Renal Pathophysiology 1 Flashcards

1
Q

WHat type of collagen makes up the GBM in kidneys?

A

type 4

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2
Q

Describe the structure of the collagen?

A

six types of alpha chains

three alpha chains will make a triple helix monomer

each monomer has a 7S domain at amino terminus and a globular noncollagenous domain NC1 at the carboxyl terminus

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3
Q

Why is it important to know the structre o the GBM colagen?

A

because the noncolagenous domain NC1 at the carbosyl terminus is usually the antigenic site for the autoantibodies in anti-GBM nephritis

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4
Q

WHat are two slit pore diaphragm proteins that can be mutated in nephrotic syndrome?

A

nephrin and podocin

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5
Q

What are the three general categories of renal disease?

A

glomerular
tubulointerstitial
vascular

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6
Q

What is azotemia?

A

the biochemical bnormalities seen in kidney disease - increased BUN and creatinine

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7
Q

What are the three general causes of azotemia?

A

prerenal (hypoperfusion)
renal disease
post-renal obstruction of urine flow

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8
Q

What are the three general characteristics of nephritis syndrome?

A

hematuria
mild to moderate proteinuria
hypertension

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9
Q

What are the 5 general charcteristics of nephrotic syndrome?

A
majoe proteinuria - over 3.5 gram/day
hypoalbuminemia
edema
hyperlipidemia
lipiduria
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10
Q

What is the clinical presentation of an acute renal failure?

A
  1. rapid onset azotemia

2. oliguria or anuria

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11
Q

What is the clinical presentation of CKD?

A

GFR persistently less than 60 mL/min for at least 3 months

persistent albuminuria

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12
Q

How will a renal tubular defect present?

A

polyuria
nocturia
electrolyte imbalance

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13
Q

How will a UTI present?

A

pyruia and bacteriuria

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14
Q

Historially, what are the 4 stages of renal disease?

A
  1. diminished renal reserve (GFR around 50% normal, but no azotemia or symptoms)
  2. renal insufficiency (GFR 20-25% normal, azotemia, anemia, HTN)
  3. renal failure (less than 20% function, edema, metabolic acidosis, uremia(
  4. End-stage renal disease (GFR less than 5% normal - terminal stage of uremia)
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15
Q

What’s the aboslute ideal analyte to measure clearance?

A

inulin, but it breaks down immediately in the body so you need to do a continuous iV influsion of it

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16
Q

What’s the issue with creatinine as an analyte?

A

10-20% of the creatinine in the urine was secreted by the proximal tubule - this numbe varies among individuals, so it can overestimate the GFR by a small range or a big range depending on the person

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17
Q

We usually just use formulas to estimate GFR, but when do we still use clearance measurements?

A

with unusual body habitus

rapidly changin kidney function

patients with GFR of 60 or greater (for kidney donor evals, research protocols, etc)

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18
Q

What is a normal BUN?

A

10-20 mg/dl

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19
Q

What are some things that would increase the BUN and give a false positive?

A

increased synthesis - catabolism (burns, fevres, stress), high protein diet, GI bleed, Hemolysis, malignancy

20
Q

What are some pre-renal causes of increased BUN?

A

decreased rneal perfusion/low flow states: hypotension/shock, CHF, dehydration, renal vein thrombosis

21
Q

Why is the BUN sensitive to decreased renal perfusion?

A

in low flow states, the renin-angiotensin system is activated

Na and water reabsorpion is increased and urea is passively reabsorbed along with the Na and water, so you get an increase in serum BUN concentration

22
Q

What is a normal creatinine range?

A

.7-1.5 (but remember clinical picture)

23
Q

What is a normal BUN to Cr ratio?

A

10:1 to 20:1

24
Q

An elevated BUN-Cr ratio usually means…

A

it’s a pre-renal condition due to dispropotionate increase in proximal urea reabsorption which accompanies the reabsorption of water

if it was renal or post renal, it would be a normal ratio

25
How can the FeNa help determine pre-real vs renal causes?
FeNa less than 1% favors pre-rnal because of the renin-angiotensin system activation in prerenal FeNa over 2% favors a renal or postrenal cuase
26
Is it always abnormal to have proteinuria?
normal urin will actually have up to 150 mg/24 hours
27
What does a urine dipstick test for?
presence of albumin only - you'll miss gamma light chains
28
When can you have a fals positive urine dipstick?
alkaline urine gross hematuria dilute urine
29
What test can see both albumin and light chains?
acid precipitation
30
What are some causes of preotinuria without renal disease?
postural orthostatic proteinuria - 3-5% of young adults transient functional (heavy exercise, cold exposure, fever) CHF massive obesity constrictive pericarditis renal vein thrombosis
31
Proteinuria with renal disease will be characterized by what if the issue is glomerular?
albumin and small globulins
32
Proteinuria with renal disease willb e characteried by what if the issue is tubular?
beta2 microglobulin
33
What percentage of people are born with urinary tract malformations congenitally?
10%
34
What is kidney agenesis?
the kidney fails to develop completely bilateral is fatal unilvetal is compatible with normal fucntion
35
What is renal hypoplasia?
failure of the kidney to develop to a normal size - can be bilateral or unilateral
36
What number of renal lboes is required for a diagnosis of hypoplasia?
6 or less (normal is 12)
37
What is an ectopic kidney?
located above the pelvic brim or down in the pelvis.
38
WHat is a horseshoe kidney>
when the two kidneys are fused at the upper or lower poles to form a single kidney
39
Describe cystic renal dysplasia?
enlarged, multi-cystic irregular kidneys cysts with undifferentiated mesenchyme including cartilage, immature collecting ducts and plattened epithelium
40
What is the inheritance pattern for adult polycystic kidney disease?
autosomal dominant
41
Is polycystic kidney disease bilateral or unilateral?
bilateral
42
When do most people show symptoms in PKD?
it's gradual cyst growth, and often renal function is maintained until later in life
43
What are the two genes associated wtih PCKD?
PKD1 on chromosome 16 - encodes polycystin1 (an integral membrane protein) PDK2 on chromosome 4 (encodes polycystin 2, a nonspecific calcium permeable channel)
44
What do polycystin1 and polycystin2 have in common and why to mutations cause PKD?
THey are both found on priary cilia of the tubular cells these cilia help orient the cells appropriately - hugely important in the kidney because the basolateral side has to be different from the luminal side, otherwise you get excretion of substances into spaces where it shouldnle, lading to cyst formation
45
What are the extra-renal anomalies in adult PKD?
liver cysts - usually asymptomatic intracranial berry aneurysms - CHECK! mitral valve prolapse