Histo: Renal Disease Pt.1 Flashcards
List the major functions of the kidneys.
- Excretion of metabolic waste products and foreign chemicals
- Regulation of fluid, electrolytes and acid/base balance
- Regulation of blood pressure (renin)
- Regulation of calcium and bone metabolism (1,25-dihydroxy vitamin D)
- Regulation of haematocrit (EPO)
List some key anatomical features of the kidneys.
- Retroperitoneal
- T12-L3
- Right kidney lies lower
- Mean length = 11cm
- Normal weight = 115-170g
What proportion of cardiac output goes to the kidneys?
20%
By what mechanism is blood filtered through the glomerulus?
- High hydrostatic pressure (60 mmHg)
- Podocytes create a charge-dependent (anionic) and size-dependent barrier
- Filtration rate = 125 ml/min
Describe the role of the
proximal convoluted tubule.
-
Proximal convoluted tubule
- Actively absorbs sodium
- Carries out hydrogen exchange to allow carbonate resoprtion
- Co-transport of amino acids, phosphate and glucose
- Reabsorption of potassium
Describe the role of the loop of Henle.
Loop of Henle
- Descending limb and thin ascending limb: permeable to water, impermeable to ions and urea
- Ascending limb: actively resorbs sodium and chloride
- This creates a counter-current multiplier that is aligned with the vasa recta
Describe the role of the distal convoluted tubule.
Distal convoluted tubule
- Impermeable to water
- Regulates pH by active transport of protons and bicarbonate
- Regulates sodium and potassium by active transport (aldosterone)
- Regulates calcium (PTH, 1,25-dihydroxy vit D)
Describe the role of the collecting duct.
Collecting duct
- Reabsorb water (principal cells, ADH)
- Regulates pH (intercalated cells, proton excretion)
Describe how disease of the kidney can be classified according to the part of the nephron it affects
1. Glomerulus
Nephrotic:
- Primary = MCD, FSGS, MGD
- Secondary = diabetes, amyloidosis, SLE
Nephritic:
- Acute post-infectious (post-streptococcal)
- IgA nephropathy (Berger Disease)
- Rapidly progressive glomerulonephritis
- Alport’s syndrome (hereditary nephritis)
- Thin basement membrane disease (Benign familial haematuria)
2. Tubules & interstitium
- Acute tubular necrosis
- Tubulointerstitial nephritis
3. Blood vessels
- Thrombotic microangiopathies (HUS, TTP)
Describe how immune complex deposition can lead to renal disease.
Complex deposition in the glomerulus results in complement and inflammatory cell activation resulting in damage to the kidney
List some genitourinary malformations of the kidney.
- Agenesis
- Renal fusion
- Ectopic kidney
- Renal dysplasia
- PUJ obstruction
- Posterior urethral valve
- Vesicoureteric reflux
- Ureteral duplication
Outline the presentation of polycystic kidney disease.
- Hypertension
- Haematuria
- Flank pain
Adult onset
What is the inheritance pattern of polycystic kidney disease and which genes are implicated?
Autosomal dominant (most of the time)
Genes: PKD1 and PKD2
NOTE: PKD is associated with an increased risk of berry aneurysms (and subarachnoid haemorrhage)
In which group of renal patients do renal cysts often develop?
What do they increase the risk of?
- Patients with end-stage renal disease who are on dialysis
- Cysts are often multiple, bilateral and cortical and medullary
NOTE: cystic disease is associated with increased risk of malignancy (papillary renal cell carcinoma)
What is Alport syndrome?
Genetic condition affecting type IV collagen. Leads to triad of:
- Kidney disease
- Hearing loss
- Eye changes (lenticonus, cataracts)
