Robbins - Renal path

Question 1

What is the function of podocytes?

What happens when they are injuried? What types of way can be they be injuried?

Answer 1

Podocytes (visceral epithelial cells) form the filtration barrier that depends on both the anionic charge as well as the slit diaphragms (separation based on charge AND size)

When injuries occur –> proteinuria

• Injuries that cause effacement, retraction, detachment, and vacuolization allow protein (mainly albumin) to escape into Bowman space

Question 2

Impetigo

Answer 2

A contagious bacterial skin infection most common among preschool children that usually produces blisters or sores on the face, neck, hands, and diaper area.

Primarily caused by Staph. aureus and can also be caused by Strep.pyogenes

Question 3

What is another name for PSGN (post-strep glomerulonephritis)?

Answer 3

Acute proliferative glomerulonephritis.

The only difference is that this term applies to after an infection of any source and is not limited to only strep.

You have the same characteristics as PSGN such as the development of the sub-epithelial “humps”

Question 4

What is Goodpasture syndrome? What is the disease process? What renal disease state is it associated with?

How does it look on histology?

Answer 4

• Goodpasture is autoantibodies to the basement membrane present in the glomerulus and the lungs. This syndrome typically results in both pulmonary (hemoptysis) and renal symptoms.
• The auto-antibodies are targeted to the α3 chain of type IV collagen.
• IF will reveal a linear pattern of staining of the glomerulus. Histology will likely reveal “crescents” in the glomerulus.
• Associated with rapidly progressive glomerulonephritis

Question 5

Another name for membranoproliferative glomerulonephritis type II.

What is classically seen in this disease?

Answer 5

Dense deposit disease

Disease process is the deposit of imune complexes intramembrously.

Disease is also associated with the presence of C3 nephritic factor (which stabilizes C3 convertases) causing an increase in C3 resulting in an abnormal increase in activation of complement

Histology is characterized by thickening of only the basement membrane and small electron-dense deposits

Question 6

What is Berger disease? What are some predispositions to this disease?

Answer 6

aka IgA nephropathy

Increased risk/frequency in patients with celiac disease and liver disease

Characterized by mesangial IgA deposition

Question 7

Where are deposits found in IgA nephropathy?

Answer 7

Mesangium

Question 8

What does IgA nephropathy classically follow? (what occurs typically before IgA nephropahy?)

Answer 8

Mucosal (ie respiratory or GI) infection.

IgA is a mucosal antibody. Any infectious process that affects the mucous membranes can technically stimulate the production of IgA which if there is excess can deposit in the mesangium of the kidneys and cause Berger’s disease.

Question 9

What is the classic presentation of Alport syndrome? What is the pathogenesis?

Answer 9

Alport syndrome is due to a mutation in a gene for the α5 chain of type IV collagen.

Classically presents as:

• isolated hematuria
• sensory/hearing loss
• ocular disturbances

Question 10

IgA nephropathy - what is the pattern of inheritance?

Answer 10

X-linked in 85% of cases

Rest can be autosomal recessive or dominant