Renal Disorders and Glomerulonephritis Overview

Concurrent pyuria and dysuria indicate UTI.
Recent URTI suggests either postinfectious GN or IgAN.
Positive family history for renal disease is a key factor.
Unilateral flank pain, potentially radiating to the groin, is suggestive of ureteral obstruction due to calculus or blood clot.
Persistent or recurrent flank pain could be associated with the rare loin pain hematuria syndrome.
Symptoms of prostatic obstruction in older men, like hesitancy and dribbling, are concerning.
Recent vigorous exercise or trauma can trigger hematuria.
History of bleeding disorder or bleeding from multiple sites due to uncontrolled anticoagulation is important to note.
Cyclic hematuria in women, more prominent during and shortly after menstruation, suggests endometriosis of the urinary tract.
Medications can cause nephritis.

Glomerulonephritis signifies inflammation of the glomerulus.
Inflammation implies immune system activation.
Immune system activation can be triggered by antigens present in the glomerulus (endogenous) or deposited in the glomerulus (exogenous).
Both cases require antibody binding.
Immune complex (antigen already bound to antibody) deposition is a crucial factor.
Activation of neutrophils directly leads to respiratory burst (ANCA).
Loss of regulation of complement contributes to inflammation.

Inflammatory lesions are present in 50% of cases.
Renal function loss within weeks to months.
Some cases have insidious onset, with initial symptoms like fatigue and edema.
Most present with a serum creatinine level (Scr) greater than 264 micromol/L.
Severe renal failure manifests in conditions like uremia (nausea, dyspnea, pericarditis).
Pulmonary renal syndrome can present with hemoptysis.

Less than 15 years of age: Postinfectious GN, membranoproliferative GN
15-40 years of age: Postinfectious GN, lupus, Crescentic GN, Fibrillary GN, membranoproliferative GN
More than 40 years of age: Crescentic GN, Mixed cryoglobulinemia, Fibrillary GN, Postinfectious GN

Usually not done in: Postinfectious GN, mixed cryoglobulinemia, and anti-GBM Ab Dx (serologic diagnosis is sufficient).
Generally required in: Lupus nephritis, Small vessel vasculitis.

Repeating an abnormal urinalysis within a few days is recommended.
If hematuria is transient with no obvious etiology, potential causes include:
- Fever
- Infection
- Trauma
- Exercise

One study of 1032 patients evaluated by US, IVP, urinary cytology, and cystoscopy showed a malignancy incidence (bladder, kidney, or prostate) of 2.4%.
Neither cytology nor IVP reliably detected all tumors.
US was very accurate for renal tumors.
Cystoscopy was required for reliable diagnosis of bladder or prostatic Ca.
All but one tumor occurred in patients older than 50 years of age.

If glomerular bleeding is excluded in cases with ongoing unexplained hematuria, diagnostic work-up should include a search for lesions in the kidney, collecting system, ureters, and bladder.
Diagnostic yield increases with age and is higher for gross hematuria than for microscopic hematuria.

Preferred initial imaging modality, combining benefits of conventional CT with those of IVP.
In combination with cystoscopy, it provides a complete evaluation of the GU system.
Increased sensitivity and specificity in detecting renal masses, calculi, pelvicalyceal and ureteric transitional cell Ca, compared to other modalities.

If there is no clue to a specific diagnosis, IVP or US can be used to look for stones, renal mass, or polycystic disease.
IVP is the first choice in young patients.
- It can detect medullary sponge kidney.
- In older patients, it detects lesions in the renal pelvis and ureters.
If contraindications to IVP exist, an US should be performed.
Young patients with a normal IVP don't need an US (yield of significant findings is low).
Older patients with a normal IVP should undergo US or helical CT scan.
Helical CT scan provides better visualization of small renal tumors.

Urine cytology is recommended for patients at increased risk for urothelial Ca.
Sensitivity of urine cytology:
- Greatest for Ca in situ of the bladder (90%).
- Limited for upper tract transitional Ca ( > 65% false negative rate)

Glomerular Dx is present in at least 50% of cases (IgAN or Thin basement membrane Dx).
Hypercalciuria or hyperuricosuria can contribute to hematuria.
AVM or fistulas are rare causes of hematuria.
- Usually associated with gross hematuria, high output cardiac failure, and HPT.
- Confirmed by arteriography or CT scanning.
Loin pain-hematuria syndrome is poorly defined.
- Characterized by severe and unrelenting flank pain.
- Hematuria with dysmorphic red cell.
- In some cases due to Thin GBM Dx.
- Possible psychological component.

Screening for hematuria is NOT recommended in patients without symptoms of urinary tract disease.

Suspected due to red or brown urine.
Color change doesn't necessarily reflect the degree of blood loss (1 ml of blood/1l of urine can cause a visible color change).

Examination of urine sediment under a microscope is the gold standard.
Urine dipsticks for Hb detect 1-2rbc/hp field—very sensitive.
- More false positive results.
False negative results are unusual.
- Negative dipsticks exclude abnormal hematuria.

Hematuria can be a symptom of underlying disease.
Causes vary with age.
Most common causes:
- Inflammation or infection of the prostate or bladder.
- Stones.
- Malignancy or BPH in older patients.
- Glomerulonephritis.