pathomechanisms of the most important renal symptoms and signs m. tatár Ústav patologickej...

Pathomechanisms of the most important renal symptoms and signs 

M. Tatár

Ústav patologickej fyziológie JLF UK

The most frequent symptoms and signs of renal diseases

• hematuria, lumbar pain, !proteinuria!

• polyuria and polydipsia, oliguria and anuria, dysuria

• edema, renal encephalopathy

Glomerular disorders

proteinuria hematuria

Proteinuria • Prerenal

higher plasmatic concentrations of low molecular proteins: tissue degradable products, proteins of acute phase (fever), myoglobin in rabdomyolysis, light immunoglubulin chains in myeloma

• Glomerular

protein leak through GBM; selective, nonselective

• Tubular

excretion of low-molecular proteins (1-microglobulin, 2-microglobulin) with resorption in proximal tubule

• pyuria and hematuria could mimic proteinuria

Proteinuria

• Healthy adult subject : 150 mg/24hplasma proteinsproteins from urinary tract

• Intensity1g/24 h – small proteinuria3.5 g/24 h - proteinuria accompanying nephrotic syndrome (10-30 g/24 h)

Hematuria

• Renal glomerular originnonglomerular hematuria of renal origin (tumor

bleeding, cysts)

• SubrenalMucosal hyperemia due to inflammationBleeding from urinary tract: urolitiasis, tumors,

trauma

Tubular disorders

oliguria polyuria glycosuria cystinuria edema

Oliguria ( 500 ml/day)

• Renal hypoperfusion in low blood pressure hydrostatic pressure in glomerulus - GFR

Prerenal ARF

• Desquamation of necrotic tubular epithelial cells Na resorption – activation of TG mechanismtubular blockleak of tubular fluid into the interstitiumIntrarenal ARF (ischemic or toxic)

• Block in urinary tract with hydronephrosisPostrenal ARF

• Uremia: vomiting, apathy, somnolence, foetor azotaemicus, acidotic breathing; later bleeding, pericarditis, coma

• Complications: hyperkalemia, lung and brain edema

Polyuria with polydipsia

• High liquid intakeHypervolemia: natriuresis; low ADH production

• Osmotic diuresisproximal tubule disorders: low resorption of Na a glucosehyperglycemia: tubular maximumchronic renal insufficiency: residual nephrons (increased GFR in nephron, insufficient Na resorption, decreased medullar osmolality)

• Diabetes insipidusHypoosmolal urine ( 100 mOsm/1kg); risk of dehydration)

• Late diuretic phase of ARFepithelial regeneration; risk of dehydration and hypokalemie

Nephrotic syndrome

• High proteinuria ( 3.5 g/1.73 m2/day)

• Hypoproteinemia increased protein katabolism

increased transfer into the extravascular space lost in stool insufficient proteosynthesis in liver

• Hyperlipidemia increased synthesis in liver

• Edema

Edema

• Subjects with hypovolemia and activation of RAA - (30%)- small glomerular abnormalities - clasic theory

• Subjects with hypervolemia without RAA activation, low renin and aldosteron- more serious morphological disorder- diabetic nephropathy, membranous glomerulonephritis- increased total Na reabsorption – resorption in distal tubule (hyposensitivity to atrial natriuretic peptide)- primary edema

Izostenuria

• Urine osmolality equal to plasma - disorder of countercarrent mechanism

• Accompanied with negative concentration trial and polyuria = chronic renal insufficiency

Uremia in CRI

Fatique – anemia

Anorexy, nausea, vomitus – metabolic breakup

Foetor azotaemicus – bacterial breakdown of urea to ammonia

Diarrhea with bleeding - uremic gastroenteritis

Dyspnoe – heart failure, metabolic acidosis, anemia

Headache, visual troubles – arterial hypertension

Polydipsia

Apathy, insomnia, delirium, coma – renal encephalopathy

Pain and deformity in bones – renal osteodystrophy

Uremic toxicity

ureacreatininmethylguanidineuric acideindol, fenolacetoin, buthylenglycol …

Urinary tract disorders

renal colicdisuriaincontinence

Pain

• Retroperitoneal in lumbar regionhydronephrosis, cystic kidneys

infarction

pyelonephritis

• Renal colic with hematuriaureter block with stone (increased peristalsis and dilatation)symptoms of acute abdomen with peritoneal irritation

• Pain durin micturition (dysuria)cystitis, uretritis

Acute nephritic syndrome

face edemamacroscopic hematuriaoliguria hypertension