Overview

Nephrology is the branch of medicine that focuses on the structure, function, and diseases of the kidneys. The kidneys are vital organs responsible for filtering blood, removing waste products, balancing fluids and electrolytes, regulating blood pressure, and producing hormones. Nephrology encompasses both acute and chronic conditions, ranging from infections and stones to chronic kidney disease (CKD) and end-stage renal disease (ESRD).

Kidney Structure and Function

Anatomy

  • Location: Retroperitoneal, on either side of the spine.
  • Structure: Each kidney contains about 1 million nephrons, the functional unit.
  • Nephron Components: Glomerulus, Bowman’s capsule, proximal tubule, loop of Henle, distal tubule, collecting duct.

Kidney Diagram

Functions

  1. Filtration: Removes waste and excess substances from blood.
  2. Reabsorption: Recovers essential nutrients and water.
  3. Secretion: Eliminates additional wastes.
  4. Hormone Production: Erythropoietin (stimulates red blood cell production), renin (regulates blood pressure), and activation of vitamin D.

Common Kidney Diseases

  • Acute Kidney Injury (AKI): Sudden loss of kidney function, often reversible.
  • Chronic Kidney Disease (CKD): Gradual loss of kidney function over months/years.
  • Glomerulonephritis: Inflammation of the glomeruli, impacting filtration.
  • Nephrolithiasis: Formation of kidney stones.
  • Polycystic Kidney Disease (PKD): Genetic disorder causing cysts in kidneys.
  • Diabetic Nephropathy: Damage due to long-term diabetes.
  • Hypertensive Nephropathy: Damage from chronic high blood pressure.

Diagnosis and Monitoring

  • Urinalysis: Detects protein, blood, and other abnormalities.
  • Blood Tests: Measure creatinine, urea, and estimated glomerular filtration rate (eGFR).
  • Imaging: Ultrasound, CT scan, MRI.
  • Biopsy: Examines kidney tissue for definitive diagnosis.

Treatments

  • Medications: ACE inhibitors, ARBs, diuretics, immunosuppressants.
  • Dialysis: Hemodialysis or peritoneal dialysis for ESRD.
  • Transplantation: Kidney transplant for eligible patients.
  • Lifestyle Modifications: Diet, blood pressure control, diabetes management.

Interdisciplinary Connections

  • Cardiology: Hypertension and heart failure are closely linked to kidney health.
  • Endocrinology: Diabetes is a leading cause of CKD.
  • Immunology: Autoimmune diseases can affect the kidneys (e.g., lupus nephritis).
  • Oncology: Some cancers and treatments can impact renal function.
  • Nutrition: Dietitians play a key role in managing CKD through tailored nutrition plans.

Famous Scientist Highlight: Richard Bright

Richard Bright (1789–1858) is considered the “father of nephrology.” He first described the link between kidney disease and edema, leading to the term “Bright’s disease” for various nephritic syndromes.

Environmental Implications

Kidney health is influenced by environmental factors such as:

  • Water Quality: Exposure to heavy metals (lead, cadmium) and toxins can cause nephrotoxicity.
  • Air Pollution: Fine particulate matter has been associated with increased CKD risk.
  • Climate Change: Rising temperatures and dehydration can exacerbate kidney problems, especially in vulnerable populations.
  • Pharmaceuticals: Improper disposal of medications can contaminate water sources, affecting both human and animal kidney health.

Recent research highlights the growing burden of CKD in regions with poor environmental regulation and limited access to clean water.

Recent Research

A 2022 study published in Nature Reviews Nephrology (“Environmental exposures and kidney disease: a global perspective”) found that environmental pollutants contribute significantly to the global burden of kidney disease, particularly in low- and middle-income countries. The authors call for improved regulation and public health interventions to mitigate these risks.

Citation:
Stenvinkel, P., et al. (2022). Environmental exposures and kidney disease: a global perspective. Nature Reviews Nephrology, 18, 389–403. Link

Surprising Facts

  1. Kidneys Filter 180 Liters of Blood Daily: The kidneys process about 180 liters of blood per day, but only 1–2 liters are excreted as urine.
  2. Silent Epidemic: CKD often has no symptoms until advanced stages, making early detection challenging.
  3. Kidney Regeneration: Unlike many organs, kidneys have a limited ability to regenerate, making damage often irreversible.

Diagrams

Summary Table

Disease Cause Symptoms Treatment
Acute Kidney Injury Infection, toxins, trauma Oliguria, edema Supportive, dialysis
Chronic Kidney Disease Diabetes, hypertension Fatigue, nausea Meds, dialysis, transplant
Glomerulonephritis Autoimmune, infection Hematuria, proteinuria Immunosuppression
Nephrolithiasis Dehydration, genetics Pain, hematuria Lithotripsy, surgery

Further Reading