Intro to Nephrology

Question 1

Part of the Nephron

Answer 1

1. Bowmans Capsule
   where the glomerulurs is and where filteration occurs of substances out of the blood into the filtrate (urine) go
2. Proximal Convuluted Tubule
   when 85% of the electrolytes and water are reabsorbed about being filter in the glom.
3. Loop of Henle
4. Distal Convuluted Tubules
   - principle cells & interalated cells (sense the changes in the acid/base of the urine

Macula Densa
- JG cells which sense changes in the afferent arterioles and change accordingly
- granular cells: secrete renin
- mesangial cells: structural support
- macula densa cells: monitor the flow

5. Collecting Ducts
   sight of ADH action: if secreted from the posterior pituitary gland: signal to reuptake and hold onto water

Question 2

Urinalysis
what each finding would indicate
casts

Answer 2

normal protien: (minial) approx. 0-8 mg/dL
pH: 4-8 (average is 6)
specific gravity: 1.005-1.030
leukocyte esterase: (if postive: due to infection or inflammation)
nitrites: (if postive: think bacterial infection)
ketones: think glucose breakdown byproduct or DKA
crystals: think stones

Casts
- Hyline Casts: protein casts: think nephrotic syndrome, proteinuria, CHF, CRF, intense exercise
- Cellular Casts: degenerated RBC,WBC or epithelial cells
- WBC Casts: think infection; pylenephritis, postinfectiuos glom. nephrititis, inflammatory nephitis
- RBC Casts: glomerulonephritis, interstitial nephritis, acute necrosis, trauma, tumor think from thie glomerulus
- Fatty Casts: nephrotic syndromes
- Epithelia Casts: ATN “brown!!”

Question 3

what does BUN tell us
Creatitine?
Cystatin C?

Answer 3

BUN: the level of nirogenous waste breakdown accumulating in the blood –> higher BUN indicates poor renal function

Creatitine: should be elimilated by the kidneys with trace amounts in the serum; when elevated in teh serum it indiactes an issue with the filteration process of the kidenys functioning

Cystatin C: a new way and more accurate marker of kidney function: it is a byproduct of nucleated cells that is completely elimiated in the kidneys

Normal CrCL
women :100mL/min/1.73m
men: 120 mL/min/1.73

delcines on average .8 mL/min a year after 40

Question 4

what is osmolality
what is FeNa?
what is Albumin/Cr ratio?

Answer 4

Osmolatity: the amoutn of solutes within the soluation
- usually, Na+, glucose, BUN & other large soutes

if osmolaity is high = indicates additional byproducts are circualting

FeNa: fraction excreted Sodium
(urine / serum) over (urine Cr/ serum Cr) x 100

below 1% = pre-renal issue: its all being reabsored
** over 1% = intrarenal (usualy ATN) because the kidneys cant reuptake**

Albumin/Cr ratio
- detects elevated protein via a spot sample
- normally < 30

Question 5

Imaging for the kidneys

Answer 5

Ultrasound
- can detect hydronephrosis

CT : with or without contrast (watch with CKD and injured kidneys)

MRI
- can show renal artery stenosis

Radionucleic studiies
- can measure GFR

IV urography: to see vasculature (injected and xray)

Ateriography/venography: for intervention

Question 6

Kidney Biopsy Contraindications

Answer 6

done via US

Relative
- ESRD
- horseshoe kidney
- multiple cysts
- congenital abnormalities
- soliatry kidney

Absloute!
- uncorrected bleeding disorder
- severely uncontrollted HTN
- renal infection or unknown neoplasm
- hydronephrosis
- cant lay down on stomach (pt.)