Session 10 Flashcards
(35 cards)
How do patients with renal disease usually present?
Without symptoms: usually detected via screening of at risk patients.
What effect does acidosis have on patients breathing?
Kussmaul breathing patterns: strained breathing.
How does impaired tubular function manifest in patients?
Usually an impaired ability to concentrate urine so more urine produced; can cause acidosis so breathing problems; can cause glycosuria even with normal blood glucose levels.
How can renal disease cause glycosuria?
Tubular disease can lower the threshold for complete glucose resorption so glycosuria can result even if blood glucose levels are normal.
How can kidney failure cause anaemia?
Less erythropoietin is released by the kidneys so there is less erythropoiesis in the bone marrow, less RBCs are produced and RBCs have a shorter lifespan so anaemia is caused.
How will macroscopic haematuria due to renal disease normally appear?
Smoky brown colour.
If urine appears red at the start of the stream and then normal, what is the likely cause?
Bleeding in the lower urinary tract.
If urine is normal at the start of the stream and then red towards the end, what is the likely cause?
Bleeding from the bladder.
What is the most likely cause of haematuria originating in the kidneys?
IgA nephropathy.
What usually causes IgA nephropathy?
Infections elsewhere in the body, usually after an upper respiratory tract infection precipitates release of IgA in the kidneys.
How does nephrotic syndrome usually present?
Triad of symptoms: proteinuria, hypoalbuminaemia and oedema (+/- hyperlipidaemia). Always have some form of glomerular disease. Can have oedema without orthopnoea, Muehrcke’s bands on fingernails, xanthelasma, fat bodies in urine, DVT.
How can oedema due to heart failure and oedema due to nephrotic syndrome be distinguished?
Oedema due to nephrotic syndrome has no orthopnoea. May also have oedema of the face, this isnt present in oedema due to heart failure.
Describe the features on examination of nephritic syndrome compared to nephrotic syndrome.
- Raised BP and JVP in nephritic, not in nephrotic.
- Less severe oedema in nephritic syndrome.
- Less severe proteinuria in nephritic syndrome.
- More severe haemauria in nephritic syndrome.
- Red cell casts only present in nephritic syndrome.
- High serum albumin in nephritic, low in nephrotic syndrome.
Define acute kidney injury.
Clinical syndrome causing an abrupt decline in actual GFR. Serum creatinine is raised and urine volume is decreased.
What causes pre-renal failure?
Decreased blood supply to the kidney; usually due to volume depletion, heart failure or cirrhosis.
What causes intrinsic renal failure?
Disease of the renal parenchyma; usually due to ischaemia and toxic acute tubular necrosis.
What causes post-renal failure?
Obstruction; may be from structures pressing on the kidney or urinary tract obstruction.
Describe the main features of pre-renal AKI.
GFR reduced because of reduced renal blood flow; no cell damage; will respond to fluid resuscitation; causes acute tubular necrosis if untreated.
How can NSAIDs precipitate pre-renal AKI?
Reduce prostaglandin production which prevents autoregulation of renal blood flow as afferent arteries cant be dilated.
How can ACE-I and AIIR antagonists precipitate pre-renal AKI?
Prevent autoregulation of renal blood blow my preventing constriction of the efferent arterioles as they inhibit angII production/binding.
Which areas of the kidney nephron are most susceptible to damage due to ischaemia, why?
Proximal convoluted tubule and thick ascending limb of the loop of Henle, both have very high oxygen demands for active transport and are poorly supplied by oxygen physiologically as they lie in the medulla.
Why are areas of nephron in the kidney cortex not likely to be affected by ischaemia?
The cortex has a much better supply of oxygen than the medulla.
How can muscle crush injuries lead to toxic ATN?
Myoglobin is released due to muscle crush injuries, can act as a nephrotoxin and cause damage to epithelial cells in the kidney tubules.
Describe the appearance of myoglobinuria.
Urine appears dark brown, like flat coca cola.
