URINARY Section 7: Transplant Flashcards
the best treatment for end stage renal disease
tansplant
Where the transplanted kidney is most commonly placed
extraperitoneal iliac fossa so that the allograft can be anastomosed with the iliac vasculature and urinary bladder.
two major points to know first when thinking about resistance indices (RI)
- Kidney has an unforgiving capsule
- A sick kidney is a swollen kidney
RI =
If the meat (parenchyma) of the kidney is sick and swollen, but can’t expand because it is wrapped in a tight unforgiving capsule you can imagine the
blood vessels going through that kidney are going
going to get the squeeze!!
You can also probably imagine that the passive diastolic flow would be more impaired (compared to the active systolic flow) by this squeeze.
If the meat of the kidney becomes “sick” from whatever the cause might be {rejection, infection, inflammation, etc…) it swells =
Increasing resistance
RI should stay below?
Below 0.7
For the purpose of multiple choice, you should never use elevated RIs
to exclude pathology (unless the answer is normal)
3 flavors of Transplant Complications
a. Urologic
b. Vascular
c. Cancer
why do tranplanted kidneys have some mild hydro?
denervation of the transplant
loppy tone to the ureter.
If there is a true obstruction it is usually at the site of ureteral implantation to the bladder.
Common causes of tranplant obstruction?
post operative edema
scarring
technical errors leading to kinking
Hematoma in transplant
Common immediately post op
Spontenous resolution
Large post transplant hematoma can produe
hydronephrosis
Acute hematoma vs chronic
ACute = echogenic
chronic = anechoic + septated
Urinoma is usually found __ weeks post op
2 weeks
Urinoma on USD
anechoic fluid collection with no septations, that is rapidly increasing in size.
Where do most leaks (urine extravasation) go?
Ureterovesical anastomosis
How do you demosntrate urinoma?
MAG 3 nuc med
or
USD (cheaper)
When do lymphoceles start post op?
1-2 months
Cause of lymphocele
leakage of lymph from surgical disruption of lymphatics or leaking lymphatics in the setting of inflammation
most common fluid collection to cause transplant hydronephrosis.
LYmphocele
Ipsilateral lower extremity edema from femoral vein compression.
Lymphocele
Think Complex Collection + Heterogenous, Septa,
Hematoma
Simple Collection between the bladder and the kidney
Urinoma
Complex Hyperemic Collection
Abscess
Simple Collection (may have tiny septa).
Lymphocele
CT appearance of Hematoma
Appearance will depend on how acute it is. Acute = more dense.
CT appearance of Urinoma
Ifyoudoadelayed phase you can see leakage of contrast
CT appearance of Abscess
Peripheral Enhancement
CT appearance of Lymphocele
If you do a delayed phase you will NOT see leakage of contrast
Urinoma causes
These things happen from ischemia to the ureter or obstruction (usually)
an immediate failure of the graft - and you rarely see this imaged. It is basically a dead on arrival transplant.
Hyperacute Rejection
Acute rejection happens between -
Week 1-3
Acute Tubular Necrosis (ATN)
The mechanism is ischemia in the kidney after they carve it out of the Hobo (presuming the transplant is from the usual donor - Hobo found floating in the river). So in the time it takes to carve it out of the Hobo and sew it into an affluent celebrity (Selena Gomez, Tracy Morgan, etc..) there is going to be some ischemia - and therefore ATN.
transplant requiring dialysis in the first week
“Delayed Graft Function (DGF) ”
Immunosuppressive therapy necessary to keep the body from rejecting the graft can ironically end up poisoning the graft.
Cyclosporin
Cyclosporin Toxicity (Calcineurin Inhibitor) timing
Latera than ATN (around a month)
Cellular Immune. (T-Cell) Mediated rejection
Chronic rejection
Antibody / Cell Mediated rejection
Acute rejection
Ischemia During “Harvesting”
ATN
Nephrotoxic Reaction to Immunosuppressive
Cyclosporin Toxicity
Renal artery thrombosis happens when?
first month (usually minutes to hours post op)
Technical factors of Renal artery Thrombosis?
Kinking or torsion
Renal artery stenosis happens when?
first year
Easily the most common vascular complication of transplant.
Renal Artery Stenosis
Where does renal artery stenosis happen?
Anastomosis (end-to-end tpyeS)
Risk factore for renal artery stenosis?
CMV
“refractory hypertension”
REnal artery stenosis
- PSV > 200-300 cm/s. (some people say 340-400 cm/s)
- PSV ratio > 1.8-2.5x (Stenotic Part vs Non Stenotic Part)
- Tardus Parvus: Measured at the Main Renal Artery Hilum (NOT at the arcuates)
- Anastomotic Jetting
Renal Vein Thrombosis happens when?
First week
Swollen kidney 1 week post op + reversed diasolic flow =
Renal Vein Thrombosis
Reverse M sign
Renal Vein Thrombosis
Biopsy + “tissue vibration artifact” =
Arteriovenous Fistula (AVF)
(perivascular, mosaic color assignment due to tissue vibration), with high arterial velocity, and pulsatile flow in the vein.
Biopsy + graft infection/anastomotic dehiscence + Yin-yang
Pseudoaneurysm
Pseudoaneurysm
Doppler with biphasic flow at the neck of the pseudoaneurysm.
Renal transplant + Immunusuppresion therapy =
100x increased risk of developing CA
In particular, they get more nonmelanomatous skin cancer, lymphoma, and colon cancer
recommendation for all renal transplant patients
annual skin exams
RCC subtype in renal transplant?
Papillary
This is an uncommon comphcation of organ transplant, associated with B-Cell prohferation.
Post Transplant Lymphoproliferative Disorder (PTLD)
is a risk factor and that is one of the main reasons they screen for it
EBV
When is Post Transplant Lymphoproliferative Disorder (PTLD) common?
It is most common in the first year post transplant, and often involves multiple organs.
Post Transplant Lymphoproliferative Disorder (PTLD)
mass lesion encasing / replacing the hilum
Renal Transplant +BK Virus =
Urothelial Malignancy
