PathoPhysiology Chapter 27

CHAPTER 27

INTRARENAL DISORDERS

COMMON MANIFESTATIONS OF KIDNEY DISEASE

Pain• Renal pain generally felt at costovertebral

angle• Pain transmitted to the spinal cord between

T10 and L1 by sympathetic afferent neurons; may be felt throughout dermatomes of T10-L1• Due to distention and inflammation of the

renal capsule, has a dull, constant character

COMMON MANIFESTATIONS OF KIDNEY DISEASE (CONT.)

Abnormal Urinalysis Findings• Provides a foundation for the differential

diagnosis of renal dysfunction• Dipstick and microscopic urinalysis results

provide clues to intrarenal pathologies



Other Diagnostic Tests• KUB identifies gross abnormalities related to

size, position, and shape (may show renal calculi)• Renogram/renal scan shows renal vasculature• Ultrasonography differentiates tissue

characteristics• CT/MRI used to provide detailed information

about the vasculature and tissue

CONGENITAL ABNORMALITIESRenal Agenesis and Hypoplasia• Relatively rare; associated with other

congenital abnormalities• Bilateral renal agenesis not compatible with

life• Unilateral renal agenesis results in

compensatory hypertrophy of functional kidney• A single normal kidney is sufficient to

maintain normal renal function

CONGENITAL ABNORMALITIES (CONT.)

Cystic Kidney Diseases• Genetically transmitted renal disorder

resulting in cysts that can expand and disrupt urine formation and flow; may be localized to one area or affect both kidneys• Autosomal recessive forms are evident at

birth• Autosomal dominant types cause symptoms

later in life• Renal failure necessitates dialysis or

transplantation

NEOPLASMSBenign Renal Neoplasms• Symptoms depend on the size; may be

asymptomatic until large enough to form palpable abdominal mass, hematuria, and flank pain• Usually diagnosed with renal ultrasound

and/or CT scan• Nephrectomy remains treatment of choice

NEOPLASMS (CONT.)Renal Cell Carcinoma• May have familial pattern• Risk factors include smoking and obesity• Usually asymptomatic until advanced;

presenting S/S include CVA tenderness, hematuria, palpable mass• Nephrectomy is typical treatment;

metastases may be particularly resistant to radiation, immunotherapy and chemotherapy

NEOPLASMS (CONT.)

NEOPLASMS (CONT.)Nephroblastoma (Wilms Tumor)• Most common kidney cancer in children• Identified by palpable abdominal mass;

may also have pain, hypertension, and/or hematuria• Nephrectomy, radiation therapy, and

chemotherapy are used for treatment; excellent cure rate

INFECTIONAcute Pyelonephritis• Infection of renal pelvis and parenchyma

usually due to an ascending urinary tract infection• CVA tenderness a classic sign• Accompanied by fever, chills, N/V, anorexia• Presence of WBC casts is indicative of upper

UTI• Should be promptly managed with

antimicrobials to avoid decreased renal function

INFECTION (CONT.)

INFECTION (CONT.)Chronic Pyelonephritis• Can result in chronic kidney disease• Usually associated with vesicoureteral

reflux or obstructive process leading to persistent urine stasis• Ongoing inflammation causes fibrosis and

scarring and loss of functional nephrons• Diagnosed by renal imaging• Treatment includes correction of underlying

processes and extended antimicrobial therapy

OBSTRUCTIONRenal Calculi (Nephrolithiasis)• Obstructive processes result in urine stasis,

predisposing to infection and structural damage• Common causes include stones, tumors,

prostatic hypertrophy, and strictures of the ureters or urethra• Renal stones are most common

OBSTRUCTION (CONT.)

OBSTRUCTION (CONT.)Renal Calculi (Nephrolithiasis)• Complete obstruction leads to

hydronephrosis, decreased GFR, and ischemic damage due to increased intraluminal pressure• Prolonged postrenal ARF may result in ATN

and CKD• Stones tend to form in urinary tract due to

solute supersaturation, low urine volume, and abnormal urine pH

OBSTRUCTION (CONT.)Renal Calculi (Nephrolithiasis)• Most stones composed of calcium crystals;

others include uric acid, struvite, cystine, and stones associated with certain medications• Stationary stones usually asymptomatic;

stone migration causes intense renal colic pain abrupt in onset and may radiate; N/V, diaphoresis is common

OBSTRUCTION (CONT.)Renal Calculi (Nephrolithiasis)• Most stones pass spontaneously• Other interventions may be necessary

including lithotripsy or endoscopic approaches• Stones tend to recur; prevention enhanced

by high fluid intake to dilute the urine and dietary changes based on the type of stone

GLOMERULAR DISORDERS• Glomerulopathies alter glomerular capillary

structure and function• Damage mediated by immune processes• May result in some combination of

hematuria, proteinuria, abnormal casts, decreased GFR, edema, and hypertension

GLOMERULAR DISORDERS (CONT.)

Glomerulonephritis• Immune response to variety of potential

triggers; may have primary or secondary etiology• Attraction of immune cells to the area of

inflammation results in lysosomal degradation of the basement membrane• GFR may fall due to contraction of

mesangial cells resulting in decreased surface area for filtration


Glomerulonephritis• Treatment may include steroids,

plasmapheresis, and supportive measures such as dietary and fluid management• Management of systemic and renal

hypertension• ESRD is a common outcome of chronic

glomerulonephritis; dialysis or kidney transplantation may be necessary



Nephrotic Syndrome• Occurs due to increased glomerular

permeability to proteins• Urinary loss of 3 to 3.5 g of protein per day• Proteinuria leads to hypoalbuminemia and

generalized edema; decreased blood colloid osmotic pressure; increase in liver activity can cause hyperlipidemia and hypercoagulability



Nephrotic Syndrome• Treatment is conservative; consists of

symptom management• Management of underlying process when

identified• Many cases resolve spontaneously but can

progress to ESRD

Education

PathoPhysiology Chapter 27