Nephrology

Question 1

Acute Interstitial Nephritis

Answer 1

Causes 25% of drug induced AKI.

Causes - penicillin, rifampicin, NSAIDs, allopurinol, furosemide, SLE, sarcoid, Hanta virus, staph

= fever, rash, arthralgia, renal impairment, HTN

Inv - eosinophilia, sterile pyuria, WC casts

TIN with Uveitis
= young females, fever, weight loss, painful red eyes
Inv - leukocytes and protein

Question 2

Acute Tubular Necrosis

Answer 2

Most common cause of AKI, reversable in early stages

Causes
Ischaemic - shock, sepsis
Nephrotoxins - aminoglycosidess, myoglobin (rhabdomyolisis), radiocontrast, lead

= oligouric phase, polyuric, recovery

Inv. - urea, creatinine, K, muddy brown casts

Question 3

Acute Tubular Necrosis vs Pre-renal Uraemia

Answer 3

-Poor reabsorption of Na and water in ATN but low osmolarity as a lot more water relative to Na
-In pre-renal uraemia, the kidneys hold on to Na to preserve volume

Urine sodium - pre-renal (v), ATN (^)
Urine osmolarity - pre-renal (^), ATN (v)
Fluid challenge - pre-renal (good), ATN (poor)
Urea:creat - pre-renal (^), ATN (normal)

Question 4

ADPKD

Answer 4

Type 1 - 85%, Chr 16, earlier renal failure
Type 2 - 15%, Chr 4

= HTN, recurrent UTI, abdo pain, renal stones, haematuria, CKD, liver cysts, berry aneurysms

Screening using abdo US = two cysts <30yrs, two cysts bilaterally <60yrs, four cysts bilaterally 60+

-> Tolvaptan (vasopressin 2 antagonist, slows progression)

Slightly increased risk of RCC

Question 5

ARPKD

Answer 5

Less common, Chr 6 (fibrocystin)

= (infancy) abdo mass, renal failure, Potter’s syndrome 2nd to oligohydramnios, liver fibrosis

Diagnosed on prenatal US, biopsy (lesions at right angle to cortical surface)

Question 6

Alport’s

Answer 6

X linked dominant, more severe in males

Defect in T4 collagen = abnormal GBM

= (childhood) microscopic haematuria, renal failure, bilateral SN deaf, lenticonus (lens protudes into ant. chamber), retinitinis pigmentosa

Inv - biopsy (splitting of lamina densa, basket weave), genetic testing

Question 7

Amyloidosis

Answer 7

Extracellular deposition of amyloid

Inv. - congo red staining gives apple green birefringence, serum amyloid precursor scan, biopsy (skin, rectum, abdo)

Question 8

Goodpasture’s (anti-GBM)

Answer 8

Anti-GBM Ab against T4 collagen, small vessel vasculitis

RF - 2M:F, peak in 20s and 60s

= pulmonary haemorrhage, rapidly progressive GN (protein and blood)

Inv - biopsy (IgG deposits along GBM), raised transfer factor

-> plasma exchange, steroids, cyclophosphamide

Question 9

AV Fistula

Answer 9

Direct connection between artery and vein, 6-8wks to develop

Preferred access for haemodialysis

Comp - infection, thrombosis, stenosis, steal syndrome

Question 10

Diabetetes Insipidus

Answer 10

Cranial (v ADH secretion by pit)
Causes - idio, head injury, pit surgery, sarcoid, haemochromatosis, craniopharyngioma, DIDMOAD

Nephrogenic (insensitivity to ADH)
Causes - lithium, ^Ca, v K, genetic (aquaporin)

= polyuria, polydipsia, high plasma osmolarity vs low urine osmolarity, water deprivation test

-> desmopressin for cranial, thiazides and low salt for nephro

Question 11

EPO

Answer 11

Hematopoietic growth factor, for production of RBCs

Used in CKD, chemotherapy

SE: accelerated HTN (encephalopathy, seizures), bone aches, flu-like, rash, pure red cell aplasia (Ab against EPO), thrombosis (^PCV), iron def

If not responding to EPO, think iron def

Question 12

Renal Artery Stenosis

Answer 12

2nd to atherosclerosis, 10% fibromuscular dysplasia (^^F)

Link - takayasus arteritis

= HTN, flash pulmonary oedema, AKI after ACEi

Question 13

Focal Segmental Glomerulosclerosis

Answer 13

Nephrotic, young adults

Causes - idio, HIV, heroin, Alport’s, sickle cell, 2nd to IgA nephropathy

Inv - biopsy (FS sclerosis, effacement of feet)

-> steroids +/- IS

*high recurrence after renal transplant

Question 14

Haemolytic Uraemic Syndrome

Answer 14

Thrombosis in small blood vessels leads to thrombocytopenia and haemolysis

Causes - Shiga toxin-producing E.coli 0157, pneumococcal, HIV

= kids, AKI, microangiopathic hemolytic anemia and thrombocytopenia

Inv - FBC, U&Es, blood film (schistocytes, helmet cells), negative coombs, stool culture

-> supportive (fluids, blood, dialysis)
NO Abx

Question 15

HSP

Answer 15

IgA mediated small vessel vasculitis, self-limiting, overlaps with IgA nephropathy

= child post-infection, palpable purpuric rash, over bum/ extensors, local swelling, abdo pain, polyarthritis

Inv - monitor BP and urinalysis

-> analgesia, supportive

Question 16

IgA Nephropathy

Answer 16

Bergers disease

Commonest cause of GN in world

= young man, macroscopic blood 1-2d after URTI, no proteinuria

-> ACEi if persistent proteinuria

Question 17

Membranoproliferative GN

Answer 17

Also called mesangiocapillary

Type 1 - 90%, linked to Hep C, biopsy (immune deposits, tram-track)

Type 2 - dense deposit disease, low C3, C3b nephritic factor, biopsy (dense deposits)

Type 3 - linked to hep B and C

-> steroids

Question 18

Membranous GN

Answer 18

Commonest GN in adults, 3rd most common cause of ESRF

Causes - idio (APL Ab), cancer (prostate, lung, lymph), penicillamine, NSAIDs, AI, hep B, malaria, syphilis

Inv - biopsy (spike and dome EM)

-> all get ACEi/ ARB, if severe give steroids + cyclophosphamide

1/3 spont remit, 1/3 remain proteinuric, 1/3 ESRF

Question 19

Minimal Change Disease

Answer 19

Most common GN in kids (75%)

Causes - ^^idio, NSAIDs, rifampicin, Hodgkin’s, thymoma, glandular fever

= nephrotic, normal BP, selective proteinuria (mid-size, albumin/ transferrin)

Inv - normal LM, fusion of podocytes/ foot effacement EM

-> PO steroids

1/3 have one episode, 1/3 infrequently relapse, 1/3 frequent

Question 20

Nephrotic Syndrome

Answer 20

Proteinuria - >3g / 24hr
Low albumin - <30
Oedema

• Loss of AT-3 and protein C = thrombosis
• Loss of thryoxine binding globulin = v total but not free thyroxine levels
• ^hepatic lipogenesis due to falling oncotic pressure = high cholesterol

Question 21

Contrast Nephrotoxicity

Answer 21

25% inc in creatinine within 2-5d of contrast

RF - known renal issues, >70yrs, dehydration, HF, NSAIDs

Prevention - IV 0.9% NaCl at 1ml/kg/hr for 12 hours before and after

If at high risk, stop metformin for 48hrs before and until renal function is normal

Question 22

Post Strep GN

Answer 22

7-14 days after group A hemolytic strep - pyogenes

Immune complex deposition in glomerulus causing acute diffuse proliferative GN

= young children, headache, malaise, haematuria, oedema (proteinuria), oliguria, HTN

Inv - v C3, ^ASO, biopsy (subepithelial humps EM, granular/ starry sky IF)

Question 23

Rapidly progressive GN

Answer 23

Rapid loss of renal function associated with epithelial crescents in glomeruli

Causes - Goodpasture’s, Wegener’s, SLE, microscopic polyarteritis

= nephritic syndrome (blood, protein, oliguria, HTN)

Question 24

Renal papillary necrosis

Answer 24

Causes -
Severe acute pyelo
Diabetic nephropathy
Obstructive nephropathy
Analgesic nephropathy (NSAIDs)
Sickle cell anaemia

= macro haematuria, loin pain, proteinuria

Question 25

Graft rejection

Answer 25

HLA system is the major histocompatibility complex in humans, Chr 6 Most important HLA is DR then B then A Post-op complications - ATN of graft, vascular thrombosis, urine leak, UTI Hyperacute (min-hrs) Pre-existing Ab against ABO or HLA, T2HS, widespread thrombosis -> Need to remove Acute (<6months) HLA mismatch, cell-mediated = no symptoms, ^creat, pyuria, proteinuria -> steroid/ IS Chronic (>6m) Ab and cell-mediated, fibrosis Post-transplant IS- monitor BP, glucose, lipids, renal function, risk of SCC and BCC

Question 26

Rhabdomyolysis

Answer 26

Skeletal muscle breaks down, releases breakdown products into blood (myoglobin, potassium, phosphate and CK) RF - fall, seizure, marathon runner, statins (w/ clarithro), crush = AKI (^^creat), 5x normal CK, myoglobinuria (dark, dip +blood), v Ca (binds myoglobin), ^K, ^phosphate, met acidosis -> IV fluids, urinary alkalinization

Question 27

Dipstick +blood

Answer 27

Transient UTI, period, vig. exercise, sex Persistent Cancer, stones, BPH, prostatitis, urethritis (chlamydia), kidney problems Red but not +blood = beetroot, rifampicin, doxorubicin

Question 28

Stauffer Syndrome

Answer 28

Paraneoplastic disorder, 5% of RCC ? ^IL6-> hepatic dysfunction (cholestasis, hepatosplenomegaly) = sudden RUQ pain, nausea, jaundice and deranged LFTs

Question 29

Drugs to Stop in AKI

Answer 29

Diuretics ACEi/ ARB Metformin (risk of toxicity) NSAIDs - keep aspirin 75mg Lithium (risk of toxicity) Aminoglycosides Digoxin (rick of toxicity)

Question 30

RRT Indications

Answer 30

A - Acidosis E - Electrolytes (^K) I - Intoxicants (lithium, salicylate) O - Overload U - Uraemia (pericarditis, encephalopathy)

Question 31

Renal Tubular Acidosis

Answer 31

^Cl metabolic acidosis due to renal tubular pathology (normal anion gap) Type 1 Causes - RA, SLE, Sjogren's, NSAIDs Distal tubule unable to excrete H+, loss of K = hyperventilation, FTT, renal stones -> treat with bicarbonate Type 2 Causes - Fanconisyndrome, Wilson, acetazolamide Prox tubule can't reabosorb bicarb, loss of K = osteomalacia Type 3 Mixed, extremely rare Type 4 (most common) Causes - hypoaldosteronism, DM Reduced proximal ammonium excretion, ^K -> fludrocortisone and bicarbonate

Question 32

Causes of AKI

Answer 32

Prerenal (most common) Inadequate blood supply to kidneys - hypovolemia, renal artery stenosis Renal Intrinsic damage (only one with proteinuria) - GN, AIN, ATN, rhabdomyolysis, tumour lysis - gentamicin if prev. treatment for UTI Post-renal Back pressure reduces function of the kidney - renal/ ureteric stone, BPH, external compression of ureter

Question 33

Common causes of CKD

Answer 33

DM HTN Age PCKD Meds - NSAIDs, PPI Glomerulonephritis Chronic pyelonephritis

Question 34

Anaemia of CKD

Answer 34

Causes - v EPO production, v iron absorption Normocytic normochromic anaemia, usually when GFR<35 -> check iron status, EPO

Question 35

Renal Bone Disease

Answer 35

In CKD there is; High phosphate - can't excrete it Low Active Vit D - can't activate it Low calcium -- lack of vit D and high phosphate Secondary PTH - due to all 3 above, ^osteoclast Osteomalacia: vit D def, increased bone turnover without enough calcium Osteosclerosis: compensatory osteoblast^ but not mineralised properly Rugger jersey spinal XR (sclerosis of ends of vertebral body, malacia in centre) -> v phosphate in diet, phosphate binders (SE: ^Ca, vascular calcification), vit D (alfacalcidol), parathyroidectomy

Question 36

Common Nephrotic syndromes

Answer 36

Minimal change Membranous Focal segmental GS Diabetic Amyloid

Question 37

Common nephritic

Answer 37

Rapidly progressive GN IgA nephropathy Alport Overlap - Diffuse proliferative, membranoproliferative and post strep

Question 38

Extra renal manifestations of PKD

Answer 38

Cerebral aneurysms Hepatic, splenic, pancreatic, ovarian cysts MR Colonic diverticula Aortic root dilatation, dissection Abdominal wall hernia

Question 39

AKI Staging

Answer 39

Diagnose if ^creat by 26+ in 48hrs OR ^creat by 50%+ in 7 days OR urine output <0.5ml/kg/hour for >6hrs Staging 1 - creatinine increase ≥ 1.5-1.9 x baseline OR urine <0.5ml/kg/hr for 6 hours 2 - creatinine ≥ 2-2.9 x baseline OR urine <0.5ml/kg/hr for 12 hours 3 - creatinine ≥ 3 x baseline OR creatinine increase to ≥ 354 OR urine <0.3ml/kg/hr for 24hrs OR RRT

Question 40

CKD - classification

Answer 40

1) eGFR >90 (must be other evidence of damage e.g., U&Es/ proteinuria) 2) 60-90 + other evidence 3a) <60 3b) <45 4) <30 5) <15 (failure - need dialysis or transplant) eGFR based on serum creatinine, age, sex, ethnicity - effected by pregnancy, muscle, red meat

Question 41

CKD - Extras

Answer 41

HTN -> ACEi (investigate if GFR reduces >25% or creatinine rises >30%), furosemide Proteinuria Albumin: creatinine, first pass morning -> refer 70+ or 30 + haematuria, ACEi and SGLT2 inh Most CKD patients have bilaterally small kidneys (excl. early DM, PCKD, amyloid)

Question 42

Diabetic Nephropathy

Answer 42

Annual albumin: creatinine (early morning) -> ACEi if 3+, v protein, control glucose, statins BP drugs if >135/85 (or 130/80 in T1 w/ albuminuria) - aim for 140/90