Kidney

The Human Kidney: Anatomy, Physiology, Disorders & Treatment Guide

1. Introduction

  • The kidneys are vital organs responsible for filtering blood, removing waste, balancing electrolytes, and regulating blood pressure.
  • Each person has two kidneys, located on either side of the spine.
  • Common kidney disorders include chronic kidney disease (CKD), kidney stones, infections, and kidney failure.

2. Anatomy of the Kidney

  • Location: Lower back, behind the abdominal organs.
  • Structure:
    • Cortex: Outer layer containing filtration units.
    • Medulla: Inner region containing nephrons.
    • Renal Pelvis: Collects urine before passing to the ureter.
  • Nephrons (Functional Unit):
    • Glomerulus: Filters blood.
    • Tubules: Reabsorb nutrients and regulate water balance.
  • Blood Supply:
    • Renal Arteries: Deliver oxygen-rich blood.
    • Renal Veins: Carry filtered blood back to circulation.
  • Urinary Connection:
    • Kidneys → Ureters → Bladder → Urethra.

3. Physiology of the Kidney

  • Filtration:
    • Removes waste (urea, creatinine) from the blood.
  • Electrolyte & Fluid Balance:
    • Regulates sodium, potassium, and calcium levels.
  • Blood Pressure Regulation:
    • Produces renin, which controls blood vessel constriction.
  • Red Blood Cell Production:
    • Releases erythropoietin (EPO) to stimulate bone marrow.
  • Acid-Base Balance:
    • Maintains pH by excreting hydrogen ions.

4. Common Disorders & Pathophysiology

A. Chronic Kidney Disease (CKD)

  • Cause: Progressive loss of kidney function.
  • Risk Factors: Diabetes, hypertension, obesity.

B. Kidney Stones (Nephrolithiasis)

  • Cause: Hard deposits of calcium, oxalate, or uric acid.
  • Risk Factors: Dehydration, high salt diet, genetics.

C. Acute Kidney Injury (AKI)

  • Cause: Sudden loss of kidney function due to infection, shock, or toxicity.
  • Risk Factors: Sepsis, dehydration, medication toxicity.

D. Urinary Tract Infection (UTI) & Pyelonephritis

  • Cause: Bacterial infection affecting the bladder or kidneys.
  • Symptoms: Fever, back pain, burning urination.

E. Polycystic Kidney Disease (PKD)

  • Cause: Genetic disorder leading to cyst formation in kidneys.
  • Complications: Hypertension, kidney failure.

F. Kidney Cancer

  • Common Type: Renal Cell Carcinoma.
  • Risk Factors: Smoking, obesity, hypertension.

5. Signs & Symptoms of Kidney Disorders

  • Early Symptoms:
    • Fatigue, swelling in feet and hands.
    • Frequent urination, foamy urine (proteinuria).
  • Advanced Symptoms:
    • High blood pressure.
    • Muscle cramps, nausea, confusion.
  • Red Flags:
    • Blood in urine (hematuria).
    • Sharp back pain (kidney stones).
    • Severe swelling or sudden weight gain.

6. When to See a Doctor

  • Persistent swelling, fatigue, or high blood pressure.
  • Changes in urination (color, frequency, pain).
  • Unexplained back pain or fever.

7. Emergency Signs Requiring Immediate Care

  • Sudden loss of urination (kidney failure).
  • Severe flank pain with vomiting (kidney stones).
  • High fever with chills (kidney infection).

8. Diagnostic Process

  • Clinical Examination: Blood pressure, swelling assessment.
  • Laboratory Tests:
    • Serum Creatinine & BUN: Kidney function markers.
    • eGFR (Glomerular Filtration Rate): Measures kidney efficiency.
    • Urine Analysis: Detects protein, blood, infection.
  • Imaging Tests:
    • Ultrasound: Detects kidney size, cysts, or stones.
    • CT Scan: Detailed imaging for stones or cancer.
    • Renal Biopsy: Identifies kidney disease progression.

9. Likely Diagnoses

  • Chronic Kidney Disease (CKD).
  • Kidney Stones.
  • Acute Kidney Injury (AKI).
  • Polycystic Kidney Disease.
  • Urinary Tract Infection (UTI).

10. Treatment Options

A. Medications

  • For CKD & High Blood Pressure:
    • ACE Inhibitors (Lisinopril, Ramipril).
    • Diuretics (Furosemide) for fluid control.
  • For Kidney Stones:
    • Pain Relief (Ibuprofen, Acetaminophen).
    • Alpha-Blockers (Tamsulosin) to ease stone passage.
  • For UTIs:
    • Antibiotics (Ciprofloxacin, Nitrofurantoin).
  • For Anemia in CKD:
    • Erythropoietin (EPO) injections.
  • For Kidney Cancer:
    • Targeted Therapy (Sunitinib, Sorafenib).
  • Approximate Medication Costs (USD):
    • ACE Inhibitors: $10–$50/month.
    • Diuretics: $5–$50/month.
    • Painkillers for Stones: $10–$100.
    • Antibiotics for UTIs: $20–$100 per course.
    • EPO Injections: $200–$500 per dose.

B. Surgical/Procedural Interventions

  • Dialysis (For Kidney Failure) ($300–$5,000 per session).
  • Kidney Transplant (For End-Stage CKD) ($100,000–$300,000).
  • Lithotripsy (Shock Wave Therapy for Stones) ($5,000–$10,000).
  • Nephrectomy (Kidney Removal for Cancer) ($20,000–$50,000).

C. Lifestyle Modifications & Home Remedies

  • For CKD Prevention:
    • Low sodium, potassium diet.
    • Adequate water intake (but not excessive).
  • For Kidney Stones:
    • Drink at least 2–3 liters of water daily.
    • Reduce salt and oxalate-rich foods (spinach, nuts).
  • For UTI Prevention:
    • Urinate after intercourse.
    • Cranberry supplements.

11. Precautions & Prevention

  • Control Blood Pressure & Blood Sugar.
  • Limit Painkiller Use: NSAIDs can harm the kidneys.
  • Stay Hydrated: Prevents kidney stones and infections.
  • Get Regular Kidney Function Tests: If at risk.

12. Prognosis & Recovery

  • CKD: Progressive but manageable.
  • Kidney Stones: Usually pass naturally; large ones require treatment.
  • Kidney Infections: Fully treatable with antibiotics.
  • Kidney Cancer: Prognosis depends on early detection.

13. Cost of Treatment

  • Kidney Function Tests: $100–$500.
  • Dialysis (Per Session): $300–$5,000.
  • Kidney Transplant: $100,000–$300,000.
  • Kidney Stone Surgery: $5,000–$20,000.

14. Frequently Asked Questions (FAQs)

  1. How can I improve kidney function?
    • Stay hydrated, reduce salt and protein intake, manage blood pressure.
  2. What foods are bad for the kidneys?
    • Excess salt, red meat, processed foods, alcohol.
  3. Can kidney disease be reversed?
    • CKD is not reversible but can be slowed with treatment.
  4. What is the best treatment for kidney stones?
    • Hydration, pain relief, lithotripsy for large stones.
  5. How do I prevent kidney infections?
    • Good hydration, proper hygiene, treating UTIs early.
  6. Is dialysis a permanent solution?
    • No, a kidney transplant is the only permanent cure for kidney failure.
  7. Can kidney stones be dissolved naturally?
    • Some can, but large stones may require medical treatment.
  8. What is the life expectancy with kidney failure?
    • With dialysis: 5–10 years on average.
    • With transplant: 10–20+ years.