our service. When the diagnostic hypothesis of systemic lupus erythematosus (SLE) was raised, tests were requested for diagnostic investigation, with fine speckled nuclear ANA 1:160, C3 hypocomplementemia, reagent anticardiolipin IgM and 24-h proteinuria of 957 mg. Due to the diagnosis of SLE with persistent proteinuria without loss of renal function, it was decided to perform a renal biopsy to better elucidate the condition before instituting immunosuppression. The biopsy showed 23 glomeruli with mild to moderate hypercellularity, with reduced capillary lumen and occasional neutrophils in these areas, 2 of them with a focus of fibrinoid necrosis. The immunohistochemistry showed as alteration the presence of complement, positive C3 fraction 3+/3+ with coarse granular pattern, of global and diffuse distribution in capillary loops. The morphological findings associated with the immunofluorescence exam correspond to acute diffuse intracapillary glomerulopathy (post-streptococcal glomerulonephritis). Since the patient meets the criteria for SLE, with proteinuria, but with renal biopsy not suggestive of lupus nephritis, but of another pathology (ADGN), it was decided to introduce methotrexate 12.5 mg/week, prednisone 20 mg/day due to cutaneous activity and articulate. The patient evolved with resolution of proteinuria and normalization of C3 with the instituted treatment. CONCLUSIONThe presence of proteinuria in SLE patients should draw our attention to one of the most serious complications of this disease, which is lupus nephritis. However, its differential diagnosis is extensive and renal biopsy should be performed whenever possible, since other diagnoses may not require immunosuppression.

Amyloidosis can mimic or occur concomitantly with several rheumatological diseases, and it is necessary to pay attention to this pathology as a differential diagnosis of immune-mediated diseases.

Objective: To highlight the importance of the new classification criteria for the macrophage activation syndrome (MAS) in systemic juvenile idiopathic arthritis in order to reduce morbidity and mortality outcome related to this disease. Case description: A 12-year-old female patient with diagnosis of systemic juvenile idiopathic arthritis under immunosuppression therapy for two years developed cough, acute precordial chest pain, tachypnea, tachycardia and hypoxemia for two days. Chest tomography showed bilateral laminar pleural effusion with bibasilar consolidation. The electrocardiogram was consistent with acute pericarditis and the echocardiogram showed no abnormalities. Laboratory exams revealed anemia, leukocytosis and increased erythrocyte sedimentation rate, as well as C-reactive protein rate and serum biomarkers indicative of myocardial injury. Systemic infection and/or active systemic juvenile idiopathic arthritis were considered. She was treated with antibiotics and glucocorticoids. However, 10 days later she developed active systemic disease (fever, evanescent rash and myopericarditis with signs of heart failure) associated with macrophage activation syndrome, according to the 2016 Classification Criteria for Macrophage Activation Syndrome in Systemic Juvenile Idiopathic Arthritis. She was treated for five days with pulse therapy, using glucocorticoids, immunoglobulin and cyclosporine A, with improvement of all clinical signs and laboratory tests. Comments: Myopericarditis with signs of heart failure associated with MAS is a rare clinical presentation of systemic juvenile idiopathic arthritis. Macrophage activation syndrome occurs mainly during periods of active systemic juvenile idiopathic arthritis and may be triggered by infection. Knowledge about this syndrome is crucial to reduce morbidity and mortality.

BACKGROUNDTakayasu's arteritis (TA) is a rare, chronic inflammatory disease, more common in women of reproductive age, which affects the aorta and its branches and can cause stenosis, occlusion and aneurysms. The pathophysiology is not fully understood, but there is a T cell-mediated immune response that results in granulomatous inflammation in all layers of the vessel. Enteropathic arthritis is a spondyloarthritis (SpA) that occurs in patients with inflammatory bowel diseases (IBDs) and other gastrointestinal diseases and treatment depends on whether the involvement is axial or peripheral. Large granular lymphocyte leukemia (LGL) is a rare lymphoproliferative disease with expansion of CD8+ cells, which can coexist with autoimmune diseases in around 35.7%. Studies describe that 1/5 of patients with TA have extravascular manifestations, such as SpA and IBD. A study in South Korea included 268 patients with TA, 19% had extravascular manifestations: arthritis (11.9%), sacroiliitis (7.1%) and IBD (2.6%). It was also shown that sacroiliitis in patients with TA differs from the general population, being more common in women and presenting a low incidence of positivity for HLA-B27. To date, the pathophysiology between TA and IBD is unclear, but HLA haplotypes (HLABw52 and DR2) are common in both. In 1998, the first cases of coexistence of UC, ankylosing spondylitis (AS) and TA were described. A study in a Norwegian population showed a prevalence of SpA and Crohn's disease (CD) among TA patients of 7% and 8%, respectively. Farrant et al. showed that only 29 cases were reported in the literature of patients with TA and CD. Another study found 7-9% of IBD cases in TA patients. Guzel et al. observed 69 patients with TA and of these, 20.3% had SpA. CASE REPORTFemale patient diagnosed with TA at 25 years old, diagnosed with UC at 53 years old, evolved with left proximal interphalangeal arthritis. She had sacroiliitis on MRI and HLA B27 positivity with a diagnosis of peripheral SpA, and methotrexate (MTX) was started. Currently, at age 63, she evolved with lymphocytosis and neutropenia with a diagnosis of LGL. Hematology was chosen for maintaining MTX indefinitely and the patient maintained control of the condition. CONCLUSIONThe literature describes an association between TA, IBD and SpA with still unknown pathophysiology that relates these diseases; however, there seems to be a connection between them as we find more and more cases described, and these associations should always be remembered.

BACKGROUNDSystemic lupus erythematosus (SLE) is a multifactorial, chronic inflammatory, autoimmune disease more common in women, with alternating periods of exacerbation and remission. It presents cutaneous, joint, cardiac, pulmonary, renal, hematological and neuropsychiatric manifestations, the latter being present in 25-70% of patients, and may be the initial manifestation of the disease and occur even in the absence of other symptoms. As a differential diagnosis of neuropsychiatric alterations, vitamin B 12 deficiency should be considered, whose symptoms will be reversible if they have a short period of evolution, but may have permanent sequelae if treatment is not indicated early. CASE REPORTFemale patient, 56 years old, with a history of previous hospitalization due to inflammatory polyarthralgia, dyspnea on moderate exertion, visual hallucinations and psychomotor agitation. The psychiatric team started risperidone as symptomatic, with improvement of hallucinations. During the investigation, anemia, thrombocytopenia and serositis were evidenced, with negative ANA. The diagnostic hypothesis of SLE with lupus psychosis was raised and pulse therapy with methylprednisolone 3 g was performed in an external service. The patient evolved with an improvement in the condition, being discharged from the hospital with prednisone 40 mg/day and risperidone. After a short period, the psychiatric condition recurred with insomnia, psychomotor agitation, and hallucinations even when using risperidone. Neurology team hypothesized Parkinsonism secondary to risperidone and recommended replacement with quetiapine. The symptoms improved and she was discharged with an outpatient return. After reassessment of the case, hydroxychloroquine was introduced and the other medications were maintained due to the diagnostic hypothesis of probable SLE, but the patient was lost to follow-up. After one year, she returned to the emergency room with severe anemia, and 4 packed red blood cells were transfused. Complementary tests showed pancytopenia and vitamin B 12 55 (VR 114-890) deficiency. During hospitalization, she again presented visual hallucinations, psychomotor agitation and disorientation, and replacement of this vitamin was performed, without immunosuppression or use of steroids, and the patient showed improvement of the initial complaints and normalization of leukocytes and platelets, maintaining anemia. Thus, the diagnosis of SLE was ruled out and it was confirmed that the manifestations were only due to vitamin B 12 deficiency. CONCLUSIONNeuropsychiatric manifestations may result from SLE as long as other causes are ruled out, mainly metabolic disorders and infections. In this case, the patient showed improvement in clinical symptoms and laboratory tests after vitamin B 12 replacement, and the behavioral disorder was attributed to the deficiency of this vitamin.