Test 5: Renal Flashcards
What are the (7) functions of the Kidneys?
Lecture & 1211-1214
Formation of urine by:
1. Excretion of metabolic waste products: Urea, creatinine, bilirubin, drugs and hormone metabolites
2. Regulation of water and electrolyte balance
3. regulation of arterial blood pressure: RAAS
4. Regulation of acid/base balance: excretion of H+ & reabsorption of bicarb
5. erythrocyte production (erythropoietin)
6. Production of Calcitriol (1,25 dihydroxy vitamin)
7. Gluconeogenesis
Structural components of the Kidney
lecture & 1211-1212
- cortex: outer layer
- Medulla: inner part of the kidney and consists of regions called pyramids
—–Pyramids: organized tissue in the medulla that communicates with the renal pelvis - Minor and major calyx: chambers receiving urine from the collecting ducts and form the entry into the renal pelvis
- Nephron: functional unit. consists of: renal corpuscle, proximal tubule, loop of Henle, distal tubule, and collecting duct. (can not be regenerated)
Glomerulus
-definition
-structure
-function
1212
-A tuft of fenestrated capillaries that loop into the Bowman’s space, like a “fist pushed into bread dough”
INITIAL FILTRATION SITE OF NEPHRON
-Glomerular filtration membrane
——1. inner capillary endothelium (fenestrae)
——2. middle basement membrane (collagen and proteoglycan)
——3. outer layer of capillary or visceral epithelium (podocytes/filtration slits/slit membranes)
-membrane allows all components of the blood to be filtered with the exception of blood cells and plasma proteins with a high molecular weight. Filtrate passes through the three layers of the glomerular membrane and forms the primary urine.
WATER FREELY PERMEATES
NEED A VIDEO, THIS IS SO CONVOLUTED WHEN EXPLAINED LIKE THIS
What are the types of nephron (3)?
-prevalence
-approximate location
1212
-Cortical: 85% of all nephrons, originate close to the surface of the cortex or in the midcortex and extend into the medulla
-Midcortical: have short or long loops
-Juxtamedullary: 12% of nephrons lie near, and have long loops that extend deep into the medulla and are important for the concentration of urine.
——specialized vasculature surrounding their peritubular capillaries called VASA RECTA that absorb fluid determining the urine concentration
What are the (7) major blood vessels of the kidney?
1215-1216
- Renal arteries: off the abdominal aorta
- Interlobar arteries: subdivisions that travel down renal columns and between pyramids to form afferent glomerular arteries
- Arcuate arteries: branches of interlobar arteries at the cortical medullary junction.
- Glomerular capillaries: 4-8 vessels arranged in a fist like structure. arise from afferent arteriole and empty into efferent arteriole MAJOR RESISTANCE VESSELS FOR THE REGULATION OF INTRARENAL BLOOD FLOW
- Peritubular capillaries: surround convoluted portions of the proximal and distal tubules and the loop of Henle. Adapted for cortical and juxtamedullary nephrons.
- Vasa Recta: network of capillaries that forms looks and closely follows the loops of Henle; ONLY BLOOD SUPPLY TO THE MEDULLA/ IMPORTANT FOR THE FORMATION OF CONCENTRATED URINE.
- Renal veins: follow the arterial path in reverse direction and have same names as corresponding arteries, then dump into the inferior vena cava.
What is glomerular filtration rate (GFR)?
How is it controlled?
1217
-The filtration of the plasma per unit of time, which is directly related to the perfusion pressure of the glomerular capillaries.
-neuronal and hormonal regulation
What is Tubular Reabsorption?
1219
-the movement of fluids and solutes from the tubular lumen into the peritubular capillary plasma
-as filtrate progresses through the renal tubules a selective process of reabsorption occurs.
-essential nutrients (glucose and amino acids), electrolytes, and water are actively and passively transported back into the bloodstream.
What is glomerular filtration?
1219 & AO
-First step in urine formation
-Driven by hydrostatic pressure, water and small solutes are forced from the blood across the glomerular filtration barrier into the bowman’s capsule forming INITIAL FILTRATE
-Filtrate is similar to blood plasma but lacks proteins and cellular components
What keeps large proteins from ending up in urine?
1219
Molecule size compated to small size of filtration slits in glomerular epithelium
Negative charge of the filtration membrane repels the negative charge of the macromolecules like protein.
–though positively charged macromolecules can permeate more easily than negative or neutral charged particles.
What is tubular secretion?
1219
-the transfer of substances from the plasma of the peritubular capillary to the tubular lumen.
-simultaneously, unwanted substances are actively transported from the blood into the filtrate. Including metabolic waste, H+, drugs/toxins etc.
-secretion shapes the final composition of the filtrate preparing it for its role as urine
What is the function of the glomerular membranes endothelium?
1213
-REGULATE vasomotor tone: Synthesize nitric oxide (dilation) and endothelin-1(constriction) to help regulate glomerular blood flow
-FACILITATE homeostasis: fluid electrolyte balance
-CONTROL trafficking of leukocytes into the glomerulus
What is the function of the glomerular basement membrane?
What is it made of?
1213-1214 & AO
-structural integrity/scaffolding for both the endothelium and the podocyte layer
-Size and charge based barrier (keep protein, allow water and small solutes to pass)
-Collagen and proteoglycan
What is the function of potocytes?
1213-1214 & AO
-Final filtration barrier
-prevents albumin leakage into filtrate
-maintains and repairs the glomerular membrane
What are the (4) ways to increase GFR?
1217-1218, 1220 & AO
- increase glomerular hydrostatic pressure
—–Increased vascular volume or MAP, dilation of afferent arterioles allowing more blood in, or constricting of efferent arterioles slowing the outflow and increasing pressure - Increased Bowman’s capsule hydrostatic pressure
—–obstruction of urinary tract (stones or BPH) initially increase pressure (though sustained obstruction decreases GFR long term) - Decrease glomerular capillary colloid osmotic pressure
—–increased intake of protein or temporary conditions (hyperglycemia) increase oncotic pressure gradient, affecting fluid dynamics across the membrane. - Hormones and Autacoids
—–angiotensin II constricts EFFERENT arterioles
—–nitric oxide, prostaglandins, bradykinin dilate AFFERENT arterioles
What are the (2) ways to decrease GFR?
1220-1221 & AO
- Change blood flow
—–Sympathetic nervous system
———Norepi: constriction of BOTH afferent and efferent arterioles reducing overall renal blood flow
———Epi: constricts AFFERENT arterioles decreasing flow INTO the glomeruli - Hormone
—–Endothelin: vasoconstricts afferent arterioles
Proximal tubule
What is it?
Reabsorption?
Secretion?
Controlled by?
1214 & Lecture & AO
longest and most metabolically active segment, VERY WATER PERMEABLE
Reabsorbs 65-70% of filtrate to reclaim:
-Na, Cl, K, Phos, bicarb, glucose and amino acids
Secretes: H+, organic acids and bases (bile salts, uric acid and catecholamines)
Control: Angiotensin II (increased H2O & Na), parathyroid hormone DECREASES Phos reabsorption
Thin DESCENDING loop of Henle
Reabsorption?
Secretion?
Controlled by?
Lecture & AO & 1214
HIGHLY water permeable, creates highly concentrated filtrate (water leaves)
Reabsorption: small amounts of Na
Secretion: None
Control: None
Thin ASCENDING loop of Henle
Reabsorption?
Secretion?
Controlled by?
Lecture & AO & 1214
Permeable to IONS NOT WATER
actively transports Na and Cl creating a hyperosmolar environment
Reabsorption: None
Secretion: None
Control: None
Thick ASCENDING loop of Henle
Reabsorption?
Secretion?
Controlled by?
Lecture & AO & 1214
IMPERMIABLE TO WATER AND UREA
REABSORPTION: Na, Cl, K, Ca, Mg, and bicarb
SECRETION: H+
Control:
-Angiotensin II increases Na absorption and secretion of H+
-Parathyroid hormone increases reabsorption of Ca
NOT PHOS
Collecting Tubules
Reabsorption?
Secretion?
Controlled by?
Lecture & AO & 1214-1215
Final conduit of nephron, receive concentrated urine from multiple distal tubules. Hormones influence last modifications before it is delivered to renal pelvis for excretion
Reabsorption: Na, Cl, Ca and bicarb, possibly H2O
Secretion: K, H+ and Urea
Control:
-Aldosterone increases NaCl Reabsorption and K secretion
-Vasopressin increases H2O reabsorption
-ANP decreases Na reabsorption
Medullary Collecting ducts
Reabsorption?
Secretion?
Controlled by?
Lecture & AO
segment that traverses the hyperosmolar medulla allowing further water reabsorption under the influence of ADH
Reabsorption: Urea and H2O (if ADH)
Secretion: Na, K, H+ and bicarb
Control: ADH increases H2O reabsorption
Creatinine Clearance (CrCl)
Lecture & AO & 1226
Provides a good clinical measure of GFR as it only over estimates GFR by a small amount because the renal tubules secreta a small amount of creatinine themselves (book)
Overestimates actual kidney function (lecture & AO)
NOTES:
GFR (mL/min)= (Urine creatinine x volume of urine)/(Plasma creatinine)
REQUIRES A SINGLE BLOOD TEST AND A 24 HOUR URINE SAMPLE
Cystatin C
What is it?
What does it tell you?
Lecture & AO & 1226
Stable protein in serum (made by all nucleated cells) filtered at the glomerulus and metabolized in the tubules. ESTIMATES GFR (blood test)
More accurate insight into kidney function, considered a reliable marker of renal function. (BOOK: particularly good for mild to moderate impaired renal function)
ELEVATED = LOWER GFR
GEM: not influenced by infection, diet, inflammation, gender, age, or race making it a stable marker for assessing kidney function.
RBCs in Urine/hematuria
What does it indicate?
What conditions cause it?
Lecture & AO & 1227
Bleeding in the urinary tract
Glomerular nephritis: inflammation or damage to the glomeruli
Trauma: injury to the urinary tract
Kidney stones: cause irritation and bleeding
WBCs in the urine/pyuria
What does it indicate?
Lecture & AO & 1228
Infection/UTI esp when bacteria are also present
If present a culture & sensitivity should be done
Casts
What are they?
What are the types?
What does each type indicate?
Lecture & AO & 1228
accumulations of cellular precipitates, coagulated proteins in the renal tubules
Cellular debris: AKI
RBC casts: tubular or glomerular injury
WBC casts: inflammation, often pyelonephritis
Epithelial Casts: tubular injury/ degeneration of tubular lumen or necrosis of the renal tubules
Broad Waxy Casts: prolonged stasis and severe tubular injury (bad sign= CKD)
Effect of aging on kidneys (5)
Lecture & AO & 1229-1230
- Hypertrophy: compensatory mechanism or compensate for loss of function (kidney donation, trauma, certain diseases)
- Nephron loss: around 40 # of nephrons begins to decrease.
—–Decrease in renal blood flow & GFR
—–Diminished ability to remove waste and balance electrolytes - Atrophy: shrinking and loss of functional capacity
—–decreased tubular reabsorption can cause glucosuria, or impair acid base balance - Decreased production of Vit D: ability to hydroxylate vit D to tis active form (calcitriol) diminishes.
—–affects calcium absorption in intestines, possible hypocalcemia, leading to osteoporosis - Bladder Function:
—–Neurogenic: nerve changes can cause overactive bladder, urgency and frequency
—–External causes:
———Hormones: reduced estrogen affect bladder function and increase risk of UTI. PBH can obstruct urinary flow causing difficulty urinating and frequency
———Cardiovascular disease: HF can affect kidney function and fluid balance leading to increased urinary frequency
———Position changes/Diurnal Nocturia: shift in fluid balance can cause increased nighttime urination, as fluid retained in tissues during the day is mobilized when lying down at night.
AKI
Definition
Stages
lecture & AO & 1252-1253
sudden onset kidney failure to filter waste products effectively. Can develop over hours to days and is often reversible with appropriate treatment
Stage 1: RISK 1.5-1.9x baseline Cr OR an increase of 0.3mg/dL or more
Stage 2: INJURY 2-2.9x baseline Cr within 48hrs
Stage 3: FAILURE 3.0 or more x baseline in 48hrs, OR SCr 4 or more, OR initiation of renal replacement therapy
Pre-Renal AKI
Causes
Lecture & AO & 1253-1254
HYPOPERFUSION MOST COMMON CAUSE OF AKI
Causes:
-Hypovolemia/Hemorrhage/Hypotension
-Decreased cardiac output/heart failure
-Abdominal Compartment syndrome
-Systemic Vasodilation/shock/cirrhosis/hepatorenal syndrome
Intrarenal AKI
Causes
Lecture & AO & 1253
Most common cause of intrarenal AKI is ATN
Direct damage to kidney
Causes:
-Vascular (renal artery stenosis, renal vein thrombosis)
-Microvascular (malignant HTN, vasculitis, HELLP etc)
-Glomerular (post infectious glomerulonephritis, endocarditis, lupus nephritis)
-Tubulointerstitium (ATN from surgery/shock etc, inflammatory, nephrotoxicity, AIN- acute interstitial nephritis, bilateral acute pyelonephritis)
What is ATN?
Cause/mechanism?
What are the types?
1253-1255
Acute Tubular Necrosis OR Acute Interstitial Necrosis
more severe form of AKI resulting in failure to restore blood volume or pressure and oxygen delivery causing ischemic cell injury. Reperfusion injury with cell death can also occur
Ischemic ATN most often occurs after surgery but also associated with sepsis, obstetric complications, severe hemorrhagic trauma, and severe burns.
Nephrotoxic ATN usually caused by exposure to IV contrast or nephrotoxic medications (NSAIDS, ACEi, ARBs and antibiotics especially aminoglycosides)
Post Renal AKI
Cause
Lecture & AO & 1255
OBSTRUCTION
Causes:
-Kidney stones
-BPH
-Tumors or strictures
AKI
Clinical manifestations
Diagnosis
Treatment
Lecture & AO & 1257
Manifestations
-Sudden Oliguria
-Dark urine
-Edema
-Fatigue
-SOB
-Confusion
-CP or pressure secondary to fluid buildup
Diagnosis:
Elevated SCr & BUN
Electrolyte imbalance
UA: casts/crystals etc identification of cause
Ultrasound or CT: assess kidney size and rule out obstruction
Renal Biopsy: elect cases to diagnose intrinsic renal disease
Treatment:
PREVENTION
Avoid nephrotoxic meds, hypovolemia and hypotension
Reverse cause
CKD
Definition
Causes
Lecture & AO & 1259
Gradual loss of kidney function over a period of months to years. Typically irreversible and progressive.
Causes:
-Diabetes: diabetic nephropathy
-HTN*: Hypertensive Nephrosclerosis
-Glomerulonephritis: chronic inflammation
-Polycystic Kidney disease: long infection-> scarring
-Obstructive Uropathy: long term obstruction -> renal damage
DIABETES IS THE LEADING CAUSE
HTN SECOND LEADING CAUSE
CKD
Clinical Manifestations
Diagnosis
Lecture & AO & 1260
-Often asymptomatic in early stages
-Fatigue/weakness
-HTN
-Edema (LEGS AND AROUND EYES)
-Urine changes
-Muscle cramps and restless legs
-nausea and vomiting
-itching
-Azotemia
-Uremia
-Uremic Syndrome
Diagnosis:
-GFR < 60mL/min/1.73m2 x 3 months or more with implications for health
-Elevated Serum Cr & BUN
-UA (persistent proteinuria, hematuria etc)
-Electrolyte imbalance
-Anemia (decreased erythropoietin)
-Ultrasound (structure and size)
-Biopsy (occasional for specific cause)
What is Azotemia?
1260
increased serum urea, SCr, and other nitrogenous compounds related to decreased kidney function
Acute on Chronic Kidney Injury
AO
Deterioration in kidney function that occurs in individual with preexisting chronic kidney disease. Represents an acute insult superimposed on chronic injury
Diagnosis:
Marked increase in SCr & BUN
Rapid electrolyte imbalance
Definition of Oliguira
1266
UOP Less than 400mL/24 hours
CKD Staging
AO & 1258
Stg 1: Normal or high GFR (>90), usually no symptoms, HTN common
Stg 2: GFR 60-89, mild damage, HTN, increasing SCr and urea
——–Stg 1 & 2 focus on managing underlying causes
Stg 3: GFR 30-59, moderate damage, HTN, increased SCr and urea
——–Stg 3 increased risk of cardiovascular disease
Stg 4: GFR 15-29, severe damage, HTN, increased SCr and urea, erythropoietin deficiency anemia, hyperphosphatemia, increased triglycerides, metabolic acidosis, hyperkalemia, salt/water retention.
——–Stg 4 prepare for renal replacement therapy
Stg 5: GFR < 15, End stage Severe same symptoms as stg 4
——–Stg 5 criitcal symptoms requires dialysis or transplant
What is Acute Interstitial Nephritis (AIN)
Organizer & Google
Possible etiology for AKI
Allergic reaction, often to medications (abx like PCN, NSAIDS, tylenol, lasix, allopurinol etc.).
Patho: AIN is characterized by an inflammatory infiltrate of mononuclear cells and T lymphocytes in the kidney interstitium, along with edema. The infiltrate may also include plasma cells and eosinophils. Interstitial fibrosis may develop later in the disease.
Up to date: It is most often induced by drug therapy. AIN is also caused by autoimmune disorders or other systemic disease (lupus, Sjögren’s, sarcoidosis, kawasaki), a variety of infections remote to the kidney (eg, Legionella, leptospirosis, and streptococcal organisms), immunoglobulin G4 (IgG4) disease, and tubulointerstitial nephritis with uveitis.
ATN vs AIN
Google
ATN: acute tubular necrosis
-Caused by DIRECT toxicity or, more frequently, ischemia
-rapid onset
-more prominent tubular epithelial cell injury
AIN: Acute interstitial nephritis
-caused by ALLERGIC reaction to substance, therefore immune attack is the direct offense
-gradual onset, starting subtly
-history of systemic symptoms like fever, rash, arthralgias, and flank pain
-more prominent interstitial edema and cellular infiltrates
Main way to differentiate is the rapid onset for ATN, and the systemic symptoms of AIN
What secondary effects does CKD have on the skeletal system?
AO & 1263
-Mineral and bone disorder: disrupts the balance of Ca, phos and PTH
-Vit D deficiency: impaired renal function reduced activation of vit D decreasing Ca absorption
-Hyperphosphatemia: can’t excrete phos
-Secondary hyperparathyroidism: low Ca and high phos stimulate excess PTH causing bone resorption.
What secondary effects does CKD have on the CV system?
AO & 1264
-Hypertension overload & RAAS
-Overload-> decreased CO & increased cardiac workload -> left ventricular hypertrophy & CHF (of course pulmonary edema)
-Dyslipidemia promotes atherosclerosis
-Vascular: ischemic heart disease, PVD
-Pericarditis: uremic toxins cause pericardial inflammation
-Anemia: increased CO demand adds to cardiac workload on already taxed heart
What secondary effects does CKD have on the Endocrine system?
AO & 1264-1265
-Both sexes have a decrease in circulating sex hormones
—-Men have reduction in testosterone that can cause impotence, oligospermia and germinal cell dysplasia -> infertile
—-Females decreased estrogen, amenorrhea, anovulation, difficulty maintaining a pregnancy to term and early menopause
-Insulin Resistance: ability of the kidney to degrade insulin is reduced and the half life of insulin is prolonged causing insulin resistance
-Hypothyroidism: “nonthyroidal illness syndrome” uremia delays the response of thyroid stimulating hormone receptors and T3 levels are often low.
-PTH/hyperparathyroidism: disrupted Ca/phos balance
What secondary effects does CKD have on the Hematologic system?
AO & 1264
-Reduced Erythropoietin -> anemia -> decreased tissue oxygenation -> worse kidney disease
-Uremic toxins -> decrease life and quality of RBCs (anemia), impairs platelet function both adhesion and aggregation (thrombocytopathy) -> bleeding risk (more common in later stage CKD) or coagulopathy -> PE, DVT, MI, Stroke
What secondary effect does CKD have on the Neurologic system?
AO & 1264
-Uremia: direct affect on brain function -> encephalopathy
—-Neuromuscular irritation -> hiccups, muscle cramps and twitching
-Electrolyte imbalances affect nerve and muscle function -> neuropathy & restless leg syndrome
-HTN -> hypertensive encephalopathy and increased stroke risk
What is Urolitiasis?
Common types?
AO & 1234-1237
formation of stones in any part of the urinary tract
TYPES, MANIFESTATIONS, PATHO AND DIAGNOSIS ARE THE SAME FOR ALL THE STONE TYPES
Types:
-Calcium: calcium oxalate and calcium phos
-Uric acid: high protein diet or gout
-Struvite: chronic UTI
-Cystine: genetic disorder that causes cystinuria
What is nephrolithiasis?
What is cystolithiasis?
What is ureterolithiasis
AO &1234
Nephro: kidney stones or renal calculi
Cysto: bladder
Uretero: urethra
Urolithiasis
Clinical Manifestations?
Patho?
Diagnosis?
AO & 1234-1237
Manifestations:
-Severe, sharp pain in flank or lower back
-hematuria
-nausea and vomiting
-dysuria
Patho:
-supersaturation of urine causes crystallization of minerals
-crystals nucleate and grow (form and aggregate)
-Retention, if they don’t pass they keep growing
-obstruction: get large enough to obstruct urinary flow -> hydronephrosis
Diagnosis:
-non-contrast CT, ultrasound or xray with IV pyelogram
-UA: hematuria and crystalluria
-blood: kidney function and metabolic abnormalities
NEPHROTIC syndrome
What is it?
Patho?
Causes?
AO & 1250-1251
Excretion of 3.5g or more of protein in the urine per day
Patho: glomerular filtration of plasma proteins, particularly albumin, exceeds tubular reabsorption.
–increased permeability of glomerular basement membrane
–excess loss of protein esp. albumin
–hypoalbuminemia ->edema
–low protein stimulates hepatic lipoprotein synthesis -> hyperlipidemia -> worse glomerular disease
–anorexia -> malnutrition -> lower protein
-loss of anti-clotting factors and increased liver synthesis of clotting factors -> hypercoagulability-> clots
-Primary causes: minimal change disease, focal segmental golmerulosclerosis, and membranous glomerulonephritis
——–Minimal change disease: most common cause of nephrotic syndrome in children. Damage to microvasculature in the kidneys.
-Secondary causes: DM, amyloidosis, lupus, infections, drugs, malignancy
NEPHROTIC syndrome
Clinical manifestations?
Diagnosis?
Treatment?
AO & 1251-1252
Manifestations:
-Proteinuria: >3.5g/day
-Hypoalbuminemia
-Edema: severe often in face, legs and abdomen (preorbital and pedal)
-Hyperlipidemia: high lipids and cholesterol
-Urine that looks “foamy”
-hypothyroidism
-thrombotic events
Diagnosis:
-24 hour urine collection shows protein > 3.5g
-Serum albumin level falls to <3g/dL
-increases serum cholesterol, phospholipids and triglycerides
-fat bodies may be present and float in urine
-hematuria, possibly casts
Treatment:
-Consuming moderate protein restriction, low fa, salt restricted diet
-glucocorticoids to control immune mediated disease and may be combined with immunosuppressive drugs
-targeted immune therapy for steroid resistant cases
NEPHRITIC syndrome
Clinical manifestations?
Diagnosis?
Treatment?
Lecture & AO & 1250-1252
Manifestations:
-hematuria- often with red cell casts
-oliguria
-HTN
-proteinuria- less severe than nephrotic syndrome
-edema- mild to moderate, more often in the face (preorbital and pedal)
-hypothyroidism
-thrombotic events
Diagnosis:
-UA: hematuria & possible red cell casts
-blood: high Cr and low GFR
-Serologic: identify underlying cause
-biopsy: definitive dx and guide for treatment
Treatment:
With rapid progression:
-high dose corticosteroids
-cyclophosphamide (chemo/immunosuppressive)
Supportive care:
-antihypertensives
-diuretics
-abx
-possibly plasmapheresis and HD
NEPHRITIC syndrome
What is it?
Patho?
Causes?
Lecture & AO & 1250-1252
Hematuria and red blood cell casts in urine, HTN, edema, and oliguria. Proteinuria is present but less severe.
-post infectious glomerulonephritis (hep B & C, post strep)
-IgA nephropathy (Berger’s disease)
-Lupus nephritis
-membranoproliferative glomerulonephritis
-rapidly progressive glomerulonephritis
Patho:
-Immune complex deposition creates inflammation and damage to the glomerular capillaries
-glomerular inflammation causes hematuria
-reduction in GFT causes retention of waste products & fluid -> HTN, oliguria, elevated Cr
-loss of anti-clotting factors and increased liver synthesis of clotting factors -> hypercoagulability-> clots
Hemolytic Uremic Syndrome
What is it?
Patho?
Manifestations?
Lecture & AO & 1278-1279
acute disorder characterized by hemolytic anemia, thrombocytopenia, and acute renal failure
–usually triggered by infection with E. Coli that produce SHIGA TOXIN MOST COMMON IN CHILDREN
-Can also be genetic/autoimmune
Patho:
-Toxins (or mutations) cause direct injury to endothelial cells lining blood vessels particularly in the kidneys
-Damaged endothelium -> widespread platelet activation -> thrombi in small vessels
-RBCs are damaged as they pass microvascular clots causing hemolytic anemia
-Microthrombi in renal vasculature decrease blood flow -> AKI –> maybe renal failure
Manifestations:
-Prodromal Diarrheal Illness: often have BLOODY DIARRHEA PRECEEDING ONSET
-“TRIAD OF SYMPTOMS:”
—-Microangiopathic hemolytic anemia: fatigue, pallor and jaundice
—-Thrombocytopenia -> bruising, petechiae and increased bleeding risk
—-AKI: presents with oliguria or anuria, hematuria, proteinuria and elevated Cr & BUN
Other sx:
-general: fever, HTN, lethargy and irritability
-Neuro: seizures, stroke, or encephalopathy due to microthrombi in the brain
Polycystic Kidney Disease
What is it?
Patho?
Manifestations?
Lecture & AO & 1273
Genetic disorder
-Autosomal Dominant Polycystic Kidney Disease (ADPKD)- more common usually manifests in adulthood
-Autosomal Recessive Polycystic Kidney Disease (ARPKD)- more severe but less common, often presents in infancy or early childhood
Patho:
-defects in formation of epithelial cells and their cilia result in cyst formation in all parts of the nephron.
-cysts in other organs: liver, pancreas, and ovaries/seminal vesicles may occur
–vascular complications HTN aortic and intracranial aneurysms and heart valve defects may develop
Manifestations:
-HTN- earliest and most common sx
-Hematuria
-flank pain
-recurrent uti
-kidney stones
-hepatic cysts
-intracranial aneurysms
-cardiac valve abnormalities
—-Eventually leads to ESRD requiring HD or transplant
