RAD 240 Pathology

1. Pathology of the Kidney & Urinary Tract RAD 240 Pathology Radiological Sciences, Department of Health Sciences Week of November 17, 2013 Dr Shai Lecture 7

2. overview • Kidney structural abnormalities • Diseases of the glomerulus • Systemic diseases • Diseases of tubules, vessels, & interstitium • Neoplasms • Pathologies of renal tract

3. Renal anatomy

4. Structural – congenital kidney disorders • 1. AGENESIS of the kidney • UNILATERAL in 1/1000 births • Solitary kidney undergoes hypertrophy • Susceptible to infections • Males 2:1 females, left kidney usually absent • BILATERAL in 1/3000 births, part of Potter’s syndrome • Abnormal face, urinary tract and nervous system • Oligohydramnios* in pregnancy as kidneys not present to contribute amniotic fluid (absence of fetal urine) • Not compatible with post natal life (DEATH)

5. CONGENITAL CON’T • B. HYPOPLASIA • Kidneys fail to reach normal adult size (congenitally or from shrinkage), often a result of early life chronic infection • C. ECTOPIC KIDNEYS • 1 or 2 kidneys in abnormal position (usually pelvis) • D. HORSESHOE KIDNEY • Poles of kidneys are fused, usually inferiorly, to form a large U-shaped (horseshoe) kidney • 1/500 people, asymptomatic as collecting systems are normal • 2 to 8 times more likely to develop Wilm’stumours in children

6. Horseshoe kidneys Animated view CT abdomen – horseshoe kidney

7. Ultra sound horseshoe kidney Pathology specimen – horseshoe kidney

8. Cystic Kidney Diseases • Includes: Hereditary, developmental and acquired disorders • Important: • 1. appropriate patient management to delay onset of renal failure • 2. Appropriate genetic counseling to relatives at risk

9. Adult Polycystic Kidney Disease (APKD) • Hereditary (Autosomal Dominant, 50% are new mutations) • Linked to alpha globin cluster on chromosome 16 • Both kidneys replaced by cysts, develop over years • Incidence: 1/250 live births • Associated with berry aneurysms (cerebral), liver cysts, pancreas, lung • In stillborns* or neonates with enlarged kidneys (15 times normal size) with radiating cystic pattern (SUNBURST PATTERN) • Prognosis*: usually die within 2 months of life

10. Cystic disease of renal medulla • Medullary sponge kidney (tubular ectasia) • Multiple cysts develop in renal papillae • Incidence: 1/20,000 • Renal function not impaired, but calculi (renal stones) develop and predispose* individual to renal colic & infection CT - KIDNEY

11. GLOMERULUS ANATOMY & HISTOLOGY

12. Glomerular Diseases • Typically caused by structural abnormalities • 4 significant components may be damaged: • i) endothelial cells lining the capillary • Ii) glomerular basement membrane (BM) • Iii) mesangium: supporting mesentery to the capillary comprised of mesangial cells (phagocytic cells) & associated matric • Epithelial cells or podoctyes, coat outer layer of BM

14. Patterns of glomerular disease • Most diseases affect different glomeruli to varying degrees • Global: affecting entire glomerulus uniformly • Segmental: affecting one glomerular segment, sparing others • Diffuse: affecting all glomeruli in both kidneys • Focal: affecting proportion of glomeruli, sparing others • Eg. “diffuse global” or “ focal segmental”

15. Aetiology of glomerular diseases • Primary (majority): disease begins in glomerululus • Types: proliferative*, membrnaous, glomerulosclerotic, minimal change lesions • Secondary: 2ndary to systemic disease (immune complex mediated, metabolic, vascular) • Hereditary: Alport’s Syndrome, Fabry’s disease, congenital nephortic syndrome

16. Diagnosis & Symptoms • Histologically • Glomerular response to injury • Percutaneous* needle biopsy • Immunological comple deposition investigation Symptoms • Aymptomatichaematuria* • Haematuria without proteinaemia, continuous or intermittent, does not cause renal failure • Aymptomaticproteinuria* • Proteinuria >0.3 g / 24 hours, without haematuria, continuous, orthostatic (postural), or transient • Acute Nephritic syndrome • Sudden haematuria, proteinuria, hypertension • Loin pain, headache, orbital oedema*

17. Nephrotic syndrome • Proteinuria >3.5 g / 24 hrs, with hypoproteinaemia, oedema, hypercholesterolaemia • Chronic Renal failure • Irreversible deterioration in renal function caused by the destruction of nephronsover time • Impairment of excretory, metabolic, endocrine functions of kidney • Management: excretory function may be replaced by dialysis, metabolic and endcrine functions need transplant to re initiate

18. Proliferative glomerulonephritis • Group of disorders characterized by histological degrees of proliferation in mesangial & epithelial cells in glomerulus • Types • Diffuse proliferative • Rapidly progressive • Focal proliferative • Membranoproliferative • * these are patterns of reactions, not diagnoses

19. Diffuse proliferative glomerulonephropathies • Diffuse, global, acute inflammation • From deposition of immune complexes in glomeruli • Stimulated by infection • Aetiology: post streptococcal infection , or less frequently viruses, protozoas and other bacterial infection

20. Rapdily progressive glomerulonephritis • CRESCENTIC GLOMERULONEPHRITIS (RPGN) • From severe glomerular injury characterized by formation of cellular crescent shaped masses within Bowman’s space • Often post streptococcal • Crescent shaped masses are composed of epithelial cells & macrophages, causing glomerularischaemia

21. Focal proliferative glomerulonephritis • Acute inflammation within cellular proliferation in a few glomeruli (focal), affecting one segment (segmental) • Better known as focal segmental proliferative glomerulonephritis • Primary: mesangialIgA disease, Goodpasteur’s syndrome • Secondary: systemic endocarditis, vasculitis, connective tissue disease

22. Membranoproliferativeglomerulonephritis • MPGN • Diffuse, global pattern of glomerulonephritis with thickening of membrane • Primary: idiopathic • Secondary: associated with SLE, endocarditis, cerebral shunts

23. Minimal change disease • LIPOID NEPHROSIS • No significant abnormality can be detected by light microscopy* • Children, under age 6 years, males more than females • Aetiology: unknown • Pathogenesis: thought to be immunological • Morphological features: on electron microscopy* diagnostic loss of epithelial foot processes, tubules show accumulation of lipid in cells • Prognosis: good, no permanent renal damage

24. Minimal change disease – electron microscopy

25. Hereditaryglomerulonephritis • 1. Alport’s Syndrome • Clinical triad: deafness, glomerulonephritis, ocular lesions • X linked inherited*, mutatin of COLIValpha5 gene • Clinical features: glomerulonephritis (microscopic haematuria & proteinuria in childhood, later nephrotic syndrome), ocular disease & deafness to high pitched sounds • 2.Fabry’s syndrome • Rare, X linked recessive syndrome • Glycosphingolipid metabolism, resulting in painful extermities, red hyperkeratotic papules on skin*, proteinura, renal failure • Congenital Nephrotic Syndrome: rare, mesangial proliferation or glomerulosclerosis

26. Chronic Glomerulonephritis • Chronic renal failure with small contracted kidneys, and all glomeruli are hyalinized (end stage kidneys) • Macroscopically: affected kidneys are small, granularity of external surface, scarring from nephron hyalinization • Microscopically: hyalinization of glomeruli

27. Systemic diseases • Systemic lupus erythematosus • Renal involvement causes diffuse or focal glomerular disease • Basis of glomerular damage is immune complex deposition in basement membrane, BM thickens • HenochSchonleinpurpura • Immune complex mediated systemic vasculitis • Affects small arteries in skin, joints, gut, kidneys

28. Bacterial Endocarditis • Renal lesions in infective endocarditis from immune complexes or embolism infarction of heart valve vegetations • Diabetic Glomerulosclerosis • Diabetic glomerular damage causes increased permeability of capillaries in the BM, leading to proteinuris and nephrotic syndrome • Pathogenesis: not fully understood, involves deficiency in proteoglycans, glomerular hypertrophy, BM thickening, mesangial cell hypertrophy • Histologically • 1) capillary wall thickening – mild proteinuria • 2) diffuse glomerulosclerosis • 3) nodular glomerulosclerosis

29. Amyloidosis • Amyloid, an extra cellular fibrillar protein* is deposited in tissues, including kidney • Amyloid fibrils deposited in BM, and mesangium • Proteinuria & nephrotic syndrome & chronic renal failure • Wegener’s Granulomatosis • Immune complex, systemic, necrotizing vasculitis, affecting nose, respiratory and renal tracts • Polyarteritisnodosa • Systemic disease, inflammatory necrosis of walls of small & mediums sized arteries • Necrosis of medium sized arteries causes infarcts in the kidney, as fibrinoid necrosis

30. Vascular Diseases • Benign Nephrosclerosis • Hyaline arteriosclerosis of the kidney, associated with benign hypertension* • It is an important complication of long term benign hypertension, chronic renal failure being the most important outcome • It is the commonest nephropathy, found in about 75% of autopsies over the age of 60 years • Long standing hypertension cuases reduced blood flow to glomeruli, caused by vascular changes, branches of renal artery thicken with hypertrophy of muscular media, results in ischaemia with scarring. • Afferent arterioloes undergo hyalinization (arteriosclerosis) • Clinically: increase blood urea & reduction in creatinine clearance • Prognosis: <5% die from renal failure, death from congestive heart failure associated with renal failure

31. nephrosclerosis

32. Malignant nephrosclerosis • Renal disease associated with malignant hypertension • Pathogenesis: in accelerated hypertension, the rise in blood pressure is rapid, large muscular vessels undergo fibroplastic proliferation, BUT NO MUSCULAR HYPERTROPHY • Afferent arterioles undergo necrosis, and necrosis of glomerular capillary network. • 90% of cases untreated cause death.

33. Renal artery stenosis • Narrowing of renal arteries, from atherosclerosis or arterial fibromusculardysplasia • Outcomes • Chronic ischaemia of affected kidney • Renovascular hypertension • Inadequate perfusion of kidney caused by renal artery stenosis leads to hypertension, and abnormal activation of the renin-angiotensin system

35. Neoplasms of the kidney • Benign tumours • Cortical adenoma: epithelial tumours of renal tubular epithelium • Macroscopically: discreet nodules < 20mm diameter in cortex • Microscopically: well differentiated large clear cells • Renal hamartoma: commonest benign tumour of kidney, made of spindle cells • Macroscopically: firm white nodules in medulla, 3-10mm size • Microscopically: spindle cells • Angiomyolipoma: hamartoma* composed of smooth muscle, blood vessels, and fate.

36. Renal hamartoma

37. Malignant tumours of kidney • Renal cell carcinoma • Adenocarcinoma made of renal tubular epithelium, in adults • 3% of all carcinomas, 90% of primary malignant renal tumours • Males 3:1 females • Associated with tobacco use, and patients with von HippelLinday syndrome, paraneoplasticsyndomes (hypercalcaemia, hypertension, polycythaemia)* • Macroscopically: tumours in upper pole of kidney, rounded masses, yellow surface with areas of haemorrhage & necrosis • Microscopically: clear of granular cell types (referring to cytoplasm of cells) • Symptoms:haematuria, loin pain, loin mass • Prognosis: 70% chance 10 year survival

39. Renal cell carcinoma imaging

40. Wilm’sTumour • Nephroblastoma • Malignant embryonaltumour derived from primitive metanephros* • Common in childhood, peak 1 to 4 yrs age • 3 types identified • Commonest : tumoursuppresor gene WT1 located on chromosome 11 • Macroscopically: large rounded masses of solid, fleshy white lesions with necrosis. Tumour is aggressive, rapidly growing, extends beyond capsules into mesentery • Microscopically: composed of up to 4 elements {primitive blastematous tissue, immature glomerular structures, epithelial tubes, stroma of spindle cells) • Presents with abdominal mass, treat with chemo and radio therapy

41. Wilm’stumour Macroscopical changes in Wilmstumour and CT imaging of Wilm’stumour

42. Urinary tract obstruction • Obstruction of urine drainage from kidney at ANY level within urinary tract • Intrinsic lesions: within ureteric wall or lumen (eg urinary calculus*, necrotic debris*, fibrosis after trauma or infection) • Extrinsic lesions: from external pressue (egtumours of rectum or bladder, pregnancy, retroperitoneal fibrosis) • Locations • Renal pelvis: calculi, tumours • Pelviureteric junction: strictures, calculi, ext compression • Ureter: calculi, ext compression (pregnancy, fibrosis, tumour) • Bladder neck: tumour, calculi • Urethra: porstatic hyperplasia or carcinoma, stricture

44. Pathogenesis: obstruction at any point causes increased presure, superior to blockage, with dilatation of renal pelvis and calyces (hydronephrosis) • Obstruction ate pelviureteric junction > hydronephrosis • @ ureter> hydro ureter with subsequent hydronephrosis • @ bladder neck> bladder distension with hypertrophy of bladder muscle > hydroureter and hydronephrosis • Hydronephrosis effects: • Fluid entering the collecting ducts cannot empty into renal pelvis, and intra renal resorption of fluid occurs • If the obstruction is removed at this stage: normal renal function resumes

45. Urolithiasis (urinary calculi) • Formation of stones in the urinary tract (U/S) • 1-5% population in UK, usually after 30 years age, males> females • Can form anywhere in urinary tract, usually in renal pelvis • Composition of stones • Calcium oxalate (80%) • Triple phosphates (15%) magnesium ammonium phosphate stones • Uric acid (5%) • Calculi in cystinuria and oxalosis • Aetiology: acquired (urinary tract obstruction, persistent urinary tract infections, reduced urine volume from dehydration; or inherited 1ary metabolic disorders, cystinuria, etc

47. Mechanism of stone formation involves excess solute in urine (primary increase in metabolite or stasis) or due to reduced solubility of solute in urine (persistently low pH) • Calculi vary in size, from sand like particles to large staghorn stones which fit the whole renal pelvis and branch into calyces • If calcium deposition occurs, nephrocalcinosis • Symptoms: • Renal colic* with nausesa & vomitting caused by passage of small stones along ureter • Dull ache in loins • Strangury* desire to pass something that will not pass (stones in bladder) • Recurrent urinary tract infections (UTI) • Management: rest, analgesia, warmth, fluid intake to pass small stones <5mm, or ureteroscopy or lithotripsy

48. Urinary calculi imaging

49. CYSTITIS • Inflammation of bladder • Extremely common, mostly women because of shorter urethra (less traveling distance for bacteria) • Aetiology • Infection or irritants (radiation) • Bacterial (E Coli, proteus, strep faecalis, staphylococcus) • Viral (adenovirus), fungal (candida), parasites (schistosoma)

50. Macroscopically: acute inflammation with oedema, erythema & ulceration of bladder mucosa • Microscopically: infiltration of mucosa with acute inflammatory cells