Pre-Renal Disease Flashcards
Clinical and morphological presentation of renal diseases:
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Acute Kidney Injury (AKI):
- occurs when sudden decrease in
GFR - GFR maintained by sufficient blood
flow to the kidneys and nephron - usually reversible
- GFR dependent on a pressure
gradient between the incoming
blood at the afferent capillaries and
pressure in the Bowman’s space: net
filtration pressure
AKI: Pre-Renal Disease:
- hypoperfusion: reduced perfusion
to the kidneys in afferent arteriole - occurs whether a patient has
hypovolaemia, euvolaemia,
hypervolaemia
5 causes of pre-renal injury:
- intravascular volume depletion:
absolute hypovolaemia (most
common) - decreased cardiac output
- renal vasoconstriction
- renovascular diseases (anatomical)
- drugs that impair autoregulation
and GFR in specific setting by
affecting vascular tone of afferent
and efferent arterioles
Pre-Renal Injury: Intravascular Volume Depletion- Absolute Hypovolaemia:
- Haemorrhage: trauma, surgical, GI
- GI losses: diarrhoea, vomiting
- Renal losses: drug induced/osmotic
diarrhoea, diabetes
insipidus, adrenal
insufficiency - Skin/Mucous Membrane: burns,
hyperthermia - Third Space losses: pancreatitis,
hypoalbuminaemia
Causes of Pre-Renal Injury: Decreased Cardiac Output:
- Diseases of myocardium,
pericardium, valves, conducting
system - Pulmonary hypertension, PE,
positive pressure mechanical
ventilation - systemic vasodilatation: sepsis, liver
failure, anaphylaxis - Drugs: antihypertensives,
anaesthetics, drug overdose
Causes of Pre-Renal Injury: Renal Vasoconstriction (4):
- noradrenaline (sepsis treatment
when BP drops, too much NA causes
contraction) - liver disease
- sepsis
- hypercalcaemia
Causes of Pre-Renal Injury: Renovascular Diseases - Anatomical:
- atheroscleorsis (lipid deposition in
tunica media spills over into intima
narrowing blood vessels, rupture
results in thrombosis and narrowing
of renal arteries. - thromboembolic disease
- renal artery dissection
Causes of Pre-Renal Injury: Drugs:
-
ACE inhibitors
- inhibition of prostaglandin
synthesis by NSAIDs during renal
hypoperfusion - Angiotensin II receptor blockers:
candesartan
AKI causing Drugs: PCT:
- tubular cell toxicity
- aminoglycosides
- amphotericin B
- cisplatin
AKI Causing Drugs: Interstitial Nephritis:
- NSAIDs
- Rifampicin
AKI Causing Drugs: Renal Tubules/Blood Vessels:
- acyclovir
- ampicillin
ACE Inhibitor Therapy Worsening Renal Function:
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efferent arteriole constricted to maintain pressure for GFR
ACE inhibitor dilates efferent arteriole, reducing intravascular pressure, reduces GFR.
NSAIDs:
constriction of afferent arteriole and therefore reduce GFR
Long term ACE inhibitor protects the small blood vessels from high blood pressure or high intra-glomerular pressure from glomerular sclerosis = renoprotective
only stop in acute situations
Acute Kidney Injury: Renal:
- develops when there is a disruption
to the anatomy or function of the
nephron - can occur independently or as a
consequence of pre-renal AKI - defined by the area of nephron
disruption
Acute Kidney Injury: Renal Causes:
- Acute Tubular Necrosis:
- most common
- ischaemia/ toxic injury to PCT - Acute Interstitial Nephritis:
- Drug induced: NSAIDs, penicillin
- Infection: TB
- Immune-mediated: SLE, sarcoid - Glomerular Disease:
- Nephrotic/Nephritic Syndrome
- primary: antiglomerular
basement membrane
disease
- secondary: immune complex
mediated: IgA
nephropathy - Tubular Obstruction:
- Meyloma
- Rhabdomyolysis
Acute Kidney Injury: Post-Renal:
- following acute obstruction of
urinary flow - increased intra-tubular pressure
and reduction in GFR - acute urinary tract obstruction leads
to impaired renal blood flow and
inflammatory processes
contributing to diminished GFR
Acute Kidney Injury: Post-Renal Causes:
- Ureter: stones, RFP, ureterocoele
- Bladder: malignancy
- Prostate: cancer, BPH
- Urethra: stricture disease, posterior
urethral valve - Extrinsic compression of ureters:
pelvic malignancy, lymph nodes
Causes of Acute Kidney Injury:
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Pre-Renal AKI Symptoms:
- severe dehydration symptoms:
- sunken eyes
- dry skin
- decreases skin elasticity
- dry mouth and eyes
- tachycardia
- dizziness standing or sitting up:
orthostatic hypotension
AKI: Diagnosis: Pre-Renal:
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Pathophysiology of Pre-Renal AKI:
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Pre-renal insult and renal injury both result in AKI but pre-renal is
reversible
renal is often reversible but can lead to CKD
Distinguishing Pre-renal insult from acute tubular necrosis
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Renal Disease involves
parenchymal changes
Acute Kidney Injury
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Chronic Kidney Disease occurs how many days after the acute kidney injury
> 90 days
AKI Staging:
- stage 1: serum creatinine 1.5-1.9x
reference value - stage 2: 2.0-2.9x reference value
- stage 3: 3.0x reference value
Pre-Renal Acute Kidney Injury can lead to acute tubular necrosis.
true or false?
true
pre-renal can lead to parenchymal changes seen in renal disease
Chronic Kidney Disease:
- kidney waste filtration becomes
worse over time - gradually develops
- result of chronic illnesses like
diabetes and hypertension - patients often asymptomatic and
often discovered incidentally
Causes of chronic kidney disease:
- diabetes mellitus (type 1& 2)
- uncontrolled hypertension
- chronic glomerulonephritis
- hereditary renal diseases
- chronic tubulointerstitial nephritis
- congenital kidney anomalies
- chronic pyelonephritis
- renal stones and obstructive
uropathy - chronic infection of kidney: TB
Stages of chronic kidney disease
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Staging of CKD:
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Relationship between GFR and Creatinine in early stages of AKI
- reduction in GFR may coexist with
normal serum creatinine
Renal Vascular Disease:
- affects blood flow to and from
kidneys - causes kidney damage, failure and
high BP - manifestation of renal vascular
disease:
- Renal Artery Stenosis (RAS)
- Renal Artery Thrombosis
Renal Artery Stenosis:
- manifestation of renal vascular
disease - causes kidney injury and high BP
- smokers
- high cholestrol, triglycerides,
diabetes, obesity, heart disease
family history
Renal Artery Thrombosis:
- manifestation of renal vascular
disease - blood clot in the renal artery
AKI Investigations:
- bloods: FBC (high urea, creatinine)
(anaemia if loss of blood)
(WBC high if sepsis) - serological: U&E, CRP, multiple
myeloma screen (blood
and urine) - Blood and Urine Cultures
(bacteraemia) - Urine Microscopy
- urine Dipstick: blood, proteins, WBC
CRP = inflammation
- immunological tests:
- ANCA, ANA, dsDNA (serum)
- Viral serology: Hep B/C, HIV
- Imaging: CXR, USS Kidney Ureter
Bladder, Ct KUB - Renal Biopsy: intrinsic renal disease
ABG:
- metabolic acidosis: low pH, low
pCO2, low bicarb
Management of AKI
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Treatment of Pre-renal AKI:
- fluids
- maintain sufficient BP
- antibiotics for sepsis
- renal replacement therapy (RTT):
- fluid overload
- hyperkalaemia
- metabolic acidosis
- uraemia
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult
AKI: Urine Microscopy: Epithelial Cell Cast:
acute tubular necrosis
AKI: Urine Microscopy: RBC cast:
glomerular diseases
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: WBC cast:
tubulointersitial disease/pyelonephritis
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
AKI: Urine Microscopy: Hyaline cast:
pre-renal insult, cast nephropathy in multiple myeloma
