Nephrology Flashcards
Site of EPO production
Interstitial cells of the peritubular capillaries
Active form of vitamin D
1,25 dyhydroxycholecalciferol (calcitriol)
1st hydroxylation in LIVER via 25-alpha hydroxylase
2nd hydroxylation in the KIDNEY via 1-alpha hydroxylase
Contains vasa recta and longer loops of Henle
Juxtamedullary nephrons
Components of juxtamedullary apparatus
Macula densa - in the walls of distal tubule
JG cells - walls of afferent arteriole
Lacis cells
Detects changes in BP
Macula densa
Secretes renin
JG cells
Physiologic fxn of RENIN
None
Physiologic fxn of angiotensin I
None
Physiologic fxn of angiotensin II
Vasoconstricts afferent and efferent arteriole
Systemic vasoconstriction
Stimulates thirst
Increases ADH, Cortisol, Epinephrine, Norepinephrine, Aldosterone
Site of aldosterone production
Zona glomerulosa of adrenal cortex
Action of aldosterone
Inc Na reabsorptrion
K secretion
H secretion
ADH action
Insertion of aquaporins/water channels in the distal tubules and collecting ducts
Triggers for ADH secretion
Increased plasma osmolarity
Decreased blood volume
Decreased blood pressure
Effect on GFR: Afferent arteriolar vasodilation
Increases GFR
Effect on GFR: afferent arteriolar vasoconstriction
Decrease GFR
Effect on GFR: efferent arteriolar vasodilation
Decrease GFR
Effect on GFR: moderate efferent arteriolar vasoconstriction
Increases GFR (Inc glomerular capillary hydrostatic pressure)
Effect on GFR: severe efferent arteriolar vasoconstriction
Decreases GFR (Inc glomerular capillary oncotic pressure: donnan effect)
Albumin (negatively-charged) attracts positively-charged ions like Na which then attracts water
Donnan effect
Absorb K and secrete H
Intercalated cells
“Constant load delivered to the distal tubule”, mechanism for autoregulation of GFR
Tubuloglomerular feedback
“Percentage of solute reabsorved is held constant”, another mechanism for autoregulation
Glomerulotubular feedback
Substances with no Transport Mechanism and Renal Threshold (exhibits Gradient-Time Transport)
Sodium, and all passively transported solutes
Ascending limb of LoH is permeable to
Sodium
(Mnemonic: ASINding limb is permeable to solute)
Impermeable to water
Descending limb of LoH is permeable to
Water, impermeable to solute
Normal pH in arterial blood
7.40
Normal pH in venous blood, interstitial blood
7.35
Normal pH in intracellular fluid
6.0 - 7.4
Normal pH in urine
4.5-8.0
Normal pH in gastric HCl
0.80
Normal pH in vaginal secretion
3.5-4.5
Diuretic causing METABOLIC ACIDOSIS
Acetazolamide
Mnemonic: ACIDazolamide
Diuretics causing METABOLIC ALKALOSIS
Loop diuretics
Thiazide diuretics
Hyaline cast
Ghost-like, no significance in absence of proteinuria
RBC cast, what disease?
Nephritic syndrome
WBC cast, what disease?
Acute pyelonephritis
Acute tubulo-interstitial nephritis
Rebal tubular cast / granular cast, what disease?
Acute tubular necrosis
Fatty cast, what disease?
Nephrotic syndrome
Waxy cast, what disease?
Chronic renal failure
Compensation depends on adaptive changes produced by renal hypertrophy and adjustments in tubuloglomerular feedback and glomerulotubular balance
Bicker’s intact nephron hypothesis
Physiologic adaptations to nephron loss also produce unintended clinical consequences
Bricker’s trade off hypothesis
A rise pf at least 0.3mg/dL or 50% higher than baseline within 24-48 hours period
Acute kidney injury
Reduction in urine output to 0.5mL/kg per hour for longer than 6 hours
Acute kidney injury
Oliguria definition
High bone turnover with increased PTH levels
Osteitis fibrosa cystica
Classic lesion of secondary hyperParathyroidism
Low bone turnover with LOW or NORMal PTH levels
Osteomalacia and adynamic bone disease
Devastating condition seen almost EXCLUSIVELY in patients with advanced CKD and heralded by livedo reticularis
Calciphylaxis
Calcific uremic arteriolopathy
Calciphylaxis
Calcific uremic arteriolopathy
Ill-defined sensations of sometimes debilitating discomfort in legs/feet relieved by frequent leg movement
Restless leg syndrome
Urine-like odor on the breath secondary to breakdown of urea to ammonia in saliva and is often associated with an unpleasant metallic taste
Uremic fetor
Seen in patients with CKD who have been exposed to gadolinium
Nephrogenic Fibrosing Dermopathy
Stage of CKD where exposure to Gadolinium should be minimized
CKD Stage 2 (GFR 30-59mL/min)
Stage of CKD where exposure to Gadolinium should be AVOIDED unless medically necessary
CKD Stage 3-5 (GFR
FOCAL
> 50% involvement of glomeruli seen in light microscopy
DIFFUSE
SEGMENTAL
> 50% injury to each glomerular tuft
GLOBAL
Kidneys have subscapular hemorrhages with a “flea-bitten” appearance
Endocarditis-associated GN
Clasically present with fever, purulent rhinorrhea, nasal ulcers, sinus pain, polyarthralgias/arthritis, cough, hemoptysis, shortness of breath, microscopic hematuria, and 0.5-1g/24H proteinuria
Wegener’s granulomatosis with polyangitis
Range of protein in microalbuminuria
30-300mg/24H
Autoimmune disease where antibodies are directed against a3 NC1 domain of collagen IV
Goodpasture’s disease (anti-GBM disease)
May result from mutations affecting any of five ion transport proteins in the TAL
Bartter’s syndrome
Clinical syndrome mimics the effects of chronic ingestion of LOOP DIURETICS
Bartter’s syndrome
Due to mutations in the Thiazide-sensitive Na-Cl co-transporter, NCCT, in the DCT
Gittelman’s syndrome
Syndrome which resembles effects of THIAZIDE DIURETICS
Gittelman’s syndrome
Severe form of bartter’s syndrome in which neonates present with pronounced volume depletion and failure to thrive, fever, vomiting and diarrhea from PGE2 overproduction
Hyperprostalandin E syndrome
Mimics a state of aldosterone EXCESS by the presence of early and severe hypertension, often accompanied by HYPOkalemia and metabolic Alkalosis, but plasma aldosterone and renin levels are LOW
Liddle’s syndrome
Triad of heavy metal (lead) nephropathy
Saturnine gout
Hypertension
Renal insufficiency
Results from long term use of compound analgesic preparations containing phenacetin, aspirin and caffeine
Analgesic neohropathy
Renal biopsy finding of interstitial fibrosis and tubular atrophy OUT OF PROPORTION to degree of glomerulosclerosis or vascular disease
Tubulointerstitial nephritis
Degenerative changes of the renal arterioles OUT of PROPORTION to the other morphologic defects
Chronic uric acid nephropathy
Inability to maximally concentrate urine due to reduced collecting duct responsiveness to AVP and defective transport of sodium and chloride in the loop of Henle
Hypercalcemic nephropathy
Pentad of thrombotic thrombocytopenic purpura (TTP)
Hemolytic anemia Thrombocytopenia Neurologic symptoms Fever Renal failure
MOST SEVERE manifestation characterized by accelerated hypertension, a rapid decline in renal function, nephrotic proteinuria, and hematuria
Scleroderma Renal Crisis
ONION SKINNING and can be accompanied by glomerular collapse due ro reduced blood flow
Renal lesion in Scleroderma renal crisis
Normal points of narrowing in ureter
Ureteropelvic jxn
Ureterovesical jxn
Bladder neck and urethral meatus
Criterion STANDARD in measurement of albuminuria
Accurate 24ahour urine collection
MOST useful imaging study in nephrology
Renal UTZ
ONLY diagnostic test to elucidate etiology of eraly stage CKD in the absence of a clinical diagnosis
renal biopsy
MOST sensitive test for RENAL VEIN THROMBOSIS
CT angiography
STANDARD radiologic procedure for diagnosis of neohrolothiasis
helical CT scanning WITHOUT radiocontrast enhancement
Most common form of renal replacement therapy
Hemodialysis
Clear indications for initiation of RRT for patients with CKD
Uremic pericarditis
Encephalopathy
Intractable muscle cramping
Anorexia and nausea not attributed to reversible causes such as PUD
Evidence of malnutrition
Fluid and electrolytes abnormalities, principally HYPERkale ia or ECF vol overload, refractory to other measurements
Offers the BEST potential for complete rehabilitation
Kidney transplantation
Educational programs should be commenced in CKD when
No later than stage 4 CKD
Most common therapeutic modality for ESRD
Hemodialysis
Dialysis access with HIGHEST long-term patency rate
Fistula
Most important complication of AV graft
Thrombosis of graft and graft failure
Most common acute complication of hemodialysis, particularly among DM patients
Hypotension
Preferred buffer in peritoneal dialysis patients
Lactate
Most common additives to peritoneal dialysis solutions
Heparin
Antibiotics
Insulin
Most common organisms in peritoneal dialysis-related peritonitis
Gram-positive cocci including
Staphylococcus (skin origin)
ABSOLUTE indication for the urgent initiation of dialysis or for the intensification of dialysis
Uremic pericarditis
Renal disease associated with multiple myeloma
Renal amyloidosis
Most common form of AKI
Prerenal azotemia
Most common cause of CKD
DM
Patchy necrosis, PCT and LoH affected, relatively short lengths of tubules affected
Ischemic type ATN (in hypovolemia)
Extensive necrosis, PCT and DT affected, relatively longer lengths of tubules affected
Toxic type ATN (in use of Aminoglycosides, radio-contrast dyes)
Acts as ESSENTIAL mediator of increased intraglomerular capillary pressure by selectively increasing efferent arteriolar vasoconstriction relative to afferent arteriolar tone
Angiotensin II
MAJOR pathway for reducing excess total body K+
renal excretion
Three broad categories of AKI
Prerenal azotemia
Intrinsic renal disease
Postrenal obstruction
MOST common clinical associated with prerenal azotemia
Hypovolemia
Decreased cardiac output
Medications that interfere with renal autoregulatory responses (NSAIDs and ARBs
Most common causes of Intrinsic AKI
Sepsis
Ischemia
Nephrotoxins
Usual clinical course of contrast-induced neohropathy
A rise on SeCrea beginning 24-48houra following exposure
Peaking within 3-5 days
Resolving within 1 week
Most common protein in urine and produced in the TAL of LoH
Uromodulin/ Tam-Horsfall protein
Diseases with LARGE kidneys and CKD
DM Nephropathy
HIV-associated nephropathy
Infiltrative diseases
Occ acute interstitial nephritis
Provide DEFINITIVE diagnostic information about AKIs and CKDs
Kidney biopsy
Hallmark of AKI
Build-up of nitrogenous waste products, manifested as an elevated BUN concentration (azotemia)
DEFINITIVE treatment of hepatorenal syndrome
Liver transplantation
Continuous RRT preferred in patients with
Severe hemodynamic instability
Cerebral edema
Significant volume overload
Chronic renal failure typically corresponds to
CKD Stage 3-5
End-stage renal disease refers to
Stage 5 CKD (
Protein-creatinine ratio
Signifies chronic renal damage-persistence in the urine of:
>17mg of albumin/g creatine in males
>25mg albumin/g creatinine in adult females
Good SCREENING test for early detection of renal disease
Microalbuminuria (esp in DM)
Thiazide diuretics have limited utility in
CKD stages 3-5
Alkali supplementation may be recommended to slow catabolism and CKD progression when
Serum bicarbonate concentration falls below 20-23 mmol/L
ONLY indication water restriction
Hyponatremia and volume overload
OPTImal management of secondary hyperparathyroidism and osteitis fibrosa
PREVENTION
Major side effect of calcium-based phosphate binders
Total-body calcium accumulation and Hypercalcemia
Leading cause of morbidity and mortality in patients at every stage of CKD
Cardiovascular disease
MAJOR risk factor for ischemic cardiovascular disease
Presence of any stage of CKD
One of the MOST common complications of CKD
Hypertension
Among the STRONGEST risk factors for the cardiovascular morbidity and mortality in CKD
Left ventricular hypertrophy and dilated cardiomyopathy
Absence of hypertension may signify the presence of
Salt wasting form of renal disease
Effect of antihypertensive therapy
Volume depletion
May signify poor left ventricular fxn
CKD patients with DM or proteinuria >1g per24h, blood pressure should be REDUCED to
125/75mmHg (salt restriction should be the first line therapy)
Anemia seen in CKD
Normocytic, normochromic anemia
Seen as EARLY as CKD Stage 3
UNIVERSAL by CKD Stage 4
PRIMARY cause of anemia
Insufficient production EPO by diseased kidneys
ESSENTIAL to ensure an optimal response to EPO in patients with CKD
Iron supplementation
Target Hgb concentration in CKD
100-115g/L
Peripheral neuropathy usually becomes clinically evident after the patient reaches
CKD stage 4
Common in advanced CKD and is often and indication for initiation of dialysis
Protein energy malnutrition (consequence of low protein and caloric intake)
Assessment of protein-energy malnutrition should begin at -
Stage 3 CKD
Metfor,in is CONTRAINDICATED when
GFR is less than half of normal
FIRST line mgt of pruritus in CKD
Rule out unrelated skin disorders, such as scabies and treatment of hyperphophatemia
Indication for therapy with ACE inhibitor or ARBs
Protein excretion >300mg (esp in DM Nephropathy)
MOST important initial diagnostic step in evaluation of a patient presenting with elevated serum creatinine is
Distinguish newly diagnosed CKD from acute or subacute renal failure
Renal failure in GN BEST correlates histologically with
Tubulointerstitial nephritis rather than type of inciting glomerular injury
“Thyroidization” of kidney
appearance similar to thyroid follicles
chronic Gn
Chronic tubulointerstitial nephritis
Chronic pyelonephritis
Rbc cast or dysmorphic red blood cells found in the sediment
Glomerulonephritis
MOST common causes of GN throughout the world
Malaria and Schistosomiasis (save for subacute bacterial endocarditis)
Closely followed by: HIV, chronic hep B and C
M proteins related to IMPETIGO
M types 47, 49, 55, 2, 60, and 57
M proteins related to PHARYNGITIS
M types 1, 2, 4, 3, 25, 49 and 12
Primary treatment or endocariditis-assoc Gn
Eradication of the infection with 4-6 weeks antibiotics
Wire-loop appearance
lupus nephritis
Correlate BEST with the presence of renal disease in lupus nephritis
Anti-dsDNA antibodies
The ONLY reliable method of identifying the morphologic variants of lupus nelhritis
Renal biopsy
Class with MOST varied course of lupus nephritis
Class III nephritis
Describes global, diffuse proliferative lesions involving the vast majority of glomeruli
Class IV nephritis
Has the worst renal prognosis (without treatment)
Crescentic GN
Predisposed to renal-vein thrombosis and other thrombotic complications (like patients with idiopathic membranous nephropathy)
Class V nephritis
Signs and symptoms of Nephrotic syndrome
EPAL Edema Proteinuria HypoAlbuminemia hyperLipidemia
Diseases presenting with Nephrotic Syndrome
Minimal change disease (Lipoid) Membranous GN DM Nephropathy Renal amyloidosis Focal-segmental GN
Signs and symptoms of Nephritic syndrome
OHHA Oliguria Hematuria Hypertension Azotemia
Absorbs Na and H2O and secrete K
Principal cells
Key finding in nephritic syndrome
RBC cast
Non nephritic, non nephrotic glomerular disease
IgA nephropathy
Membranoproliferative GN
Most common GN worldwide
IgA nephropathy
Recurrent episodes of macroscopic hematuria during or immediately following an URTI often accompanied by proteinuria
Persistent asymptomatic microscopic hematuria
IgA nephropathy
Prominent systemic symptoms Younger age (
HSP
Anti-PR3 antibodies
Wegener’s granulomatosis with polyangitis
anti-MPO antibodies
Churgg-strauss or microscopic polyangitis
Necrotizing triad of Wegener’s granulomatosis
Necrotizing vasculitis
Necrotizing Glomerulitis
Necrotizing Granulomas
Most prolifetive of the three types of MPGN
Type I MPGN
MOST common cause of nephrotic syndrome in children
Minimal change diseaes (Lipoid nephrosis
Most common cause of nephritic syndrome in children
Post-strep GN (PSGN)
1st lime therapy in minimal change
Prednisone
Glomeruli located at corticomedullary jxn: so if the renal biopsy is from superficial tissue, the lesion can be MISSED, which sometimes leads to misdiagnosis of MCD
Pathologic changes of FSGS are most prominent in
Highest reported incidences of renal vein thrombosis, pulmonary embolism and DVT
MGN
Most common cause of neohrotic syndrome in the elderly
Focal segmental glomerulonephritis
SENSITIVE indicator for the presence of diabetes
Thickening of GB!
EARLIEST manifestation of DM Nephropathy
Increase in albuminuria
Potent risk factor for cardiovascular events and death in patients with type 2 DM
Microalbuminuria
Schistosoma spp MOST commonly assoc with clinical renal disease
Schistosoma mansoni
Hallmark of ADPKD
Phenotypic heterogeneity
Most common cardiac valvular abnormality in ADPKD
MVP and aortic regurgitation
Most common genetic cause of ESRD in childhood and adolescence
Nephronophthisis
Most common renal abnormality in tuberous sclerosis
Angiomyolipoma
Gittelman’s syndrome is distinguished from Most forms of Bartter’s syndrome by the presence of
Severe HYPOmagnesemia
HYPOcalciuria
Mainstay of treatment for cystinuria
HYDRATION, achieve UO of 2.5L/day
Hallmark feature of tubolointerstitial neohritis with uveitis
Painful anterior uveitis
Predominant pathology in chronic tubulointerstital nephritis
Interstitial fibrosis
Acute tubulointerstitial neohritis most often presents with
Acute renal failure
1st line therapy in scleroderma renal crisis unless contraindicated
ACE inhibitor
Most common type of urolithiasis
Calcium stones
Struvite stones
Proteus mirabilis forming staghorn calculi
Hereditary, contains sulfur
Cystine stones
Size of ureteral stones which may pass spontaneously
Radiopaque on standard xrays
Calcium stones
Struvkte stones
Cystine stones
Radiolucent on standard xrays
Uric acid stones
Most common metabolic abnormality found in patients with nephrolithiasis
Idiopathic hypercalciuria
Major risk factor for uric acid stone formation
Persistently acidic urine
Indication of upper GUT involvement
Unilateral back or flank pain
Fluoroquinolones commonly used in UTI
Ofloxacin, ciprofloxacin and levofloxacin
All fluoroquinolones are effective against short course therapy for Cystitis except
Moxifloxacine
Most common cause of bilateral hydronephrosis in boys
Ofloxacin, ciprofloxacin and penicillin