2025 – PAGE 384 – NEPHROLOGY

GLOMERULONEPHRITIS

In order to choose an answer that has the word glomerulonephritis in it, make sure there is at least some hematuria. Other findings can include an elevated BUN, proteinuria, oliguria, and HTN.

IGA NEPHROPATHY

IgA nephropathy results in recurrent episodes of hematuria. It may be worse during or after a URI or GI infection. During an episode, urinalysis will show RBC casts and some ridiculously high number of RBCs. In between episodes there can be microscopic hematuria. Labs will show absolutely no complement issues. Diagnose by obtaining a renal biopsy and noting IgA and IgG mesangial deposits (and C3). The condition is the most common cause of primary glomerulonephritis, but the prognosis varies and this can be self-limited.

PEARLS: PROTEINURIA is a BAD prognostic sign. Do NOT order an IgA level because it can be high OR normal. Therefore, a normal IgA level doesn’t help you. Since this can come on after a URI, it can get confused with post-streptococcal glomerulonephritis (PSGN). Remember that PSGN has a low C3 level, and IgA nephropathy has normal complement levels.

MEMBRANOPROLIFERATIVE GLOMERULONEPHRITIS (MPGN)

Membranoproliferative glomerulonephritis (MPGN) is a histological finding. There are multiple types and multiple etiologies, including infections, autoimmune disorders and lymphoma. Findings may include hematuria, proteinuria and high blood pressure. Microscopy shows TRAM TRACK lesions on biopsy. C3 levels can be, but are not always, low. For the various types of MPGN, C4 levels are usually normal.

MNEMONIC: MEMBERS OF PARLIAMENT (MPGN) riding a TRAM on TRACKS leading to a circus LOOP OF FIRE. (LOOP = Lupus since SLE patients can get MPGN. Low-yield.)

RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS (RPGN)

Rapidly progressive glomerulonephritis (RPGN) is low-yield. Presents with glomerulonephritis findings/symptoms + crescents on biopsy. Give immunosuppressives and plasmapheresis.

NEPHROTIC SYNDROME

Nephrotic syndrome can present with generalized edema, periorbital edema, or genital edema. The classic triad of symptoms is Edema + Proteinuria + Hypoalbuminemia, and other symptoms may include hyperlipi­demia ± HYPOnatremia ± hematuria. There can also be hypercoagulability (assume it’s due to the loss of plasmin in the urine). Patients lose albumin and other proteins in the urine, and the resulting low serum albumin causes 3^rd spacing of fluid and thus edema. The TBW might be normal, BUT the intravascular compartment is hypovolemic and patients can get HYPOnatremia. Urine sodium is very LOW, as is the FeNa. Etiologies include minimal change disease, focal segmental glomerulonephrosis (FSGS), membranous nephropathy, congenital nephrotic syndrome, and membranoproliferative glomerulonephritis (MPGN).

• MINIMAL CHANGE NEPHROTIC SYNDROME(AKA MINIMAL CHANGE DISEASE, MCNS): Usually found in toddlers or elementary school-aged children. This is the most common etiology of nephrotic syndrome. Symptoms may include abdominal pain, diarrhea, and decreased urine output with a NORMAL CREATININE. Biopsy will show loss of FOOT PROCESSES. These children generally have a good prognosis and respond well to steroids (usually prednisone) ± an ACE inhibitor.
  • PEARL: Any time you are giving long-term steroids, consider getting a PPD first.
• FOCAL SEGMENTAL GLOMERULONEPHROSIS (FSGS): As the name suggests, biopsy will show focal segments of some glomeruli (not all) that have scarring (sclerosis).
• MEMBRANOUS NEPHROPATHY: Look for nephrotic syndrome in an adolescent. Biopsy will show diffusely thickened capillary loops or “Thickened Membranes in Membranous Nephropathy.”
• CONGENITAL NEPHROTIC SYNDROME: Can present with massive edema (anasarca). Treat these children with a high-protein diet, albumin infusions, and possibly an ACE-inhibitor. As a last resort, these children may need a bilateral nephrectomy.
• MEMBRANOPROLIFERATIVE GLOMERULONEPHRITIS (MPGN): Please refer to the MPGN section above.
• MNEMONICS: nEPHrotic syndrome = Edema + Proteinuria + Hypoalbuminemia. Regarding the etiologies, try renaming nephrotic syndrome to MePhroteinuric syMdroMe. The M’s are to help you remember Minimal change nephrotic syndrome, Membranous nephropathy, and MPGN. “Phroteinuric” is to remind you that you need to look for Proteinuria. Remember, in the E-P-H, the H stands for hypoalbuminemia, NOT hematuria. Unlike glomerulonephritis, you do not always see hematuria in nephrotic syndrome. Think “–itis” = inflammation = RBCs.