Glomerulonephritis – Symptome und Ernährung

Glomerulonephritis (GN) represents a diverse spectrum of renal disorders unified by primary inflammatory damage to the glomerular apparatus, driven predominantly by immunological dysfunction. While the inflammatory process may initially confine itself to the glomeruli, its downstream effects frequently extend to secondary alterations within renal tubules, the interstitial compartment, and vascular structures, primarily due to impaired filtration and pathological proteinuria. The etiology remains elusive in a substantial proportion of cases, though current evidence implicates aberrant immune responses—either through the deposition of immune complexes within glomerular capillaries or direct autoantibody-mediated injury. Analogous to other immune-mediated conditions, GN may manifest as recurrent exacerbations, periods of remission, or a steadily progressive chronic course. Acute presentations often arise as allergic-inflammatory responses to persistent or recurrent bacterial infections within the host, whereas chronic glomerulonephritis occasionally emerges as a sequela of untreated acute disease but more commonly develops *de novo*. The onset is frequently insidious, sometimes remaining clinically silent for years, with gradual glomerular fibrosis, sclerosis, and replacement by fibrous tissue ultimately culminating in end-stage renal failure and uremia. Classification distinguishes between *primary GN*—where pathology is restricted to the glomeruli and clinical/laboratory abnormalities stem directly from their malfunction (e.g., postinfectious GN)—and *secondary GN*, wherein glomerular injury arises as a complication of systemic diseases such as diabetes mellitus, systemic lupus erythematosus, or amyloidosis.

Acute glomerulonephritis presents with a constellation of concerning clinical features, including: severe, localized pain in the lumbar region of the spine, a marked reduction in daily urine output (oliguria), edema predominantly affecting the upper body—particularly the face and periorbital areas—as well as microscopic hematuria (defined by the presence of more than three erythrocytes per high-power microscopic field). Additional findings include moderate proteinuria (exceeding 2.5 grams per day, with values above 3.5 g/day indicative of full-blown nephrotic syndrome), generalized physical weakness, anorexia, excessive daytime somnolence, elevated systemic arterial pressure, dark—often brownish-red—urine discoloration, febrile episodes, and potential convulsive seizures. In chronic glomerulonephritis, the clinical picture typically involves: frothy urine (reflecting significant protein content), persistent hematuria, generalized soft-tissue edema, ascites, diminished physical endurance, chronic fatigue, anemia, recurrent headaches, and sustained arterial hypertension. Essential diagnostic evaluations comprise: comprehensive urinalysis (assessing proteinuria and hematuria), serum biochemical profiling (focusing on renal function markers such as creatinine and blood urea nitrogen, alongside electrolyte balance—sodium and potassium), abdominal ultrasonography for structural assessment, and—when clinically indicated—renal biopsy to facilitate histopathologic examination of glomerular alterations.

The diet and the exact nutritional recommendations should be selected on a case-by-case basis, depending on the function of the kidneys. Therefore, the dietary effects depend on: serum urine levels (norm 2.5 6.7 mmol/l 15 40 mg/dl), serum creatinine levels (60 120 μmol/l 0.7 1.35 mg/l), daily fluid balance (balance of fluid intake and intake during the course of the fluid cycle). However, the overall values of urine intake depend on kidney levels.