Approach to Proteinuria, Pyelonephritis & Renal Neoplasia Flashcards
what do protein losing nephropathies cause
in dogs
weight loss, lethargy, poor appetite
severe urinary protein loss
when would you suspect pyelonephritis
with a positive urine culture has systemic signs
what renal neoplasia do cats get
lymphoma
what renal neoplasia do dogs get
carcinoma
what is proteinuria
increase in amount of protein in the urine
what are the physiological causes of proteinuria (4)
- strenous exercise
- seizure
- fever
- stress
what are the pre renal causes of proteinuria
abnormal concentration of protein presented to kidney
what are renal causes of proteinuria
defective renal function or inflammation of renal tissue
what are post-renal causes of proteinuria
inflammation in the ureter, bladder, urethra, prostate
what are the presenting signs of proteinuria
none usually
its detected on dipstick
or signs of underlying disease, signs due to low serum protein
what are signs of underlying disease of proteinuria
neoplasia
infectious disease
renal failure
what are the signs of low serum protein in proteinuria
weight loss
lethargy
poor appetite
ascites
pitting edema
what can cause false positives of proteinuria dipstick
alkaline urine
contamination
what can cause false negatives of proteinuria dipstick
- acidic urine
- bence jones proteinuria
does hematuria affect the protein content in the urine
no
unless the urine is discoloured red
does pyuria have an affect on urine protein concentration
inconsistent effect
what will history and clinical exam help you distinguish in proteinuria
if it is a physiological cause
what will hematology and biochem help you distinguish in proteinuria
identify pre renal causes
what will history, clinical exam, urinalysis and imaging help you distinguish in proteinuria
identify post-renal causes
how would you distinguish renal or post renal inflammation as a cause of proteinuria
examine urine sediment for inflammatory cells
perform urine culture and sensitivity
why is it important to quantify proteinuria (3)
- evaluate severity of renal lesions
- assess disease progression
- assess response to treatment
how do you quantify proteinuria
- 24 hour urine protein measurement
gold standard, difficult so not used clinically
- urine protein:creatinine ration
how is the UP:C ratio calculated
urine protein (mg/dl)/urine creatinine (mg/dl)
what is the purpose of UP:C ratio
negates the effect of urine volume and concentration
results correlate well within 24 hour urine protein excretion
what are renal proteinuria causes (4)
- renal inflammation
- glomerular diseases
- tubular diseases
- chronic renal failure
how does renal inflammation cause proteinuria
inflammation in the kidney cause protein to leak into the filtrate
ex. pyelonephritis, acute tubular nephrosis
how does glomerular disease lead to proteinuria
due to increased glomerular permeability
what would the UP:C be in glomerular disease
tends to be >2.0 once disease established
what is protein losing nephropathy caused by
severe proteinuria due to primary glomerular disease
what are tubular diseases
ex. faconi syndrome
relatively rare
how do tubular diseases cause proteinuria
due to reduced tubular reabsorption of normally filtered proteins
what does the UP:C ratio tend to be in tubular disease
magnitude of proteinuria usually low
tends to be <2.0
why does proteinuria occur in CRF (2)
caused by adaptive changes to nephron loss
- hyperfiltration in remaining nephrons secondary to glomerular capillary hypertension –> glomerular protein loss
- tubular dysfunction also occurs –> reduced protein intake from ultrafiltrate –> tubular protein loss
what is the magnitude of proteinuria in CRF
usually low (unless the CRF is a consequence of primaru glomerular disease)
what are the causes of protein losing nephropathies (3)
- developmental abnormalities in basement membrane (rare)
- amyloid deposits in glomerulus
- glomerulonephritis due to immune-complex deposition in glomerulus
what breeds does developmental abnormalities in the basement membrane
english springer spaniels and bull terriers
defects in type IV collagen
what breeds have a genetic predispositions of amyloid deposits
Shar pei, beagle, abyssinian and siamese
what is glomerulonephritis
groups of conditions in which immune complexes are deposited in the glomeruli
what are the causes of glomerulonephritis (2)
- chronic antigenic stimulation
- often unknown (idiopathic)
what are the causes of chronic antigenic stimulation in glomerulonephritis (3)
- inflammatory (immune-mediated diseases, chronic inflammatory diseases)
- infectious (endocarditis, lyme disease, leishmaniasis)
- neoplasia
is glomerulonephritis more common in cats or dogs
more common in dogs
what are the early clinical signs of PLN (3)
- may be no clinical signs
- loss of body condition
- lethargy, anorexia
what are the later clinical signs of PLN (4)
- abdominal/pleural effusions
- subcutaneous piting edema
- acute onset blindness (hypertensive retinopathy)
- thromboembolic disease (pulmonary thromboembolism)
what are the very late signs of PLN
uremic syndrome (due to CRF)
what would the hematology/biochem signs be of PLN (3)
- low albumin
- normal or mildly increased globulin
- possibly increased cholesterol
if the animal is low albumin what should you do when investigating a PLN (2)
- urine sample (to look for proteinuria)
- bile acid stimulation test (rule out concurrent liver disease)
what are the findings of nephrotic syndrome (4)
- proteinuria
- hypoalbuminemia
- ascites/edema
- hypercholesterolemia
may also have
systemic hypertension
hypercoagulability
how would you perform a renal biopsy
- tru cut with ultrasound guidance
- via key hole technique
- laparoscopically
- at laparotomy
what is hypercoagulability caused by (5)
- mild thrombocytosis
- increased platelet adhesion and aggregation
- loss of antithrombin (works with heparin, plays role in modulating thrombin and fibrin production)
- altered fibrinolysis
- relative increase in large clotting factors
what can hypercoagulability
can lead to thromboemboli (lungs/brain)
how do you treat PLN (6)
- identifty and eliminate underlying disease (infections, skin disease, neoplasia)
- treat hypertension (ACE inhibitor, amlodipine, ARBs)
- treat proteinuria
- treat hypercoagulability
- manage uremia if present
- consider immunosuppression
how do you treat proteinuria in a PLN (3)
- renal diet
- ACE inhibitors
- +/- angiotensin receptor blockers
how do you treat hypercoagulability
low dose aspirin or clopidogrel
what should you not do to treat a PLN
- drain abdominal effusion unless difficulty breathing
- treat with diuretics unless difficulty breathing (can cause dehydration and renal decompensation)
what does the prognosis of PLN depend on (3)
- underlying cause (often unknown)
- severe dysfunction
- response to therapy
what is pyelonephritis
interstitial inflammation of the kidney associated with bacterial infection
what are the causes of pyelonephritis
- ascending infection (usually)
- hematogenous spread (less common)
what could predispose to pyelonephritis
- immunosuppression may predispose
- chronic renal failure
what are the acute signs of pyelonephritis (8)
- mild renomegaly
- renal pain
- fever
- anorexia
- dehydration
- weight loss
- PUPD
- vomiting
what are the chronic signs of pyelonephritis (2)
- normal or small kidneys (due to fibrosis)
- pain and fever not usually present
how is pyelonephritis diagnosed
can be difficult to distinguish from bacterial cystitis
what laboratory changes would you see with pyelonephritis (8)
- hematuria
- pyruria
- sub optimal urine concentrating ability
- WBC casts (not always)
- positive urine culture (not always)
- neutrophilic leukocytosis (not always)
- ultrasound: mild hydronephrosis without uretral dilation
- azotemia (only if progressed to CRF)
what clues would indicate that its more than just bacterial in pyelonephritis (4)
- leukocytosis present (unlikely with bacterial cystitis)
- presence of dilute urine
- presnce of ultrasound chnages in kidney
- recurrence of infection after short course of antibiotics for bacterial cystitis (pyelonephritis 4-6 weeks treatment)
how do you treat pyelonephritis
antibiotics for 4-6 weeks
choose based on culture and sensitivity
what antibiotics could you use in treating pyelonephritis while you wait for culture and sensitivity
amoxycillin clavulanate (not intact males)
potentiated sulphonamides
what are other causes of renal pain (7)
- pyelonephritis
- renal calculi
- acute nephrosis
- hydronephrosis (early)
- renal trauma
- abscesses
- neoplasia (rarely painful)
what can be difficult to distinguish from renal pain
spinal pain or other causes of abdominal pain (ex. pancreatitis, peritonitis)
what are primary renal neoplasia (4)
- renal adenocarcinoma
- renal lymphoma
- renal sarcoma
- nephroblastoma (very rare)
what are metastatic renal neoplasias
hemangiosarcomas
what are presenting signs of renal neoplasia 7
- weight loss
- inappetance
- hematuria
- abdominal distention/abdominal mass
- PUPD
- uremia (rare)
- paraneoplastic syndromes (rare)
what are clinical signs of renal carcinomas (4)
- few clinical signs in early stages
- hematuria and weight loss
- unilateral (usually) renomegaly
- rarely causes renal azotemia
what paraneoplastic syndromes can cause renal carcinomas (2)
- polycythemia
- hypertrophic osteopathy
what causes polycythemia in renal carcinomas
due to erythropoietin production by tumour or
due to renal hypoxia
can cause neurological signs
what is hypertrophic osteopathy in renal carcinomas
soft tissue swelling of long bones
progresses to periosteal reaction/periosteal new bone formation
how do you diagnose renal carcinomas
- renal ultrasound
- ultrasound FNA
how do you treat renal carcinomas
ensure sufficient function in contralateral kidney
nephrectomy
what are the presenting signs of renal lymphomas (4)
- weight loss
- inappetance
- PUPD
- renomegaly
what is renal lymphoma more common in
more common in cats than dogs
what does renal lymphoma cause
renal azotemia
tendency to spread to CNS
how do you diagnose renal lymphoma
- renal ultrasound
- FNAs of kidneys
how do you treat renal lymphoma (2)
- multi agent chemotherapy (COP or CHOP)
- azotemia may resolve with treatment
what are non-neoplastic causes of renomegaly (5)
- renal inflammation (acute nephrosis, acute pyelonephritis, FIP, leptospirosis)
- amyloidosis
- hydronephrosis
- polycystic kidney disease (PKD)
- portosystemic shunts
what breed of cats is polycystic kidney disease common in
Persian and persian cross cats
autosomal dominant
mutation in PKD-1 gene
what dog breeds does PKD also occur in
- bull terrier
- carin terrier
- whw terrier
