Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disease characterized by the progressive development of multiple bilateral renal cysts. It is the most common monogenic kidney disease associated with kidney failure and can progress to advanced chronic kidney disease and the need for renal replacement therapy.
It is not only a kidney disease. It is a systemic disease. It may be associated with:
Over time, multiple cysts appear that increase in number and size, enlarge the kidney volume, progressively compress healthy parenchyma, and reduce kidney function until advanced CKD. The kidneys can reach very large sizes and occupy a large part of the retroperitoneum and abdomen. This point is especially relevant for the transplant urologist.
The disease can remain asymptomatic for years. Later, the following may appear:
HypertensionIt is a common manifestation and may appear before advanced deterioration of kidney function.
Flank or abdominal painMay be related to kidney size, intracystic hemorrhage, infection, stone disease, or mass effect.
HematuriaMay result from cyst bleeding, stone disease, or other causes that must be evaluated according to context.
Urinary tract and cyst infectionsAn infection within a cyst can be especially problematic.
Kidney stonesThey may coexist and complicate management.
Compressive symptomsExtremely large kidneys can cause abdominal distension, early satiety, digestive discomfort, physical limitation, and chronic pain.
Finally, end-stage kidney disease may develop and the patient may require dialysis or a kidney transplant.
Before the transplant we should not look only at the kidneys. ADPKD may be accompanied by polycystic liver disease, intracranial aneurysms, cardiovascular abnormalities, abdominal hernias, and diverticular disease, among other manifestations.
The evaluation should individualize extrarenal screening according to personal and family history and clinical features.
Management is multidisciplinary. The general goals are:
Blood pressure controlEssential to reduce cardiovascular and renal risk.
Management of cardiovascular risk factorsIn selected patients at risk of rapid progression, tolvaptan may be used, with specific indications, contraindications, and monitoring.
When the disease progresses to advanced kidney failure, the alternatives are hemodialysis, peritoneal dialysis, or kidney transplant. Peritoneal dialysis remains a possible alternative, although massively enlarged kidneys or liver and abdominal wall hernias can make it difficult in certain patients.
Here the specifically urological problem begins. We must answer:
These questions are more important than simply asking "does the patient have large kidneys?"
The anatomy must be carefully evaluated. We should assess:
It is recommended to consider renal imaging within the year before the anticipated time of transplant to exclude solid lesions or complex cystic lesions.
Not routinely
Having large polycystic kidneys is not, by itself, an automatic indication for nephrectomy. Nephrectomy adds operative time, bleeding, transfusion risk, injury to neighboring organs, morbidity, hospitalization, and possible loss of residual kidney function. Native nephrectomy is recommended only when there is a specific indication and the benefit outweighs the risks.
We should consider nephrectomy when there is a concrete reason. Recognized indications include:
This is one of the situations of greatest interest to the surgeon. We must ask ourselves: is there enough anatomical space to place the graft without compromising its position, vessels, or urinary tract? If there is not adequate space, nephrectomy may be indicated.
There is no single answer for all patients.
UnilateralMay be sufficient when the main goal is to create space for the graft. Potential advantages: less surgical aggression, lower risk of bleeding, shorter operative time, and preservation of the other kidney and possibly some residual function.
BilateralMay be considered in selected situations: severe bilateral symptoms, recurrent infections, recurrent bleeding, significant pain, or other specific clinical indications.
The choice between unilateral and bilateral should be individualized according to the clinical scenario and the experience of the team.
We have three possibilities: before the transplant, simultaneous with the transplant, or after the transplant. This decision is one of the central teaching points of the lesson.
It may be necessary in certain clinical scenarios. But it should not be done routinely. It can cause loss of residual kidney function, the need to start or intensify dialysis, anemia, bleeding, transfusion, sensitization, and delay of the transplant.
Current recommendations favor, when feasible, performing the nephrectomy during or after the transplant rather than before, owing, among other reasons, to the risk of transfusion, complications, and the possibility of preventing or delaying a preemptive transplant.
In selected patients, native kidney nephrectomy can be performed in the same operation as the kidney transplant. It can be especially attractive when we need to create space for the graft.
Advantage: solving both problems in a single intervention. Disadvantage: it increases the complexity and duration of the surgery. For this reason, patient selection and the experience of the team are essential.
If the patient is asymptomatic and there is sufficient space, we can initially keep the native kidneys. If pain, infections, bleeding, complications, or suspicion of a tumor appear later, we can consider nephrectomy after the transplant. This avoids subjecting every patient up front to a surgery that many will never need.
Historically, many giant polycystic kidneys were treated with open surgery. Today there are different possibilities: open nephrectomy, laparoscopic, hand-assisted laparoscopic, or selected minimally invasive approaches.
The choice depends on: kidney size, anatomy, previous surgeries, team experience, need for simultaneous surgery, and patient characteristics.
When technically feasible, hand-assisted laparoscopic nephrectomy is suggested over open nephrectomy; the evidence is of low certainty, but the less invasive approach is associated, among other things, with a lower need for transfusion in the studies evaluated.
These kidneys can be of extraordinary size, with displaced anatomy, adhesions, large cysts, reduced working space, difficulty identifying the hilum, proximity to the colon, spleen, liver, and pancreas, and renal vessels that are difficult to expose.
For this reason, nephrectomy of a giant polycystic kidney should not be considered a simple nephrectomy merely because the kidney has no tumor. It can be technically demanding.
We must anticipate: bleeding, transfusion, vascular injury, bowel injury, splenic injury, pancreatic injury, infection, ileus, hernia, wound complications, and the possible need for conversion in minimally invasive approaches.
In the transplant candidate, transfusion carries a further consideration: it may promote immunological sensitization. Therefore, avoiding an unnecessary nephrectomy before the transplant is relevant both surgically and immunologically.
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Patient with ADPKD + advanced CKD, transplant candidate:
1. ImagingEvaluate: kidneys + cysts + masses + stones + iliac space.
2. Is there a specific indication for nephrectomy?Individualize according to the clinical scenario.
4. When?Prefer minimally invasive when feasible and adequate experience is available.
Clinical pearl for residents
The question is not "does this patient have large polycystic kidneys?" The right question is "do these kidneys create a specific indication to remove them before, during, or after the transplant?"
A 54-year-old patient with ADPKD, stage 5 CKD, and an available living donor. He has markedly enlarged bilateral kidneys. He has no recurrent infections, significant hematuria, significant pain, or suspicion of a tumor. The CT shows that the right kidney extends deep into the pelvis and leaves little room to implant the graft.
Would you perform a systematic bilateral nephrectomy?
No. There is no indication to remove both kidneys merely because of ADPKD.
Could a nephrectomy be indicated?
Yes. Lack of space for the graft is a recognized indication.
Do we necessarily need to remove both kidneys?
No. A unilateral nephrectomy can create the necessary space.
Would you necessarily perform it several months before the transplant?
No. It must be individualized. When feasible, current recommendations favor avoiding routine pretransplant nephrectomy and considering performing it simultaneously or afterward, depending on the indication and clinical situation.