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