About 60% of all ADPKD patients are estimated to have a chronic pain syndrome, and often this is the initially presenting symptom of an ADPKD patient that brings them to medical attention. An excellent review of this field can be found in a 2001 Kidney Internal article by Bajwa et al.
There are many potential reasons for ADPKD patients to get pain syndromes:
1. Cyst Growth: Obviously the growing cysts themselves can cause pain by compressing on other structures or stretching out the renal capsule.
2. Cyst hemorrhage: Hemorrhage into a cyst can also occur, causing acute pain. Sometimes this is associated with gross hematuria, though only if the cyst is in communication with the rest of the nephron.
3. UTI's/recurrent pyelonephritis: not surprisingly, this is more common in women than in men. Again, because not all cysts communicate with the urine, it’s possible that you can have a cyst infection even with a sterile urine. If there is an infection, it’s also important what antibiotic you chose, since not all antibiotics have good penetration into the cysts. Penicillins, for example, are not very good at penetrating cysts; fortunately, both quinolones or Bactrim are quite good at cyst penetration.
4. Nephrolithiasis: up to 25% of ADPKD patients have nephrolithiasis; the most common type of stone in ADPKD is uric acid stones.
5. Chronic back pain: enlarging cysts can cause increased abdominal girth, leading to increased lumbar lordosis.
6. Polycystic liver disease: the same process which causes cyst formation in nephrons commonly causes cyst formation in bile ductules, though this is usually asymptomatic. Occasionally, severe liver cyst growth can cause severe abdominal distension and pain.