What are the clinical presentations of nephrolithiasis?

Clinical Presentations of Nephrolithiasis

The most common clinical presentation of nephrolithiasis is acute flank or abdominal pain, often accompanied by nausea, vomiting, and hematuria, though the absence of hematuria does not rule out kidney stones. 1

Classic Presentations

Pain Characteristics

• Renal colic: Severe, colicky pain typically located in the flank or lower abdomen
• Pain radiation: Often radiates from the flank to the groin following the ureter pathway
• Pain intensity: Usually sudden onset and severe, described as one of the most intense pains experienced
• Pain duration: May last minutes to hours with fluctuating intensity

Associated Symptoms

• Hematuria: Present in approximately 90% of cases 1
• Nausea and vomiting: Common accompanying symptoms due to pain severity
• Urinary urgency and frequency: May occur, especially when stones approach the bladder
• Low-grade fever: May be present but high fever suggests infection

Atypical Presentations

• Bilateral inguinal pain: Some patients may initially present with bilateral inguinal or periumbilical pain before developing the classic flank pain 2
• Painless hematuria: Some patients may present with only blood in urine without significant pain
• Urinary tract infection symptoms: Dysuria, frequency, urgency
• Asymptomatic: Stones may be discovered incidentally during imaging for other conditions

Presentations Based on Stone Location

1. Kidney stones (nephrolithiasis):

   • Dull, aching pain in the flank or back
   • Pain may be intermittent

2. Ureteral stones (ureterolithiasis):

   • Severe colicky pain
   • Pain radiation to groin or genitals
   • More likely to cause renal colic

3. Bladder stones (cystolithiasis):

   • Suprapubic pain
   • Pain at end of urination
   • Interrupted urinary stream

Special Populations

Pediatric Patients

• May present with less specific symptoms
• Abdominal pain may be more generalized
• Hematuria may be the only presenting sign 3

Pregnant Patients

• Similar presentation to non-pregnant adults
• Diagnostic approach differs due to imaging concerns
• Management requires multidisciplinary approach 4

Complications Presenting as Initial Symptoms

• Urinary tract obstruction: Hydronephrosis, decreased urine output
• Infection: Fever, chills, sepsis if complete obstruction with infection
• Renal impairment: Elevated creatinine if bilateral obstruction or obstruction of solitary kidney
• Page kidney: Rare complication where subcapsular hematoma compresses renal parenchyma causing hypertension 5

Diagnostic Considerations

Laboratory Findings

• Urinalysis: Hematuria (microscopic or macroscopic) in 90% of cases
• Urine pH: Helpful in determining stone type (acidic pH suggests uric acid stones)
• Serum chemistry: May reveal metabolic abnormalities

Imaging

• Non-contrast CT: Gold standard for diagnosis
• Ultrasound: First-line imaging in pregnancy and pediatric patients 3, 4
• KUB radiography: Limited role but may detect radiopaque stones 3

Differential Diagnosis

Several conditions may mimic nephrolithiasis:

• Pyelonephritis
• Appendicitis
• Diverticulitis
• Ovarian torsion
• Ectopic pregnancy
• Abdominal aortic aneurysm
• Page kidney 5

Clinical Pearls

1. Absence of hematuria does not rule out nephrolithiasis - approximately 10% of confirmed cases may not present with hematuria 1

2. Atypical pain locations can occur, including isolated abdominal or inguinal pain 2

3. Fever with flank pain should raise concern for infected obstructing stone (pyelonephritis), which is a urologic emergency

4. Recurrent stone formers may recognize their symptoms and present with high diagnostic certainty

5. Bilateral flank pain is uncommon and should prompt consideration of other diagnoses or bilateral stones

By recognizing both typical and atypical presentations of nephrolithiasis, clinicians can ensure prompt diagnosis and appropriate management to reduce morbidity and prevent complications.