1 Patho5 - Kidney i 2015b

5.1. KIDNEY PATHOLOGY I: GLOMERULAR DISEASES December 13, 2012

Ma. Josefa D. Mesina, M.D., F.P.S.P. Objectives:     

Review the normal gross and microscopic features of the kidney Define/describe the different clinical manifestations/syndromes pertaining to renal diseases Describe the pathologic mechanisms behind glomerular, tubulointerstitial and vascular diseases Describe the morphologic changes Discuss the clinical outcome/prognosis of the different diseases in the kidney

LEGEND:  Powerpoint and lecture  Robbins  Must remember

ANATOMY 2 MAJOR DIVISIONS  

Upper urinary tract (kidney) Lower urinary tract (pelvicalcyceal system, ureters, bladder and urethra)

PHYSIOLOGIC FUNCTIONS OF THE KIDNEY__ 

Excretes the waste products of metabolism

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Serves to convert more than 1,700 liters of blood per day into about 1 liter of a highly specialized concentrated fluid called urine

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Regulates the body’s concentration of water and salt With the lungs, it maintains the acid-base balance Serves as an endocrine organ—secreting hormones such as erythropoietin, renin and prostaglandins

RENAL PATHOLOGY Definition of Terms: *Azotemia  Biochemical abnormality that refers to an elevation of the blood urea nitrogen (BUN) and creatinine levels  Related largely to a decreased glomerular filtration rate (GFR)  Consequence of many renal disorders, but it also arises from extrarenal disorders  Prerenal Azotemia: encountered when there is hypoperfusion of the kidneys that impairs renal function without parenchymal damage (e.g. hemorrhage, shock, volume depletion, congestive heart failure)  Postrenal Azotemia: encountered whenever urine flow is obstructed beyond the level of the kidney, wherein relief of the obstruction is followed by the correction of the azotemia *Uremia  When azotemia becomes associated with a constellation of clinical signs and symptoms and biochemical abnormalities  Characterized by: failure of renal excretory function, metabolic and endocrine alterations resulting from renal damage  Manifests secondary involvements of the GIT (uremic gastroenteritis), peripheral nerves (neuropathy), and heart (uremic fibrinous pericarditis)

Clinical Manifestations of Renal Diseases

The study of kidney diseases is facilitated by dividing them into those that affect the four basic morphologic components: glomeruli, tubules, interstitium, blood vessels.  This approach is useful since the early manifestations of disease affecting each of these components tend to be distinct.

NEPHRITIC SYNDROME  Acute onset of usually grossly visible hematuria, mild

GROSS FEATURES OF THE KIDNEY

RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS  Nephritic syndrome with rapid decline (hours to

to moderate proteinuria, hypertension presentation of acute poststreptococcal glomerulonephritis

 Classic

days) in GFR

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NEPHROTIC SYNDROME  Heavy proteinuria (>3.5 gm/day), hypoalbuminemia, severe edema, hyperlipidemia, lipiduria

ASYMPTOMATIC HEMATURIA OR PROTEINURIA OR COMBINATION  Manifestation of subtle or mild glomerular Fig. 1. Normal Kidney

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abnormalities

150 g - average weight of adult kidney 1 -1.5 cm - cortical thickness Normal to have a minimal amount of fat

ACUTE RENAL FAILURE  Dominated by oliguria or anuria and recent onset of azotemia (see acute tubular necrosis)

Major parts:  Cortex—outer region  Medulla—inner region  Collecting system—which consists of the proximal portion of the ureter that is connected to the renal pelvis, which branches inward to the kidney towards the major calices and branches further to the minor calices

RENAL TUBULAR DEFECTS  Dominated by polyuria, nocturia and electrolyte disorders  Result of diseases that either directly affect tubular structure or cause defects in specific tubular functions

URINARY TRACT INFECTION  Bacteriuria amd pyuria (bacteria and lymphocytes)  May be symptomatic or not  May affect the kidney (pyelonephritis) or the bladder (cystitis)

Melgar|Mendoza|Montenegro|Pascual|Santos, P.

Kidney Pathology I: 2015B

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NEPHROLITHIASIS  Renal stones  Manifested by severe spasms of pain (renal colic) and hematuria  Often with recurrent stone formation

URINARY TRACT OBSTRUCTION OR RENAL TUMORS

Fig. 2. Components of Glomerulus

 Varied clinical manifestations

CHRONIC RENAL FAILURE  Prolonged signs and symptoms of uremia  End result of all chronic renal parenchymal diseases  Stage I (Diminished Renal Reserve): GFR is 50% of normal. Serum BUN and creatinine levels normal. Asymptomatic. More susceptible to develop azotemia with additional renal insult.  Stage II (Renal Insufficiency): GFR is 20-50% of normal. Azotemia is present, with anemia and hypertension, as well as polyuria and nocturia. Sudden stress may precipitate uremia.  Stage III (Chronic Renal Failure):