Renal Flashcards
Pre-renal causes of renal disease
Decr blood flow to kidneys:
- Shock
- Heart Failure
- Hypotension
- Renal artery stenosis
- Dehydration
Renal Causes of Renal Disease
GN (nephritic/nephrotic)
ATN
Interstitial disease
- Vascular (vasculitis, thrombus/dissection)
- Infiltration (sarcoid, Tb)
- Systemic (SLE, DM)
Post-renal causes of renal disease
Urinary tract obstruction:
- prostate obstruction
- strictures
- stones
- clots
- malignancy
- sloughed papillae occluding lumen (DM)
Causes of glomerular nephritis
Autoimmune (SLE, HSP) Drugs Infection Malignancy Primary GN
Causes of ATN
Pre-renal damage
Nephrotoxins (aminoglycosides)
Contrast medium
Rhabdomyolysis (muscle breakdown) !!
Interstitial disease causes
Drugs (penicillin allergy)
Infiltration (lymphoma, infection-Tb, post-chemo, Sarcoid)
Causes of renal vascular damage to kidneys
Vasculitis
Malignant HTN
Large vessel occlusion (thrombus, dissection)
What does a urine dipstick detect?
Leucocytes
Nitrates
Blood
Protein
RAAS
JGA detects decr in renal perfusion -> activates RAAS:
Renin secreted from kidneys -> converts angiotensinogen to angiotensin 1 -> ACE converts angiotensin 1 to angiotensin 2 -> Ang II does the following to incr BP:
- incr symp activity
- Incr Na/H20 reabsorption; incr K excretion
- Aldosterone secretion from adrenals
- Vasoconstriction to increase BP
- ADH/vasopression secretion from posterior pituitary -> aquaporins inserted into collecting duct increases Na reabsorption
1-5 increase circulating volume and BP leading to reperfusion of JGA
What is the commonest renal cause of kidney disease?
ATN
Nephrotic Syndromes
- Membranous nephropathy most common cause for adults
- Minimal change disease most common cause for kids
- FSGS
- Membranoproliferative GN
- Secondary causes due to hepB/C, SLE, NSAIDs, neoplastic syndrome, diabetic nephropathy, amyloidosis
Nephritic Syndromes
- IgA nephropathy most common cause for adults
- Post-infectious (strep) GN
- Rapidly progressive GN (IgA, vasculitis, anti-GBM/Goodpastures GN)
Ways to evaluate volume status
Capillary refill, Mucus membranes and skin turgur, urine output
Peripheral oedema, JVP
What is the protein deposited in the kidneys in Multiple Myeloma called?
Bence Jones Protein or M protein (light chains) or paraprotein
Blood tests in kidney disease
UE FBC LFT Clotting CRP ABG If systemic cause suspected: Ig and paraprotein electrophoresis, C3/C4, autoantibodies (ANCA, ANA, Anti-GBM), blood culture - low C3 indicates immunological cause - low C4 indicates SLE
Investigations for kidney malfunction
Renal USS shows cysts/small kidneys/masses
CTKUB: obstruction (non-contrast) or IVU (contrast for strictures)
XRKUB: stones
Urine dipstick (proteinuria, haematuria)
Urine spot test (microalbuminuria)
Urine MCS (glomerular in origin, infection?)
Renal biopsy -> immunohistochemistry
Signs of chronic kidney disease
Small kidneys on USS Anaemia Low Ca, high PTH High phosphate High creatinine/low GFR
Complications of AKI
- Electrolyte imbalance: Hyperkalaemia, hypnatraemia
- Acid base: metabolic Academia
- Fluid balance: Pulmonary Oedema from fluid overload (need diuretics or dialysis)
- Uraemia (need dialysis at this stage)
Nephritic syndrome criteria
Haematuria mostly Oedema HTN Mod-severe decr GFR Non-nephrotic range proteinuria
Nephrotic syndrome criteria
Proteinuria mostly
Hypoalbuminaemia -> pitting oedema
Hypercholesterolaemia
Normal-mild decr GFR
Most common cause of childhood nephrotic syndrome and prognosis/treatment
Minimal change disease
- Good prognosis with steroids
Most common cause of adult nephrotic syndrome and prognosis/treatment
Membranous nephropathy (primary/secondary causes)
Prognosis: 1/3 get better on own w supportive care; 1/3 relapse/remit; 1/3 progressive renal failure
Treatment: BP control, supportive measures only
Complications of CKD
CV disease leading cause of death due to poorer prognosis after AMI
Dyslipidaemia
Oedema
Metabolic Acidosis due to increased H retention
Anaemia due to Epo deficiency and decreased RBC survival time
Hyperkalaemia due to reduced K excretion
CKD mineral and bone disorder due to incr PO4 which suppresses Ca which stimulates rise in PTH to stimulate Ca resorption from bone -> SECONDARY HYPERPARATHYROIDISM and calcification of soft tissues and vasculature
Vitamin D deficiency due to inability to add the second OH onto 25 hydroxyvitamin D -> OSTEOMALACIA
What are medications that impair K excretion?
K sparing diuretics
ACE inhibitors
NSAIDs