CFB PBL 4

Question 1

State the definition and classifcation of chronic kidney disease and its main pathogenic causes

Answer 1

DEFINITION: Kidney damage shown by abnormal albumin excretion / decreased kidney function shown by low GFR - persists for more than 3 months

PATHOGENIC CAUSES:

1. VASCULAR: - renal artery disease
   - Hypertenstion (leading to vascular damage)
2. IMMIUNOLOGICAL I g A nephropathy - due abnromal IgA 1 which leada to IgA 1 polymerisation, which then deposists in glomeruli, leading to inflammation + damage

OR : IgA nephropathy due to chronic mucosal infection + persistant IgA response, which then deposit in glomeruli, leading to inflammation + damage

AUTOIMMUNE (CAUSES LUPOSE, MULTIPLE SCLEROSIS, RHEUMATIC ARHIRITIS,

Membranous glomerulonephritis - increases the deposition of antigen-antibody complex, which deposit in basement membrane of the glomeruli, leading to inflammation and damage

Chronic systemic infection - increases the deposition of the antigen-antibody complex, which then deposit on surface of glomeruli, leading to inflammation and damage

3. Metabolic - DIABETES
4. URINARY TRACT OBSTRUCTION - tumours, kidney stones,
5. Any cause: - GENETIC, UNTREATED CHRONIC INFECTION, DRUGS, CHRONIC ALCHOHOL, congenital abnormalities

Question 2

Main signs + symptoms of CKD (and what causes these)

Answer 2

NAUSEA: due to build up of toxins in blood from uremia
Itching - due to deposists of uremia in skin
PULMONARY ODEMA CAUSING COUGH WITH SPUTUM:
-due to decreased oncotic pressure (which is due to albumin loss in urine)
-due to increased hydrostatic pressure due to vasoconstriction leading to high BP, hypervolemia because of aldosterone and ADH

PERIPHERAL OEDEMA: fluid build up due to reduced albumin in blood, albumin in bloof helps keep fluid in blood vessels + prevents in from leaking into other tissues

WEIGHT LOSS - CKD decreases apetitie - CKD affects glucose sensitive neurones in brain - also due to vomitting caused by uremia

Question 3

Major complications of chronic renal failure and their pathogenic mechanisms

Answer 3

CHD - leads to atheroscleorsis, leads to damage of coronary arteries ( all due to high BP)

Arterial calcifications - calcium phosphate deposits in blood vessels

Valvular disease - ventricular enlargement + hypertrophy

Ventricular hypertrophy - due to increased EDV and increased afterload as Ang II causes vasoconstriction, so heart has to pump harder to narrowed blood vessels

PULMONARY OEDEMA:
due to decreased oncotic pressure (which is due to albumin loss in urine)
-due to increased hydrostatic pressure due to vasoconstriction leading to high BP, hypervolemia because of aldosterone and ADH

Metabolic Bone Disase:

Osteomalacia - reduced bone mineralisation (Vit D deficiency, leads to bone resorption)

Renal osteodystrophy (STAGE 4,5 OF CKD) - Increased phosphorus, which binds to free Ca - this activates parathyroid gland to release parathyroid hormone which increases Ca resorption from bone into blood

Anemia:
- Low erythropoitein (EPO) production
- Increased uremia, increased platelet dysfunction, increased gastric bleeding
-Increased urea in exretion
-haemodilation - due to increased fluid retention

Question 4

Treatment options and management of patients with chronic renal failure

Answer 4

• Control of BP (hypertension) - ACE inhibitors + angiotensin receptor blockers
• Control of metabolic acidosis - bicarbonate supplements
• Treating protein urea - ACE inhibitors + diet restriction
• Hyper lipidymia - statins (reduce cholestrol)
• Dialysis (stage 4) - if other symptoms persist, start dialysis at early stage
• TRANSPLANT

Question 5

Describe dietry restictions for patients with CKD

Answer 5

• limiting SODIUM intake: this helps manage BP and therefore, fluid retention
• limiting PROTEIN intake: this reduces kidney workload and prevents increase in pressure inside glomerulus (basically, reduce strain on working part of kidney)
• limiting POTASSIUM intake: when kidneys not working, no potassium excreted, therefore, build up of K+ in blood leading to heart arrythmias
• limiting PHOSPHORUS: increased levels of phosphorus in blood lead to bone disease. Increased phosphorus, decreased Ca, because phosphorus surpresses Vit D production which is needed for Ca reabsorption
• limiting FLUIDS: to manage fluid retention
• avoid ALCOHOL: increases BP = further damage to kidneys