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