Kidney Transplantation/Dialysis

Question 1

When should you start dialysis?

Answer 1

When the risks of uremia outweigh the risks of dialysis.
Possible indications include refractory volume overload, refractory hyperkalemia, uremic pericarditis (can lead to pericardial effusion–> emergent), metabolic acidosis, severe hyperphosphatemia, calcium abnormalities)

Question 2

What are the symptoms of uremia?

Answer 2

Nausea, anorexia, vomiting, funny taste in the mouth, confusion, lethargy, coma, seizures.

Question 3

Describe hemodialysis.

Answer 3

Most common in US. Outpatient, usually. Generally done 3x/week, but can also do short daily or overnight. Access via AV fistula, AV graft, or catheter.

Question 4

Describe the AV fistula.

Answer 4

Arterio-venous fistula. Make a condiut between a native artery and vein. The wall of the vein thickens due to increased blood flow. The AV fistula should go in the non-dominant arm.

• -lowest infection rate
• -longest lasting
• -requires the fewest procedures to maintain

BUT

• -takes months to use, sometimes never mature
• -risk of steal syndrome (diversion of blood, loss of perfusion to hand)
• -involves lots of needle pokes.

3 locations: Radiocephalic (radial artery/cephalic vein); brachiocephalic (brachial artery/cephalic vein); brachiobasilic (Brachial artery/basilic vein)

Question 5

Describe AV grafts.

Answer 5

2nd best option.

• -Synthetic conduit, so no maturation period.
• -Good blood flow
• -higher rate of infx than AV, but less than catheter

BUT

• -high rate of stenosis
• -shorter lifespan
• -risk of steal syndrome
• -needles

Question 6

Dialysis catheter

Answer 6

Worst option. Most common method in this country. Typically placed in IJV and terminates in SVC

Pros
--immediate use
--no needles
--no surgery
Cons
--highest infx risk
--high rate of dysfunction (fibrosis etc)
--requires site care
--assx with high mortality rate

Question 7

Describe peritoneal dialysis.

Answer 7

Much cheaper therapy, done daily. More common worldwide. Cath placed into peritoneal cavity. Fluid with high glucose concentration instilled into cavity. Water moves into peritoneal space and solutes removed.

Complications: peritonitis, exit site infections, catheter dysfunction, hernias, metabolic complications (hyperglycemia), scarring of the peritoneal membrane.

Question 8

Compared to dialysis, transplant basically increases survival by ___.

Answer 8

2x (doubles life expectancy, roughly).

Question 9

What is warm ischemia?

Answer 9

Time of cardiac death to cold perfusion. Particularly harmful to kidney allograft. (60 minutes max).

Question 10

Cold ischemia:

Answer 10

Time from cold perfusion to implantation (24-36 hours).

Question 11

What are the three categories for donor kidneys?

Answer 11

SCD (Standard Criteria) = braindead
DCD (Donation after Cardiac Death) = cardiopulmonary death followed by retrieval
ECD (Donor age greater than 60, or 50-59 with 2/3 death by CVA, elevated creatinine, HTN)

Question 12

Transplant Immunology takes into account:

Answer 12

ABO blood type, HLA (6 considered 2 each of HLA-A; -B, -DR)

Question 13

Class I

Answer 13

HLA A, B, C (all nucleated cells, present to CD8)

Question 14

Class II

Answer 14

HLA DR, DP, DQ (on APC only. present to CD4).

**A, B, DR considered the most important.

Question 15

What are the two types of rejection?

Answer 15

Cellular and Antibody. T vs B cell mediated.

Cellular - treat with IV steroids, anti-thymocyte globulin
Ab - plasmapheresis, IVIG, rituximab

Question 16

3 categories of drugs used in immunosuppression.

Answer 16

1) Calcineurin inhibitor (tarolimus)
2) proliferation inhibitor (MMF, sirolimus
3) tertiary agent (prednisone)

Question 17

Side effects of Calcineurin inhibitors?

Answer 17

Nephrotoxicity, HTN, diabetes

Question 18

Side effects of proliferation inhibitors

Answer 18

Cytopenias, GI toxicity

Question 19

Side effects of steroids?

Answer 19

Weight gain, HTN, diabetes, hyperlipidemia, bone loss, cataracts. Most patients wish to dump the steroids.

Question 20

Side effect common to all immunosuppressive drugs?

Answer 20

Infection and malignancy.

Question 21

How should you approach transplant AKI?

Answer 21

Same as usual. Pre-renal, renal, or postrenal. Also think about the timeline - how far from operation are we?

Do physical exam, UA, urine culture, lab assessment, imaging, then biopsy if needed.

Question 22

What are the Ddx for pre-renal AKI in a transplant patient?

Answer 22

Volume depletion, hypotension
Renal artery thrombosis (rare, within 1 week)
CNI side effects (constriction of renal artery from the calcineurin inhibitor, i think)

Question 23

What is the Ddx for renal AKI in a transplant patient?

Answer 23

Delayed graft function
Acute rejection (cellular or ab)
Recurrent primary kidney disease
Infection (UTI, Polyomoa virus)

Question 24

What is the Ddx for postrenal AKI in a transplant patient?

Answer 24

Obstruction (lymphocele, ureteral stricture, urine leak, hematoma)

all repaired surgically.