What physical sign should be looked for in a patient with bilateral renal cysts and potential Autosomal Dominant Polycystic Kidney Disease (ADPKD) experiencing pain in the scapular area?

Physical Sign for Scapular Pain in ADPKD

In a patient with bilateral renal cysts and suspected ADPKD presenting with scapular area pain, you should immediately assess for Murphy's sign or percussion tenderness over the kidneys, as referred pain from cyst complications (hemorrhage or infection) commonly radiates to the scapular region. 1

Understanding Pain Referral Patterns in ADPKD

Pain in ADPKD patients typically originates from the kidneys but can present in atypical locations due to referred pain patterns:

• Flank, abdominal, or lumbar pain should be investigated systematically, but pain can radiate to the scapular area, particularly when cyst complications are present 1
• Scapular pain specifically suggests upper pole renal cyst involvement or diaphragmatic irritation from large cysts 1

Critical Physical Examination Findings to Assess

For Cyst Hemorrhage (Most Common Cause of Acute Pain)

• Costovertebral angle tenderness on percussion - this will be positive ipsilateral to the bleeding cyst 2
• Palpable flank mass or increased kidney size on deep palpation 2
• Abdominal pain on palpation - present in all patients with acute cyst hemorrhage 2
• Look for gross hematuria - this accompanies scapular/flank pain in hemorrhagic cysts 2

For Cyst Infection (Second Most Important Differential)

• Fever >38°C - strongly suggests cyst infection rather than hemorrhage 2
• Localized tenderness over the affected kidney with guarding 2
• Sequential examination - infected cysts show progressive tenderness over days, while hemorrhage presents acutely 2

Diagnostic Algorithm for Scapular Pain

Step 1: Vital Signs and Initial Assessment

• Temperature >38°C points toward infection 2
• Normal temperature with acute onset suggests hemorrhage 2

Step 2: Targeted Physical Examination

• Perform bilateral costovertebral angle percussion - asymmetric tenderness localizes the problem 2
• Deep palpation of both flanks - assess for asymmetric enlargement or focal tenderness 2
• Check for peritoneal signs - suggests cyst rupture or severe infection 2

Step 3: Laboratory Correlation

• WBC >10,000/μL + CRP >15.0 mg/dL = cyst infection 2
• Normal WBC with hematuria = cyst hemorrhage 2

Common Pitfalls to Avoid

• Do not dismiss scapular pain as musculoskeletal without ruling out renal complications - referred pain from upper pole cysts commonly presents this way 1
• Do not rely solely on imaging location - abdominal pain can be present even when the primary pathology is in the upper kidney pole radiating to scapula 2
• Avoid chronic NSAID use for pain management as this worsens renal function 3

When Physical Findings Suggest Specific Complications

If hemorrhage is suspected (acute pain + hematuria + normal temperature):

• CT imaging will show high-density mass-like area or overall high density in the affected cyst 2
• Physical exam helps localize which kidney, but imaging confirms diagnosis 2

If infection is suspected (fever + elevated inflammatory markers):

• MRI with diffusion-weighted imaging (DWI) shows increased intensity in infected cysts 2
• FDG-PET/CT is superior for localizing infected cysts when clinical exam is equivocal 3
• Physical exam changes sequentially - repeat examination helps localize the infected cyst 2

Pain Management Considerations

• Non-pharmacologic interventions should be attempted first 3
• For refractory pain with identifiable dominant cysts on exam, consider cyst aspiration or sclerotherapy 3
• Longitudinal eGFR slope monitoring aids in identifying pain from progressive cyst enlargement 1
• Spinal cord stimulation may provide relief for severe refractory mechanical or visceral pain 1