What causes sharp pain in the left kidney area?

Sharp Left Kidney Pain: Causes and Management

The most common cause of sharp left kidney pain is acute renal colic from kidney stones, which presents as severe unilateral flank pain radiating to the groin or genitals and requires urgent medical assessment within 30 minutes. 1

Primary Causes of Sharp Left Kidney Pain

Kidney Stones (Nephrolithiasis) - Most Common

• Acute renal colic is characterized by abrupt onset of severe unilateral flank pain radiating into the groin or genitals 1
• Over 80% of patients with renal colic have hematuria on urinalysis, though absence does not exclude the diagnosis 1
• Stones smaller than 3 mm are usually not identified by ultrasound, and stones of all sizes may be missed 1
• Patients typically cannot find a comfortable position and may have associated nausea and vomiting 1

Acute Pyelonephritis (Kidney Infection)

• Presents with flank pain, fever, and systemic signs of infection 1
• Patients with shock or fever must be admitted to hospital immediately 1
• On ultrasound, kidneys may be enlarged with hypoechoic parenchyma and loss of normal corticomedullary junction 2
• Requires urgent evaluation of vital signs to exclude shock and systemic infection 1

Polycystic Kidney Disease (ADPKD)

• Flank, abdominal, or lumbar pain can result from cyst enlargement, infection, hemorrhage, or stone formation 1
• Pain caused by cyst enlargement can be identified through longitudinal eGFR slope monitoring 1
• Nephrectomy is reserved for severe intractable pain, typically with advanced kidney disease 1

Subcapsular Hematoma (Page Kidney)

• Can present identically to nephrolithiasis with flank pain and hematuria but causes secondary hypertension 3
• Results from compression of renal parenchyma by hematoma activating the renin-angiotensin-aldosterone system 3
• May occur without recent trauma history 3
• Diagnosed on CT imaging and managed conservatively with hypertension control using ACE inhibitors 3

Critical Red Flags Requiring Emergency Evaluation

You need immediate emergency department evaluation if you have: 1, 4

• Fever combined with flank pain
• Inability to pass gas or stool
• Severe abdominal tenderness with guarding
• Vomiting that prevents oral intake
• Bloody stools
• Signs of shock (rapid heartbeat, confusion, low blood pressure)
• Pain unrelieved after one hour of analgesia

Immediate Assessment Algorithm

Within 30 Minutes of Symptom Onset

• Medical assessment should occur within 30 minutes for acute symptoms 1
• Examination must include abdominal assessment to establish site of maximal tenderness and exclude peritonitis 1
• Vital signs assessment (pulse, blood pressure, temperature) to exclude shock and systemic infection 1

Diagnostic Testing

• Urinalysis for hematuria supports the diagnosis of renal colic (present in >80% of cases) 1
• Both kidneys should be imaged to identify unilateral kidney or bilateral disease 1
• The bladder should be imaged as part of the evaluation 1

Imaging Strategy

• Ultrasound is useful for differential diagnosis and can identify hydronephrosis, stones with acoustic shadowing, and pyelonephritis 2
• CT abdomen and pelvis with IV contrast has 98% diagnostic accuracy for identifying complications and alternative diagnoses 4
• Non-contrast CT is the gold standard for detecting kidney stones 1

Immediate Pain Management

After assessment, analgesia should be given to provide pain relief within 30 minutes 1

First-Line Treatment

• Injectable non-steroidal analgesic, preferably diclofenac 75 mg intramuscular, is recommended 1
• Intramuscular injection is the best route; oral and rectal administration are unreliable 1
• Complete pain control should be maintained for six hours or longer 1

Alternative When NSAIDs Contraindicated

• Opiate combined with antiemetic (morphine sulfate and cyclizine) should be given 1

Treatment Failure Protocol

• If pain is not alleviated within 60 minutes, immediate hospital admission should be arranged by telephone 1
• This does not require a second visit; effect can be checked by phone 1

Other Important Considerations

Life-Threatening Mimics to Exclude

• Leaking abdominal aortic aneurysm, especially in patients over 60 years 1
• Ruptured ectopic pregnancy in women of reproductive age 1
• These require immediate hospital admission 1

Follow-Up Care

• Telephone follow-up one hour after initial assessment and analgesia administration 1
• Patients should maintain higher fluid intake and attempt to sieve urine to catch any stones 1
• Fast-track imaging within 7 days of symptom onset for patients managed at home 1

Chronic Pain Considerations

• Medullary sponge kidney can cause chronic severe pain with exceptionally high stone formation rates (3.1 stones per patient-year) 5
• Chronic kidney disease patients have >60-70% prevalence of pain, which significantly impacts quality of life 6, 7

Common Pitfalls to Avoid

• Do not assume kidney stones without imaging, as other serious conditions present identically 3
• Absence of hematuria does not exclude renal colic 1
• Small stones (<3 mm) are usually not visible on ultrasound 1
• Variations in renal anatomy (duplicated systems, horseshoe kidney) may be mistaken for pathology 1
• Never delay analgesia beyond 30 minutes from assessment 1