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A short guide for patients and families: what cystic kidney disease is, how to read a card, and where to go next in PKD Digest.
What is cystic kidney disease?
Cysts are fluid-filled sacs. Cystic kidney disease covers different conditions involving cysts in the kidneys; their causes and effects vary. Autosomal dominant polycystic kidney disease (ADPKD) is one of them, not the whole picture. This digest covers cystic kidney disease in general, so not every card will apply to your diagnosis.
Interactive anatomy
The kidney, in 3D
Spin the kidney, open a cross-section, and compare a healthy kidney with a polycystic one to see where cysts grow.
Drag to rotate · pick a structure below to highlight it
Stylised illustration of a kidney with the structures listed below.
Structures in the model
| Outer layer, where the nephrons concentrate. | |
| Inner layer in pyramids that carries urine. | |
| Cups around the tip of each pyramid that drain urine into the pelvis. | |
| Central cavity that collects the urine. | |
| Tube that carries urine to the bladder. | |
| Bring blood in to be filtered and carry it back out (artery red, vein blue). | |
| Fluid sacs that replace healthy kidney tissue. | |
| Soft fatty tissue cushioning the renal pelvis — not cysts. |
Simplified educational illustration — not a diagnosis, a scan, or a prognosis.
What to keep track of, and how to read a card
Keep your questions, the name of your diagnosis, and the results and medicines discussed with your care team together for appointments. Ask your team what to monitor and how often; a research update is not a personal care plan.
Each card offers two perspectives: a plain-language summary for patients and families, and a short clinical note for clinicians. Switch between them, check the date and original source, and bring questions about relevance to your care team. Do not change treatment based on a card.
What counts as evidence here
Some habits have strong support for blood pressure and heart protection. None has high-quality proof of slowing cyst growth itself. Below, consensus advice comes first; research-only ideas are marked as such.
Water
Drink enough to avoid dehydration, especially in heat, exercise or on tolvaptan. But a 3-year trial (PREVENT-ADPKD) found prescribed extra water did not slow kidney growth — so high water intake is sensible supportive care, not a proven brake on cysts.
Movement
Aim for about 150 minutes a week of moderate activity plus some resistance work, adapted to what you can do. Exercise helps blood pressure, weight, sleep and mood; no trial shows it directly slows cysts. If kidneys are markedly enlarged, ask your team about contact sports and very heavy lifting.
Food and salt
Keep salt low (about 5–6 g of salt a day), eat balanced meals, and keep a healthy weight — higher salt and excess weight are linked to faster progression. High-protein eating is discouraged; strict low-protein diets are unproven for ADPKD and risk malnutrition.
Ketogenic diets and fasting
Research-only for now: animal studies and short human feasibility trials show signals, but KDIGO 2025 advises against routine use to slow ADPKD outside trials — with open questions on cholesterol, kidney stones and nutrition. Only consider inside a supervised trial.
Seek care promptly for
Sudden severe flank pain or visible blood in urine, fever with urinary symptoms, signs of kidney stones, very high blood pressure readings, sudden worst headache or vision changes, and any tolvaptan sick-day situation (vomiting, diarrhoea, inability to drink).
Where to go next
Start with the latest weekly digest, browse cards one by one on the timeline, or revisit a past issue in the archive.
Educational curation only — not medical advice. This guide does not replace advice from your care team.