What are the next considerations for a 71-year-old male with a history of nephrolithiasis, benign prostatic hyperplasia (BPH), and left renal cyst, presenting with obstructive urinary symptoms, despite treatment with Flomax (tamsulosin) 0.4 mg, and recent laboratory results showing normal renal function and a prostate-specific antigen (PSA) level of 1.3?

Differential Diagnosis

• Single most likely diagnosis
  • Benign Prostatic Hyperplasia (BPH) with obstructive symptoms: The patient's symptoms of slow stream, nocturia, and occasional frequency, along with the presence of an obstructing prostate with a medial lobe on cystoscopy and a heterogeneous prostate on pelvic sonogram, strongly support this diagnosis. The patient's minimal response to Flomax also suggests a significant obstructive component.
• Other Likely diagnoses
  • Chronic Pelvic Pain Syndrome: The patient's complaint of occasional bilateral flank pain could be related to this condition, especially given the presence of BPH and the urethral shadowing stone.
  • Overactive Bladder: The patient's symptoms of frequency and nocturia, along with the finding of thick bladder walls on pelvic sonogram, could suggest overactive bladder, possibly secondary to the obstructive effects of BPH.
  • Nephrolithiasis: Although the patient has a history of nephrolithiasis and the current renal sonogram does not show any calculi, the occasional bilateral flank pain could indicate a possible new stone or residual stone fragments.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Prostate Cancer: Although the patient's PSA is currently low (1.3), any increase or abnormal digital rectal exam findings would necessitate further investigation, including biopsy, to rule out prostate cancer.
  • Urinary Tract Infection (UTI) or Pyelonephritis: Despite the patient denying dysuria, fever, and hematuria, a UTI or pyelonephritis could still be present, especially with the finding of cystitis cystica, and would require prompt antibiotic treatment.
  • Bladder Cancer: The presence of cystitis cystica and the patient's age increase the risk for bladder cancer, making it essential to monitor and investigate any changes in symptoms or findings on cystoscopy.
• Rare diagnoses
  • Interstitial Cystitis: This condition could be considered if the patient's symptoms of frequency, nocturia, and pelvic pain persist despite treatment for BPH and other likely diagnoses.
  • Urethral Stricture: The presence of a urethral shadowing stone and obstructive symptoms could suggest a possible urethral stricture, although this would be less common in the absence of a history of trauma or instrumentation.