3/1 renal Flashcards
Renal tubular acidosis (RTA): type 1
- Whats happening?
- What will urine pH be?
- H/K exchanger in the alpha intercalated cell does not work. You can’t secrete H in exchange for resorbing K. Leads to hypokalemia.
- Also, if intercalated cell can’t secrete H that means it cant resorb bicarb into blood stream. B/c the acidity needs to be even.
- urine pH will be more basic than normal, pH > 5.5
RTA 1
- risk for what?
- potential causes?
- calcium phosphate kidney stones (due to urine pH and bone turnover).
- acidic environment promotes bone resorption.
-amphotericin B toxicity, analgesic nephropathy, multiple myeloma (light chains), and congenital anomalies (obstruction) of the urinary tract.
What do all RTAs lead to?
Non-anion gap hyperchloremic metabolic acidosis.
RTA 2
- whats happening?
- does it cause hypo/hyperkalemia?
- so whats the big problem?
- urine pH?
- defective bicarb resorption in PCT.
- excess bicarb in PCT carries Cl (and thus Na) w/it down tubule. Macula densa senses this excess Cl & mistakes it for hypotension & inc. renin prod. Leads to high aldo state & aldo stimulates loss of protons & K in exchange for Na.
- so leads to hypokalemia.
- big problem = not enough phosphate = can’t buffer the acid = leads to metabolic acidosis.
-urine pH < 5.5. alpha intercalated cells acidify the urine.
RTA 2
- inc risk for what?
- causes?
- inc. risk for hypophosphatemic rickets.
- Fanconi syndrome (e.g., Wilson disease), chemicals toxic to proximal tubule (e.g., lead, aminoglycosides), and carbonic anhydrase inhibitors.
RTA 4
- whats happening?
- whats the big problem here?
- hypoaldosteronism, aldo resistance, K sparing diuretics.
- The resulting hyperkalemia impairs ammoniagenesis in the proximal tubule. Decreases the buffering capacity and dec. the H+ excretion into urine.
- big problem is not enough ammonia, so not enough buffering for acid, so you can’t excrete as much acid, leads to metabolic acidosis.
- pH < 5.5. Not enough ammonia.
What leads to acidification of urine?
- if buffers are used up and you have to excrete straight up protons into the tubule, the pH will decrease fast. That will destroy the conc. gradient quickly and you wont be able to secrete any more protons. This can easily lead to a metabolic acidosis.
- This explains why the pH of RTA 2 and 4 is acidic yet they’re both still causing a metabolic acidosis.
*you need ammonia and phosphate to get rid of your acid.
ammonium in your urine represents what?
2/3 of the acid lost in urine.
phosphoric acid in your urine represents what?
1/3 of the acid lost in urine
-titrateable acid.
Total acid lost in urine =
= (H2PO4-) + (NH4+)
*which equals the same amount of bicarb added to your body.
Possible causes of RBC casts
-Glomerulonephritis, ischemia, or malignant HTN.
Possible causes of WBC casts
Tubulointerstitial inflammation, acute pyelonephritis, transplant rejection.
Possible causes of waxy casts
Advanced renal disease/chronic renal failure.
Why do you get high hct in nephrotic?
- its a relative polycythemia.
- fluid all leaving into interstitum. So RBCs get more concentrated.
How can you get anemia in nephrotic syndrome?
-spill transferrin.
- Sizes of pores in glomerulus
- size of albumin
- Endothelial cell fenestration: 40 nm
- Glomerular basement membrane pore: 4 nm
- Foot processes slit pore: 4 nm
-albumin = 3.5 nm, but repelled by neg. charge. If not it can pass.
Focal segmental glomerulosclerosis
- nephrotic/nephritic?
- IC? If so, where?
- risk factors?
- do steroids work?
- nephrotic
- no immune complex
- Black, mexican, idiopathic, HIV, sickle cell, heroin use, obesity, interferon treatment.
- inconsistence response to steroids.
- Most common cause of death in SLE pts?
- more common glomerular problem?
- second most common glomerular problem?
- renal failure
- # 1 common = diffuse proliferative glomerulonephritis (nephritic).
-#2 = membranous nephropathy (nephrotic).
Membranous nephropathy
- nephrotic/nephritic?
- IC? If so, where?
- EM presentation?
- Risk factors?
- response to steroids?
- nephrotic
- yes. IgG & C3. Subepithelial.
- spike & dome
- Caucasian, Ab to phospholipase A2 receptor, drugs (ie. NSAIDs, penicillamine), infection (HBV, HCV), SLE, any solid tumors.
- poor response to steroids.
Ab to phospholipase A2 receptor
-risk factor for which glomerular disease?
Membranous nephropathy.
Membranous nephropathy
-what are the “spikes”?
-IgG & C3.
Effacement of podocytes seen in which diseases?
Minimal change & focal segmental glomerulosclerosis.
Minimal change disease
- nephrotic/nephritic?
- IC?
- EM?
- cause?
- which cancer is it associated with?
- nephrotic
- no ICs.
- effacement of podocytes
- problem w/immunologic function. Hence its association w/resp.infections, immunizations, atopic disorders, & excellent response to steroids. Thus, dmg to podocytes probly immuno as well, most likely IL-13 mediated.
- Hodgkins lymphoma (massive overprod of cytokines).
Hodgkin lymphoma associated w/which glomerular disease?
Minimal change disease
What is lipoid nephrosis and why is it called that?
In Minimal Change Disease, the defective glomerular filtration charge barrier results in increased filtration and subsequent tubular resorption of lipoproteins, ultimately leading to lipid-laden proximal tubular cells—hence the name “lipoid nephrosis”.
Which is the only nephrotic syndrome w/excellent response to treatment?
minimal change disease, steroids.
amyloidosis
-what visualization technique do you use to visualize the apple green birefringence?
-light microscope.
6 causes of nephrotic syndrome: in pairs.
- minimal change + FSGS = effacement of foot process
- Membranous + MPGN = IC deposition
- 2 systemic disease that affect glomerulus (DM + amyloidosis)
- subepithelial immune complex deposits =
- subendothelial deposits =
- deposits w/in basement membrane =
- membranous glomerulonephritis
- type 1 MPGN
- type 2 MPGN
Type 1 MPGN
- nephrotic or nephritic?
- where are ICs?
- associated w/what?
- mixed, both nephrotic & nephritic.
- sub-endothelial: tram tracks
- HBV, HCV
Type 2 MPGN
- nephrotic or nephritic?
- where are ICs?
- associated w/what?
- mixed, both nephrotic & nephritic.
- membranous IC deposits “dense deposits”.
- associated with C3 nephritic factor (stabilizes C3 convertase dec. serum C3 levels).
C3 convertase
-type 2 MPGN
C3 =C3 convertase=> C3a + C3b
- you usually get rid of C3 convertase right after you use it b/c you only want it active for a very limited amount of time.
- but in type 2 pts - they have Ab that stabilizes the c3 convertase. Will overactivate complement.
- you’ll get a decreased serum C3.
- you’ll get inflammation and damage in the glomerulus.
- The C3 is the immune complex thats being deposited in the basement membrane and causing the damage!
- inflammation in glomerulus is more so a nephritic syndrome than a nephrotic syndrome. This disease can cause both nephritic and nephrotic
Which glomerular disease has the lowest serum C3 levels?
-type 2 MPGN
hyaline arteriolosclerosis
-preferetially affects which vessel?
- efferent arteriole
- hence the role of ACE inibitors in DM.
eosinophilic nodular glomerulosclerosis
aka DM glomerulo-nephropathy & kimmelsteil wilson nodules.
Oliguria & HTN
-nephrotic or nephritic?
- nephritic
- nephrotic doesn’t get oliguria or HTN.
PSGN
- after pharyngitis, impetigo, or both?
- inc or dec complement levels?
- both
- dec. complement levels
PSNG
-how long after infection will it occur?
- 2-3 weeks after.
* IgA nephropathy just a few days after.
Goodpastures
-hemoptysis or hematuria usually first?
-hemoptysis.
“wire looping” of capillaries?
- seen in what?
- most associated w/what extra-renal disease?
- Diffuse proliferative GN
- SLE