Acid-base disturbances in nephrotic syndrome: analysis using the CO2/HCO3 method (traditional Boston model) and the physicochemical method (Stewart model).

BACKGROUND: The Stewart model for analyzing acid-base disturbances emphasizes serum albumin levels, which are ignored in the traditional Boston model. We compared data derived using the Stewart model to those using the Boston model in patients with nephrotic syndrome. METHODS: Twenty-nine patients with nephrotic syndrome and six patients without urinary protein or acid-base disturbances provided blood and urine samples for analysis that included routine biochemical and arterial blood gas tests, plasma renin activity, and aldosterone. The total concentration of non-volatile weak acids (ATOT), apparent strong ion difference (SIDa), effective strong ion difference (SIDe), and strong ion gap (SIG) were calculated according to the formulas of Agrafiotis in the Stewart model. RESULTS: According to the Boston model, 25 of 29 patients (90%) had alkalemia. Eighteen patients had respiratory alkalosis, 11 had metabolic alkalosis, and 4 had both conditions. Only three patients had hyperreninemic hyperaldosteronism. The Stewart model demonstrated respiratory alkalosis based on decreased PaCO2, metabolic alkalosis based on decreased ATOT, and metabolic acidosis based on decreased SIDa. We could diagnose metabolic alkalosis or acidosis with a normal anion gap after comparing delta ATOT [(14.09 - measured ATOT) or (11.77 - 2.64 × Alb (g/dL))] and delta SIDa [(42.7 - measured SIDa) or (42.7 - (Na + K - Cl)]). We could also identify metabolic acidosis with an increased anion gap using SIG > 7.0 (SIG = 0.9463 × corrected anion gap-8.1956). CONCLUSIONS: Patients with nephrotic syndrome had primary respiratory alkalosis, decreased ATOT due to hypoalbuminemia (power to metabolic alkalosis), and decreased levels of SIDa (power to metabolic acidosis). We could detect metabolic acidosis with an increased anion gap by calculating SIG. The Stewart model in combination with the Boston model facilitates the analysis of complex acid-base disturbances in nephrotic syndrome.

Two Cases of Proteinase 3-Anti-Neutrophil Cytoplasmic Antibody (PR3-ANCA)-related Nephritis in Infectious Endocarditis.

We herein report two cases of proteinase 3-anti-neutrophil cytoplasmic antibody (PR3-ANCA)-related nephritis in infectious endocarditis. In both cases, the patients were middle-aged men with proteinuria and hematuria, hypoalbuminemia, decreased kidney function, anemia, elevated C-reactive protein (CRP) levels, and PR3-ANCA positivity. Each had bacteremia, due to Enterococcus faecium in one and Streptococcus bovis in the other. One patient received aortic valve replacement therapy for aortic regurgitation with vegetation, and the other underwent tricuspid valve replacement therapy and closure of a ventricular septic defect to treat tricuspid regurgitation with vegetation. These patients' urinary abnormalities and PR3-ANCA titers improved at 6 months after surgery following antibiotic treatment without steroid therapy.

Hypertensive Crisis and Left Ventricular Thrombi after an Upper Respiratory Infection during the Long-term Use of Oral Contraceptives.

A 34-year-old woman who had been using oral contraceptives for 10 years developed hypertensive crisis with papilloedema after an upper respiratory infection. Laboratory data showed hyperreninemic hyperaldosteronism and elevated levels of fibrinogen, fibrin, and fibrinogen degradation products. Echocardiography demonstrated two masses (18 mm) in the left ventricle. On the fourth hospital day, cerebral infarction, renal infarction, and upper mesenteric artery occlusion suddenly occurred despite the blood pressure being well-controlled using anti-hypertensive drugs. Echocardiography revealed the disappearance of the left ventricular masses, which suggested left ventricular thrombi. Cessation of the contraceptives and administration of heparin, warfarin, and anti-platelets drugs improved her general condition.

Clinicopathological analysis of glomerulopathy with fibronectin deposits (GFND): a case of sporadic, elderly-onset GFND with codeposition of IgA, C1q, and fibrinogen.

A 67-year-old Japanese man with recurrent nephrotic syndrome and impaired kidney function had a sporadic, elderly-onset case of glomerulopathy with fibronectin deposits. The daily urinary protein, serum albumin, blood urea nitrogen, and creatinine levels were 3.6 g/day, 2.7 g/dL, 19.5 mg/dL, and 1.70 mg/dL, respectively. Kidney biopsy samples were evaluated using electron microscopy and demonstrated membranoproliferative glomerulonephritis-like lesions with massive subendothelial depositions and no fibrillary structures. Immunofluorescent studies showed 1+ staining for IgA, C1q, and fibrinogen. Anti-fibronectin immunostaining demonstrated that the subendothelial deposits were positive for fibronectin. The administration of prednisolone and mizoribine improved the nephrotic syndrome.

Proteinase 3 anti-neutrophil cytoplasmic antibody (PR3-ANCA) positive IgG4-related retroperitoneal fibrosis: utility of PET-CT with 18F-fluorodeoxy glucose (FDG).

A 55-year-old man showed a serum creatinine level of 1.51 mg/dL, CRP of 0.79 mg/dL, and proteinase 3 anti-neutrophil cytoplasmic antibody (PR3-ANCA) of 43.9 EU (normal range: below 10). The serum levels and ratios of IgG1, IgG2, IgG3, and IgG4 to total IgG were 1,570 mg/dL (49%), 1,190 mg/dL (37%), 82 mg/dL (3%), and 351 mg/dL (11%), respectively. Positron emission tomography and CT with (18)F-fluorodeoxyglucose (PET-CT) demonstrated retroperitoneal fibrosis. After a diagnosis of IgG4-related retroperitoneal fibrosis with PR3-ANCA was made, oral prednisolone improved serum creatinine and the titer of PR3-ANCA to normal levels, with no abnormal findings on PET-CT.

Thrombotic thrombocytopenic purpura in a patient with rapidly progressive glomerulonephritis with both anti-glomerular basement membrane antibodies and myeloperoxidase anti-neutrophil cytoplasmic antibodies.

A 61-year-old Japanese woman with rapidly progressive glomerulonephritis exhibited both anti-glomerular basement membrane (GBM) antibodies (920 EU) and myeloperoxidase anti-neutrophil cytoplasmic antibodies (MPO-ANCA; 66 EU). Multiple plasma exchanges with fresh frozen plasma preceded by 500 mg/day intravenous methylprednisolone and 30 mg/day oral prednisolone decreased anti-GBM antibody and MPO-ANCA antibody titers to 106 EU and below 10 EU (normal ranges), respectively. Thrombotic thrombocytopenic purpura (TTP) manifests itself as a moderate decrease in the activity of disintegrin-like and metalloproteinase with thrombospondin type 1 motif, 13 (ADAMTS13) protein levels to 35% of normal; ADAMTS13 deficiency is only symptomatic when levels are less than 50%. This patient's disease was resistant to extensive plasma exchange, leading to her death from respiratory distress and perforation of the alimentary tract secondary to cytomegalovirus infection. Autopsy demonstrated severe crescentic glomerulonephritis associated with linear IgG, IgA, IgM, and C3 deposits along the glomerular capillary walls. This case is an uncommon example of combined double antibody-positive crescentic glomerulonephritis and refractory TTP.

Membranous nephropathy (bubbling appearance and spike formation) without immunoglobulin deposition in a patient with systemic lupus erythematosus.

A 53-year-old Japanese man with systemic lupus erythematosus developed proteinuria and hematuria after a urinary stone episode. A light microscopic study of a kidney biopsy specimen demonstrated a bubbling appearance and spike formation of the basement membrane. Immunofluorescent studies revealed that there were no significant depositions of immunoglobulins, such as IgG (-), IgA (-), IgM (+/-), kappa light chain (+/-), lambda light chain (+/-), or C3 (-) in the glomerular capillary wall, though C1q was present as one-plus positive staining in mesangial areas. Electron microscopic studies showed that the thickness of the basement membrane varied from thin to thick without electron dense deposits, and that the cellular components of the podocyte were irregularly present in the basement membrane. Urinary protein decreased after the usage of prednisolone and mizoribine; however, proteinuria aggravated after an episode of urinary stone during the same treatment.

Acute renal failure due to IgM-lambda glomerular thrombi and MPGN-like lesions in a patient with angioimmunoblastic T-Cell lymphoma.

A 70-year-old man with angioimmunoblastic T-cell lymphoma developed acute renal failure. Laboratory data showed decreased levels of serum C3, C4, and CH50, elevated immunoglobulin M (IgM) levels, and the presence of cryoglobulinemia (IgM-lambda). Renal biopsy showed membranoproliferative glomerulonephritis-like lesions with azan-red-stained thrombi in the glomerular capillary lumen. Immunofluorescence showed that IgM-lambda stained strongly in the glomerular capillary lumen, equal to the azan-red-stained thrombi, whereas C3 and C4 staining was negative. Electron microscopy showed electron-dense deposits in the subendothelial space and glomerular thrombi lacking fine fibrillar structure. These findings suggest that cryoglobulin, which consists of monoclonal IgM-lambda, induced glomerular thrombi and acute renal failure in a patient with angioimmunoblastic T-cell lymphoma.