URINARY ABNORMALITIES
الدكتور خلدون ذنون- كلية طب نينوى- المرحلة الرابعةObjectives
The following topics is essential to be known by the student:
1. Urine volume abnormalities.
2. Diagnosis and causes of heamaturia.
3. Causes, types, significance and diagnosis of proteinuria.
4. Definition of nephrotic syndrome, causes and management.
Disorder of urine volume
Anuria: No urine output caused by acute vascular occlusion & total UT obstruction.
Oliguria: urine volume<500ml/24hr e.g dehydration, ARF.
Polyuria: urine volume>3L/24hr.e.g excess fluid intake, osmotic (hyperglycaemia), cranial diabetes insipidus, nephrogenic DI (genetic, drugs & toxin e.g lithium, diuretic, hypercalcaemia, Interstitial renal disease).Haematuria Bleeding from the kidney&UT.
Causes: clotting disorder, renal cyst, tumours,vascular malformation, glomerular disease, interstitial renal disease, stones, UTI, trauma.Normal individual have occasional RBC in urine &also during menstruation.
Persistent haematuria is abnormal.
Macroscopic haematuria mainly caused by tumours.
Dipstick test can detect 15 RBC/ml urine.
Urine exam. is important to establish the cause of haematuria.i.e WBC+ bacteria = infection, Dysmorphic RBC+ RBC cast =glomerulonephritis.
It may be seen after strenuous exertion.
Causes of red or dark urine
Haematuria
Haemoglobinuria
Myoglobinuria in rhabdomyolysis.
Food dyes: beet root.
Drugs: phenolphthalein, senna, rifampicin, levodopa.
Porphyria
Alkaptonuria
Isolated microscopic haematuria
Normal renal function, no hypertension, insignificant proteinuria.
Causes
Thin GBM disease: autosomal dominant, benign condition.
Alports synd., IgA nephropathy, vascular malformation.
Renal cysts & stones.
Nephritic syndrome
Haematuria, edema & fluid retention, hypertension,oliguria. Caused by many types of glomeulonephritis.Proteinuria
Low molecular weight (LMW) protein are normally filtered at the glomerulus & reabsorbed by tubular cells, <150mg/day lost in urine.LMW protein >150mg indicate tubular proteinuria e.g B2-microglobulin, rarely exceeds 1.5-2gm/24hrs, if>2gm indicates glomerular disease.
Glomerular lesion lead to filtration of large MW protein e.g albumin as in diabetic nephropathy.
Normally <30mg/24hr albumin is lost in urine. Microalbuminuria 30-300mg/24hr occurs in D.M associated with (risk of atherosclerosis.
Albuminuria >3.5gm/24hr indicate nephrotic syndrome.
Minor albuminuria occurs in: vigrous exercise, fever, & heart failure.
Orthostatic proteinuria occurs during the day, benign .
Bence jones proteinuria due to clone of B lymphocytes & plasma cells secrete IG light chain detected by IEPH occurs in amyloidosis & myeloma.
Urine protein mg/L ( urine creatinine mmol/L ratio <2.5-3.5 mg/mmol done on single sample of urine is an indicator of protein loss in urine/24hr instead of 24hr urine collection.
NEPHROTIC SYNDROME
Generalized oedema, S.albumin( 30gm/L, proteinuria ( 3.5 gm/24hrs.
Main causes of NS
Neonates: congenital.Caucasian children: minimal change nephropathy.
Black children: focal & segmental glomerulosclerosis.
Adults: membranous nephropathy & focal and segmental glomerulosclerosis.
Mesangiocapillary GN.
SLE.
Diabetic nephropathy.
Amyloidosis.
Features & complications
Generalized oedema due to Na & water retention( oedema of face, legs, hands, genital areas, ascites, pleural effusion. Blood volume may be normal,(or (.Hypercoagulability ( venous thromboembolism, due to loss of inhibitors of coagulation &(production of coagulation factors.
Hypercholesterolaemia ( occlusive arterial disease.
Hypogammaglobulinaemia ( pneumococcal infections.
Management
Find the cause & treat it.NS in children needs high dose steroid.
Adults need renal biopsy except in: D.M, hypertension without haematuria.
Low Na diet & diuretics, in severe edema loop diuretics are combined with thiazides & amiloride.
Salt poor albumin i.v: given in hypovolaemia, cause diuresis.
Anticoagulation in chronic and severe NS.
Lipid lowering drugs(HMG-CoA reductase inhibitors).
Treat infections & immunise against pneumococci.