1 medicine nephrology

8/15/2019 1 Medicine Nephrology

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NEPHROLOGY


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Definition and classification/staging system for acute kidneinjury (AKI)

AKI stage Creatinine criteria Urine output criteria

• AKI stage I Increase of serum creatinine by≥ 0.3 mg/dl (≥ 26.4 μmol /L)

orincrease to ≥ 150% – 200% from baseline < 0.5 ml/kg/hour for > 6 h

-------------------------------------------------------------------------------------------------------------------• AKI stage II Increase of serum creatinine to

> 200% – 300% from baseline < 0.5 ml/kg/hour for > 12

-------------------------------------------------------------------------------------------------------------------• AKI stage III increase of serum creatinine to

> 300% from baseline < 0.3 ml/kg/hour for > 24or or

serum creatinine ≥ 4.0 mg/dl anuria for 12 hou≥ 354 μmol /L) after a rise of at least 44 μmol /L

ortreatment with renal replacement therapy


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ATN vs. Prerenal AzotemiaIndices Prerenal ATN

UNa < 20 > 40

FeNa < 1% > 4%

U/PCreat > 40 < 20

FeUN < 35% >70%


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Urinary Sediment Findings in Intra-Renal AcuRenal Failure

Intra-renal AcuteRenal Failure

Dysmorphic Hematuria

Red cell casts

Oval fat bodies

Fatty Casts

Muddy brown casts

Renal tubular epithelialcells and casts

White cells

White cell castsEosinophiluria

GlomerulonephritisAtheroembolic diseaseThrombotic

microangiopathy

Minimal changediseaseFocal segmentalglomerulosclerosis

Albuminuria Tubular proteinuria

Tubular epithelialinjury

-Ischemic-Nephrotoxic

InterstitialnephritisUrinary tract

infection

D

U

Cc


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Acute Renal failureIntroduction to casts

Hyaline Cas

• Better seewith low

• Non-spec• Compose

Tamm-Hmucoprot


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Acute Renal Failure

Waxy Casts:• Smooth app• Blunt ends.• May have a • Felt to be la

degeneratinrepresentativdisease.

Granular Casts:•

Represent dcellular castprotein.

• Nonspecific


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Acute Renal FailureFatty Casts:

• Seen in patients wsignificant protei

• Refractile in app

• May be associatefree lipid in the u

• Can see also “ovbodies” – RTE’have ingested lip

• Polarize – demo

“Maltese cross”.


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Acute Renal Failure

Muddy • High

of AT

• Pigmgranuseen hypecan bfor th


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Acute Renal Failure

White Bloo• Raises co

interstitia

• Can be se

other infldisorders

• Also seenpyelonep


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Acute Renal Failure• Hematuria

Nonglomerular hematu

• Urologic causes.

• Bladder/Foley traum

• Nephrolithiasis.

• Urologic malignancy

• May be “ crenatedupon age of urine, os

– NOT dysmorphic.


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Acute Renal Failure

Red Blood Cell Cas

• Essentially diagnvasculitis orglomerulonephri

Dysmorphic Red Ce

• Suggestive of glo

bleeding as seen glomerulonephri

• Blebs, buds, memloss.

• Rarely reported iconditions – DM


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Acute Renal FailureCrystals – Pretty and important.

Uric acid crystals:• Seen in any setting of

uric acid and an acidi• Seen with tumor lysis

Calcium oxalate crystals• Monohydrate – du

may be needle-like.• Dihydrate – envelop• Form independent of• Seen acutely in ethyl

ingestion.


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Conditions that Lead to Pre-renal Acute Renal Failure

Generalizedor Localized Reduction in

Renal Blood Flow

IschemicAcute Renal Failure

Intravascular Volume Depletion

Decreased Effective Circulating VolumeCHF Cirrhosis Nephrosis

MedicationsCYA, TacrolimusACE inhibitors NSAIDS

Radiocontrast Amphotericin BAminoglycosides

HepatorenalSyndrome

Sepsis

Large-vessel Renal VasRenal Artery ThrombRenal Artery EmboliRenal Artery Stenosi

Small-vessel Renal VascVasculitis AtheroThrombotic MicroTransplant Reject


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Common Causes of Drug Induced AIN• NSAIDS• Antibiotics

– Penicillins• methacillin• Ampicillin, amoxacillin, carbenacillin, oxacillin• Cephalosporins

– Quinolones (ciprofloxacin) – Anti-tuberculous medications (rifampin, INH, ethambutol) – Sulfonamides (TMP-SMX, furosemide, thiazides)

• Miscellaneous – Allopurinol, cimetidine, dilantin


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Acute Glomerulopathies• RPGN most commonly seen with:

– Lupus nephritis (DPGN, class IV) – Pauci-immune GN (ANCA associated) – Anti-GBM disease – less commonly: IgA, post-infectious

• Nephrotic presentations of ARF – Collapsing FSGS (HIV nephropathy) – Minimal change disease with ATN

• Thrombotic microangiopathies (HUS, TTP, malignant hyperten

scleroderma kidney, pre-eclampsia)


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Hepatorenal Syndrome - Major Criteria• Chronic or acute liver disease with advanced hepatic failure and portal

hypertension• Low GFR, as indicated by a serum creatinine >1.5 mg/dL or a creatinine

clearance < 40 mL/min• Absence of shock, ongoing bacterial infection, fluid loss, and current or

recurrent treatment with nephrotoxic drugs. Absence of gastrointestinal flosses (repeated vomiting or intense diarrhea) or renal fluid losses (asindicated by weight loss > 500 gm/d for several days in patients with ascwithout peripheral edema or > 100 gm/d in patients with peripheral edem

• No sustained improvement in renal function (decrease in serum creatinin1.5 mg/dL or less or increase in creatinine clearance to 40 ml/min or moafter withdrawal of diuretics and expansion of plasma volume with 1.5 Lisotonic saline

• Proteinuria < 500 mg/d and ultrasonographic evidence of obstructive uroor parenchymal renal disease.


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Hepatorenal syndrome - Minor Criteria

•

Urine volume < 500 mL/day• Urine sodium < 10 mEq/L• Urine osmolality > plasma osmolality• Urine red blood cells < 50 per high-pow

field•

Serum sodium concentration < 130 mEq CURRENT STAR MCQS


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CURRENT STAR MCQS• Abdominal Compartment Syndrome

– Presence of IAP >20 that is associated with a single or multiple organ system faCauses severe oliguric or anuric renal failure. Tx: surgical decompression.

• Acute Phosphate Nephropathy – AKI from Nephrocalcinosis after use of oral sodium phosphate (phospho soda)

colonoscopy.• Orlistat associated AKI

– AKI from Oxalate nephropathy due to enhancing oxalate absorption with increaurinary excretion.

• IVIG associated AKI – AKI from osmotic nephrosis from sucrose-containing formulation.

• Herbal, Home remedies – Arsenal X, Chromium picolinate, Chineses Herb Xi Xin with aristolochic acid;

Mouring Cypress, Snake gallbladder, Star fruit (oxalate), Ma Huang (ephedra),Juice

D fi iti f


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Definition ofCKD-Mineral and Bone Disorder

A systemic disorder of mineral and bonmetabolism due to CKD manifested by eitheone or a combination of the following:

• Abnormalities of calcium, phosphorus, PTH, vitamin D metabolism

• Abnormalities in bone turnover, mineralizationvolume, linear growth, or strength

• Vascular or other soft tissue calcification

Moe S, et al. Kidney Int 69: 1945, 2006


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Mechanism of Cyst Formation

1. Mutation(s) leads to changes in epithelial cell behavior2. Tubule epithelial cells proliferate to form cyst3. Electrolytes and water accumulate in cyst lumen


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Cystic diseases of kidney• ADPKD•

ARPKD• VHL : AD,hemangioblastoma, RCC (40-70%)• TS: angiomyolipomas in CNS• MSK : AD, 3rd & 4 th decade, stones, recurrent hematu• NPH =3 types:juvenille,infantile,adolescent. AR.

Cerebellar ataxia , hepatic fibrosis• MCK = AD. 3rd & 4 th decade.


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