nephrotic syndrome

aetiology

glomerulonephritis (GN) - 80% of cases
metabolic causes:
- diabetes mellitus
- amyloidosis
- lymphoma
- neoplasia / cancer / tumours esp. lung cancer
- multiple myeloma
- dermatoses
- HbS
- myxoedema
collagen vascular disorders eg. systemic lupus erythematosus (SLE), polyarteritis nodosa (PAN)
infection
- malaria
- cytomegalic inclusion disease
- syphilis
- infective endocarditis (including SBE)
- staphylococcus
- leprosy
mechanical:
- renal artery stenosis
- renal vein thrombosis
- IVC thrombosis
- constrictive pericarditis
- renal malignancies
- chyluria
drugs - gold, mercurials, penicillamine
hypersensitivity - serum sickness, smallpox vaccination
congenital and familial

CXR
ECG
FBE, U&E, LFTs, glucose as initial investigations and consider venous blood gas and ketones in diabetic
FWT urine looking for protein, blood, casts
- normal urinary albumin is less than 25mg/dL
- early morning spot urine protein:creatinine ratio (typically > 3-3.5mg protein to mg creatinine
start strict fluid balance chart
daily weigh
avoid transfusing with serum albumin as likely to just leak out into urine
blood pressure control eg. GTN patch, oral ACE inhibitors
if fluid overloaded consider starting low dose bd frusemide - consider iv rather than oral as GIT absorption may be impaired and diuretic efficacy is impaired BUT risk of otoxicity is higher than usual
once nephrotic syndrome confirmed by low serum albumin and high urinary protein:
- MSU m/c/s including phase contrast micro, protein:CRN ratio
  - normal urinary albumin:CRN ratio is < 2.5mg/mmol CRN
- 24hr urine for protein, free light chains, protein electrophoresis, Bence-Jones proteins
- CT KUB and/or renal USS
- discuss with nephrology and consider sending bloods for:
  - HbA1c (if diabetic)
  - Hb electrophoresis
  - serum light chains
  - Ca, Phosphate, Mg, TSH
    - if hypocalcaemia then also do PTH, 25OH vit D
  - coagulation profile
  - HIV, HepB/C if at risk
  - uric acid, CK, fasting lipids
  - ESR, CRP, ANA
    - if ANA +ve then consider: dsDNA, ENA, rheumatoid factor, ANCA, C3/4
- admit under nephrology