Tubulointerstitial, Vascular and Chronic Kidney Diseases

Question 1

What is acute interstitial nephritis?

Answer 1

Inflammation of renal tubules & interstitium

Question 2

What are some causes of acute interstitial nephritis?

Answer 2

– hypersensitivity reaction to drugs – infections – autoimmune diseases–SLE, Sjogren’s

Question 3

How do drug induced cases of acute interstitial nephritis resolve?

Answer 3

Drug-related cases are usually reversible – idiosyncratic – recur with re-exposure – older patients particularly susceptible

Question 4

How do we treat acute interstitial nephritis ?

Answer 4

• Most drug-related cases resolve when offending drug is discontinued • Treat associated infections • Treat the underlying cause in autoimmune disorders

Question 5

What are morphological features of acute interstitial nephritis ?

Answer 5

– Inflammation and edema of interstitium with involvement of tubules (tubulitis) sparing glomeruli and vessels – Lymphocytes, plasma cells, eosinophils – May see granulomas

Question 6

What is acute pyelonephritis?

Answer 6

Acute inflammation of the kidney due to a bacterial infection – urinary route: Usually gram negative bacilli – hematogenous route

Question 7

Predisposing conditions to what disease? – urinary obstruction–congenital or acquired – urinary tract instrumentation – vesicoureteral reflux – pregnancy – diabetes

Answer 7

Pyelonephritis

Question 8

Where do you find the inflammatory cells in Pyelonephritis?

Answer 8

PMNs between the tubules but also within the tubules

Question 9

Chronic renal failure results from direct tubular toxicity of light chains, tubular obstruction by casts and interstitial inflammation in 25% of pt with what disease?

Answer 9

Multiple Myeloma

Question 10

Multiple Myeloma causes cast nephropathy how?

Answer 10

• Due to excessive production and urinary excretion of light chains • Factors that favor intratubular precipitation and cast formation: hypercalcemia, volume depletion & nephrotoxins

Question 11

How does multiple myeloma present?

Answer 11

Presenting features: – older patients, usually over 40 – renal insufficiency & proteinuria – history of bone pain, fractures – hypercalcemia – monoclonal light chains in blood or urine

Question 12

How does multiple myeloma look on LM, IF and EM?

Answer 12

• LM: Crystalline, fractured casts in tubules with associated cellular reaction
• IF: May see light chain predominance
• EM: Electron dense, fractured casts

Question 13

How doe you treat myeloma cast nephropathy?

Answer 13

Acutely, hydration and urinary alkalinization to prevent tubular obstruction by casts & chemotherapy or stem cell transplantation

Question 14

Acute interstitial nephritis is often caused by drugs and characterized by what?

Answer 14

interstitial inflammation with eosinophil predominance, eosinophilia, eosinophiluria

Question 15

Pyelonephritis is ofen due to ascending UTI and characterized by what?

Answer 15

interstitial and tubular inflammation and the presence of bacteria on urine culture

Question 16

Myeloma cast nephropathy occurs in patients with multiple myeloma and is characterized by what?

Answer 16

fractured tubular casts with either lambda or kappa light chain predominance

Question 17

What is hypertensive nephrosclerosis?

Answer 17

Chronic kidney disease in a patient with long-standing, poorly controlled HTN & Proteinuria is often present

Question 18

What are some morphologic features of hypertensive nephrosclerosis?

Answer 18

– Gross: Normal to slightly small with finely granular subcapsular surface
– LM: Subcapsular glomerular sclerosis, tubular atrophy, interstitial fibrosis, arteriolar hyaline

Question 19

What causes renovascular hypertension?

Answer 19

Renal artery stenosis is a secondary cause of hypertension with 2 main causes: atherosclerosis & fibromuscular dysplasia
Other causes–trauma, dissection, extrinsic compression

Question 20

What does renal artery stenosis cause hypertension?

Answer 20

decreased kidney perfusion causes the kidney activate the RAAS

Question 21

When should you suspect renal artery stenosis?

Answer 21

– early or late onset HTN
– difficult to control HTN
– abdominal or flank bruit
– renal failure after starting ACE-inhibitor

Question 22

How do you diagnose renal artery stenosis?

Answer 22

– CT with contrast
– MRA
– Renal arteriography
– Doppler U/S
– Captopril renogram
– Renal vein renin sampling

BASICALLY IMAGE IT

Question 23

What are some morphological features of renal artery stenosis?

Answer 23

Atherosclerosis & fibromuscular dysplasia ( usually younger women with intimal, medial and adventitial forms)

Question 24

Where does fibromuscular dysplasia usually occur?

Answer 24

• Renal artery – 60-75% (bilateral – 35%)
• Cervicocranial arteries – 25-30%
• Visceral arteries – 9%
• Extremity arteries – 5%
Two vascular beds involved in up to 28%

Question 25

What does medial fibroplasia of FMD usually look like?

Answer 25

• Alternating thinned media and thickened fibromuscular ridges
• Forms “string of beads” radiographically
• Beading is larger than caliber of artery
• Middle to distal artery

Question 26

How do you treat renal artery stenosis?

Answer 26

– Surgical revascularization
– Angioplasty and stenting
– Medical management only

Question 27

What do renal cortical infarcts look like?

Answer 27

• Renal artery occlusion – extensive parenchymal infarction
• Smaller branch=wedge-shaped infarct, Pale with hyperemic border, Coagulation necrosis & Hemorrhage and acute inflammation at edge
• Fibrotic (later)

Question 28

What is atheroembolic disease and when does it occur?

Answer 28

• Disruption of atherosclerotic plaques can cause acute and subacute renal failure
• Occurs after procedures that disrupt plaques in the aorta, leading to a shower of cholesterol emboli that lodge in the renal microvasculature

Question 29

What are the possible outcomes of an infarcted kidney?

Answer 29

– Stabilized or normal renal function in mild, isolated cases
– Chronic, progressive deterioration in renal function in subacute cases
– End-stage renal disease in severe cases
– Permanent dialysis may be necessary

Question 30

Thromobotic microangiopathy is characterized by what?

Answer 30

Characterized by thrombosis in capillaries and arterioles
– Microangiopathic hemolytic anemia
– Thrombocytopenia (can have purpura)
– Renal failure

Question 31

Hemolytic uremic syndrome occurs when?

Answer 31

Often occurs after intestinal infection with E. coli O157:H7

Question 32

Renal artery stenosis can be caused by atherosclerosis or FMD and clinically presents as what?

Answer 32

resistant HTN or kidney dysfunction (often after ACE-I or ARB)

Question 33

Atheroembolic disease causes acute and progressive renal dysfunction and often occurs when?

Answer 33

after arterial angiography & has histopathologic evidence of clefts in vascular lumen

Question 34

What is chronic kidney disease?

Answer 34

• Progressive irreversible renal insufficiency that develops over months to years
• May ultimately lead to end-stage renal disease: Kidneys no longer function to maintain life (GFR<10 ml/min)

Question 35

What are the main causes of CKD?

Answer 35

Main causes:
– Diabetes
– Hypertension
– GNs
– Cystic diseases

Question 36

What happens to kidney size in CKD?

Answer 36

Kidney size usually (but not always) reduced but normal or large kidneys may be seen with: Diabetes, Amyloidosis, HIV, Cystic kidney diseases

Question 37

What can we see happen secondarily to CKD?

Answer 37

Anemia (decreased erythropoietin production occurs below GFR of 60 ml/min), Hypertension and 2° hyperparathyroidism (decreased renal synthesis of 1,25-dihydroxy-D3 and decreased phosphate excretion contribute to hypocalcemia,hyperphosphatemia, and renal osteodystrophy)

Question 38

Other findings with CKD include?

Answer 38

– metabolic acidosis • decreased secretion of ammonium and retention of phosphates & sulfates
– hyperkalemia
– inability to maintain sodium & water balance
– coagulopathy–platelet dysfunction
– sensorimotor neuropathy

Question 39

CKD presents with physical symptoms of chronic uremia which are what?

Answer 39

– lethargy, fatigue
– day-night sleep reversal
– anorexia, nausea & vomiting
– pruritus
– restless legs syndrome
– uremic pericarditis

Question 40

What are the management goals with CKD?

Answer 40

– preserve renal function and delay progression to end-stage renal disease
– prevent or minimize adverse effects
– institute renal replacement therapy when necessary

Question 41

What can we do to slow the progression of CKD?

Answer 41

– Control hypertension (ACE-I, ARB)
– Reduce proteinuria
– Control blood sugar
– Smoking cessation
– Disease-specific therapy as indicated

Question 42

What other things can we do to try to help CKD progression?

Answer 42

– Dietary restrictions: Na+, K+, phosphorus and protein?
– Control hyperlipidemia
– Correct anemia
– Correct acidosis
– Dialysis or kidney transplant when necessary usually GFR < 10

Question 43

What is the most common cause of CKD and
ESRD in the US?

Answer 43

DIABETES

Question 44

What does CKD result in?

Answer 44

– HTN
– Metabolic acidosis
– Increased risk of hyperkalemia
– Secondary hyperparathyroidism • Due to phosphorus retention and impaired calcitriol production
– Anemia due to Epo deficiency

Question 46

How is ESRD treated?

Answer 46

with dialysis or kidney transplantation