Renal Flashcards
Briefly describe AKI
The hallmark of AKI is progressive azotemia which is commonly associated with a range of other disturbances
- metabolic derangements (metabolic acidosis and hyperkalaemia)
- disturbances of boody fluid balance
- variety of effect on most body systems
Causes a divided into
1) prerenal - those that decrease renal blood flow
2) Intrarenal0 those that produce a renal parenchymal injury
3) post renal - obstruct flow
Renal parenchymal injury can be subdivided into
1) glomeruli
2) intra-renal vasculature
3) renal interstitium
ATN is another broad category of intrinsic injury that dose not fall into the above categories
DIscuss RBC profile in CKD
Impaired EPO, shortened RBC surivial, haemolysis, haemodilution and GI blood loss all play a roles in the normocytic normochromic anaemia that is usually present with AKI
Although mild thrombocytopenia may occur it is thought that the toxic affect of increased circulating uremia is the cause of the bleeding tendency
List pre-renal causes of AKIU
Volume loss
- GIT losses
- Renal diuresis
- blood losses
- insensible losses
- third spacing
- pancreatitis
- peritonitis
- trauma
- burns
Cardiac causes
- MI
- Valvular disease
- CMX
- Decreased effetive arterial volume
- antihypertensives
neurogenic
- Sepsis
- anaphylaxis
- liver disease
- nephrotic syndrome
List post renal causes of AKI
Intrarenal and ureteral causes
- renal calcli
- sloughed papilla
- malignancy
- retroperitoneal firbosis
- uric acid, oxalic acid or phosphate crystal preciptation
- sulfonamide, methotrexate, acyclovir or indinavir preciptation
Bladder
- Bladder stone
- clot
- prostatic hypertrophy
- cancer
- neurogenic bladded
Urethra
- phimosis
- stricutre
Describe acute glomerulonephritis as a cause for intrinsic acute renal injury
May represent a primary renal process or may by the manifestation of any of a wide range of other disease entities
Signs includ
- dark urine
- HTN
- oedema
- CHF
The presence of haematuria, proteinuria or red cell cast is highly suggestive glomerulonephritis
Causes
1) Systemic
- SLE
- IE
- Systemic vasculaitis (PAN, waegners)
- HSP
- HIV associated nephropathy
- goodpastures
2) Primary renal
- PSGN
- RPGN ( SLE, Wegeners, PAN, goodpasture)
Describe Acute interstitial nephritis and list its causes
Usually precipitated by drug exposure or by infection
Drug induced AIN is poorly understood but the absence of a clear relationship to the dose and recurrence of the syndrome on challenge of the drug suggest that it is immunological in natures.
The most common incrimnated drugs are
- penicillins
- duretics
- NSIADS
Typically present with rash, fever, eosinophilia and eosinophiluira
Causes
- Drugs (many)
- Toxins
- infections
- MM
list causes for intrarenal vascular disease of the kidney
Large Vessel
- Renal artery thrombosis or stenosis
- renal vein thrombosis
- atheroembolic disease
SMall and medium sized vessles
- scleroderma
- malignant hypertesnion
- HUS
- TTP
- HIV associated microangiopathy
Describe ATN and list causes for the same
The most common precipitant of ATN is renal ischaemia occuring during surgery or after trauma and sepsis. The remainder of cases occur in the setting of medical illness usually as a result of the administration of nephrotoxic aminoglycosides antibiotics or radioconstrast agent or in associated with rhabdo.
The two major causes of ATN are
1) Ischaemia
- shock
- sepsis
- severe pre-renal azotemia
2) nehroptoxins
- antibiotics
- contrast
- myoglobinuria
- haemoglobinuria
Discuss radiocontrast induced ATN and its risk factors
Large retrospective cohort studies including high risk patient receiving iodinated contrast material. Finding include
1) among the general population with egfr >45 CI-AKI does not occur
2) Among those with egfr of 30-45 confer a small risk of CI-AKI
3) >30 CI Aki appears higher
Risk factors
- dehydration
- age>60
- diabetes
- metformin use
- pre-existing renal failure
- multiple myeloma
- ongoing episode of AKI
Can consider volume expansion in those who are at high risk for CI AKI - 3ml/kg over 1 hour follwed by 1.5ml/hr for 4 hours after contrast load)
?Role of NAC
Briefly discuss Casts
Indicates upper renal tract cause
1) Hyaline case - those that are devoid of contents and are seen with dehydration after exercise or in associated with glomerula proteinuria
2) Red cell cast - indicate glomerula haematuria
3) white cell cast imply the presence of renal parenchymal inflammation
4) granular casts are composed of cellular remanants and debri
5) Fatty casts like oval fat bodies generally are associated with heavy proteinuria
Describe the RIFLE classification of Acute renal failure
Stage 1: RISK
- increase of 1.5 time baseline of creat
- urine output <0.5ml/kg/hr for 6 hours
Stage 2: INJURY
- increase of 2 time baseline of creat
- urine output <0.5ml/kg/hr for 12 hours
STAGE 3: FAILURE
-Increase of 3 times the baseline or serum creatinine >355 or when there has been an acute risk fo greater than 44mmol for 24 hours or anuria for 12 hours
STAGE 4 LOSS
-persistent acute renal failure: complete loss of kidney function for longer than 4 weeks
Stage 5 - ESRD
-ESRD for longer than 3 months
Discuss clinical effects of uremia secodnayr to CKD
CVS
- Failure due to chronic fluid overload, chronic anaemia
- Arrhythmias secondary to electrolyte disturbance
- Percarditis with or without fluid accumulation can progress to tamponade
Resp
-APO - body weight measurement are the most accurate way to decide if overloaded
Neuro
- Lethargy
- Somnolence
- difficulty conentrating
- Seizures
- uremic encephalopathy
GIT
- ANorexia
- nausea and vomtign
Derm
- Yellowish tigne
- uremic frost the result of the deposition of urea from evaporated sweat on skin
- diffuse pruritis is often a major source of discomfort
MSK
-osteodystrohy
Immunological
-increased susceptibility to infection even when not challenged by the invasive procedures of dialysis
Haem
- Anaemia - normochromic normocytic
Describe the process of peritoneal dialysis and potential advantage over HD
Here the pateints peritoneum functions as the dialysis membrane. Dialysate is infused through a surgically implanted silastic catheter (Tenckhoff) that penetrates the lower abdominal wall
Fluid exchange are performed several times dailly typically by the patient at home.
Advantages over HD
- Greater patient independence
- avoidance of anticoagulation
- smoother control of volume and htn
- medications such as insulin and antibiotics can be administered via the IP route
The main disadvantage is the significant risk of bacterial peritonitis.
Discuss complications of HD
VASCULAR ACCESS RELATED COMPLICATIONS
- Bleeding from the dialysis puncture -usually can be stopped with firm prssure
- thrombosis - loss of thrill should prompt investigation for this
- Infection
NON VASCULAR ACCESS RELATED
1) Hypotension - usually the result of an acute reduction in circulating intravascular volume and fialure of the patients homeostatic mechanims to compensate
2) GI bleeding - low baseline HB, low clotting factors - overt bleeding from the GI tract often cuased by angiodysplsia or PID is common and can be dramatic
3) SOB - usually volume overload
4) CVS
- MI
- most patient with CKD are high risk for MI and most chest pain during or directly after dialysis should be concerning for MI.
5) CNS
- Disequilbrium syndrome a constellation of sympomts and signs due to rapid changes in body fluid composition and osmolaltiy during HD
- Tupically patients have headache, malaise nausea and vomtiign and muscle cramps but in more severe cases features may include ALOC, seizures or coma.
Discuss DDX of hypotension in HD pateint
1) CVS
- MI
- pericarditis with effusion
- arrythmias
- excessive fluid removal
- cardiogenic shock
2) resp
- overload
- PE
- air emoblism
Metabolic
- hyperkalaemia or hypokalaemia
- hypercalcaemia
- hypermag
Drug
- drug releated
- Dialysate induce
Anaphylaxis
