Pain in kidney fossa

Specialty: Nephrology and urology.

• unilateral or bilateral costovertebral pain
• high lumbar pain of renal origin
• dull high back pain

Why it occurs

• Acute pyelonephritis (bacterial infection of the renal parenchyma and pelvis that produces edema and sudden distension of the renal capsule)
• Renal infarction (occlusion of a renal arterial branch by thrombus or embolus that causes ischemia and severe acute pain)
• Renal vein thrombosis (with acute renal congestion and marked increase in organ size, common in nephrotic syndrome)
• Acute glomerulonephritis (bilateral glomerular inflammation distends the renal capsule causing bilateral dull pain)
• Complicated renal cyst (rupture, intracystic hemorrhage or infection of a simple cyst or in the context of autosomal dominant polycystic kidney disease)
• Acute non-lithiatic hydronephrosis (obstruction due to stenosis of the pyeloureteral junction or neoplastic extrinsic compression)

Initial workup

Kidney and urinary tract ultrasound to assess the size of the kidneys, the presence of masses, cysts or hydronephrosis; complete blood analysis (creatinine, BUN, blood count, CRP, electrolytes); urine culture and blood cultures if there is fever; Abdominal and pelvic CT with and without contrast (test of choice if renal infarction, perinephritic abscess or renal trauma is suspected).

Standard management

• Metamizole magnesium — 1-2 g every 8 hours intravenously or intramuscularly for analgesic control) or Ketorolac (30 mg IV every 8 hours, use with caution and for short periods to avoid nephrotoxicity
• Ceftriaxone — 1-2 g IV every 24 hours for empirical treatment of acute pyelonephritis) or Levofloxacin (750 mg IV or PO every 24 hours as an alternative
• Controlled intravenous fluid therapy to maintain adequate intravascular volume and preserve renal perfusion.