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Subject: Loin Pain/Hematuria Syndrome
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A rare and poorly understood syndrome characterized by unexplained chronic, severe, intermittent or persistent, unilateral or bilateral loin/flank pain with microscopic or gross hematuria
It is a diagnosis of exclusion.
Treatment requires reassurance, careful management of analgesia, and psychological support.
Range: 10 to 70 years
70% of cases are in females.
More common in White female in 20s to 30s
Several hypotheses have been proposed such as microvascular abnormalities, complement activation on arterioles, renal vasospasm, veno-caliceal fistula, abnormal ureteral peristalsis, intratubular crystal formation, abnormal platelet function, or psychogenic nature.
Glomerular basement membrane abnormalities (too thick or thin) leading to glomerular wall rupture and passage of red blood cell (RBC) into the urinary space, causing tubular obstruction and back leak of glomerular filtrate with resultant parenchymal edema and stretching of renal capsule have been proposed.
50% of patients have a history of nephrolithiasis.
Chronic flank pain (>6 months) that is severe, unilateral or bilateral, persistent or recurrent. The duration is variable and may persist for months. Pain may or may not radiate to groin area and may be associated with a low-grade fever, nausea and vomiting, or dysuria.
Hematuria can be intermittent, microscopic, or gross.
Low-grade fever, CVA tenderness variably present
A diagnosis should be made after a thorough evaluation and exclusion of alternative etiologies:
Obstructive or nonobstructive nephrolithiasis
Urinary tract infection
Adult polycystic kidney disease
Renal cell cancer
Recurrent papillary necrosis
Recurrent renal thromboembolism
Recurrent renal vein thrombosis
Nutcracker syndrome (left renal vein entrapment)
Normal renal function tests
Urinalysis (UA) shows >5 RBC/HPF but may be absent during pain-free period.
The presence of dysmorphic RBC or RBC casts is possible but not necessary.
Spot urine protein to creatinine ratio is normal (<0.3).
CT of abdomen with/without contrast is normal.
Urine culture is negative.
Coagulation studies are normal.
Consider nephrology consultation for renal biopsy in the presence of dysmorphic RBC/RBC cast and proteinuria or abnormal kidney function to exclude underlying glomerular disease.
Renal angiography to exclude arteriovenous (AV) malformation
Cystoscopy/ureteroscopy to evaluate stone, tumor, other pathology of bladder and ureter
No consensus on validated diagnostic criteria.
All standard hematologic and chemistry evaluation should be normal.
Controversial. Most recommendations are based on observational studies, small case series, and anecdotal reports.
A multidisciplinary approach partnering medical management with cognitive behavioral therapy should be exhausted prior to invasive or surgical interventions (1,2)[C].
Nonopioid analgesic and adjuvant analgesics
An angiotensin-converting enzyme inhibitor (ACEI). It was believed to reduce the frequency and severity of the episodes of gross hematuria and flank pain by reducing glomerular hydrostatic pressure (1,2,3)[C].
Pain management specialist
Nephrology if renal biopsy considered
Intrathecal morphine pump (1,2)[C]
Transcutaneous electrical nerve stimulation (1,2)[C]
Percutaneous regional nerve blocks of splanchnic, intercostal, or celiac nerve (1,2)[C]
Surgical sympathectomy with renal capsulotomy (1,2)[C]
Catheter-based bilateral renal denervation (3,5)[C]
Laparoscopic nephrectomy with renal autotransplantation of the involved kidney is used to preserve renal function and provide sustained relief of intractable pain. Pain might recur within 2 years or occur in transplanted or contralateral kidney due to renal reinnervation or psychosocial problem (1,2,3)[C].
Admission criteria/initial stabilization: pain exacerbation with intractable pain/nausea or vomiting
Intravenous (IV) fluids in case of poor oral intake
IV or patient-controlled analgesia may be used to control pain.
Discharge when pain is under control.
It is a chronic pain syndrome with medical and psychological aspects.
Nephrectomy should be considered as a last resort.
1/3 of patients have a spontaneous resolution after a mean of 3.5 years conservative treatment.
Invasive procedures are a last resort.
Kidney function is preserved.
Hematuria typically persists.
High rate of opiate addiction and total disability
Dialysis if bilateral nephrectomy is performed.
R10.9 Unspecified abdominal pain
R31.9 Hematuria, unspecified
R31.2 Other microscopic hematuria
R31.0 Gross hematuria
789.09 Abdominal pain, other specified site
599.70 Hematuria, unspecified
599.72 Microscopic hematuria
599.71 Gross hematuria
86208007 Loin pain-hematuria syndrome (disorder)
Loin pain/hematuria syndrome is a controversial disease with uncertain cause and pathophysiology.
All standard labs and renal imaging are normal.
The diagnosis is made after a thorough evaluation and exclusion of alternative etiologies.
A multidisciplinary approach combining medical management and cognitive behavioral therapy should be exhausted prior to invasive or surgical interventions.