Lecture 6: Urinary System Flashcards
What is a nephron?
Functional unit of the kidney
How many nephrons does a kidney contain?
More than a million
What is the function of the urinary system?
Filter waste produces from the blood, reabsorb water and nutrients from the tubular fluid and secrete excess substances in the form of urine
What are congenital diseases of the urinary system?
- Anomalies of number and size
- Anomalies of rotation, position and fusion
- Anomalies of renal pelvis and ureter
What is unilateral renal agenesis?
A rare congenital anomaly in which only one kidney forms
What is supernumerary kidney?
A rare anomaly in which a small, third kidney forms
What is hypoplastic kidney?
Appears as a miniature replica of normal kidney, with good function
What is malrotation?
Rotation on the longitudinal or horizontal axis
What is an ectopic kidney?
Kidney with an abnormal position, such as in the pelvis or near the diaphragm
What is a kidney growing in the pelvis called?
Pelvic kidney
What is a kidney near the diaphragm called?
Intrathoracic kidney
What is crossed ectopia?
An ectopic kidney that lies on the same side as the normal kidney and is commonly fused
What is a horseshoe fusion?
Kidneys that are fused at the lower poles
What is a complete fusion?
A rare anomaly that produces a single irregular mass that has no resemblance to normal renal structure
What are other names for complete fusion kidney?
Disk, cake, lump and doughnut kidney
What is the most common type of kidney fusion?
Horseshoe fusion
What is duplication (duplex kidney)?
A common anomaly that causes a duplication of ureters and ureterovesical orifaces
What can duplication be complicated by?
Osbstruction or vesicouretral reflux with infection
What is a ureterocele?
A cystic dilation of the distal ureter near its insertion into the bladder
What are the two types of ureterocele?
Simple and Ectopic
Where is a simple ureterocele usually found?
In adults
Where is a ectopic ureterocele usually found?
Almost exclusively in infants and children
What is ectopic ureterocele usually associated with?
Urethrea duplication
What are posterior uretral valves?
Thin transverse membranes in the urethra that block urine flow in male infants
What can posterior urethra valves cause?
Bladder outlet obstruction and can lead to severe hydronephrosis, hydroureter and renal damage
What type of x-ray best demonstrates posterior urethral valves?
VCUG - voiding cystourethrogram
What are inflammatory disorders of the urinary system?
- Glomerulonephritis
- Pyelonephritis
- Renal tuberculosis
- Papillary necrosis
- Cystitis
- Urinary calculi
What is Glomerulonephritis?
Inflammation of the tiny filters in the kidneys that causes albumin and red blood cells to leak into the urine
When does glomerulonephritis normally occur?
On its own or as part of another disease, such as lupus or diabetes but most commonly several weeks after an acute respiratory ear infection
What does glomerulonephritis cause?
Oliguria, which is a smaller than normal amount of urine
What is pyelonephritis?
An inflammation of the kidneys and renal pelvis caused by pyogenic (pus-forming) bacteria
What is acute pyelonephritis?
A sudden, severe kidney infection that causes the kidneys to swell and can permanently damage them
How is pyelonephritis usually treated?
With antibiotics and with surgery if severe enough
What are common features of pyelonephritis in imaging?
Patchy distribution that only affects one kidney
Where does pyelonephritis usualy originate in?
Bladder and ascends to the ureter to involve the kidneys
What patients is pyelonephritis most common in?
Women and children and patients with obstructions of the urinary tract
What are symptoms of pyelonephritis?
High fever, chills, sudden back pain that spreads to the abodome, dysuria (painful urination) and pyuria (pus in urine)
What is renal tuberculosis?
A secondary infection that usualy occurs 5-10 years after primary infection and can result in small granulomas in the cortical portion of the kidney
What is papillary necrosis?
A destructive process of the kidneys that decreases kidney function and can lead to failure
What are predisposing factors of papillary necrosis?
Diabetes, pyelonephritis, UTI, urinary tract obstruction, sickle cell disease and phenacetin abuse
What is Cystitis?
An inflammation of the urinary bladder that is caused by the spread of bacteria present in fecal matter
Who does cystitis most commonly affect?
Women, due to their shorter urethra
What are other causes of cystitis?
Catheterization of the bladder and retrograde flow from a urine bag and sexual intercourse
What are symptoms of cystitis?
Frequent urination, urgency and burning sensation, bloody urine, bad smell of urine
What is the most common nosocomial urinary infection?
Cystitis
What is urinary calculi?
Kidney stones that most commonly form in the kidneys
What are the causes of kidney stones?
Underlying metabolic abnormlaity (hypercalcemia), any cause of increased calcium excretion in the urine, urinary stasis and infection
When do kidney stones produce issues?
When they are lodged in the ureter and cause partial obstruction
What are types of Cysts and tumors of the urinary system?
- Renal cysts
- Polycystic kidney disease
- Renal Carcinoma
- Wilms tumor
- Carcinoma of the bladder
What are renal cysts?
The most common unifocal mass of the kidney that are fluid filled and usually unilocular
What is polycystic kidney disease?
An inherited disorder in which multiple cysts cause enlargement of the kidneys and progressive impairment
What do 1/3 of patients with polycystic kidney disease also have?
Liver cysts
What do 10% of people with polycystic kidney disease have?
One or more saccular (berry) aneurysms of cerebral arteries that can rupture
What other conditions usually affect patients with polycystic kidney disease?
Hypertension
What is renal carcinoma?
Also known as Hypernephroma and is the most common renal neoplasm
What patients is hypernephroma common in?
Patients older than 40 years old
Where does hypernephroma originate in?
In tubercular epithelia of the renal cortex
What is the classic symptom triad of hypernephroma?
- Hematuria
- Flank pain
- Palpable abdominal mass
What are the stages of renal carcinoma?
Stage 1: Less than 7 cm
Stage 2: Greater than 7 cm
Stage 3: Spread to Gerota’s fascia
Stage 4: Spread to lymph nodes and other organs
What is a Wilms tumor?
Nephroblastoma and is the most common abdominal neoplasm of infants and childhood
Where does a wilms tumor arise from?
Embryonic renal tissue
What is carcinoma of the bladder?
The 4th most common cancer in men over the age of 50 that originates in the epithelium
What are predisposing factors of carcinoma of the bladder?
Industrial chemicals and cigarette smoking
What is renal vein thrombosis?
A rare disease that occurs when a protein called amyloid builds up in organs and causes them not to work properly
What patients does renal vein thrombosis occur most in?
Children who are severly dehydrated
What modality best diagnosis renal vein thrombosis?
MRA (magnetic resonance angiography) which detects abnormally strong signal from the reanl veins
In adults, what is renal vein thrombosis most often a complication of?
Chronic glomerulonephritis, amyloidosis, pyelonephritis, trauma, thrombus extension from IVC, renal tumors
What is acute renal failure?
A rapid deterioration in kidney function that is the result of accumulation of nitrogen-containing wastes in the blood
What are the characterisitics of acute renal failure?
Urine-like odor or fishy breath
What are the two types of acute renal failure?
Prerenal and postrenal
What are prerenal causes?
Decreased blood flow to kidney, cardiac failure and renal artery obstruction
What are postrenal causes?
Urine outflow obstruction from both kidneys from prostatic disease or functional obstruction of the bladder neck
What are other causes of acute renal failure?
Kidney disease, nephrotoxic agents, intravascular hemolysis, large amounts of myoglobin in the circulation from muscle trauma
How does Chronic renal failure reflect?
Prerenal, postrenal or intrinsic kidney disease
What are causes of chronic renal failure?
- Bilateral renal artery stenosis
- Bilateral ureteral obstruction
- Intrinsic renal disorders like chronic glomerulonephritis, pyelonephritis and familial cystic diseases
