Tubulointerstitial, Vascular, & Chronic Kidney Diseases - Regner Flashcards
Acute Interstitial Nephritis
Describe it briefly. What are its three main causes?
Acute Interstitial Nephritis
Inflammation of renal tubules & interstitium
Causes:
- Drug hypersensitivity (PCNs, NSAIDs, sulfonamides, rifampin)
- Infections
- Autoimmune diseases
Acute Interstitial Nephritis
How is it diagnosed?
Acute Interstitial Nephritis
- Look for signs of hypersensitivity rxn:
- Fever, arthralgia, maculopapular rash
- Peripheral blood eosinophilia
- Urinalysis can show:
- Eosinophils
- WBCs + WBC casts
- RBCs
Acute Interstitial Nephritis
How is it treated?
Acute Interstitial Nephritis
- Discontinue offending drug
- Treat associated infections
- Treat underlying cause in autoimmune disorders
- Corticosteroids sometimes used
Acute Interstitial Nephritis
Describe the microscopic morphology
Acute Interstitial Nephritis
- Renal interstitial inflammation and edema.
- Tubule involvement (tubulitis)
- Spares glomeruli and vessels
- Lymphocytes, plasma cells, eosinophils
- May see granulomas
Acute Pyelonephritis
- Describe it briefly. How does the condition reach the kidneys?
- What is its typical cause?
Acute Pyelonephritis
- Acute kidney inflammation due to bacterial infection
- Urinary route
- Hematogenous route
- Urinary tract pathogens
- Often Gram negative bacilli
- E. coli
- Proteus
- Enterobacter
- Often Gram negative bacilli
Acute Pyelonephritis
Name five conditions that can predispose an individual to acute pyelonephritis.
Acute Pyelonephritis
- Urinary obstruction (congenital or acquired)
- Urinary tract instrumentation (catheter, etc.)
- Vesicoureteral reflux (backward urine flow)
- Pregnancy
- Diabetes
Multiple Myeloma
- Describe it.
- In what ways does it affect the kidneys?
- How does the kidney damage present in clinic?
Multiple Myeloma
- A cancer of plasma cells that typically produce excessive amounts of abnormal antibody fragments, esp. the Ig light chain.
- Myeloma cast nephropathy: Chronic renal failure (25% of pts) results from:
- Direct tubular toxicity from Ig light chains
- Tubular obstruction by casts
- Interstitial inflammation
- Presents as an AKI
Multiple Myeloma
Name three predisposing factors that favor intrutubular precipitation of Ig light chains and cast formation?
Multiple Myeloma
- Hypercalcemia
- Volume depletion
- Nephrotoxins
Multiple Myeloma
- What is the typical age of presentation?
- What are typical presenting features?
- What is a useful diagnostic test for renal involvement (“cast nephropathy”)?
Multiple Myeloma
- Older, usually >40yrs
- Features:
- Renal insufficiency & proteinuria
- History of bone pain, fractures
- Hypercalcemia
- Monoclonal Ig light chains in blood or urine
- Renal biopsy followed by microscopy
Multiple Myeloma
What morphologic features of cast nephropathy are seen using:
- Light microscopy?
- Immunofluorescent microscopy?
- Electron microscopy?
Multiple Myeloma
- LM: Crystalline, FRACTURED casts in tubules with cellular reaction (looks like the cells try to wall off the light chain casts)
- IF: May see light chain predominance (e.g. use anti-kappa chain Ab → lots of glowy stuff)
- EM: Electron dense, fractured casts
Multiple Myeloma
How is it treated?
Multiple Myeloma
- Acutely, to prevent tubular obstruction by casts:
- Hydration
- Urine alkalinization
- Long term:
- Chemotherapy
- Stem cell transplantation
Name four types of renal vascular disease.
- Hypertensive nephrosclerosis
- Renovascular hypertension
- Atheroembolic disease
- Thrombotic microangiopathy
Hypertensive Nephrosclerosis
- In what context is this disease seen?
- What urinalysis finding is often present?
- What is the gross morphology?
- What is the microscopic morphology?
Hypertensive Nephrosclerosis
- Context: long-standing, poorly controlled HTN
- Urinalysis: proteinuria
- Gross: kidney has finely granular subscapular surface
- Light microscopy: glomerular sclerosis, tubular atrophy, interstitial fibrosis, arteriolar hyalinosis.
What is the renal microscopic morphology seen in Malignant Hypertension?
- Mucoid intimal thickening of arteries (“onion skin”)
- Glomerular capillary wrinkling
- Duplication of GBM (also seen in Thrombotic Microangiopathy)
Renovascular Hypertension
- What are the two main causes of this condition?
- What other disease can be caused secondary to this condition?
- How?
Renovascular Hypertension
- Causes:
- Atherosclerosis
- Fibromuscular dysplasia
- Can result in secondary systemic HTN
- How: Decrease in renal blood flow causes activation of RAAS, stimulating vasoconstriction and fluid retainment
Renovascular Hypertension
When should you suspect this disease?
Renovascular Hypertension
- Atypically early OR late onset HTN
- Difficult to control HTN
- Bruit in abdomen or flank
- Renal failure after starting ACE-I
- Kidney has become dependent on RAAS activation to obtain sufficient blood flow
Renovascular Hypertension
Name a few methods useful for diagnosing this condition.
Renovascular Hypertension
- Contrast CT
- MRA (like MRI, but Angiography)
- Renal arteriography
- Doppler Ultrasound
- Others
Fibromuscular Dysplasia
- Who does it typically affect?
- Briefly describe the disease
- Which vessels are typically affected?
- What is the radiographic morphology of affected vessels?
Fibromuscular Dysplasia
- Younger women
- (Wiki) “A non-atherosclerotic, non-inflammatory vascular disease that causes abnormal growth within the wall of an artery”
- Often affected (~30% have two affected vascular beds):
- Renal artery (60-75%, bilateral in 35%)
- Cervicocranial arteries (25-30%)
- Visceral and extremity arteries
- Alternating thinned media and thickened fibromuscular ridges, causing a “string of beads” appearance on radiography
Renal Artery Stenosis
- Name three ways it can be treated / managed.
Renal Artery Stenosis
- Surgical revascularization
- Angioplasty and stenting
- Medical management only
Renal Cortical Infarction
- What is the gross morphology of this type of infarct?
- How does the infarct appear when the occlusion occurs:
- In the renal artery?
- In a smaller branch?
Renal Cortical Infarction
- Appearance:
- Pale w/ hyperemic border
- Hemorrhage & actue inflammation at edge
- Coagulative necrosis
- Later on, becomes fibrotic
- Pale w/ hyperemic border
- Occlusion:
- Renal artery: Extensive parenchymal infarction
- Smaller artery: Wedge-shaped infarct
Atheroembolic Disease
- Describe the pathology. What is the typical emboli type?
- What is a common cause?
- Aside from the kidney microvasculature, what other sites are commonly infarcted by these emboli?
- What is a common blood and urine finding?
Atheroembolic Disease
- Disruption of atherosclerotic plaques - acute and subacute renal failure due to shower of cholesterol emboli
- Procedures that disrupts aortic plaques
- Other sites:
- Bowel
- Digits
- Brain (stroke)
- Eosinophils found in blood or urine (due to activation of C5a - chemotaxis)
Thrombotic Microangiopathy (TMA)
Name 4 conditions that often cause TMA
Thrombotic Microangiopathy (TMA)
Causes:
- Microangiopathic hemolytic anemia
- Subtype of hemolytic anemia - hemolysis occurs in small vessles due to endothelial pathology)
- Seen in SLE, HUS (Hemolytic uremic syndrome)
- HUS often secondary to intestinal E. coli infection
- Thrombocytopenia
-
TTP (Thrombotic Thrombocytopenic purpura)
- (Wiki) defective zinc metalloprotease causes abnormal proteolosis of VWF - VWF pieces unfold & aggregate
- Renal failure
Thrombotic Microangiopathy (TMA)
Describe the pathogenesis of TMA
Thrombotic Microangiopathy (TMA)
Thrombosis formation in capillaries and arterioles causes endothelial injury & activation, platelet aggregation
CKD
- What are four major causes of CKD?
- At approximately what GFR can the kidneys no longer function to maintain life?
CKD
- Causes:
- Diabetes (#1 cause of CKD in the US)
- HTN
- Glomerulonephritis
- Cystic Diseases
- GFR < 10 ml/min
CKD
In CKD, kidney size is usually, but not always, reduced. Name four conditions in which CKD can occur with normal-sized or large kidneys.
Normal or large kidney size with CKD:
- Diabetes
- Amyloidosis
- HIV
- Cystic kidney diseases
CKD
Name some potential consequences of CKD.
CKD
Major Consequences
- Anemia (Epo deficiency)
- Hypertension (reduced excretion ability & RAAS activation)
- Secondary Hyperparathyroidism
- Decreased renal synthesis of Vitamin D3 causes hypocalcemia, increasing PTH
- Increased phosphorus retention also increases PTH
Other Consequences
- Metabolic acidosis
- Decreased ammonium secretion, retention of phosphates & sulfates
- Hyperkalemia
- Disturbed sodium/water balance
- Coagulopathy (platelet dysfunction)
- Sensorimotor neuropathy
CKD
Decreased urea excretion in CKD leads to chronic ______.
What are the symptoms of this?
Chronic uremia
Symptoms:
- Lethargy & fatigue
- Day-night sleep reversal (huh. neat.)
- Anorexia, nausea, & vomiting
- Pruritis
- Restless legs syndrome
- Uremic pericarditis
CKD
How is CKD treated?
CKD
To treat CKD, control its causes:
- control HTN (ACE-I, ARB)
- control blood glucose
- control hyperlipidemia
- smoking cessation
And correct its consequences:
- Reduce proteinuria
- Correct anemia
- Correct acidosis
- Dietary restrictions if needed
Once severe (GFR < 10 ml/min), dialysis or transplant will likely be necessary.
