Polycystic Kidney Disease (ADPKD) — Viva Defence

Opening statement (SASPOP, delivered aloud)

"Ms Kowalski is a 40-year-old woman with ADPKD whose disease is now demonstrably fast: her eGFR has fallen 16 mL/min over 4 years, and her height-adjusted total kidney volume places her in Mayo class 1D — a rapid-progression class — on typical bilateral imaging. Her main problems are: rapid progression with enough preserved function to protect, which makes her a genuine tolvaptan candidate under the TEMPO and REPRISE evidence; a family history of intracranial aneurysm in an affected sister, which is a selective-screening indication she has not yet acted on; hypertension that is currently well controlled on an ACE inhibitor; and a young family in whom the inheritance question is unresolved. My plan is to confirm her progression stage, run the tolvaptan shared-decision conversation properly — benefit quantified against aquaresis, monitoring and cost — arrange her MR angiography, and open the family counselling with her children's testing deferred until they can decide for themselves." [1] [2] [5]

Structured problem list

1. Rapidly progressing ADPKD — Mayo 1D, eGFR 52 falling about 4 per year. Two independent rapid-progression signals; the phenotype with proven tolvaptan benefit [1] [3].
2. Tolvaptan decision pending — she is informed and motivated; the consultation must quantify benefit and name burden (aquaresis, scheduled LFTs, interactions, cost) rather than simply prescribe [2] [6].
3. Family history of intracranial aneurysm — her sister's screen-detected aneurysm is her own indication for MR angiography [5].
4. Hypertension, currently controlled on perindopril — continue RAAS blockade; she is at the age edge of the HALT-PKD low-target population, so I individualise rather than chase 110/75 [4].
5. Two children at 50% risk each — counselling, the right not to know, and reproductive-history questions belong in the record [6].
6. Future renal replacement planning — distant but real; transplant is usually the excellent option in ADPKD and worth planting early [8].

Integrated management plan

• Confirm and document the stage: typical bilateral disease, htTKV in Mayo 1D, eGFR slope about 4 mL/min per year — record the two concordant rapid-progression signals, because that is what the drug decision and any funding application rest on [1].
• Run the tolvaptan conversation as a shared decision. The numbers for her: TEMPO 3:4 slowed kidney growth and eGFR decline in early CKD; REPRISE, which includes her exact eGFR band (25–65), slowed decline by about 1.3 mL/min/1.73 m² per year. The costs: several extra litres of urine daily for as long as she takes it; liver function tests monthly for 18 months then every 3 months for the small, reversible, idiosyncratic hepatocellular injury risk; CYP3A interactions; sick-day rules; and cost. She teaches — classroom toilet access is a practical issue we plan around, with morning dosing early and a fluid strategy [2] [3] [6].
• If she starts: baseline LFTs, sodium, renal function; split dosing titrated from 45/15 mg toward 90/30 mg as tolerated; the full monitoring schedule in writing; a clear stop rule for significant transaminase elevation [6].
• Arrange MR angiography now. A first-degree relative with an aneurysm — especially in an affected sister — is a defined selective-screening indication; if an aneurysm is found, small anterior-circulation lesions are usually managed with interval imaging under neurosurgical guidance, and screen-detected ADPKD aneurysms followed long-term mostly remain stable [5].
• Blood pressure: continue perindopril; target individualised — she is 40 with established CKD, so I aim for standard intensive CKD targets rather than the HALT-PKD under-50-with-preserved-GFR target of below 110/75, and I watch for dizziness [4] [6].
• Lifestyle with mechanism: water intake around 2–3 litres daily to keep urine dilute while her GFR permits; salt restriction to potentiate the ACE inhibitor; avoid chronic NSAIDs; cardiovascular risk management [7] [4].
• Family conversation: her children are 8 and 11 — I recommend deferring their testing until they can participate in the decision as adults, unless a clinical indication arises; document her relatives' status; offer clinical-genetics referral if she wants to discuss reproductive options for the future [6].
• Long-range planning: annual review of BP, renal function and (on-treatment) LFTs; re-image kidney volume only when it would change a decision; and plant the transplant seed — ADPKD patients do well on RRT and best of all after transplantation, so timely referral when her trajectory approaches stage 5 is the plan, with native nephrectomy reserved for defined problems, never routine [8] [6].

Probing questions with model answers

"Her eGFR is already 52. Isn't she too far along for tolvaptan?" — "No — that is exactly what REPRISE answered. TEMPO 3:4 enrolled early disease with big kidneys; REPRISE then randomised adults with eGFR 25 to 65 and still showed slower decline, about 1.3 mL/min/1.73 m² per year better than placebo. At 52 with a slope of 4, she has years of function worth protecting — the patients with nothing left to protect are the ones on dialysis, not the ones in stage 3. The guideline reflects that combined evidence." [2] [3]

"What will you tell her about side effects?" — "Two categories, plainly. First, the mechanism: tolvaptan blocks the vasopressin V2 receptor, so she will pass several extra litres of urine a day, every day — thirst, nocturia, and for a teacher, real planning around classroom access. It is the commonest reason people stop, and I say that before she starts, not after. Second, the rare but serious: idiosyncratic hepatocellular injury — a small excess of significant transaminase elevations in the trials, reversible on stopping — which is why the liver blood test schedule is mandatory: monthly for 18 months, then every 3 months, with a defined stop rule." [2] [6]

"Her sister's aneurysm is only 4 millimetres. Why image her at all?" — "Because the indication is the family history, not the sister's lesion size. ADPKD aneurysms cluster in families, and a first-degree relative with an aneurysm or subarachnoid haemorrhage is one of the defined selective-screening indications — alongside prior rupture, high-risk occupations and pre-transplant work-up. If we find a small anterior-circulation aneurysm, the extended follow-up data are reassuring — most screen-detected ADPKD aneurysms remain stable and are managed with interval imaging under neurosurgical advice — and finding nothing is also an answer that lets her stop worrying with evidence." [5] [6]

"Would you screen every ADPKD patient for aneurysms?" — "No — universal screening is not recommended. The harm-benefit turns on selection: a positive screen commits a patient to surveillance or intervention for lesions that mostly never rupture, so I screen those with enriched risk — family history, prior rupture, occupations where sudden incapacity endangers others, pre-transplant — and I counsel everyone else about the thunderclap-headache red flag that overrides any screening protocol." [5] [6]

"Her blood pressure is 124/78. The HALT-PKD target is 110/75 — why are you not pushing lower?" — "Because HALT-PKD's low target was proven in 15-to-49-year-olds with preserved GFR above 60 — she is 40 but her GFR is 52, outside the trial's renal-function band, so I individualise rather than extrapolate. The durable lesson I take from HALT-PKD is that hypertension is renal in ADPKD and ACE inhibitors are first-line, and that in the young-with-preserved-GFR phenotype, lower is better for kidney volume and LV mass. For her I hold standard intensive CKD targets and watch tolerability." [4]

"Her 11-year-old wants to know if he has it. What do you do?" — "I slow that conversation down. He is asymptomatic and 11 — testing him now answers an adult's anxiety, not a child's medical need, and it removes his choice. My recommendation to her is to defer testing until each child is old enough to decide for themselves, typically adulthood, with counselling first and ultrasound second if they proceed — unless a clinical indication appears earlier, like hypertension or symptoms, which would change the calculus. I also make sure she knows reproductive options existed and exist for her siblings — including preimplantation genetic testing — because families talk." [6]

"She asks you directly: will tolvaptan keep me off dialysis?" — "Honest answer: it slows the decline, it does not stop it. At her slope, slowing by the REPRISE magnitude could add years before she needs renal replacement — meaningful time with her kids at the ages they are now — but the honest framing is delay, not escape. And I add the good news she hasn't asked about: if and when she needs replacement, ADPKD patients do relatively well — registry data show better survival than other kidney diseases, and transplantation in particular is usually an excellent option. That frames tolvaptan as buying good time toward a good transplant, which is the truthful version of hope." [3] [8]

Communication points

• Frame tolvaptan as her decision, made with numbers: "The drug slows the slide; it doesn't stop it, and it asks a lot of you daily — let me show you both sides and then it's your call." [2] [3]
• Normalise the aneurysm screen as prudence, not panic — "your sister's finding means we check you once, carefully, and then we know." [5]
• Protect the children's autonomy explicitly — document that testing is deferred until they can decide, and that this is a recommendation, not a rule. [6]
• Keep the long view hopeful and specific: blood pressure controlled, progression slowed, aneurysm checked, transplant as the planned landing if the kidneys fail. [8]