U of U PA School Structural and Genetic Kidney Diseases

How does the kidney develop?

Develops from mesopnephric tissue in renal pelvis

Ascends from pelvis to adult position

What is a horseshoe kidney?

When both kidneys remain in lower abdomen and are fused at lower poles

Usually still have 2 ureters

What prevents a horseshoe kidney from ascending?

Inferior mesenteric arteries

How does a horseshoe kidney present? (4)

Usually asymptomatic

Reflux symptoms

Obstructions

Stone formation

How do renal cysts change with age?

Increase in incidence

How does the cyst wall, echogenicity, septations, calcifications, and mural nodules appear on renal imaging for simple cysts?

Cyst wall - Thin

Echogenicity - Anechoic

Septations - Absent

Calcifications - Absent

Mural nodules - Absent

How does the cyst wall, echogenicity, septations, calcifications, and mural nodules appear on renal imaging for complicated cysts?

Cyst wall - Thick

Echogenicity - Internal echos from pus, hemorrhage, or protein

Septations - Present

Calcifications - Present

Mural nodules - Present

What increases the risk of complicated cysts being malignant? What imaging is needed?

Increases in modularity, septations, and vascularity increase risk of it being malignant

Need eval by contract CT or MRI

What are the two types of polycystic kidney disease?

ADPKD - Autosomal dominant polycystic kidney disease

ARPKD - Autosomal recessive polycystic kidney disease

How is ADPKD diagnosed? What isn't recommended?

If <40 years old

-3+ cysts between both kidneys

If 40-59 years old

-2 cysts in each kidney

If >60

-4 cysts in each kidney

Genetic testing expensive and not recommended

What are the renal clinical features of polycystic kidney disease? (4)

Can be silent and incidental finding on imaging

Larger cyst can cause pain or flank discomfort

Decrease GFR

ESRD based on cyst volume:kidney volume

What are the extra renal clinical features of polycystic kidney disease?

Liver cysts most common

Cysts in other abdominoperineal organs

Intracranial aneurysms that can lead to subarachnoid hemorrhage

How do liver cysts present? Who is most at risk?

Pain, early satiety, ascites, portal hypertension

More common in obese females

How should polycystic kidney disease be managed?

Delay progression to ESRD

Treat cyst infections with quinolones then aspiration if antibiotics not effective

Surgery may be needed for pain management

How should progression to ESRD be managed in polycystic kidney disease?

BP controlled to 110/70

Tolvaptan

What is medullary sponge kidney?

Inherited dilation of medullary collecting duct

Prone to recurrent stones

How is medullary sponge kidney diagnosed?

Intravenous pyelogram

What is alport syndrome?

Hereditary X linked mutation in type IV collagen in basement membranes

Affects kidneys, eyes, and inner ear

How does alport syndrome present? (4)

Hematuria constant and uninterrupted from birth

CKD progressing to ESRD in adolescence to middle age

Males often have hearing loss

Ocular lesions

How do ocular lesions present in alport syndrome?

Anterior lenticonus - Rare

-Diagnostic of Alport syndrome

Temporal retinal thinning - happens in nearly all Alport

-No change to vision

What is renovascular disease?

Unilateral/bilateral:

-Renal artery stenosis

-Syndromes resulting from disease of renal arteries reducing blood flow to kidneys

What can renovascular disease cause? (4)

Renovascular hypertension

Ischemic nephropathy (decreased GFR due to decreased perfusion)

Fibromuscular dysplasia

Atherosclerosis

What is fibromuscular dysplasia (FMD)?

Medial fibroplasia of renal artery presenting as early onset hypertension between 15-50

More common in females

What is the most common cause of renovasular hypertension? What can it lead to ?

Atherosclerotic renovascular disease affecting proximal renal arteries

More common in older males

Can lead to CKD and ESRD due to ischemic nephropathy

How does renovascular hypertension happen? Why does renovascular disease cause CKD?

Activation of mechanisms to defend renal perfusion and GFR

-Associated with hypokalemia

Ischemic renal parenchyma that can lead to renal fibrosis and atrophy

When should renovascular disease be suspected? (4)

Premature hypertension

Resistant hypertension

Hypertension with hypokalemia

Rise in creatinine >30% after starting ACE/ARB

-Due to excessive drop in intraglomerular pressure and GFR

How is renovascular disease diagnosed?

Renal artery dopplers

MRA of renal vessels

Renal angiography

How is renovascular disease treated?

Medicines to treat hypertension

Revascularization

-PTCA and stenting for resistant hypertension or decresed GFR

-Always done for FMD