Week 3 - A - Pathology 1 - Glomerulonephritis and Pyelonephritis (and renal function scans)) Flashcards
What is the renal parenchyma?
The renal parenchyma is the functioning part of the kidney that filters blood and makes urine
What is the difference between glomerulonephritis and pyelonephritis?
Glomerulonephritis is non-infective inflammation of the glomerular tufts leading to glomerular dysfunction
Pyelonephritis is infection in the kidneys
Glomerulonephritis primarily starts in the glomerular tufts before affecting other areas, where is affected secondarily?
In then goes on to have tubelointerstitial changes
There are a variety of different types of glomerulonephritis which we will be taught about Which type of glomerulonephritis is associated with changes to podocytes?
This would be minimal change glomerulonephritis (effacement of podocytes)
Why does the effacement (wiping out) of the podocyte foot process occur and what does this cause?
Thought to occur due to T cells releasing cytokines
This causes the negatively charged podocyte foot processes to be wiped out and therefore cant repel large proteins like albumin leading to the proteinuria and hypoalbuminaemia
What is the most common type of nephrotic syndrome seen in children?
This is minimal change nephrotic syndrome
What is the anti-glomerular basement antibody syndrome features? What is the syndrome known as?
Goodpasture’s syndrome
Glomerulonephritis and alveolar pulmonary haemorrhage causing haemoptysis
Pyeloneprhtiis is Bacterial infection of renal pelvis, calyces, tubules and interstitium.
What is the most common causative organism?
Escherichia coli
Pyeloneprhitis is usally caused by coliforms, name 2 of the coliforms and describe the distribution of infection?
Escherichia coli
Klebsiella pneumoniae
The infection of the kidneys usually has a patchy distribution
What other organ is also usually infected in pyelonephritis due to the ascending infection?
Cystitis - bladder
Why are girls more likely to get urinary tract infection? Why are pregnant women also more likely to get pyelonephritis?
They have a shorter urethra (4cm compared to 20cm)
Pregnant women have ureteric dilatation and therefore infection can more likely reach the kidneys
Any urinary tract obstruction can increase the chances of pyelonephritis Name some causes of urinary tract obstruction?
Renal caliculi
Prostatic hyperplasia
Strictures (in ureter)
Tumour, within or pressing on urinary tract
Congenital condition in which urine flows retrograde, or backward, from the bladder into the ureters/kidneys. (can be congenital, primary or it can be secondary due to ostruction)
This is known as vesicoureteric reflux - congenital is due to valves not closing properly leading to backflow of urine
The reflux can lead to infection and cause scarring of the bladder What can this scarring lead to?
Scarring can lead to secondary hypertension
What is one other condition that may predispose to pyelonephritis? Affects the sugar levels
Diabetes
Characterized by renal inflammation and fibrosis induced by recurrent or persistent renal infection, vesicoureteral reflux, or other causes of urinary tract obstruction. The persistent infection can cause bad scarring What is this?
Chronic pyelonephritis - can lead to acute kidney injury
Large histological section of kindey in pyelonephritis- emphasizes how patchy pyelonephritis is What inflammatory cells are circled here?
The neutrophils
How is tuberculosis spread?
Spread via the haematogenous route
In tuberculous pyelonephritis, what are the presenting features?
Haematuria, loin pain
Which part of the kidney is usually affected by tuberculous pyelonephritis?
The renal parenchyma is usually affected
Renal TB is most commonely found with pyuria (pus in urine) in the absence of other common bacteria What bacteria causes TB? Describe TB lesion?
Most usually caused by mycobacterium tuberculosis
It is a caseating granulomatous inflammation (cheesy necrosis)
Mycobacterium may be seen on histology using special stains What is this stain known as?
Zeehl-Neilsen stain
Absence does not exclude TB
What is the large lesion at the bottom right of the right hand pic?
This would be a large caseous mass
What is inflammation of the bladder known as and what usually causes it?
It is known as cystitis
Usually caused by coliforms such as Klebsiella, proteus and pseudomonas
What is the common presenting complaint of a UTI?
Painful haematuria usually with signs of a fever
multiple small fluid filled cysts projecting into lumen of the bladder What is this type of cystitis?
This is known as ureteritis cystica (cystitis cystica)
Why is it important to biopsy cystitis cystica?
To differentiate from tumours
This is cystitis cystica on US but need to biopsy to differentiate
Tuberculosis; follows renal disease. Urinary spread of mycobacteria. What parasite – found in many tropical countries particularly in Egypt These can predispose to urothelial malignancy? What is the type of urethelial malignancy commonly?
This is Schistosomiasis
Can predispose to squamous cell carcinoma
Can see the egg deposits of Schistosomiasis in SCC
Urethral obstruction usually confined to males. Stricture, posterior urethral valves, prostatic disease. How can the urethral obstruction lead to the fromation of diverticulum?
This is due to the hypertrophied detrusor muscle trying to push out urine and this can cause bladder diverticulum
Dilatation of pelvicalyceal system with parenchymal atrophy. Main causes are urinary tract obstruction and reflux. What is this?
This is hydronephrosis
When is hydronephrosis bilateral?
In urethral obstruction
Unilateral tends to be more caliculi or strictures
Due to the stasis of urine in hydronephrosis, what can often follow?
Pyelonephrosis can often follow
Pyelonephrosis -secondary infection to kidney (pyelonephritis) in hydronephrosis
Can see increased diameter of ureter and a very thin rim of cortex due to dilated renal calyces
What surrounds urethra between internal and external urethral sphincter? (in men)
The prostate gland
What does a benign vs malignant enlargment of prostate feel like?
Benign feels like smooth and can have either a unilateral or bilateral enlargemnt
Malignant feels nodular/bumpy
How can GFR be measured accurately? (creatinine provides an estimate)
Inulin clearance is gold standard as 100% is filtered in the urine - however requires urine collection over several hours so is inconvenient
Radioisotope scans - inject radioisotope eg
* 51Cr-EDTA and then measure blood levels can be used to estimate GFR with high accuracy
* 99mTc-DTPA and then carry out an isotope scan
State what each of the following scans are used for when assessing renal functioning: (these are randionuclide renal scans) * Tc99m-MAG3 renogram (MAG3 is also called mercaptoacetyltriglycine) * Tc99m-DMSA scan (Dimercaptosuccinic acid)
MAG3 renogram - assesses drainage / flow of urine (useful for assessing recurrent UTIs in children)
DMSA scan - gold standard for assessing renal scarring eg from vesicoureteric reflux causing reflux nephropathy
