RENAL Flashcards
Triad of HUS?
AKI
Microangiopathic haemolytic anaemia
Thrombocytopenia
What causes HUS?
Most causes are typical HUS which is secondary to shiga toxin producing E.Coli 0157:H7
Can also be secondary to pneumococcal infections, HIV, SLE, drugs and cancer
Primary HUS is rare and is due to complement dysregulation
Investigations necessary for HUS?
FBC to look for anaemia and thrombocytopenia
Coombs test -should be negative
Blood film - shows schistocytes and helmet cells
U&Es for AKI
Stool culture looking for evidence of STEC infection. PCR for shiga toxins
Tx of HUS?
Hospital admission!
Supportive - IV fluids, blood transfusion, dialysis
Self-limiting - most pts fully recover!
Plasma exchange if very severe HUS and not associated with diarrhoea
Eculizumab has some evidence that its greater than plasma exchange alone in treatment of adult atypical HUS
What increases the risk of HUS?
Children <5
Using antibiotics or antimotility meds if STEC is suspected (e.g. loperamide) to try to Tx the gastro
Pathophysiology of HUS?
Formation of blood clots = consumes platelets = thrombocytopenia
Thrombi & damaged RBCs = affect blood flow through kidney = AKI
Haemolysis of RBCs due to thrombi partically obstructing small blood vessels = causes churning of the RBCs and rupture
Management of ascites?
- Reduce dietary sodium or ff sodium is low (<125) = fluid restrict
- Aldosterone antagonist e.g. spironolactone (if they don’t respond add a loop diuretic)
If tense ascites - therapeutic abdominal paracentesis (if large volume >5L then albumin cover is needed
If ascetic protein is <15 = prophylactic ABx to reduce risk of SBP
TIPS can be considered
Outline the management of proteinuria in CKD?
Dietary protein restriction, tight glycaemic control & manage hypertension and hyperlipidaemia
If pt has diabetes and ACR >=3 = SGLTi
If they dont have diabetes…
ACR 30-70 and hypertension = ACEi/ARB
ACR >70 = ACEi/ARB regardless of bp
How do ACEi and ARBs treat proteinuria in CKD?
ACEi inhibits the conversion of angiotensin 1 to angiotensin 2 whilst ARBs block angiotensin 2 from binding to its receptor. This leads to dilation of the efferent arteriole, reducing intraglomerular pressure and the amount of protein leaking into the urine = decreases the hyperfiltration injury
How do SGLT2i treat proteinuria in CKD?
Blocks the sodium-glucose cotransporter in the proximal tubule, leading to increased Na+ delivery to the macula densa = triggers tubuloglomerular feedback causing afferent arteriolar construction and reducing intraglomerular pressure = minimises proteinuria
Pathophysiology of diabetic nephrology?
Causes a nephrotic syndrome!
Diabetes causes non-enzymatic glycation which damages the blood vessels = thickens capillary basement membrane by increased deposition of type 4 collagen and causes atherosclerosis of arterioles = increases permeability of vessels & tublar cells to proteins
Osmotic damage to glomerular capillary epithelium = thickening of capillary basement membrane by deposits of type 4 collagen = diffuse mesangial sclerosis +/- kimmelstiel-Wilson nodule
Affects efferent arteriole before afferent arterioles = increased GFR = hyperfiltration injury = protein loss
Typical causes of focal segmental glomerulosclerosis?
HIV - most important to remember
Drugs e.g. anabolic steroids
Heroin
Alports syndrome
Sickle cell
Secondary to other renal pathology
Idiopathic
Minimal change disease what age does it affect?
75% of cases are in children
25% in adults
Cause of minimal change disease?
90% of cases are idiopathic
Other causes:
Drugs - NSAIDs and rifampicin
Hodgkin lymphoma
Thymoma
Infectious mononucleosis
Management of minimal change disease?
Low salt diet to stop body retaining any more fluid
80% of cases respond to oral corticosteroids
Cyclophosphamide is second line
Prognosis of minimal change disease?
1/3 have just one episode
1/3 have infrequent relapses
1/3 have frequent relapses which stop before adulthood
What is the difference between primary and secondary hyperaldosteronism?
Primary - adrenal glands directly responsible for producing too much aldosteronism so serum renin will be low as hypertension suppresses it
Secondary - there is a disproportionately lower bp in the kidneys = excessive renin stimulates the release of excessive aldosteronism
Causes of primary hyperaldosteronism?
B/L adrenal hyperplasia - most common
Conns syndrome - an adrenal adenoma secreting aldosterone
Rarely can be familial
Causes of secondary hyperaldosteronism?
Renal artery stenosis
HF
Liver cirrhosis and ascites
Investigations for hyperaldosteronism?
BP
Bloods - U&Es look for low K+. Blood gas look for alkalosis
Aldosterone-to-renin ratio (ARR)
CT or MRI to look for adrenal hyperplasia or tumour
If ?RAS - Renal artery Doppler/CT angio or MR angio
Adrenal vein sampling can be done from both adrenal veins to locate which gland is producing more aldosterone
Management of hyperaldosteronism?
Aldosterone antagonists e.g. eplerenone and spironolactone
Treat undelryign cause e.g. surgical removal of adrenal adenoma or a percutaneous renal artery angioplasty for RAS
Most common cause of secondary hypertension?
Hyperaldosteronism
What is anti-GBM disease?
A rare type of small-vessel vasculitis associated with pulmonary haemorrhage and rapidly progressive glomerulonephritis
Caused by anti-GBM antibodies against type 4 collagen
Associated with HLA DR2 and more common in men
Investigations when considering anti-GBM disease?
Bloods - U&Es, measure antiGBM antibody level, ANCA, complement 3&4 levels, ANA, anti-streptomycin O titre to rule out PSGN, clotting screening necessary before renal biopsy
Renal biopsy with immunofluorescence will show linear IgG deposits along the basement membrane
Raised transfer factors secondary to pulmonary haemorrhage
Management of anti-GBM disease?
Oral corticosteroids & Plasma exchange
Consider cyclophosphamide
What is the most impprtant complication of anti-GBm disease?
What makes this more likely to occur?
Pulmonary haemorrhage
Smoking, LRTI, pulmonary oedema, inhalation of hydrocarbons, young males
Pathophysiology of anti-GBM disease?
Auto-antibodies that attack the GBM and alveoli due to the presence of the type 4 collagen in both of these structures = rapidly progressive glomerulonephritis & pulmonary haemorrhage = haemoptysis and haematuria
Risk factors for bladder cancer
Males aged between 50-80
Smokers
Exposed to hydrocarbons
Pelvic radiation
Cyclophosphamide
Chronic bladder inflammation from a schistosomiasis infection, log term catheters or recurrent UTIs
Whats the most common type of bladder cancer?
Transitional cell carcinoma (90%)
Most common cause of squamous cell carcinoma bladder cancer?
Prolonged inflammation within the bladder e.g. schistosomiasis but also occasionally recurrent UTIs/long term catheters
This is why its more commonly seen in Africa and Asia
Referral criteria for ?bladder cancer?
> =45 with either unexplained visible haematuria or visible haematuria that persists/recurs after successful Tx of UTI
=60 with unexplained non-visible haematuria + either dysuria or raised WCC
Investigations for bladder cancer?
Urinalysis ans culture to exclude infection
FBC, U&Es
Urgent flexible cystoscopy
Consider CT or MRI staging scan
For complete diagnosis a transurethral resection of bladder tumour (TURBT) must be done to get a histological analysis
Management of bladder cancer?
If non-muscle invasive - may only need TURBT, may need some intra-vesicle chemotherapy
If muscle-invesive - neoadjuvant chemo & radical surgery e.g. radical cystectomy. More modern approaches now recommend TURBT & chemo & radiotherapy and suggest a similar prognosis to radical cystectomy
How does contrast cause an AKI?
Contrast agents are directly nephrotoxic to renal tubular cells but they can also alter the vasoactive substances such as renin, angiotensin etc -? Reduces glomerular blood flow
Definition of contrast media nephrotoxicity?
25% increase in Cr occurring within 3 days of IV administration of contrast media