SLO 11.5 Disorders of Human Excretory System

11.5.1 State Contributions of Al-Farabi and Abul-Qasim in Introducing the Method of Removing Stones from the Urinary Bladder

Al-Farabi (870–950 CE):

A philosopher and scientist who contributed to medical knowledge through his writings on anatomy and physiology, laying the groundwork for understanding urinary system disorders. His work indirectly supported medical advancements, including techniques for addressing bladder stones, by promoting scientific inquiry.

Abul-Qasim Al-Zahrawi (936–1013 CE):

Known as the “father of modern surgery,” he developed surgical techniques for removing bladder stones (lithotomy). Described precise methods in his book Al-Tasrif, including the use of specialized instruments to extract stones from the urinary bladder, minimizing damage to surrounding tissues. His techniques were foundational for later urological procedures.

11.5.2 Identify the Causes of Kidney Stones

Kidney stones (renal calculi) form due to:

1. Supersaturation of Urine: High concentrations of minerals (e.g., calcium, oxalate, uric acid) crystallize in urine.
2. Dehydration: Low urine volume concentrates minerals, promoting crystal formation.
3. Diet: High intake of oxalate-rich foods (e.g., spinach), sodium, or animal proteins increases risk.
4. Metabolic Disorders: Conditions like hyperparathyroidism or gout increase calcium or uric acid levels.
5. Infections: Urinary tract infections can lead to struvite stones.
6. Genetics: Family history of kidney stones increases susceptibility.
7. Low Urine pH: Acidic urine promotes uric acid stones; alkaline urine promotes phosphate stones.

11.5.3 Differentiate Between Lithotripsy and Surgery as Methods to Remove Kidney Stones

Feature	Lithotripsy	Surgery
Definition	Non-invasive procedure using shock waves to break kidney stones into smaller fragments.	Invasive procedure to physically remove kidney stones.
Types	Extracorporeal shock wave lithotripsy (ESWL) uses external shock waves.	Includes ureteroscopy (using a scope to remove stones) or percutaneous nephrolithotomy (PCNL, for large stones).
Procedure	Shock waves target stones, fragmenting them for natural passage through urine.	Involves incisions or scopes to extract or break stones under direct visualization.
Anesthesia	Usually sedation or light anesthesia.	General or regional anesthesia.
Recovery Time	Minimal; often outpatient (hours to days).	Longer; days to weeks depending on surgery type.
Suitability	Small to medium stones (<2 cm); less invasive.	Large or complex stones; when lithotripsy fails.
Risks	Bruising, blood in urine, discomfort.	Infection, bleeding, damage to urinary tract.
Example	ESWL for a 1 cm stone in the kidney.	PCNL for a staghorn calculus.

11.5.4 Describe the Causes of Kidney Failure

Kidney failure (acute or chronic) occurs when kidneys cannot adequately filter blood. Causes include:

Acute Kidney Failure:

• Sudden Blood Flow Reduction: Due to shock, dehydration, or severe blood loss.
• Toxins/Drugs: Overdose of medications (e.g., NSAIDs) or exposure to nephrotoxic substances.
• Obstruction: Kidney stones or tumors blocking urine flow.
• Infections: Severe urinary tract infections or sepsis.

Chronic Kidney Failure:

• Diabetes: High blood sugar damages nephrons (leading cause).
• Hypertension: Damages blood vessels in kidneys over time.
• Glomerulonephritis: Inflammation of glomeruli.
• Polycystic Kidney Disease: Genetic condition causing cyst growth in kidneys.
• Prolonged Obstruction: Chronic blockages (e.g., enlarged prostate).

11.5.5 Explain the Process of Peritoneal and Haemodialysis

Peritoneal Dialysis:

• Process:
  • Uses the peritoneum (abdominal lining) as a natural filter.
  • A catheter is inserted into the abdominal cavity.
  • Dialysate (a sterile solution) is introduced, absorbs waste and excess fluids from blood across the peritoneum, and is drained after a dwell time (4–6 hours).
  • Cycles (exchanges) are repeated multiple times daily (manual or automated).
• Types:
  • Continuous ambulatory peritoneal dialysis (CAPD).
  • Automated peritoneal dialysis (APD).
• Advantages:
  • Can be done at home; greater mobility.
• Disadvantages:
  • Risk of peritoneal infection (peritonitis).
  • Requires daily management.

Haemodialysis:

• Process:
  • Uses an external machine (dialyzer) to filter blood.
  • Blood is drawn from an access point (e.g., fistula in arm), passed through the dialyzer, where it is filtered across a semipermeable membrane to remove wastes and excess fluids, then returned to the body.
  • Typically performed 3 times per week, 3–4 hours per session, in a dialysis center.
• Advantages:
  • More efficient waste removal; supervised by professionals.
• Disadvantages:
  • Requires regular clinic visits.
  • Risk of vascular access complications.