Module 4: Renal: Blood Vessel Disorders Flashcards
The first topic of blood vessel disorders is Benign Hypertension. What is the gross and histology of this?
Long Standing HTN
Gross: Granular appearance of kidneys due to tubular atrophy (Effects are bilateral)
Histology: medial and intimal thickening –affects afferent arterioles – hyaline arteriolosclerosis via leakage of plasma proteins to tunica media
What are the most common cause of chronic benign hypertension
Most common cause of hyaline arteriosclerosis
–afferent arteriole
DM (but that does both arteriole) b/c remember sugar goes everywhere
What are the symptoms for chronic benign hypertension?
Generally asymptomatic with mild proteinuria
What are the complications for chronic benign hypertension?
Few progress to chronic renal failure
–renal artery stenosis: atherosclerotic plaques, atrophy of kidneys to chronic renal failure
Kidney appears granular/leathery
–tubular atrophy
Moving onto malignant hypertension. What is the gross and histological appearance of sudden malignant ?
Gross: greater than 180/120 with papilledema (cerebral edema)
–petechial hemorrhages in the kidney are called flea bitten kidney
Top Image: Necrotizing arteriolitis (fibrinoid necrosis) and again kidney has flea bitten appearance
–sudden malignant HTN get endothelial damage of afferent arteriole and you get thrombosis of the lumen (So thats why media is undergoing necrosis because lumen supplies the media with O2 so media is undergoing coagulative necrosis)
What is the histological appearance of long standing malignant HTN?
Bottom Image: Long standing — concentric due to hyperplasia of tunica media
–onion skin appearance or hyperplastic (proliferation of SM cells and intimal thickening)
What is the presentation for benign or malignant HTN?
Hematuria Oliguria Proteinuria Edema --most common in young black males
What are the complications of benign or malignant HTN?
Acute renal failure (organ damage develops in hours or days)
Cerebral Edema
Stroke
Aortic Dissection — heart failure (HTN is an important factor for the intima tear)
–affects the small vessels so anything is resulting of the burst of these vessels
Moving on to the thrombotic microangiopathies. What is the pathogenesis?
Abnormal platelet aggregation — thrombosis (fibrin) in arterioles/capillaries — microangiopathic hemolytic anemia (Schistocytes in PB smear)
The microvascular thrombi lead to what?
Ischemic injury to the kidneys, brain and heart
Patients with thrombotic microangiopathies present with what?
Thrombocytopenia Purpuric rash Acute renal failure Neurological abnormalities Fever
There are two types of Thrombotic Microangiopathies. The first one is hemolytic uremic syndrome (HUS), what is this associated with?
HUS: seen in children 1 week after bloody diarrhea caused by enterohemorrhagic E. Coli (0157:H7)
–more severe renal failure, less CNS involvement
HUS is associated with what?
Viral Infections
Shigella
Salmonella
HUS can be drug induced, by what drugs?
Quinine (tonic water) Gemcitabine Cyclosporine Ticlopidine Oral Contraceptives
The second thrombotic microangiopathies is thrombotic Thrombocytopenia Purpura (TTP), what are some features?
CNS involvement more pronounced, less severe renal failure
–associated with SLE, HIV, hematological malignancy
Moving on to the last blood vessel disorder is renal artery stenosis, what is the pathogenesis?
Occlusion of renal artery by atheromatous plaque — diffuse ischemic atrophy —- crowded glomeruli, atrophic tubules, interstitial fibrosis
Why is there no significant arteriosclerosis in renal artery stenosis?
b/c arterioles of the affected kidney is protected from transmission of high pressure due to stenotic renal artery
However in renal artery stenosis there is hypertensive arteriosclerosis in the contralateral kidney, why?
due to increased systemic pressure
What is the most common presentation for renal artery stenosis?
Most common presentation is asymptomatic b/c other kidney compensates
What are the complications of renal artery stenosis?
Renal Failure, HTN changes to heart, brain and retina
- -note: JG cells can sense hypo-perfusion to the kidney and release renin, leading to hypertension, which can cause a stroke or MI
- -if bilateral atrophy, then there is a back up of filtrates, decreased urine output (oliguria), decreased GFR and generalized edema
What do you see on investigation for renal artery stenosis?
Epigastric/flank bruit due to turbulent flow
US: asymmetrical kidney size (smaller on side of stenosis)
Doppler: measure blood flow velocities in renal arteries compared to aorta
Renal Arteriogram: Gold Standard
What is the treatment of renal artery stenosis?
Angioplasty and Stent
-indications: uncontrolled HTN, declining renal function (increased Cr) and recurrent pulmonary edema
Moving onto to cystic diseases of the kidney. First lets start with polycystic kidney disease. There is autosomal dominant and autosomal recessive. Lets first start with autosomal dominant. What is the pathogenesis?
Genetic mutations on PKD (polycystin gene) on chromosome 16 and 4 (PKD1 and PKD2) – bilaterally enlarged kidneys with multiple cysts in both kidneys
Where are the cysts from in polycystic kidney disease?
Born with cysts and they are asymptomatic and the origin in heterogenous (aka they can come from anywhere PCT, DCT, CD)
–as the kidney gets bigger the cysts get bigger
What is the presentation for polycystic kidney disease?
Bilateral Flank Pain/Mass (as the kidney gets bigger it stretches the capsule)
Hematuria (due to rupture of cysts)
Hypertension (kidneys enlarged, compress renal arteries this activates RAS system)
–however usually asymptomatic until the 4th decade of life
What extrarenal manifestations are seen in polycystic dominant kidney disease?
Hepatic cysts (NOT FIBROSIS) – most common extra renal manifestation
also get cysts in the pancreas and spleen
–intracranial aneurysms (aka berry aneurysms)
–mitral valve prolapse (problem in the spongiosa layer and accumulation of GAGs – hear a mid systolic click due to the diastolic murmur)
–diverticulosis (falsk shaped)
—aortic regurgitation
–inguinal hernia
What is seen on US for polycystic dominant kidney disease?
Multiple cysts in both kidneys (both are enlarged)
–cysts from both tubules and collecting ducts in the cortex and medulla
FISH to look for gene
What complications are seen with polycystic dominant kidney disease ?
Most common cause of death is Heart Failure or MI from HTN (hypertensive heart disease)
- -second most common cause of death is renal failure
- -can also get berry aneurysms but this is not very common leads to subarachnoid hemorrhage
Now moving on to Autosomal Recessive Polycystic Kidney disease. What is the pathogenesis?
Mutation in PKDH (fibrocystin gene) on chromosome 6 – enlarged cystic kidneys at birth
What is the origin of the cysts in polycystic recessive kidney disease?
Homogenous (only from CD and located in just the medulla)
What is seen in the babies with polycystic recessive kidney disease?
Amniotic Fluid is made by Urine therefore these fetuses are going to have very little amniotic fluid (oligohydraminos) b/c they have these cysts on the kidneys which is causing the malfunction in making urine
–leads to Potter’s syndrome
What is Potter’s Syndrome?
All due to a lack of amniotic fluid
- -pulmonary hypoplasia (Baby needs amniotic fluid for lungs to develop)
- –flat faces and low set ears (faces are compressed against the uterine wall)
- -malpositioning of the hands and feet (golf club appearance due to compression)
- –breach presentation (feet first)
What is the complications in these fetuses that have polycystic recessive kidney disease?
Die at birth from renal failure/pulmonary failure
- -if they survive birth, die from liver cirrhosis within the first few years of life. (causes cirrhosis instead of cysts in the liver)
- -note kids also get cirrhosis in alpha -1- antitrypsin deficiency
Next moving to Wilm’s Tumor, what are some general features?
Nephroblastoma (malignant mixed tumor) in children 2-5 years old
- -mutation in WT-1 and WT-2 tumor suppressor genes
- -tendency to metastasize early, especially to the lungs
What is the precursor lesion in Wilm’s Tumor?
Nephrogenic rests (abnormally persistent clusters of embryonal cells) --can be sporadic (unilateral) and familial (bilateral)
What is the presentation for Wilm’s Tumor?
Palpable abdominal mass, abdominal pain, tumor compresses renal vessels — JG cells secrete renin and lead to hypertension
What is seen on histology for Wilm’s Tumor?
Triphasic: all three are malignant
- -Blastemal: small, immature blue cells with high nuclear: cytoplasmic ratio
- -Stromal/mesenchymal: spindle shaped cells
- –Epithelial: defective tubules/glomeruli
What is the pathogenesis for Wilm’s Tumor?
Divergent Differentiation
–do a nephrectomy or may metastasize to lungs
Finally lets briefly discuss horseshoe kidney, what is the pathogenesis?
Ascent of kidney is limited by Inferior Mesenteric Vessels — fusion of lower poles of the kidneys
What conditions is horseshoe kidney seen in?
Edward (trisomy 18) and Turner’s Syndrome
What is presentation and complication of horseshoe kidney?
Presentation: asymptomatic
Complications: rare
–obstruction/kinking of the ureters –causes bilateral hydronephrosis (stones and infection)
–renal cell carcinoma
What does horseshoe kidney appear on gross?
Ureters are anterior instead of medial
