Tubulointerstitial Diseases, Vascular Diseases, and Chronic Kidney Disease Flashcards
What is acute interstitial nephritis?
Inflammation of renal tubules and interstitium
What are some causes of Acute Interstitial Nephritis?
- Hypersensitivity reaction to drugs (Penicillin derivatives, NSAIDs, sulfonamides, rifampin)
- Infections
- Autoimmune diseases (SLE, Sjorgren’s)
Drug related cases or Acute Interstitial Nephritis are usually _______
reversible
Urine analysis for acute interstitial nephritis can show…
WBCs
WBC casts
RBCs
What features associated with hypersensitivity reactions are clues to diagnosis of acute interstitial nephritis?
- fever, arthralgias, maculopapular rash
- peripheral blood eosinophilia
- Eosinophils in the urine
What are some morphologic features of acute interstitial nephritis?
- Inflammation and edema of interstitium with involvement of tubules
- Spares glomeruli and vessels
- Lymphocytes, plasma cells, eosinophils
- May see granulomas
What is acute pyelonephritis?
Acute inflammation of the kidney due to a bacterial infection through a urinary or hematogenous route
Urinary tract pathogens in acute pyelonephritis are usually what type of bacteria?
Gram negative bacilli
What are some predisposing conditions for pyelonephritis?
- Urinary obstruction – congenital or acquired
- Urinary tract instrumentation
- Vesicoureteral reflux
- Pregnancy
- Diabetes
How does pyelonephritis appear histologically?
Interstitial inflammation and inflammation within the tubules
Multiple myeloma can lead to renal failure in __% of patients
25
Chronic renal failure in Multiple myeloma results from…(3)
- Direct tubular toxicity of light chains
- Tubular obstruction by casts
- Interstitial inflammation
How does multiple myeloma lead to cast nephropathy?
- Due to excessive production and urinary exretion of light chains
- Presents as acute kidney injury
What factors favor intratubular precipitation nad cast formation in multiple myeloma?
Hypercalcemia
Volume depletion
Nephrotoxins
How does multiple myeloma present?
- Older patients (usually over 40)
- Renal insufficiency and proteinuria
- History of bone pain, fractures
- Hypercalcemia
- Monoclonal light chains in blood or urine
How does myeloma cast nephropathy appear on light microsope?
Crystalline, fractured casts, in tubules with associated cellular reaction
Treatment of myeloma cast nephropathy?
- Acutely, hydration and urinary alkalinization to prevent tubular obstruction by casts
- Chemotherapy or stem cell transplantation
What are examples of renal vascular diseases?
Hypertensive nephrosclerosis
Renovascular hypertension
Atheroembolic disease
Thrombotic microangiopathy
What is hypertensive nephroscleoris?
What symptome is often present?
Chronic kidney disease in a patient with long-standing, poorly controlled HTN
Proteinuria is often present
What are some morphologic features of hypertensive nephrosclerosis? (grossly and on light microscope)
Gross: normal to slightly small kidney with finely granular subscapular surface
Light: Subscapular glomerular sclerosis, tubular atrophy, interstitial fibrosis, arteriolar hyaline
What are morphologic features of malignant hypertension in hypertensive nephrosclerosis?
Mucoid intimal thickening of arteries, glomerular capillary wrinkling, GBM duplication
What are 2 main causes associated with renal artery stenosis as a secondary cause of hypertension?
Atherosclerosis
Fibromuscular dysplasia
How does renal artery stenosis lead to hypertension?
Due to decrease in pressure to kidney, compensation mechanism is activated which increases angiotensin II production
Angiotensin II leads to vasoconstriction and aldosterone release which increase blood pressure
A physician should suspect renal artery stenosis in patients with…(4)
- early or late onset HTN
- difficult to control HTN
- abdominal or flank bruit
- Renal failure after starting ACE inhibitor
What are some morphologic features associated with atheroscleoris in renal artery stenosis?
- Stenosis usually in proximal renal artery
- Eccentric plaque - fibrosis, cell debris, lipid and foam cells (plaque may hemorrhage or dissect)
- Medial and adventitial fibrosis
- Calcification may occur
What locations are you more likely to find fibromuscular dysplasia in renal artery stenosis?
Renal artery - 60-75% (bilateral 35%)
Cervicocranial arteries - 25-30%
Visceral arteries - 9%
Extremity arteries - 5%
How does medial fibroplasia in FMD present?
- Alternating thinned media and thickened fibromuscular ridges
- Forms “string of beads” radiographically
- Beading is larger than caliber of artery
- Middle to distal artery
What is the treatment for renal artery stenosis?
- Surgical revascularization
- Angioplasty and stenting
- Medical management only
What are some thromboembolic diseases?
- Cortical infarcts
- Renal cholesterol microembolism syndrome
- Thrombotic microangiopathy
What are morphologic features of a cortical infarct?
- Renale artery occlusion (extensive parenchymal infarction)
- Smaller branch - wedge shaped infarct
- Fibrosis
What is atheroembolic disease and when can it occur?
Disruption of athersclerotic plaques that 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
Aside from acute renal failure, other common manifestations of atheroembolic disease include…(3)
bowel infarction
Digital infarction (fingers and toes turn blue)
Stroke
Cholesterol atheroemboli affect which size arteries?
any size artery
How does eosinophilia occur with cholesterol atheroemboli?
Eosinophilia may be related to activation of C5a which is chemotactic for eosinophils
What are different outcomes associated with atheroembolic disease?
- 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
Thrombotic microangiopathy is characterized by thrombosis in __________ and ________
capillaries; arterioles
Consequences of thrombotic microangiopathy?
Microangiopathic hemolytic anemia
Thrombocytopenia
Renal failure
What are some other manifestations of thrombotic microangiopathy?
Hemolytic uremic syndrome (associated with E Coli)
TTP (thrombotic thrombocytopenic purpura)
What is the pathogenisis of thrombotic microangiopathy?
Endothelial injury and activation
Platelet aggretation leading to vascular obstruction and vasoconstriction
What is Chronic Kidney Disease and what is the last stage of its progression?
Progressive irreversible renal insufficiency that develops over months to years
Ultimately leads to end stage renal disease
What are the main causes of CKD?
Diabetes (#1)
Hypertension
Glomerular nephritis
Cystic diseases
What are some consequences of CKD?
- Anemia (decreased erythropoietin production)
- Hypertension
- 2º hyperparathyroidism (decreased synthesis of vitamin D and decreased phosphate excretion)
What are some other findings associated with CKD?
- Metabolic acidosis
- Hyperkalemia
- Inability to maintain sodium/water balance
- Coagulopathy
- Sensorimotor neuropathy
What are some physical symptoms of chronic uremia?
- Lethargy
- Anorexia
- Pruritus
- Restless legs syndrome
- Uremic pericarditis
- Day-night sleep reversal
What are the management goals for CKD?
- Preserve renal function and delaty ESRD
- Prevent of minimize adverse effects
- Institute renal replacement therapy when necessary
How can we slow the progression of CKD?
- Control blood sugar
- Smoking cessation
- Reduce proteinuria
- Control hypertension
ESRD is treated with ______ or ______ ________
dialysis; renal transplantation
