Kidney and Urinary Tract Flashcards
Horseshoe Kidney
Conjoined kidneys usually connected at lower pole
MOST COMMON congenital renal anomaly
Kidneys are abnormally located in the lower abdomen as they get stuck on the Inferior Mesenteric Artery during its ascent from the pelvis
Renal Agenesis
Absent kidney formation
Unilateral = hypertrophy of existing kidney. Hyperfiltration increases the risk of renal failure later in life
Bilateral = get oligohydraminos with potter sequence (lung hypoplasia, flat face with low set ears, developmental defects of the extremities)
Incompatible with life
Potter Sequence
lung hypoplasia
flat face with low set ears
developmental defects of the extremities
See in congenital kidney diseases like bilateral renal agenesis and PKD
Dysplastic Kidney
NONINHERITED, congenital malformation of renal parenchyma characterized by cysts and abnormal tissue (cartilage)
usually unilateral but can be bilateral (especially on tests)
Polycystic Kidney Disease Autosomal Recessive
Inherited defect leading to bilateral enlarged kidneys with cysts in the RENAL CORTEX and MEDULLA
Autosomal Recessive = Presents in INFANTS as worsening renal failure and hypertension and possibly potter sequence. Associated with congenital hepatic fibrosis (get portal hypertension) and hepatic cysts
Polycystic Kidney Disease Autosomal Dominant
Inherited defect leading to bilateral enlarged kidneys with cysts in the RENAL CORTEX and MEDULLA
Autosomal Dominant = See in young ADULTS as hypertension (from increased renin), hematuria, and worsening renal failure.
Due to mutations in APK1 or APKD2.
Associated with berry aneurysm, hepatic cysts, and mitral valve prolapse
Medullary Cystic Kidney Disease
Inherited (aut DOM) defect leading to cysts in the MEDULLARY COLLECTING DUCTS
Parenchymal fibrosis results in SHRUNKEN kidneys and worsening renal failure
Acute Renal Failure
Hallmark is azotemia , increased BUN and Creatinine, and oliguria
Can be prerena;, postrenal, or intrarenal
Prerenal Azotemia
Due to decreased blood flow to kidneys → decreased GFR, azotemia and oliguria
activation of renin/angiotensin system ultimately leads to increased reabsorption of BUN (serum BUN:Cr ratio >15)
Tubular function remains intact so fractional excretion of 500mOsm/kg
Postrenal Azotemia
Obsturction of urinary tract causes a backpressure in the kidney that decreases GFR, azotemia, and oliguria
Early Stage = increased tubular back pressure forces BUN into the serum (serum BUN:Cr ratio >15) and Tubular function remains intact so fractional excretion of 500mOsm/kg
Long standing obstruction = get tubular damage and get decreased reabsorption of BUN (serum BUN:Cr 2% and inability to concentrate the urine (urine osm<500mOsm/kg)
Acute Tubular Necrosis
Injury and necrosis of tubular epithelial cells.
Necrotic cells slough off and plug the tubules and decrease GFR.
Oliguria, brown granular casts in urine, elevated BUN and creatinine, hyperkalemia, metabolic acidosis with increased anion gap
Reversible but generally need to be on dialysis for 2-3 weeks until the tubular/stable cells reenter the cell cycle and regenerate
Dysfunctional epithelium results in decreased reabsorption of BUN (serum BUN:Cr 2% and inability to concentrate the urine (urine osm<500mOsm/kg)
Etiology may be ischemic or nephrotoxic
Acute Tubular Necrosis from Ischemia
decreased blood supply results in necrosis of tubules
Often preceded by prerenal azotemia
PROXIMAL TUBULE and MEDULLARY SEGMENT of THICK ASCENDING LIMB are particularly susceptible to ischemic damage since these segments require a lot of ATP
Acute Tubular Necrosis from nephrotoxic
Toxic agents kill tubules
Proximal tubule is particularly susceptible
Causes include:
1) AMINOGLYCOSIDES
2) heavy metals = lead
3) Myoglobinuria = crush injury to muscle
4) Ethylene glycol = see OXALATE CRYSTALS in urine
5) Radiocontrast dye
6) Urate = tumor lysis syndrome (Prevent with hydration and allopurinol prior to chemo)
Acute Interstitial Nephritis
Drug induced hypersensitivity involving the interstitium and tubules results in acute renal failure
Causes include NSAIDS, PENICILLIN, and DIURETICS
Presents as oliguria, fever, and rash days to weeks after starting a med
EOSINOPHILS in urine
resolves with removal of drug but can progress to renal papillary necrosis
Renal Papillary Necrosis
Necrosis of renal papillae
Presents with gross hematuria and flank pain
Causes include:
1)Chronic analgesic abuse (long term phenacetin or aspirin use)
2) Diabetes mellitus
3) Sickle cell trait or disease
4) Severe acute pyelonephritis
Nephrotic Syndrome
Glomerular disorder characterized by proteinuria (>3.5g/day) resulting in:
Hypoalbuminemia = pitting edema
hypogammaglobulinemia = increased risk of infection
Hypercoaguable state = due to loss of antithrombin III
hyperlipidemia and hypercholesterolemia
Minimal Change Disease
CHILDREN
idiopathic usually but also associated with Hodgkin Lymphoma (overproduction of cytokines)
EFFACEMENT of PODOCYTES via CYTOKINES on electron microscopy
Seletive proteinuria = loss of albumin but not immunoglobulin
Excellent response to steroids
Normal glomeruli on H&E stain, no immune complex deposits so negative IF
Focal Segmental Glomerulosclerosis
HISPANICS and AFRICAN AMERICANS
usually idiopathic but also associated with HIV, HEROIN, and SICKLE CELL DISEASE
Focal in that only some glomeruli are affected and segmental in that of those glomeruli that are affected only parts of them show sclerosis on H&E
Effacement of foot processes on EM
No immune complexes depsotis so negative IF
Poor response to steroids and progresses to chronic renal failure
Membranous Nephropathy
CAUSCASIAN ADULTS
usually idiopathic but also associated with Hep B+C, solid tumors, SLE, or drugs like NSAIDs and penicillamine
Get a THICK glomerular BASEMENT MEMBRANE on H&E due to subepithelial immune complex deposition.
GRANNULAR IF, subepithelial “spike and dome” appearance on EM
Poor response to steroids and progresses to chronic renal failure
Membranoproliferative Glomerulonephritis
THICK glomerular BASEMENT MEMBRANE on H&E with “TRAM TRACK” appearance due to immune complex deposition
GRANULAR IF
Type I = subenothelial complex deposition. associated with Hep B and C. “tram track” appearance seen more clearly
Type II = dense intremembranous complex disease. Associated with C3 nephritic factor (an autoantibody that stabilizes C3 convertase, leading to overactivation of complement, inflammation, and low levels of circulating C3)
Poor response to steroids and progresses to chronic renal failure
Diabetes Mellitus Nephrotic Syndrome
High serum glucose leads to nonenzymatic glycosylation of the vascular basement membrane resulting in HYALINE ARTERIOSCLEROSIS
glomerular EFFERENT ARTERIOLE is affected more than afferent leading to high glomerular filtration pressure. Leads to hyperfiltration injury leads to microalbunemia.
Eventually progresses to nephrotic syndrome that is characterized by sclerosis of the mesangium with formation of Kimmesltiel-Wilson nodules
Systemic Amyloidosis
Kidney is most commonly involved organ. Amyloid deposits in the mesangium resulting in nephrotic syndrome
get apple-green birefringence
Nephritic Syndrome
Glomerular disorders characterized by inflammation and bleeding.
See limited: proteinuira, oliguria, azotemia, salt rentention (periorbital edema and hypertension) RBC casts
HYPERCELLULAR and inflamed glomeruli
Immune complex eposition activates complement…C5a attracts NEUTROPHILS which mediate the damage
Poststreptococcal Glomerulonephritis
Nephrtic syndrome that arises 2-3 weeks after group A betahemolytic strep infection of skin or pharynx. Other organisms can cause it as well as long as they have the M PROTEIN virulence factor
Presents as hematuria, oliguria, hypertension, periorbital edema
HYPERCELLULAR and INFLAMED glomeruli
Granular IF and subepithelial humps on IM due to immune complex deposition
Rapidly Progressive Glomerulonephritis
Nephritic syndrome that progresses to renal failure in weeks to months
CRESECENTS composed of FIBRIN and MACROPHAGES in bowmans space
DIseases include Good pasture syndrome, PGSN, diffuse proliferative glomerulonephritis, wegner granulomatosis, microscopic polyangiitis, churg-strauss syndrome and distinguish by looking at the IF pattern and other clinical signs
Good pasture syndrome
Linear IF
Antibody against collagen in glomerular and alveolar basement membranes
Present with hematuira and hemopytysis
Classcially see in young adult males
can lead to Rapidly Progressive Glomerulonephritis (crescents in bowmans space)
Poststreptococcal Glomerulonephritis IF
Granular. Children rarely develops to Rapidly Progressive Glomerulonephritis but 1/4 adults do (crescents in bowmans space)
Wegner Granulomatosis
Negative IF
c-ANCA
Affects lung, kidney, and NASAL PHARYNX
can lead to Rapidly Progressive Glomerulonephritis (crescents in bowmans space)
Microscpoic Polyangitis
Negative IF
p-ANCA
can cause Rapidly Progressive Glomerulonephritis (crescents in bowmans space)
Churg-Strauss Syndrome
Negative IF
p-ANCA
Cresents
Presents with inflammation, eosinophilia, and asthma
can cause Rapidly Progressive Glomerulonephritis (crescents in bowmans space)
IgA Nephropathy/Berger Disease
IgA immune complex deposition is MESANGIUM of glomeruli
Most common nephropathy worldwide
Presents during childhood as episodic gross or microscopic hematuria w/ RBC casts, usually following a mucosal infection (since IgA production is increased in these infections)
May slowly progress to renal failure
Alport Syndrome
Inherited defect in type IV collagen (x-linked)
See thinning and splitting of the glomerular basement membrane
Presents as isolated hematuria, sensory hearing loss, and occular disturbances
UTI
Most commonly arises due to a ascending infection
increased incidence in females
risk factors include sexual intercourse, urinary stasis, and catheters
Cystitis + Lab findings
Infection of the bladder
presents as dysuria, urinary frequency/urgency and suprapubic pain but systemic signs (fever) typically ABSENT
Labs
1) Urinalysis = cloudy urine with >10 WBCs
2) Dipstick = positive leuokcyte esterase (due to pyuria) and nitrites (bacteria convert nitrates to nitrites)
3) Culture = GOLD standard. See greater than 100,000 colony forming units
Causes include E COLI, staph saprophyticus, klebsiella pneumonia, proteus mirabilis (ALKALINE URINE w/ AMMONIA scent), and Enterococcus Faecalis
Sterile Pyuria
Presence of pyuria with a negative urine culture
is highly suggestive of URETHRITIS due to chlamydia trachomatis or neisseria gonnorheae
Pyelonephritis
Infection of the kidney usually due to ascending infection
Increased risk with vesicoureteral reflux
Presents with fever, flank pain, WBC casts and leukocytosis in addition to the symptoms of cystitis
ost commonly caused by E COLI, enterococcus faecalis, and klebsiella species
Chronic Pyelonephritis
Interstitial fibrosis and atrophy of tubules due to multiple bouts of acute pyelonephritis
Due to vesicoureteral reflux (children) or obstruction (BPH or cervical carcinoma)
Leads to cortical scarring with blunted calyces
Atrophic tubules containing eosinophilic proteinaceous material resemble thyroid follicles
WAXY casts seen in urine
Nephrolithiasis
Precipitation of a urinary solute as a stone
risk factors include high concentration of solute in the urinary filtrate or low urine volume
Presents as collicky pain with hematuria and unilateral flank tenderness
Nephrolithiasis from calcium oxalate or calcium phosphate
Most common
Usually from idiopathic hypercalciuria. Also seen in Chrons disease
Treat with hydochlorothiazide (a Ca sparing diuretic)
Nephrolithiasis fromammonium magnesium phosphate
Second Most Common
Usually due to infection with urease-positive organisms (proteus vulgaris or klebsiella). Alkaline urine leads to the formation of a stone
Classically results in a STAGHORN CALCULI in renal calycys that acts as a nidus for UTI.
Must be surgically removed and drugs to remove bacteria
Nephrolithiasis from Uric Acid
3rd most common
RADIOLUCENT
hot, arid climates, low urine volume, and acidic pH
Also see in aptients with GOUT or HYPERURICEMIA (leukemia or myeloproliferative disroders)
Treat by hydration and alkalinization of urine
Give gout patients allopurinol
Nephrolithiasis from Cysteine
Rare but see in CHILDREN
Associated with cystinuria (a genetic defect in tubules that results in decreased reabsorption of cysteine)
may form STAGHORN calculi
Hydrate and alkalinize urine to treat
Chronic Renal Failure
End stage kidney disease most commonly arising from diabetes mellitus, hypertension, and glomerular disease
Clinical Features include
1)Uremia = increased nitrogenous waste products in blood (azotemia) that results in nausea, anorexia, pericarditis, platelet dysfunction, encephalopathy with asterixis and deposition of urea crystals in skin
2) Salt and water retention leads to hypertension
3) HYPERKALEMIA and metabolic ACIDOSIS
4) Anemia due to decreased erythropoietin production which is normally made by RENAL PERITUBULAR INTERSTITIAL CELLS
5) HYPOCALCEMIA due to decreased 1-alpha-hydroxylation of vitamin D by proximal renal tubule cells and hyperphosphatemia
6) Renal osteodystrophy from hyperparathyroidism (osteitis fibrosa cystica), osteomalacia, and osteoperosis (from metabolic acidosis)
Treat with transplant or dialysis (cysts develop within SHRUNKEN kidney and increases risk for renal cell carcinoma)
Angiomyolipoma
Hamartoma comprised of blood vessels, smooth muscle, and adipose tissue
Increased frequency in TUBEROUS SCLEROSIS
Renal Cell Carcinoma
Malignant epithelial tumor arising from kidney tubules
Classic triad = HEMATURIA, palpable yellow mass with clear cytoplasm, and flank pain
Also see fever, wight loss, and a variety of paraneoplastic syndromes (EPO = polycythemia, renin= hypertnesion, PTHrP = hypercalcemia, or ACTH = cushing sydnrome)
Rarely can get a L sided varicocele if the tumor expands to involve the L renal vein and obsturcts drainage of L spermatic vein
Due to loss of VHL tumor supressor gene leading to increased IGF-1 (growth) and HIF transcription (increases VEGF and PDGF)
Sporadic = ADULT smoking MALES, unilateral, UPPER pole,
Hereditary = YOUNG adults and BILATERAL. see in Von Hippel Lindau disease
Von Hippel-Lindau Disease
Autosomal dominant disorder associated with inactivation of VHL gene leading to increased risk for hemangioblastoma of the cerebellum and renal cell carcinoma
Wilms Tumor
Malignant kidney tumor comprised of BLASTEMA, primitive glomeruli and tubules, and stromal cells
Most common in YOUNG CHILDREN
Large, unilateral flank mass with hematuria and hypertension (due to renin secretion)
90% are sporadic but can also be seen in WAGR syndrome, Denys-Drash Syndrome, Beckwith-Wiedemann syndrome
WAGR syndrome
Wilms tumor Aniridia Genital abnormalities Retardation of mental and motor Associated with DELETION of WT1 tumor supressor gene
Denys-Drash Syndrome
Wilms tumor
Pregressive renal (glomerular) disease
Male pseudohermaphroditism
MUTATION of WT1 tumor`
Beckwith-Wiedemann syndrome
Wilms tumor Neonatal hypoglycemia Muscular hemihypertrophy Organomegally including tongue mutations in WT2 gene cluster
Urothelial (Transitional cell) carcinoma
Malignant tumor arising from UROTHELIAL lining of renal pelvis, ureter, BLADDER, or urethra
Risks factors includ: SMOKING, napthylamine, azo dyes, nd long term cyclophosphamide or phenacetin use
OLDER adults with PAINLESS hematuria
Flat pathway = HIGH grade flat tumor that then invades. EARLY p53 mutation
Papillary Pathways = low grade to high grade to invasive papillary structure. no p53 association
Tumors are often multifocal and reccurent ue to “field defect” = all of the lining is mutated and susceptible to developing tumor
Squamous cell carcinoma
Malignant proliferation of squamous cells in background of squamous metaplasia
Risk factors include
1) chronic cystitis (older women)
2) shistosoma hematobium infection (middle eastern men)
3) Long standing nephrolithiasis
Adenocarcinoma
Malignant proliferation of glands, usually involving the bladder
Arises from
1)Urachal remnant = tumor at dome of bladder
2) cystitis glandularis
3)exstrophy = congenital failure to form the causal portion of the anterior abdominal and bladder walls
