Proteinuria
AKI Evidence
It's all about Ions
Medicines and their mechanisms
Under the microscope
100
According to the KDIGO 2025 guideline, THIS is the proteinuria threshold (in grams per day) at which patients are considered at risk of progressive kidney function loss and should be considered for treatment
What is ≥0.5 g/day?
The ideal treatment goal is to reduce proteinuria even further — below 0.3 g/d — while maintaining an eGFR decline rate of less than 1 mL/min/year
100
In the KDIGO staging system, THIS AKI stage is defined by a serum creatinine rise to ≥3.0 times baseline, OR an increase to ≥4.0 mg/dL, OR initiation of renal replacement therapy, OR (in patients <18 years) a decrease in eGFR to <35 mL/min/1.73 m². The urine output criterion is <0.3 mL/kg/h for ≥24 hours or anuria for ≥12 hours.
What is Stage 3 AKI?
100
THIS electrolyte deficiency, commonly caused by chronic proton pump inhibitor use, leads to refractory hypokalemia due to impaired intestinal absorption
What is Hypomagnesemia?
100
THIS class of oral diabetes medications inhibits a proximal tubule transporter, increases sodium delivery to the macula densa, restores tubuloglomerular feedback, and causes an initial drop in eGFR due to reduced intraglomerular pressure (a reno-protective effect)?
What are SGLT2 inhibitors?
100
Detection of such crystals on urine microscopy suggests THESE kidney stones
What are struvite (staghorn) calculi?
These crystals precipitate in alkaline urine (pH > 7.0) and are composed of magnesium ammonium phosphate. Their presence on urine microscopy should raise concern for infection with urease-producing organisms such as Proteus mirabilis, which can lead to this type of branching renal stone.
200
According to the "4-hit hypothesis" of IgA nephropathy pathogenesis, the process begins with aberrant production of THIS specific immunoglobulin at the gut or respiratory mucosa.
What is galactose-deficient IgA1 (Gd-IgA1)?
According to the "4-hit hypothesis" of IgA nephropathy pathogenesis, the process begins with aberrant production of this specific immunoglobulin at the gut or respiratory mucosa. This molecule enters the systemic circulation, is recognized by circulating IgG and IgA autoantibodies forming immune complexes, and ultimately deposits in the glomerular mesangium to trigger inflammation and complement activation.
200
According to KDIGO, THIS anticoagulation strategy is preferred for CRRT to prolong filter lifespan compared to heparin, even in patients with higher bleeding risk, without affecting mortality.
What is regional citrate anticoagulation?
200
In CKD, THIS bone-derived hormone rises earliest in CKD, promoting phosphate excretion and reducing active vitamin D production, making it the first marker of disordered mineral metabolism
What is FGF 23?
200
THIS gut-acting NHE3 inhibitor lowers serum phosphorus in dialysis patients by reducing intestinal phosphate absorption through decreased paracellular permeability, offering an alternative to traditional phosphate binders?
What is Xphozah (tenapanor)?
200
THESE urinary crystals are pathognomonic for an autosomal recessive disorder
What are cystine crystals?
These hexagonal, flat crystals seen in acidic urine are pathognomonic for an autosomal recessive disorder of amino acid transport and indicate a high risk of recurrent nephrolithiasis beginning in childhood.
300
The Columbia Classification (2004) identifies five mutually exclusive histologic variants of FSGS based on light microscopy. Among them, this variant — characterized by wrinkling of the glomerular capillary wall with overlying podocyte hyperplasia and hypertrophy — carries the worst prognosis
What is the collapsing variant?
300
In the furosemide stress test, THIS is the IV bolus dose administered to patients who have received loop diuretics within the prior 7 days. A urine output of less than 200 mL over 2 hours after this dose predicts progression to severe AKI with a sensitivity of 87.1% and specificity of 84.1%.
What is 1.5 mg/kg of intravenous furosemide?
300
THIS classic equation states that serum sodium concentration is determined by the ratio of exchangeable sodium plus potassium to total body water, showing that hyponatremia reflects excess water and can be worsened by potassium depletion?
[Na⁺]s ≈ (Naₑ + Kₑ) / TBW.
What is the Edelman equation?
300
THIS weekly injectable GLP-1 receptor agonist was the first to show kidney outcome benefits in a dedicated renal trial (FLOW), reducing major renal and cardiovascular events in patients with type 2 diabetes and CKD?
What is semaglutide (Ozempic)?
300
THIS is the minimum number of glomeruli generally recommended in a kidney biopsy sample to diagnose or exclude a specific histopathologic pattern with reasonable confidence, according to KDIGO guidelines.
What is 8-10 glomeruli?
400
THIS 2019 trial showed that rituximab was noninferior to cyclosporine at 12 months and superior at 24 months, with more sustained remission, establishing it as the first‑line therapy in membranous nephropathy.
What is the MENTOR trial (Membranous Nephropathy Trial of Rituximab)?
In this landmark trial published in NEJM in 2019 (n=130), rituximab was compared to cyclosporine in patients with primary membranous nephropathy and proteinuria ≥5 g/day. At 12 months, remission rates were similar (60% vs. 52%), meeting the noninferiority endpoint. However, at 24 months, rituximab demonstrated clear superiority (60% vs. 20% maintained remission) driven by a dramatically lower relapse rate after treatment cessation. This trial established rituximab as a preferred first-line immunosuppressive agent over calcineurin inhibitors.
400
KDIGO guidelines provide their strongest level of recommendation (Grade 1A) against using THIS agent, once commonly given at 1–3 µg/kg/min to prevent or treat AKI in ICU
What is low-dose dopamine?
Multiple negative studies, including an adequately powered RCT, demonstrated no benefit, and the drug can actually increase renal vascular resistance in AKI patients while also triggering tachyarrhythmias, myocardial ischemia, and T-cell suppression.
400
THIS condition arises after long-standing secondary hyperparathyroidism in CKD, where parathyroid glands become autonomous (due to nodular hyperplasia and receptor downregulation), leading to hypercalcemia, hyperphosphatemia, and very high PTH, often persisting after renal transplant or in dialysis patients and requiring parathyroidectomy when refractory to medical therapy
What is tertiary hyperparathyroidism?
400
THIS humanized anti‑APRIL monoclonal antibody reduces pathogenic IgA production by targeting B‑cell signaling in IgA nephropathy.
What is sibeprenlimab (Voyxact)?
This humanized IgG2 monoclonal antibody selectively binds to and neutralizes APRIL (A Proliferation-Inducing Ligand), a cytokine that mediates antibody class switching in mature B cells and plasma cell survival. By suppressing APRIL, it reduces production of the pathogenic galactose-deficient IgA1 molecules that trigger autoantibody formation and immune complex deposition in the glomerular mesangium — directly targeting the "multi-hit" immunopathogenesis of IgA nephropathy.
400
Diagnosis suggested by this IgG signal pattern on IF
What is anti-GBM disease?
On immunofluorescence microscopy, this glomerulonephritis is characterized by intense, diffuse, linear staining for IgG along the glomerular basement membrane — in contrast to the granular pattern seen in immune-complex–mediated disease
500
THIS molecule in the phase 3 REGENCY trial showed that adding THIS targeted biologic to standard therapy significantly improved complete renal response in active lupus nephritis
What is obinutuzumab?
In REGENCY trial (NEJM, 2025), 271 adults with biopsy-proven active lupus nephritis were randomized 1:1 to receive this drug (1000 mg on day 1 and at weeks 2, 24, 26, and 52) or placebo, all on background mycophenolate mofetil and prednisone. The primary endpoint — complete renal response at week 76 (UPCR <0.5, eGFR ≥85% of baseline, no intercurrent event) — was achieved in 46.4% vs. 33.1% (adjusted difference 13.4 percentage points; P=0.02).
500
THIS multicenter RCT (published in JAMA 2025) found that an on-demand, indication-based dialysis strategy led to higher unadjusted kidney recovery than routine thrice-weekly dialysis in AKI
What is Liberate D?
Trial included 221 hemodynamically stable adults with dialysis-requiring AKI were randomized to this dialysis strategy — where hemodialysis was performed only when specific metabolic or clinical indications were met — versus conventional thrice-weekly hemodialysis. The primary outcome showed a 64% vs. 50% kidney function recovery rate at hospital discharge (absolute difference 13.8%), though the effect was attenuated after multivariable adjustment.
500
THIS multicenter RCT investigated critically ill patients with severe acidosis and AKI found that sodium bicarbonate therapy did not reduce mortality, but reduced need for KRT and bloodstream infections.
What is BICAR-ICU 2 Trial?
This multicenter RCT specifically enrolled 627 critically ill patients with severe metabolic acidemia (pH ≤7.20) AND moderate-to-severe AKI (KDIGO stage 2–3). The primary outcome of 90 days all-cause mortality was not significant. However, KRT use was significantly lower in the bicarbonate group (HR for KRT initiation 0.59, 95% CI 0.46–0.75), and ICU-acquired bloodstream infections were 50% lower (4% vs. 9%).
500
THIS oral C5a receptor antagonist blocks C5a-mediated neutrophil activation in ANCA-associated vasculitis while preserving terminal complement function against infections (hence does not require immunization against capsular bacteria)?
What is Avacopan?
500
Fan-shaped or "sheaves of wheat" crystals seen under urine microscopy usually have THIS composition
What are sulfa crystals?
These fan-shaped or "sheaves of wheat" crystals seen on urine microscopy are highly birefringent under polarized light and precipitate in acidic urine (pH < 5.5). Their formation can be prevented by aggressive hydration and urine alkalinization.