Kidney pathology 2010.1
Tubular & interstitial diseases
Kidney - cut surface
Co
*
Calyx
B
Pelvis
*
• Outer cortex (Co)
• Inner medulla
composed of
pyramids *
• Cortical columns of
Bertini (B) between
pyramids*
• Urine first collects
in calyces, pelvis
Malpighi and
Malpighian
“corpuscles”
(glomeruli)
Glomerular structure
• Arterioles
• Capillaries
• Mesangium (“between
capillaries”)
• Urinary space
surrounds glomerulus
within Bowman’s
capsule
• Urin sp -> prox tubule
Normal renal tubules
Acute pyelonephritis
•
•
•
•
•
Most severe end of spectrum of UTI
Acute bacterial inflammation of kidney
E coli, Proteus, Enterobacter, Klebsiella …
Abscesses in cortex, medulla
Polymorphs in tubules; glomeruli spared
• (CMV, polyoma virus in immunocompromised)
Acute pyelonephritis
Acute pyelonephritis
Acute pyelonephritis - clinical
• M < 1yr and over 40 yrs; F 1 - 40 yrs
• Sudden onset tenderness in costo-phrenic
angle
• Temp, rigors, cystitis
• Most resolve quickly
• May recur, become chronic
• Complications
Pathogenesis of acute pyelonephritis
• (Haematogenous spread)
• Bacterial adhesins, colonisation, ascending
infection
• Cystitis
• Vesico-Ureteric Reflux & Intrarenal Reflux,
congenital or acquired
– VUR: Urine, bacteria -> ureter
– Inrarenal reflux: Urine enters kidney papillae
Predisposing factors
• Short female urethra
• Obstruction (pregnancy, congenital, stones,
tumours, BPH)
• Bladder dysfunction
• Diabetes
• Catheters, cystoscopy, other
• Vesico-Ureteric Reflux & Intrarenal Reflux
– If no reflux, infection only in bladder
Complications of Acute Pyelo
•
•
•
•
Perinephric abscess
Pyonephrosis
*Papillary necrosis
Fibrous scars, chronic
pyelonephritis
Chronic pyelonephritis
• Scars overlying distended calyces
• Chronic inflammation and fibrosis
involving tubules and interstitium
• Two types
– Reflux nephropathy
– Chronic obstructive pyelonephritis
Reflux nephropathy
•
•
•
•
Commoner
VUR pressure threshold
Organisms
Refluxing papillae at
upper, lower poles
• Hypertension at 15-25 yrs
Chronic pyelonephritis (reflux)
Chronic pyelonephritis - reflux type
Chronic pyelonephritis, obstructive
• Older patients
• Strictures, calculi in
ureter, renal pelvis
• BPH
• Tumours
Chronic pyelonephritis - clinical
• Chronic renal failure, hypertension
• UTI (but often negative urine cultures)
• Interstitial fibrosis, tubular atrophy,
thyroidization of tubules, thick arteries, FSGS
• Accounts for 10 - 20% of patients on dialysis
• Other types of pyelonephritis
TB (L) & Xanthogranulomatous PN (R)
Non-bacterial inflammation of renal
tubules, interstitium
• Drugs/toxins: penicillins, rifampicin, NSAIDs…..
– Immune injury (types I, IV); direct, unknown
– Fever, oliguria in 50%, rash
– Micro; inflammatory cells, inc eosinophils
• Analgesic nephropathy - phenacetin, +/- aspirin, codeine
• Assoc with glomerular disease e.g. SLE, renal vasculitis
• Gout, multiple myeloma
• Renal allograft rejection
Acute interstitial nephritis
Eosinophils in drug induced
interstitial nephritis
Acute renal transplant rejection
Acute renal failure
• Sudden onset of oliguria (<400ml)
– Raised serum Creatinine
• Cause determines symptoms, prognosis
• Overall mortality is 40%
–
–
–
–
Drugs, toxins
Crescentic glomerulonephritis e.g. ANCA+ vasculitis
Genitourinary obstruction
Shock, ischaemia
Acute renal failure - pathology
• Most patients have a microscopic lesion - Acute Tubular
Necrosis (necrosis of tubular epithelial cells is a “marker”
of acute loss of renal function)
• Renal tubular epithelium sensitive to toxins, ischaemia
• Vasoconstriction -> hypoxia in outer medulla
• Two types of ATN:
• ATN due to drugs, toxins - PCT cells (95% survival)
• ATN due to ischaemia, shock or sepsis - granular casts
(20-50% survival)
Normal tubules (L) and drug-induced ATN* (R)
*
ATN, drug-induced
ATN due to toxin
ATN due to Sepsis/Ischaemia
Interstitial fibrosis and tubular atrophy in
chronic renal disease correlate with
progressive loss of renal function
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Chronic renal failure
• Progressive and irreversible loss of renal tissue
• Chronic GN, chronic PN, hypertensive nephrosclerosis,
diabetes, adult type PCKD
• Symptoms - anaemia, dehydration, nausea, metabolic bone
disease, etc
• Asymptomatic renal insufficiency present prior to this
while kidneys’ intact nephrons compensate
• Dialysis, transplant or death within 1 year of onset of CRF