Renal patho Flashcards by Matthew Chang

Explain the clinical features of nephrotic syndrome

Proteinuria = Glomerular filtration barrier damage => protein leakage

Hypoalbuminemia = Loss of albumin in urine > hepatic albumin synthesis
- Decrease oncotic P => oedema
- Increase compensatory lipoprotein production by liver => Hyperlipidemia => spill into urine => Lipiduria

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What are the pathologies of nephrotic syndrome

Minimal change disease = fused foot processes and basement membrane detachment

Focal segmental glomerulsclerosis = podocyte injury & loss

Membranous glomerulonephropathy = thickened basement membrane, IgG & C3 ‘string of pearl’

Diabetic nephropathy
- Glomeruli => GBM thickening, Kimmelstiel wilson nodules
- Tubule atrophy and thickening
- Interstitium fibrosis
- Arteriolar hyalinosis and sclerosis

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What is the m/c cause of childhood nephrotic syndrome

Minimal change disease

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What is used to treat minimal change disease and what is its MOA

Steroids eg prednisolone
Decrease inflammation and suppress damaging immune response

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What is a common complication of focal segmental glomerulosclerosis

Renal failure

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What is the m/c cause of nephrotic syndrome in adults

Membranous Glomerulonephropathy

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What is the m/c cause of end stage renal disease in SG

Diabetic nephropathy

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What are the complications of nephrotic syndrome

Loss of IgG due to urinary loss and altered production => Infection
Urinary loss of anti-clotting > pro-clotting proteins => hypercoagulability

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What are the clinical features of nephritic syndrome

Oliguria = Decreased filtration SA & GFR

Oedema and HTN = Decreased GFR => Increase RAAS => Increase Na+, H2O retention

Haematuria = Glomerular capillary damage => RBC leak into urine

Proteinuria = Glomerular barrier inflammation => Increase permeability => proteins leak

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What are the pathologies of nephritic syndrome

Post strep glomerulonephritis
- IgG, C3
- Immune complex deposition in glomeruli => inflammation

IgA nephropathy = IgA deposits in glomeruli

Lupus nephritis = IgA, IgG, IgM, C1q, C3 deposits

Membranopoliferative glomerulonephritis
- Proliferative changes of mesangium & basement thickening
- Decrease serum C3

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Which nephritic syndrome pathology is a/w URTI

IgA nephropathy

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What is the major cause of morbidity & mortality in SLE

Lupus nephritis

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What is the most common cause of glomerulonephritis

IgA nephropathy

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What are the clinical features of acute renal failure

Oliguria & increased serum creatinine

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What are the causes of acute renal failure

Pre-renal = Decreased renal blood flow eg hypotension
Renal = Decreased nephron func eg glomerulonephritis
Post-renal = Urine cannot be cleared properly

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What are investigations done for acute renal failure

Blood test = creatinine, urea, electrolytes
Urine test = Protein/Haematuria
Imaging = Ultrasound, CT, MRI
Kidney biopsy for invasive causes

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What are the most common causes of chronic renal failure

Diabetic nephropathy
Glomerulonephritis

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How is chronic renal failure diagnosed

GFR
Albuminuria/ Proteinuria

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What are the complications of chronic renal failure

Oedema = HTN/HF
Anaemia = Decreased EPO
Hyperphosphatemia, Hyperkalaemia
Hypocalcaemia, Hyponatraemia

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Describe the gross morphology of chronic renal failure

Bilateral, contracted kidneys
Loss of demarcation between cortex & medulla

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Describe microscopy of chronic renal failure

Widespread glomerulosclerosis
Tubular atrophy
Interstitial fibrosis

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Where do calculi normally form

Calyces/ Pelvis

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What are the causes of urolithiasis

Primary = Supersaturation of urine w Ca2+ salts

Secondary
- UTI involving urease producing bacteria (Proteus) => urea -> NH3 => Increase urine pH => 3x stone
- Foreign indwelling catheter =>chronic irritation => Increase UTI/biofilm formation => 3x stone
- Vit A deficiency => Squamous metaplasia of UT mucosa => stone
- Acidic urine => Increase uric acid => urate stone
- Alkaline urine => Ca2+ stone & 3x stone

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Arrange the different calculi from most to least prevalent

Ca2+ stone
3x stone
Urate stone
Cystine stone

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How does Ca2+ stone form

Ca2+ hyperabsorption in gut w prompt renal output wo hypercalcemia => Impaired renal tubular Ca2+ reabsorption

Which stone is commonly seen with proteus UTIs and how is it formed

3x stone Precipitates in alkaline pH

What conditions are urate stones a/w

Gout Leukemia

What conditions are cystine stones a/w

Genetic defects

What are the complications of urolithiasis

Urinary stasis = Stones obstruct flow Ulceration & bleeding= Stones damage UT lining Pain Fistula = Stones erode through wall

What is acute kidney injury

Sudden impaired renal func => Increase serum creatinine & decreased urine

What causes AKI

Acute tubular necrosis Ischemia/Nephrotoxins => Damage tubular epithelium => Decrease tubular function

What is the main histological finding of acute tubular necrosis

Renal tubular epithelial cells => Sloughing, swelling, vacuolation, flattening, loss of PAS+ve brush border

What are the types of AKI

Acute renal failure Acute tubular infarct

What causes acute tubular infarct

Compromised blood vessels in kidney eg renal artery thrombosis

Compare acute and chronic pyelonephritis

Acute = acute bacterial infection of kidney Chronic = Repeated/Persistent infection => scarring, atrophy & renal dysfunction

Describe the spread of acute pyelonephritis

Retrograde/ ascends form bladder Hematogenous

What are the presentations of pyelonephritis

Fever, flank pain, dysuria, pyuria, frequent micturition

What are the complications of pyelonephritis

Perinephric abscess Septicaemia Acute renal failure

What are the causes of chronic pyelonephritis

Vesicouretic reflux => inflammation => scarring Obstruction => infection => scarring

What is xanthogranulomatous pyelonephritis caused by

Proteus

What is the gross morphology and microscopy of xanthogranulomatous pyelonephritis

Gross - Replacement w yellow nodules & greyish white tissue - Enlarged kidney Microscopic - Foam cells - Giant cells - Plasma cells - Lymphocytes

What causes hydronephrosis

Congenital abnormalities Obstruction Functional disorders

What are the presentations of hydronephrosis

- Dilated renal pelvis, calyces - Enlarged kidney - Parenchymal atrophy - Urine obstruction

What is pyonephrosis

Infected hydronephrosis w frank pus in dilated calyces/ pelvis

What is hydroureter

Dilation/distension of ureter

What is pyroureter

Hydroureter w infection & pus

What are the characteristics of autosomal dominant polycystic kidney

Bilateral ballot able kidneys Multiple enlarging cysts => decrease parenchyma => decrease renal function => renal failure

What is autosomal dominant polycystic kidney a/w

Genetic = polycystin-1,2 gene mutation Hypertension

What are the different kidney neoplasms

Benign = Angiomyolipoma Malignant - Renal cell carcinoma - Urothelial carcinoma - Nephroblastoma

What are the characteristics and gross morphology of angiomyolipoma

Made of adipose cells, myoid spindle cells, blood cells Behaves like malignant tumour Gross = Unencapsulated, variegated cut surfaces, yellow fatty areas

What is the m/c mesenchymal tumour for adults > 40yo

Angiomyolipoma

What are the complications of angiomyolipoma

Rupture and bleed

What is the m/c malignant renal tumour in adults

Renal cell carcinoma

What are the types of renal cell carcinoma

Clear cell Papillary Chromophobe

What are the clinical presentations of renal cell carcinoma

Haematuria (painless) Flank mass and pain Fever

What is clear cell renal cell carcinoma a/w

VHL syndrome => chromosome 3p deletions

What is the gross morphology and histology of renal cell carcinoma

Gross - Solitary, unilateral, circumscribed yellowish cut surfaces - Foci of necrosis & haemorrhage - Renal vein invasion - Wide metastasis Histology - Polygonal cells w clear cytoplasm - Renal vein invasion

What are the findings of renal cell carcinoma

Increased hematocrits due to increase EPO production

Name 3 conditions that cause polyuria

Diabetes mellitus/ insipidus AKI polyuric phase

What are the types of urothelial carcinoma

Non-invasive papillary urothelial carcinoma Invasive urothelial carcinoma

What is the m/c malignant renal neoplasm for children

Nephroblastoma

What are the characteristics of nephroblastoma

Presents as large abdominal mass & fever Lymphohematogenous metastasis Treated w nephrectomy and chemotherapy Good prognosis

What are the gross and histological features of nephroblastoma

Gross - Well-cricumscribed gray white soft mass - Begins in renal cortex => replaces kidney Histology - Sheets of small, spindle shaped, blue cells - Abortive tubular/glomeruloid structures

Name 3 conditions that cause haematuria

UTI Urolithiasis Glomerulonephritis

Name 3 conditions that cause flank pain

Renal colic (calculi) Pyelonephritis Renal cell carcinoma

Name 3 conditions that cause oliguria

AKI Dehydration Glomerulonephritis

Which organism holds significance in hospital acquired UTI and what is the treatment

PAE Piperacillin-Tazobactam/ Carbapenem

What is the significance of candida present in urine culture

Possible contaminant (vulvovaginis candidiasis)

What are the causative organisms and empirical treatment for uncomplicated UTIs

E. coli Oral Co-trimoxazole/ Nitrofuroutoin

What are the causative organisms and empirical treatment for complicated UTIs

E. coli (#1), Kleb, Proteus IV Piperacillin-Tazobactam and Fluoroquinolone