Kidneys, Urinary Flashcards
Name three developmental disorders of the kidneys.
- Renal agenesis
- Horseshoe kidney
- Ectopic kidney
What is renal agenesis? What are the symptoms?
It is complete absence of renal tissue. Can be unilateral or bilateral. Unilateral is usually asymptomatic and the remaining kidney udergoes compensatory hypertrophy. Bilateral is fatal (Potter syndrome).
What is Potter syndrome?
Bilateral renal agenesis - fatal
What is horseshoe kidney? What are some complications?
When the kidneys fail to separate at the lower poles during development. The kidneys are unable to ascend past the inferior mesenteric artery due to the abnormal connection so they are found inferior to this artery. Can potentially compress the vena cava, aorta, or urinary tract.
What is ectopic kidney? What are some complications?
A birth defect in which a kidney is located below, above, or on the opposite side of its usual position. They are prone to infection or obstruction.
What is the etiology of hereditary cystic diseases of the kidneys?
A defect in the cilia-centrosome complex of renal tubular epithelial cells. This leads to altered growth of the epithelial cells and abnormal fluid and ECM secretion.
Describe a “simple cyst” of the kidney.
Benign, 1-5 cm, translucent, with clear fluid.
What is the etiology of Autosomal Dominant (Adult) Polycystic Kidney Disease (ADPKD)?
A defect in the cilia-centrosome complex of renal tubular epithelial cells.
What are the two main roles of the ciliated epithelial cells of renal tubules?
- Sense urine flow
2. Regulate tubule growth
What are the two gene mutations involved in autosomal dominant polycystic kidney disease? What are the protein products of these genes?
85% have mutations in PKD1 and 15% have mutations in PKD2. Products are polycystin-1 and polycystin-2 which are needed for proper ciliary function.
Describe the morphological changes seen in autosomal dominant polycystic kidney disease (5).
- Both kidneys are extremely enlarged.
- Irregular surface.
- Tons of cysts 3-4 cm in diameter filled with fluid.
- Little parenchyma between cysts due to ischemic atrophy from pressure of surrounding cysts.
- Asymptomatic cysts in the LIVER found in 1/3 of patients.
Describe the clinical features of autosomal dominant polycystic kidney disease (8).
- Asymptomatic until 4th decade - onset of renal failure.
- Flank pain (above your hips).
- Bilateral flank and abdominal masses.
- Sense of heaviness in the loins.
- Intermittent gross hematuria.
- Hypertension in 75% of patients.
- UTI
- Azotemia (elevated BUN)
Which is more common: autosomal recessive polycystic kidney disease or autosomal dominant polycistic kidney disease?
Autosomal dominant (1 in 400-1,000 births)
Autosomal recessive is 1 in 20,000 births
What gene mutation causes autosomal recessive polycystic kidney disease and what is its gene product?
Caused by a mutation in the PKHD1 gene. The gene product is fibrocystin which is needed for proper ciliary function of the tubular epithelial cells.
What is the prognosis for autosomal recessive polycystic kidney disease?
75% of infants die in the perinatal period, often from pulmonary hypoplasia (failure of lung development) due to low amniotic fluid, hepatic failure, or renal failure. Those that survive go on to develop liver cirrhosis.
Name the condition with the following characteristics:
- Numerous small cysts in the cortex and medulla of the kidneys.
- External surface of the kidneys are SMOOTH.
- Cysts are fusiform dilations of cortical and medullary collecting ducts with a radial arrangement.
- Cysts lined by cuboidal epithelial cells.
- Interstitial fibrosis and tubular atrophy seen.
- Liver is fibrotic.
Autosomal recessive (childhood) polycystic kidney disease.
What causes glomerulonephritis?
Deposition of immune complexes in the glomeruli.
Glomerulonephritis may cause proliferation of ________, ________, and ________ cells in the kidneys.
endothelial, mesangial, and epithelial cells
What is the clinical syndrome called that glomerulonephritis causes? What are the clinical manifestations of this syndrome (10)?
Nephritic syndrome, characterized by:
- Hematuria (acute, grossly visible).
- Proteinuria
- Decreased GFR
- Elevated BUN
- Elevated serum creatinine
- Oliguria (low urine output)
- Salt and H2O retention
- Hypoalbuminemia
- Edema
- Hypertension
How can group A streptococcal infection cause glomerulonephritis, leading to nephritic syndrome?
Circulating strep antibodies get trapped in glomeruli, bind complement, recruit leukocytes and inflammatory cells –> necrosis of glomeruli
Which specific antibodies and complement proteins are found in the glomeruli in the case of acute poststreptococcal gomerulonephritis in the early stage vs in the late stage?
Early: coarse, granular deposits of IgG and C3
Late: C3 deposits
What cellular changes are seen in the case of acute poststreptococcal gomerulonephritis (5)?
- Diffuse glomerular enlargement and hypercellularity (caused by intracapillary leukocytes).
- Proliferation of endothelial, mesangial and parietal cells.
- Infiltration of neutrophils and monocytes.
- Subepithelial immune complex deposits (isolated HUMPS between the outer surface of the glomerular basement membrane and the podocytes).
- Subendothelial deposits in the mesangium, between the endothelial cells and the glomerular basement membrane.
In acute poststreptococcal glomerulonephritis, ____% of children recover without complications and it is one of the ______ common childhood renal diseases.
90% recover, one of the most common childhood renal diseases
Acute poststreptococcal glomerulonephritis can cause ____-lived nephritic syndrome, which is characterized by ______, ______, ______, and ________. Additionally, _______ and facial edema may persist for several months.
short-lived nephritic syndrome, characterized by oliguria (low urine output), azotemia (high levels of nitrogen-containing compounds in blood), hematuria, and hypertension.
Proteinuria and facial edema may persist for several months.
How long does it take for the complement deposits to be cleared from the glomeruli after a case of acute poststreptococcal glomerulonephritis?
2 months
What is rapid progressive (crescentic) glomerulonephritis characterized by both clinically and cellularly?
Characterized clinically by having features of nephritic syndrome and rapid loss of renal function.
Cellular changes include glomerular necrosis, inflammation, wrinkling and breaks in the glomerular basement membrane, and proliferation of parietal epithelium (crescents) of Bowman’s capsule.
What causes anti-glomerular basement membrane (Type 1) crescentic glomerulonephritis?
Auto-reactive antibodies against the alpha-3 type of collagen IV in the glomerular basement membrane
What is Goodpasture syndrome?
A condition that causes anti-glomerular basement membrane (Type 1) crescentic glomerulonephritis and also includes antibody attack of the basement membrane in the lungs.
Note that anti-BM T cells may also play a role
Which HLA type is associated with anti-glomerular basement membrane disease?
HLA-DR2
Name the disease:
- Enlarged and pale kidneys with petechial hemorrhages on the cortical surfaces.
- Segmental necrosis and breaks in the GBM.
- Proliferation of parietal epithelial cells and migration of monocytes and macrophages that form crescents filling Bowman’s space.
- Strong, diffuse LINEAR staining of the glomerular basement membrane for IgG and C3 with immunofluorescence.
- Fibrin strands between cellular layers in the crescent.
- Eventual scarring and glomerulosclerosis.
Anti-glomerular basement membrane (Type 1) crescentic glomerulonephritis.