Tubulointerstitial Pathologies

Question 1

Acute tubulointerstitial nephritis clinical features

Answer 1

Presents with AKI
Biopsy shows inflammatory infiltrate in interstitium ± tubule
Residual CKD in up to 40%

Question 2

Acute tubulointerstitial nephritis causes

Answer 2

Drugs: Abx, NSAIDs, PPIs, diuretics, ranitidine, anticonvulsants, warfarin
Infection: Strep, Pneumococcus, Staph, Camplylobacter, E.coli, Mycoplasma, CMV, EBV, HSV, Hep A-C
Autoimmune: SLE, sarcoid, Sjogren’s, ANCA

Question 3

Acute tubulointerstitial nephritis treatment

Answer 3

Stop causative agent/treat underlying cause

Steroids used in practice but poor evidence

Question 4

Chronic tubulointerstitital nephritis features

Answer 4

Slowly progressive renal impairment

Biopsy shows interstitial fibrosis + tubular atrophy

Question 5

Chronic tubulointerstitital nephritis causes

Answer 5

Most commonly (70%) drugs: NSAIDs, lithium, calcineurin inhibitors, chemo, aminosalicyclates
Infection: TB, pyelonephritis, HIV
Immune disease
Nephrotoxins: lead, cadmium, mercury, aristolochic acid (plant poison)
Haem disorders (myeloma)
Genetic disease

Question 6

Chronic tubulointerstitital nephritis treatment

Answer 6

Stop/treat cause

Reduce progression risk as with CKD (BP, lipids etc)

Question 7

Nephrotoxic analgesics

Answer 7

NSAIDs

Question 8

Nephrotoxic antimicrobials

Answer 8

Aminoglycosides
Co-trimoxazole
Penicillins
Rifampicin
Amphotericin (anti fungal)
Aciclovir

Question 9

Nephrotoxic anticonvulsants

Answer 9

Phenytoin
Lamotrigine
Valproate

Question 10

Nephrotoxic other drugs

Answer 10

PPIs

Furosemide
Thiazides
ACEI/ARB

Lithium
Iron

Calcineurin inhibitors
Cisplatin

Question 11

Nephrotoxic anaesthetics

Answer 11

Methoxyflurane

Enflurane

Question 12

Nephrotoxic proteins

Answer 12

Igs/light chains in myeloma
Hb in haemolysis
Myoglobin in rhabdomyolysis

Question 13

Nephrotoxic crystals

Answer 13

Urate

Question 14

Nephrotoxic bacteria

Answer 14

Strep
Legionella
Brucella
Mycoplasma
Chlamydia
TB
Salmonella
Campylobacter
Leptospirosis
Syphilis

Question 15

Nephrotoxic viruses

Answer 15

EBV, CMV, HIV
Polyomavirus
Adenovirus
Measles

Question 16

Nephrotoxic parasites

Answer 16

Toxoplasma

Leishmania

Question 17

Nephrotoxic other items

Answer 17

Ethylene glycol
Radiation
Aristolochic acid (in plants)

Question 18

Analgesic nephropathy presentation

Answer 18

History of chronic painkiller use

Often silent until CKD

Question 19

Analgesic nephropathy diagnosis

Answer 19

Normal/sterile pyuria urine
Mild proteinuria
Small irregular kidneys on USS
IVU shows ‘cup and spill’ appearance
Non-contrast CT shows decreased renal mass + papillary calcification
Biopsy shows CTIN 2˚ to papillary necrosis

Question 20

Analgesic nephropathy treatment

Answer 20

Stop analgesia
Manage CKD
USS/CT urogram to exclude obstruction from sloughed papilla if sudden flank pain

Question 21

Aminoglycoside nephropathy presentation

Answer 21

Mild non-oliguric AKI after 1-2 wks aminoglycoside therapy

Question 22

Aminoglycoside nephropathy treatment

Answer 22

Prevention: single daily dose may be less nephrotoxic

Streptomycin least nephrotoxic, gentamicin most

Question 23

Radiocontrast nephropathy presentation

Answer 23

AKI 48-72hrs post IV contrast

Question 24

Radiocontrast nephropathy treatment

Answer 24

Prevention only
Pre-hydrate with IV crystalloid
Discontinue other nephrotoxics 24h pre + post procedure

Question 25

Rhabdomyolysis nephropathy pathology

Answer 25

Skeletal muscle breakdown contents increase cytokines and decrease nitric oxide so renal vasoconstriction Myoglobin filtered by glomeruli so obstruction + inflammation

Question 26

Rhabdomyolysis nephropathy presentation

Answer 26

Hx of trauma/ surgery/ immobility/ hyperthermia/ seizures Muscle pain/swelling/ tenderness AKI Red-brown urine

Question 27

Rhabdomyolysis nephropathy diagnosis

Answer 27

Serum myoglobin Plasma CK 5x upper limit Myoglobinuria false +ve for blood on dipstick with no RBC seen on microscopy Inc K+ and PO4, dec Ca

Question 28

Rhabdomyolysis nephropathy treatment

Answer 28

Supportive Urgently treat hyperkalaemia IV fluid rehydration + maintain urine output until myoglobinuria stops RRT may be needed

Question 29

Urate nephropathy pathology

Answer 29

Uric acid crystals precipitate within tubulointerstitium causing dec GFR + 2˚ inflammation Seen in tumour lysis syndrome

Question 30

Urate nephropathy treatment

Answer 30

Tumour lysis - aggressive hydration, allopurinol | Chronic disease - unclear evidence but diet/uric acid treatment may help

Question 31

Radiation nephritis presentation

Answer 31

6mths-1yr post irradiation Inc BP, protein/haematuria progressing to renal failure Prognosis linked to HT

Question 32

Radiation nephritis treatment

Answer 32

Decrease radiation dose with shielding (prevention) | CKD control measures

Question 33

Aristolochic acid nephropathy presentation

Answer 33

Disproportionate anaemia Mild proteinuria Renal dysfunction More common in Balkan areas where aristolochic acid detected in wheat

Question 34

Aristolochic acid nephropathy treatment

Answer 34

Avoid exposure Treat as CKD Screen for malignancy