Kidney’s Flashcards by Jonathan Crispin

According to the National Institute of Diabetes and Digestive and Kidney Disease, ____ in ___ people with diabetes and ___ in ____ people with high blood pressure have a kidney disease.

-1 in 3
- 1 in 5

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Why is sonography the first imaging test to evaluate the kidneys compared to CT or MRI

neither radiation nor contrast is needed; Both CT and MRI contrast agents can damage the kidneys and possibly cause the patient to acquire acute kidney injury (AKI).

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The urogenital ridge will form during the fourth week of gestation and divide into the nephrogenic cord to form the…

the urinary system

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The three morphologic stages of the kidneys?

-pronephros
-mesonephros
-metanephros

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is the earliest nephric stage and is a transitory, nonfunctional structure that disappears by the fourth week of gestation.

Pronephros

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The mesonephros forms just caudal to the pronephros and develops into the ______ and the ______, AKA the Wolffian Duct.

the mesonephric tubules and the mesonephric duct

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The ureteric bud comes off the mesonephric duct and develops into the different parts of the collecting system, such as the _____, _______, ______, and _______.

the calyces, collecting ducts, renal pelvis, and ureter.

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_______ is the last to canalize and is the most common site of obstruction in congenital hydronephrosis

The ureteropelvic junction (UPJ)

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the metanephros phase begins, and the metanephric mesoderm will form the excretory parts of the kidneys that form the ____, _____, _____, & ______

nephrons, glomerulus, Bowman capsule, and the convoluted tubules

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The kidneys become functional at about ____ weeks of gestational age?

12 weeks

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Anatomical differences between the right and left kidney?

The left kidney is located at about the level of T12–L3, whereas the right kidney is slightly lower in the abdomen owing to the larger size of the liver. The left kidney will be slightly higher, superior, in the abdomen and more toward the back, posterior, then the right kidney.

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Normal kidney measurements

~ 9-12cm in length
~5-7cm in width
~ 3-5cm in depth

The rule of thumb that commonly used in sonography is that the kidneys should be within 2 cm of each other in length.

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-Cortical thickness appears to be closely related to estimated glomerular filtration rate (eGFR), and studies have shown that in patients with a low eGFR, their cortical thickness is?

Reduced in size
~ 6-10mm is Normal Cortical Thickness
-seen in kidneys with fibrosis or chronic kidney disease

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A kidney that measures less than ____ cm is usually abnormal

9cm

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The kidney is divided into the renal parenchyma, which consists of the?

renal cortex and the medulla

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The renal cortex contains what?

Renal corpuscles – made up of the glomerulus and Bowman’s capsule, where blood filtration begins.
Proximal convoluted tubules (PCT)
Distal convoluted tubules (DCT)
Peritubular capillaries – part of the blood supply associated with reabsorption and secretion.

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The medulla is the inner portion of the renal parenchyma and contains

the loop of Henle, which is where reabsorption takes place

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The renal capsule is covered by a layer of perirenal fat, called the

adipose capsule or renal fat pad, which helps support the kidney and is a protective layer acting as a shock absorber

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The next layer anchors the kidneys to the surrounding structures and is the perirenal fascia, which is a collagen-filled, fibrous connective tissue that envelops the kidney, the adrenal gland, and the perirenal fat to form the?

perirenal space

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The perirenal fascia divides into two layers that pass in front of and behind the kidney. The anterior and posterior fascial leaflets fuse, closing off the perirenal space from the rest of the retroperitoneum. The anterior perirenal fascia is called?

Gerota fascia, which separates the perinephric fat from the paranephric fat

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Aka Gerota’s facia, The posterior renal fascia is a fibrous sheath covering the posterior side of the kidney and the perinephric space and is called?

Zuckerkandl fascia

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goes between kidney and adrenal gland

Fibrous capsule

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located superior to renal fascia

Pararenal fat

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Approximately what percent of the cardiac output enters the renal arteries

20-30%

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The renal arteries are approximately how many cm in length and mm in diameter?

4-6cm 5-6mm

Because the aorta lies to the left of the midline, which renal artery is longer?

The right renal artery (RRA) is longer than the left and travels posterior to the inferior vena cava (IVC) on its way to the kidney

Which renal vein courses between the SMA and the aorta to reach the IVC

LRV

The renal veins have a diameter of

10-12mm

The entire sequence of the renal blood flow "Really Super Important Anatomy Is Always A Good Example"

AO > Renal artery > segmental A. > Interlobar A. > Arcuate A. > Cortical Radiate A. > Afferent arterioles > Glomerulus > Efferent Arterioles > Peritubular Capillaries > Cortical Radiate V. > Arcuate V. > Interlobar V. > Renal V. > IVC

the hormones the kidneys produce

1. Erythropoietin is produced when oxygen levels in the blood are low, which signals the bone marrow to produce mature red blood cells (RBCs) to maintain healthy oxygen levels in our body. 2. Vitamin D is essential for several body functions. Vitamin D in an inactive form needs to be changed by the kidneys before it can act within the body. Active vitamin D stimulates the uptake of calcium from food, which is important for the maintenance of healthy bones. 3. Renin regulates angiotensin and aldosterone levels, called the renin–angiotensin system, and together they control blood pressure. If the kidneys are not functioning properly, they can release too much renin, causing vasoconstriction, retaining extra fluid, and increasing the blood pressure, which can lead to hypertension.

The formation of urine involves the following three processes

-glomerular filtration -tubular reabsorption (proximal convoluted tubule ) -tubular secretion (distal convoluted tubule)

How many mL of blood passes through the kidneys every minute

1,100 to 1,200 mL

The nephron is the functional unit of the kidney, and each kidney contains how many nephron’s

1 million

The functions of the nephron

control blood concentration and volume by removing water and solutes as needed, help regulate blood pH, and remove toxic wastes

A nephron is composed of the

1. Renal corpuscle (Glomerulus + Bowman's capsule) 2. Proximal convoluted tubule (PCT) 3. Loop of Henle (descending and ascending limbs) 4. Distal convoluted tubule (DCT) 5. Collecting duct

The first part of the renal tubule is called the

the proximal convoluted tubule

The second part of the renal tubule is called

the loop of Henle, as it forms a loop with a descending and ascending limb that goes through the renal medulla

The third part of the renal tubule is called

the distal convoluted tubule and is only found in the renal cortex and empties its filtrate into collecting ducts that line the medullary pyramids

is a tiny ball of capillaries inside the nephron where blood filtration begins. It plays a central role in forming urine by filtering plasma from blood.

Glomerulus

Flow of filtrate or urine beginning at glomerulus "Great Big People Like Donuts, Candy, Pie, M&M, Reese’s Pieces, and Breakfast.”

1. Glomerulus Filtration begins here. Blood is filtered through the glomerular capillaries into Bowman’s capsule. 2. Bowman's Capsule Collects the filtrate from the glomerulus. Proximal Convoluted Tubule (PCT) Reabsorption of water, ions, and nutrients occurs here. 3. Loop of Henle Descending limb: Water reabsorption. Ascending limb: Reabsorption of salts (Na⁺, Cl⁻), impermeable to water. 4. Distal Convoluted Tubule (DCT) Further selective reabsorption and secretion. Responds to hormones like aldosterone. 5. Collecting Duct Final adjustments to urine concentration under the influence of ADH (antidiuretic hormone). 6. Papilla Tip of the medullary pyramid where collecting ducts converge and release urine. 7. Minor Calyx → Major Calyx Urine drains into these funnel-shaped structures. 8. Renal Pelvis Collects urine from all calyces and channels it into the ureter. 9. Ureter → Urinary Bladder Urine is transported to the bladder for storage. 10. Urethra Final passageway for urine to exit the body.

The normal adult renal cortex sonographically appears

homogeneous with the echogenicity of the cortex less than, hypoechoic (darker) or isoechoic, to that of the adjacent liver

Echogenicity of the left kidney to the spleen

The left kidney is usually slightly hypoechoic (darker) compared to the spleen or less echogenic. So, the renal cortex should appear a little darker than the spleen.

Posterior to the renal cortex is the inner portion of the renal parenchyma, which is called

the medulla and contains the renal pyramids

is the central portion of the kidney and contains the major and minor calyces, the renal pelvis, renal vessels, fat, nerves, and lymphatics.

The renal sinus

The fat in the renal sinus is an extension of the

perirenal fat

Normal Echogenic Relationships in the Abdomen from Brightest to Least Echogenic

1. Renal sinus 2. Pancreas 3. Liver 3. Spleen 4. Renal cortex 5. Renal Pyramids

Common places where stones can get stuck within the ureters?

1. UPJ (ureteropelvic junction) 2. Where it crosses over the iliac vessels 3. UVJ (ureterovesical junction)

Renal Blood and Urine Tests

1. BUN (blood urea nitrate) - - increase indicates: renal failure, parenchymal disease, urinary obst., dehydration, etc - - decrease indicates: liver failure, overhydration, pregnancy 2. Creatinine is a waste product from the breakdown of the compound creatine produced by the muscles. - - Increase indicates: glomerulonephritis, diabetes, urinary obst., certain medications - - decrease values not a concern in renal function 3. eGFR - -Accurate indicator of kidney function as it measures how well the glomeruli are filtering the blood. - -Decreases when there is decreased blood flow to the glomerulus, urinary obstruction, and primary renal disease. - - Increases values are not a concern. Urine tests 1. Proteinuria occurs when protein or albumin is passing through the glomerulus or tubules and is ending up in the urine. 2. Hematuria is when there are RBCs in the urine. The bleeding can happen anywhere in the urinary system.

The most common cause of proteinuria is seen in patients with

diabetes or hypertension

Albuminuria is the earliest indicator of

glomerular disease and is seen with cardiovascular disease, however the most common cause is diabetes

Is an arterial measurement that is obtained from the interlobar artery and relates to renal vascular resistance and is influenced by the amount of diastolic flow?

The resistive index (RI)

The normal kidney should have an RI between? If the RI is greater what is it suggestive?

0.6 and 0.7 - - A RI greater than 0.7 is suggestive of increased vascular pressure, resistance, or compliance inside the kidney

Difference between AKI vs CKD

AKI = Acute Kidney Injury -Sudden loss of kidney function (hours to days) -Often reversible with treatment -Can lead to accumulation of waste, fluid, and electrolyte imbalances Causes: -Pre-renal (e.g., dehydration, low blood pressure) -Intrinsic (e.g., glomerulonephritis, acute tubular necrosis) -Post-renal (e.g., obstruction like stones or enlarged prostate) Signs: -Rapid rise in creatinine -Decreased urine output (oliguria or anuria) -Electrolyte imbalances CKD = Chronic Kidney Disease -Gradual, progressive loss of kidney function over months to years Often irreversible - May lead to end-stage renal disease (ESRD) needing dialysis or transplant Criteria (usually): -Decreased GFR -evidence of kidney damage (e.g., proteinuria, structural abnormalities) for ≥ 3 months Common Causes: -Diabetes mellitus -Hypertension -Polycystic kidney disease -Chronic glomerulonephritis

refers to a decrease in the size and function of the kidney, often due to chronic disease, ischemia, or obstruction. It involves loss of renal parenchyma (cortex and medulla), which may be diffuse (large area) or focal (localized).

Renal atrophy

is a congenital anomaly where one or both kidneys are abnormally small, but the internal architecture is otherwise normal. There are no scars and the kidney has normal function for its size.

Renal hypoplasia

Prominent focal bulge on lateral border of the left kidney, which gives the kidney a more triangular shape

Dromedary hump

Indentations on the surface of the kidney that reflect underlying lobular organization. Kidneys appear LOBULATED or scalloped rather than smooth after merging together from the 12 fetal lobes. No impact on kidney function, no cortical thinning, and no scarring.

Fetal Lobulations

is a normal anatomical variant of the kidney in which the renal cortical tissue between renal pyramids (columns of Bertin) is prominently thickened.

Hypertrophied column of Bertin

is a benign anatomical variant seen on renal imaging (ultrasound). It appears as a triangular, echogenic area in the upper pole of the kidney where embryologic fusion of the kidney’s lobes occurred. Most commonly seen in the right kidney, upper pole.

Junctional parenchymal defect

Anatomic variant where part of the renal pelvis is outside the renal hilum and is best appreciated in a transverse image. There will be no hydronephrosis on a midline image.

Extrarenal pelvis

A benign condition of an accumulation of excessive fat within the renal sinus and appears as an enlarged echogenic central sinus that is usually less echogenic than the normal renal sinus.

Renal sinus lipomatosis

Failure of a kidney or kidneys to develop.

Renal agenesis

is when a kidney does not ascend to its normal position in the lower abdomen

Ectopic kidney

This type of renal ectopia, both kidneys are found on the same side of the body.

Crossed ectopic kidney

Two distinct functioning kidneys connected at their lower poles by an isthmus of functioning renal parenchyma that crosses anterior to the aorta. The IMA stops their ascent, causing them to be just superior to the umbilicus.

Horseshoe kidney

is a congenital anomaly where a single kidney has two separate pelvicalyceal systems, each possibly with its own ureter. It’s the most common urinary tract anomaly. Two types: Complete duplication: Two separate ureters drain the kidney and insert independently into the bladder (or ectopically) Incomplete (partial) duplication: Two ureters fuse into one before entering the bladder

Duplicated collecting system

is a fluid-filled sac that forms in the kidney, with an epithelial lining. Most are simple, benign, and asymptomatic, but some may be complex and require further evaluation.

Renal cyst

parapelvic cyst or a peripelvic cyst occasionally may cause what symptoms

may cause pain, hematuria, or the parapelvic cyst hydronephrosis + image of a PERIpelvic cyst

The PARApelvic cyst originates in the adjacent ______ and extends into the renal sinus. They are usually single and look like a simple renal cortical cyst, just deeper in the kidney and pushing into the renal sinus echoes. The peripelvic cyst originates within the _______ itself and is not a true cyst as it does not contain serous fluid, but most contain ______. A peripelvic cyst is spherical in appearance, are usually bilateral, can cause obstruction, and usually remain unchanged in size on follow-up examinations.

-renal parenchyma (PARApelvic = PARenchyma) - renal sinus (PERIpelvic = renal SINUS) -lymphatic fluid +image of PARApelvic cyst

This type of cyst contains a thick protein fluid inside. They are not malignant and do not require surgery.

A proteinaceous cyst

A ____ cyst could be the result of the cyst increasing in size, trauma, or the patient has a predisposition to BLEEDING. As it resolves, they develop features such as calcification, thickening of the wall, and septations, giving it the appearance of a complex cyst.

hemorrhagic cyst

The Bosniak system is a scale of increasing probability of a malignant cystic RCC based upon imaging features of the renal cyst.

-Bosniak 1 or 2 cyst is a benign cyst that does not need follow-up. Malignancy 0% -Bosniak 2F cyst needs to be followed. Malignancy 5% -Bosniak 3 treatment partial nephrectomy or ablation. Malignancy 55% -Bosniak 4 cyst needs to be removed. Malignancy 100%

refers to a colloidal suspension of calcium salts, typically calcium carbonate or calcium oxalate, that settles in cystic or fluid-filled structures in the body. It is gravity-dependent, meaning it layers and settles in a characteristic way. Common locations -Renal calyces (calyceal diverticulum) -Ureter or bladder -Gallbladder -Ovarian cysts or breast cysts (less common)

milk of calcium

____ is a genetic condition that causes the growth of numerous cysts in the kidneys. The kidneys lose their ability to filter waste from the blood, leading to renal failure. There are two inherited forms: autosomal dominant, also called ___, which is the most common type. In autosomal dominant PKD, if one of the parents carries the disease gene, the child has a 50/50 chance of inheriting the disease. The other type is autosomal recessive, or ______, where both parents must have and pass along the gene mutation for the child to be affected. It affects 1 in every 1,000 to 2,000 people and is found in all races, occurring equally in both men and women. Also always affects both kidneys

-Autosomal Dominant Polycystic Kidney Disease -adult PKD -infantile PKD

is a condition in which multiple fluid-filled cysts develop in the kidneys of patients with chronic kidney disease (CKD), especially those on long-term dialysis. This disease is acquired (from CKD) not inherited (APKD) and typically affects both kidneys. It increases the risk of renal cell carcinoma.

Acquired cystic kidney disease (ACKD)

ACKD vs APKD

ACKD -affects men more than women, and patients are usually asymptomatic. -Hemorrhage into cysts is common and, when it occurs, can cause flank pain. -no association of cysts in other organs - kidneys are small in size -patient can develop an RCC, which occurs in 4% to 10% of patients APKD - inherited autosomal dominant trait and is the most common kidney disorder passed down through family members. -affects 1 in every 1,000 to 2,000 people and is found in all races, occurring equally in both men and women. -always affects both kidneys -enlarged kidneys that contain multiple cysts that vary in size and are found in both the renal cortex and the medulla.

is a rare autosomal dominant genetic disorder characterized by the formation of benign and malignant tumors and cysts in multiple organs. It is caused by a mutation in the VHL tumor suppressor gene on chromosome 3 and leads to abnormal blood vessel growth (angiogenesis). Common tumor location: -Central nervous system (CNS): Hemangioblastomas of the brain and spinal cord -Eyes: Retinal hemangioblastomas (can cause vision loss) **Kidneys: Renal cell carcinoma (often bilateral and multifocal) occurs in 70% and the leading cause of death** -Adrenal glands: Pheochromocytomas (may cause hypertension) -Pancreas : Cysts, neuroendocrine tumors -Epididymis (in males): Cystadenomas

von Hippel–Lindau disease

is the only term that can be used to describe a malignancy.

Cancer

describes any overgrowth of tissue and can be either benign or malignant.

mass

is Latin for swelling and is a general term that can be applied to something that is either benign or malignant. The term is used interchangeably with cancer, which is can be misleading.

Tumor

is a growth or lump that can be malignant or benign.

nodule

Comes from the Greek word meaning “new tissue or cell”

Neoplasm

Why are most renal masses incidental finding and found on the right kidney?

With US, renal tumors are usually incidentally discovered on a US for the gallbladder or liver; therefore, most unsuspected tumors are discovered on the right kidney.

____ tumors appear more isoechoic or hypoechoic to the normal renal cortex and are usually found as they distort the normal renal shape or inner architecture. They also have a higher risk of being malignant or a metastatic disease (spread of disease inside the body).

Larger tumors

are echogenic, making it difficult to determine whether the mass is benign or malignant. They will have a slow growth rate of 1 to 3 mm per year and 25% are benign.

Small renal masses (SRM)

About 20% of renal tumors are benign. The three most common benign masses are?

adenoma, oncocytoma, and AML

are usually less than 2 cm in size and are rarely larger than 3 cm. Larger tumors can cause a localized bulge of the renal capsule and can distort the collecting system as well as interfere with the normal function of the kidneys. They can be single or multiple masses and are found immediately below the renal capsule within the renal cortex. The sonographic appearance is a solid mass that can be hyperechoic to hypoechoic to the normal renal cortex and hypovascular with color Doppler. -are usually asymptomatic -classified as precancerous -common in older patients

Adenomas

is a relatively benign renal tumor that occurs in the cortex. They are bilateral in 13% of patients and are found in 32% of patients with an RCC. They occur more often in men and are usually found in patients in their sixties or older. -can vary in size as large as 20cm -1/3 have central stellate scar (fibrous connective tissue with bands radiating toward the periphery, causing it to resemble a star) just like some RCC -occur in other organs, with salivary gland being a common site -symptoms of pain and hematuria -difficult to differentiate from RCC and can only be definitively diagnosed with surgery.

Oncocytoma

Also known as a renal hamartoma, are benign tumors located within the renal cortex. It is composed of blood vessels (angio), smooth muscle cells (myo), and fat cells (lipo), and the tumor can vary in the amount of each cell type. Most often occurs in middle aged women, found in the right kidney, asymptomatic - flank pain, hematuria, palpable mass. Main clinical concern with this disease is the chance of spontaneous hemorrhaging. Definitive diagnosis made with CT if it contains macroscopic fat.

Angiomyolipoma

usually referred to as conventional RCC as it is the most common type, accounting for 80% of all RCC cases. It got its name because the cells in the tumor look like clear bubbles under the microscope.

Clear cell RCC

is also called a hypernephroma or renal adenocarcinoma. Factors that contribute to the disease: smoking doubles the risk, overweight, high blood pressure, men, long term use of NSAIDS. It can appear in either kidney or in pole location, highly vascular and can invade the renal veins, IVC, contralateral kidney, and nodes. Also originates in the proximal renal tubular epithelium and accounts for 5% of adult cases of cancer in men and 3% in women. Surgical resection remains the only known curative treatment.

Renal Cell Carcinoma

are malignant tumors that arise from the lining of the renal pelvis, calyces, ureter, and bladder (most common) and account for 8% to 10% of all renal cancers. Aka urothelial carcinomas. Elderly men between the ages of 60-70 years of age are the most susceptible. -Most common Urinary Tract cancer, 2nd most common renal tumor after RCC

Transitional Cell Carcinomas

The best chance of completely getting rid of TCC is what?

Nephroureterectomy (removal of the kidney and the entire length of the ureter up to the insertion of the bladder.)

______ of the renal pelvis is a rare neoplasm and is the second most common malignant urothelial tumor after TCC. The most common cause is chronic irritation from kidney stones, usually from a staghorn. Other risk factors include chronic pyelonephritis, exposure to endogenous and exogenous chemicals, and vitamin A deficiency. It is very rarely diagnosed preoperatively because of its rarity and inconclusive lab results and radiology findings. Treatment is surgical resection, which is rarely curative, and chemotherapy or radiation is usually ineffective.

Squamous Cell Carcinoma

refers to secondary malignancies—cancers that originate elsewhere in the body and spread (metastasize) to the kidney. While primary renal tumors like Renal Cell Carcinoma (RCC) are more common, metastases to the kidneys can occur, usually as part of widespread systemic disease. The two most common cancers that metastasize to the kidneys are melanomas and lung.

Metastatic Renal Tumors

refers to lymphomatous infiltration of the kidneys as part of systemic lymphoma, most commonly Non-Hodgkin lymphoma. It is far more common than primary renal lymphoma, which is rare. The kidneys are the most common abdominal organ that is affected by non-Hodgkin lymphoma. It is seen when there is widespread nodal or extranodal lymphoma. The kidneys do not contain lymphoid tissue, and involvement is by either a hematogenous spread, the most common, or as direct extension via the retroperitoneal lymphatic channels. Sonographically, the disease can be single or multiple masses that can be either anechoic or hypoechoic in appearance. Because there are few internal reflectors, the lesions can simulate renal cysts. It is, therefore, very important for the sonographer to document a lack of acoustic enhancement to show that the lesions are solid masses and not cysts. Also they have very little internal vascularity with color or power Doppler.

secondary renal lymphoma (SRL)

is the dilation of the renal pelvis and calyces due to obstruction of urine flow at some point along the urinary tract. It can be unilateral or bilateral, and it can affect one or both kidneys. Types of obstructions: -Ureteropelvic junction (UPJ) obstruction -Ureteral stones -Enlarged prostate (BPH) -Tumors (e.g., pelvic mass, bladder cancer) -Pregnancy Grading: Grade 0: No dilation Grade 1: Minimal dilation of the renal pelvis Grade 2: Dilation of pelvis and a few calyces Grade 3: Uniform dilation of pelvis and calyces Grade 4: Severe dilation with cortical thinning

HYDRONEPHROSIS

Calcium stones are the most common type of kidney stone, and there are two types,

calcium oxalate and calcium phosphate, which together account for 75% of stones, with calcium oxalate as the more common type

composed of a mixture of magnesium, ammonium, phosphate, and calcium carbonate. These stones form as a result of infection, are often large, have branches, and grow fast

staghorn stones aka struvite stones

a disease in which there is too much calcium, in the form of calcium phosphate and calcium oxalate, deposited in the kidneys, causing calcifications in the renal parenchyma, or renal medullary .

NEPHROCALCINOSIS

is a congenital (birth) defect of the kidneys involving abnormal cystic dilatation of the collecting ducts in the medullary (inner) part of the kidney. Although it is present from birth, symptoms do not occur until adolescence or in adults between the ages of 30 and 50 years. The disease has a specific appearance that no other renal disease can mimic and is characterized by cyst formation and dilatation of the medullary and papillary sections of the collecting ducts in one or more of the medullary pyramids. There is no cure. Contrast CT urography is the test of choice to make a diagnosis. US does not have the resolution to detect the disease and can only show the echogenic pyramids, similar to nephrocalcinosis.

Medullary Spongy Kidney

Is when both the renal pelvis and parenchyma are inflamed, is a tubulointerstitial (the tubules and the interstitial tissue within the kidneys just out the glomerulus.) inflammation of the kidney and is the result of a bladder infection, most commonly caused by cystitis in women and prostatitis in men, which then ascends to the kidneys. It is more commonly seen in women between the ages of 15 and 35 years and can occur in 1% to 2% of all pregnant women. Men are not as commonly affected until later in life when they have prostate enlargement, BPH (Benign Prosthetic Hyperplasia) , causing urinary retention that increases the risk of developing a UTI.

Acute Pyelonephritis

is an uncommon, severe complication of acute pyelonephritis caused by Gram-negative bacteria, most commonly E. coli. It is a necrotizing, causing necrosis, infection from acute multifocal bacterial nephritis, with extension of the infection through the renal capsule. It is characterized by the presence of gas in the renal parenchyma, collecting system, and perinephric space. US demonstrates an enlarged kidney with echogenic foci, causing a ringdown artifact, representing gas inside the kidney, which can be located in the renal parenchyma, renal sinus, or both. When there is a lot of gas clumped together, “dirty shadowing” is seen, which is like an acoustic shadow, but instead of being echo free, it is filled with echoes, not allowing visualization of structures beneath it.

Emphysematous Pyelonephritis

is a rare, severe, chronic inflammatory disorder of the kidney. It is characterized by the destruction of renal parenchyma and replacement with lipid-laden macrophages (foamy histiocytes), chronic inflammatory cells, and granulation tissue. Usually due to chronic obstruction and infection, most commonly from: -Staghorn calculus (often caused by Proteus or E. coli) Chronic pyelonephritis -The kidney is nonfunctioning and replaced with granulomatous tissue Ultrasound: Enlarged kidney Loss of normal corticomedullary differentiation Multiple hypoechoic areas (dilated calyces, abscesses) Central echogenic staghorn calculus with shadowing May mimic renal tumor

Xanthogranulomatous Pyelonephritis

is a long-standing, persistent inflammation of the kidney that leads to scarring of the renal parenchyma and calyceal system, most often due to recurrent urinary tract infections (UTIs) or urine reflux (reflux nephropathy). -Recurrent or persistent infections of the kidney. -Obstruction (e.g., stones, congenital anomalies, enlarged prostate). -Vesicoureteral reflux (VUR) – where urine flows backward from the -bladder into the ureters/kidneys. -Over time, inflammation causes: -Progressive renal scarring -Tubular atrophy -Thinning of cortex -Loss of renal function

Chronic Pyelonephritis

1. An intraparenchymal infection — pus collects inside the kidney tissue. Causes: -Complication of acute pyelonephritis (especially if untreated or in immunocompromised patients) -Hematogenous spread (bacteria travel via bloodstream) -Urinary tract obstruction or stones Ultrasound Findings: -Focal, complex fluid collection within kidney -Thick, irregular walls -Internal echoes (pus) -May show no color flow on Doppler -Surrounding inflammatory changes 2. Infection spreads outside the renal capsule into the perinephric space (between kidney and Gerota’s fascia). Causes: -Extension of renal abscess -Trauma, surgery, or perforated renal stone -Diabetic or immunocompromised patients are at higher risk Ultrasound Findings: -Hypoechoic or complex mass adjacent to the kidney -Displaces kidney -Irregular walls, possible gas (causing dirty shadowing) -No vascularity inside the abscess Both are commonly caused by a bacterial infection such as E. Coli, Proteus, or Staphylococcus Aureus.

Renal and Perinephric Abscesses

is the infection of a hydronephrotic kidney where pus accumulates in the renal collecting system (pelvis and calyces). It is a urologic emergency. It combines two issues: 1. Obstruction (often due to stones, tumors, strictures) Infection → leading to pus filling the renal pelvis and calyces 2. Ureteral obstruction (e.g., stone, congenital narrowing) -Untreated hydronephrosis -Urinary tract infection (UTI) with impaired drainage -Immunocompromised states, diabetes Ultrasound Findings: -Hydronephrosis (dilated renal collecting system) -Internal echoes within the fluid (from pus/debris) -May show fluid-fluid levels -Absent ureteral jet on Doppler (if obstructed) -Thickened walls of collecting system -Tip: Unlike simple hydronephrosis (which is anechoic), this appears dirty or complex due to the presence of pus.

Pyonephrosis

Formerly known as acute kidney failure is a sudden decline in kidney function over hours to days, resulting in. Decreased urine output (oliguria or anuria), Accumulation of waste products (elevated BUN and creatinine), Disturbance of fluid, electrolyte, and acid-base balance, decrease in GFR Causes (Grouped by Location) 1. Prerenal (↓ Perfusion)Most common cause Due to reduced blood flow to the kidneys Examples: Hypovolemia (bleeding, dehydration) Heart failure Sepsis Renal artery stenosis 2. Intrinsic (Inside the kidney) Damage to kidney tissues Examples: Acute Tubular Necrosis (ATN) (most common intrinsic cause) Glomerulonephritis Interstitial nephritis Toxins (e.g., contrast media, aminoglycosides) 3. Postrenal (Obstruction) Blockage of urine outflow Examples: Kidney stones Enlarged prostate (BPH) Ureteral obstruction Tumors

Acute Kidney Injury

AKA Nephroblastoma is a malignant (cancerous) kidney tumor that primarily affects children, most commonly between 2 and 5 years of age. It arises from immature kidney cells that fail to develop normally during fetal life. Genetic Symptoms -Painless abdominal mass (most common) -Abdominal pain or distension -Hematuria (blood in urine) -Fever -Hypertension (due to renin secretion) -Anemia (sometimes) Ultrasound Findings -Large, well-defined solid mass in the kidney -Can displace normal kidney architecture -May have areas of necrosis or cystic degeneration -Possible vascular invasion (renal vein or IVC)

Wilm’s Tumor

are produced by mucosal herniation through defects in the bladders muscle wall arising as congenital defects or acquired lesions, usually associated with diseases resulting in bladder outlet obstruction or neurogenic conditions resulting in abnormalities in bladder function with chronically raised intravesical pressure.

Bladder Diverticula

is the most common type of bladder cancer, originating from the urothelium—the inner lining of the urinary tract, which is made of transitional epithelium. Also known as urothelial carcinoma Can occur in the: Bladder (most common) Ureters Renal pelvis Urethra Risk Factors: -Smoking (strongest risk factor) -Occupational exposure to aromatic amines (e.g., dye, rubber, textile industries) -Chronic bladder infections or catheter use -Schistosomiasis (increased risk for squamous cell carcinoma, but still relevant) Clinical Features: Painless hematuria (classic symptom) Frequency, urgency, or dysuria in some cases May lead to hydronephrosis if it obstructs ureters

Transitional Cell Carcinoma

is a cystic dilation of the distal ureter as it enters the bladder. It looks like a ballooning or sac-like bulge at the end of the ureter. Key Facts: Congenital in most cases (especially in children) -Can be intravesical (within the bladder) or ectopic (extends into the urethra or bladder neck) -Often associated with duplicated collecting systems (especially in pediatric cases) Ultrasound Appearance: -Round, cystic structure inside the bladder, near the ureteric orifice -May obstruct urine flow → leading to hydronephrosis of the upper collecting system

Ureterocele

Px has lost voluntary control of voiding owing to a disturbance in the neural pathways. Depending on the nerves involved and nature of damage, the bladder becomes either overactive (spastic or hyperreflexive) or underactive (flaccid or hypotonic). Myelodysplasia (a neural tube defect consisting of defective development of part of the spinal cord) is the most common cause in infants and children. Other causes: -congenital anomalies -systemic disease -infections -trauma -brain and spinal neoplasm

Neurogenic Bladder

follows severe blunt lower abdominal or pelvic trauma or penetrating abdominal or perineal injury. If the bladder was full at the time of blunt injury, rupture is more likely to occur, spilling urine into the peritoneum.

Bladder rupture

the kidneys are often affected by a condition called diabetic nephropathy—a serious complication of long-standing diabetes mellitus. Pathophysiology: -Caused by chronic hyperglycemia damaging the glomeruli (kidney's filtering units) -Leads to glomerular basement membrane thickening, mesangial expansion, and glomerulosclerosis Ultrasound Appearance: -Increased kidney size (early to mid stages) -Increased cortical echogenicity (brighter cortex) -Poor corticomedullary differentiation -May appear "bulky but bright" on ultrasound Later stages: -Kidneys may shrink in size (advanced damage) -Signs of chronic kidney disease (CKD)

Diabetic patient kidney

Common types of stones (nephrolithiasis) “C.U.S.S”

Common Types of Stones: Calcium oxalate: Most common, Radiopaque on X-ray Uric acid: From high purine intake, Radiolucent on X-ray Struvite: From UTIs (urease bugs), Staghorn calculi Cystine Genetic (rare): Hexagonal crystals in urine

are large, branching calculi that fill the renal pelvis and calyces, resembling a deer's antlers.

Staghorn stones

is a congenital condition where the urachus (a fetal duct) fails to close after birth, leaving an open connection between the bladder and the umbilicus. Ultrasound shows an anechoic tract between the bladder and the umbilicus.

patent urachus

occurs when the middle part of the urachus fails to close, but the ends near the bladder and umbilicus are sealed off. This leaves a fluid-filled cavity between the bladder and umbilicus.

Urachal cyst

refers to a bladder wall that has become thickened with irregular muscle ridges or bands, giving it a “lumpy” or “cobblestone” appearance on imaging—especially on ultrasound or cystography.

Bladder Trabiculae

is a collection of blood within the bladder, often resulting from trauma, surgery, catheterization, or bleeding disorders.

Bladder Hematoma

is a rare catecholamine-secreting tumor arising from chromaffin cells within the bladder wall—part of the extra-adrenal paraganglia. Can cause episodic hypertension, especially during urination (micturition attacks)

Pheochromocytoma

is a small, T-shaped device made of plastic wrapped with copper wire, inserted into the uterus for long-term, reversible contraception. Effective for up to 10 years -Hormone-free contraceptive option -Highly effective (>99%) -Rapid return to fertility after removal

Copper IUD

Embedded IUD

is a plastic, non-medicated intrauterine device shaped like a double “S” or trapezoidal loop. It was one of the earliest IUD designs used widely from the 1960s through the 1980s.

Lippes Loop IUD

is not an intrauterine device (IUD) for contraception but a permanent female sterilization device. It is a small, flexible coil placed in the fallopian tubes to cause tubal occlusion.

Essure

Used to support pelvic organs in cases of prolapse.

Pessary

means an enlarged spleen beyond its normal size over >12-13 cm in length. Due to infections, hematologic disease, congestion, storage disease, inflammatory or autoimmune disease. Often asymptomatic.

Splenomegaly

is a fluid-filled cavity within the spleen. They are rare and can be classified as: Primary (true) cysts: Have an epithelial lining, usually benign -cause either congenital, or parasitic (hydatid) Secondary (false or pseudocysts): No epithelial lining, usually post-traumatic or due to infarction/hemorrhage,

Splenic cyst

is a parasitic cyst caused by the larval stage of the tapeworm Echinococcus granulosus (most common) or E. multilocularis. It primarily affects the liver and spleen, but can occur in other organs. Ultrasound: Classic appearance: Well-defined cystic lesion with daughter cysts inside (multi-vesicular appearance) “Water lily sign”: floating membranes inside cyst after detachment of endocyst Calcifications may be present in the cyst wall (chronic)

Hydatid cyst

is the death of splenic tissue due to interruption of its blood supply, usually from arterial occlusion. Ultrasound: Early phase: may be normal or subtle hypoechoic area Later phase: wedge-shaped, peripheral, hypoechoic area with sharp borders No internal vascularity on Doppler Over time, may become more echogenic or scarred

Splenic infarction

is a localized collection of blood within or beneath the splenic capsule, usually due to trauma. Two types: -Subcapsular hematoma: Blood collects between spleen and its capsule, typically crescent-shaped -Intraparenchymal hematoma: Blood collection inside splenic tissue

Splenic hematoma

a type of cancer originating from lymphocytes (B-cells or T-cells). It may be primary (rare) or secondary as part of systemic lymphoma. Two types: -Primary involvement: confined mainly to spleen and splenic hilar nodes -Secondary involvement: common in non-Hodgkin lymphoma and some Hodgkin lymphoma cases Ultrasound: -Splenomegaly with hypoechoic nodules or masses -Multiple small nodules or a large mass can be seen -May have heterogeneous echotexture

Splenic Lymphoma

is a benign vascular tumor of the spleen, the most common benign splenic tumor. Composed of a tangle of blood vessels, Usually small and asymptomatic, Often discovered incidentally on imaging. Ultrasound: -Usually a well-defined, hyperechoic (bright) lesion in the spleen -Sometimes mixed echogenicity if thrombosis or fibrosis present

Splenic hemangioma

is a localized collection of pus within the spleen caused by infection. Causes: -Bacterial infection: Often from hematogenous spread (e.g., endocarditis) -Immunocompromised states: Diabetes, HIV, malignancy -Trauma: Secondary infection of splenic hematoma or infarct -Contiguous spread: From adjacent infections Ultrasound: -Hypoechoic or complex cystic lesion with irregular margins -May contain internal echoes or septations -Possible gas bubbles (echogenic foci with shadowing) indicating gas-forming organisms

Splenic abscess

is the anatomical layer of fat and connective tissue located just in front of the mammary gland (breast parenchyma) and behind the skin and subcutaneous tissue. -Lies between the skin and the fibroglandular breast tissue -Contains subcutaneous fat and skin structures such as sweat glands, hair follicles, and blood vessels -On imaging (especially ultrasound), it appears as a thin hypoechoic (dark) layer under the skin -Separates the skin from the deeper breast tissue (fibroglandular zone)

Premammary Zone

Aka Fibroglandular Zone; Location: Central portion of the breast, behind the premammary zone Composition: Glandular tissue (lobules and ducts) plus fibrous connective tissue Imaging: Appears denser and more echogenic (brighter) on ultrasound and mammogram Clinical: Most breast pathologies including cancers arise here

Mammary Zone

Location: Posterior to the mammary zone, in front of the pectoralis major muscle Composition: Mostly fat and connective tissue Imaging: Hypoechoic or fatty layer on ultrasound Clinical: Important for surgical planning and implant placement

Retromammary Zone

are fibrous connective tissue bands that support the breast by connecting the deep fascia (pectoral fascia) to the dermis (skin) of the breast. Help maintain breast shape and contour. Also anchor breast tissue to the overlying skin and underlying chest wall. Ultrasound -Seen as thin echogenic (bright) linear bands running through the breast tissue -Best visualized in the radial plane -May become distorted, thickened, or tethered in malignancy (pulling of ligaments = skin dimpling)

Cooper’s ligament

are tumor suppressor genes. They help repair DNA damage through homologous recombination. Inherited mutations in these genes lead to impaired DNA repair, increasing cancer risk. They are passed on in an autosomal dominant pattern. “BR east CA ncer gene”

BRCA1 and BRCA2

is a standardized system created by the American College of Radiology (ACR) to categorize breast imaging findings and guide clinical management. “0 to 6 – The Higher the # the higher the Risk, the More You Act” 0 = Zero certainty → need more views 1 & 2 = Chill 3 = Watch 4 = Worry → Biopsy (A,B, and C) 5 = Definitely cancer 6 = Already diagnosed

BI-RADS

cystic dilatation of a milk duct or ducts with inspissated milk. It is usually rounded and may become infected. Found during lactation. Are well defined and may have a fat-filled level. Usually resolve though may be aspirated.

GALACTOCELE

are small & located at the skin surface. From obstructed sebaceous gland or hair follicle. Oily material causes low level echoes. Asymptomatic unless infected. Well-defined. Scattered internal echoes and enhancement. Need a stand- off pad to visualize or 15 MHz transducer

SEBACEOUS CYSTS

Inflammation of the breast often during lactation but can be from other reasons such as infected or ruptured cysts. Usually bacteria and may spread through ducts, blood, or lymph. Clinical: painful, swollen breast, may have nipple discharge Sono: ectasia of ducts

Mastitis

acute thrombophlebitis of the superficial veins of the chest wall and breast. Anticoagulant therapy. -Clinical: tender cord-like mass. Skin may be red due to local infection. -Sono: dilated tubular superficial vein with internal echoes of the clot, absence of flow. -Edema of skin. May need a stand-off pad.

MONDOR DISEASE

most common benign masses in ages 15-35. Develop in response to estrogen stimulation. Slow growing, usually 1-5 cm in size. Tender, clinically firm, rubbery, mobile, palpable. Unilateral or bilateral. Sono: homogeneous, low-level echoes, smooth sharply marginated borders, often has a macrolobulated contour, hypovascular, horizontally orientated (wider than it is tall), round or ovoid, usually through transmission with refraction edge shadowing, occasionally may mimic malignancy. Older adenomas may undergo involution, calcification. May have peripheral CD or as feeder vessels

FIBROADENOMA

Rare large tumor with rapid growth. Consists of epithelial and fibrous tissue; ages 40-50. Can be huge, usually benign, rarely becomes malignant and then has the potential to mets to lung, bones, and liver. Palpable non-tender, mobile mass. May stretch and bulge the skin. Ultrasound: -Large, well-circumscribed hypoechoic or heterogeneous mass -May resemble a fibroadenoma, but typically larger and grows faster -May show cleft-like spaces (leafy pattern)

PHYLLODES TUMOR

benign breast enlargement associated with estrogen-testerone levels and hormonal imbalances. Steroid use can be a cause. Usually in older men or prepubertal boys.

GYNECOMASTIA

Is a type of fibroadenoma, is a common benign breast tumor composed of fibrous stroma and glandular epithelium. Over time, especially in older women, it may undergo degenerative changes, including calcification. Ultrasound: -Hypoechoic or heterogeneous mass -Shadowing may be seen due to dense calcifications -Margins typically smooth and well-defined “Popcorn fibroadenoma”

Calcified Fibroadenoma

is a rapidly growing, benign breast tumor that occurs in adolescents and young women, usually between ages 10–20. It is a variant of fibroadenoma, with increased stromal and epithelial cellularity, but no malignant potential. Often seen during puberty. Ultrasound: -Well-defined, oval or lobulated hypoechoic mass -Homogeneous internal echoes -Posterior acoustic enhancement -No internal calcifications (typically)

Juvenile Fibroadenoma

disease of the breast is a rare form of breast cancer involving the epidermis of the nipple and areola, typically associated with an underlying ductal carcinoma in situ (DCIS) or invasive ductal carcinoma. Accounts for 1–4% of all breast cancers, typically occurs in women >50 years, can rarely occur in men. Malignant glandular cells migrate along the lactiferous ducts to the nipple surface from an underlying carcinoma. → Think of persistent, one-sided nipple rash or crust that’s unresponsive to skin treatment.

Paget’s Disease

refers to a pulled-in or inverted appearance of the nipple that was previously normal (everted). It can be benign or pathologic, depending on the context.

Nipple retraction

Sonographic characteristics of breast mass “S.O.M.E.Post.”

1.shape: round, oval, irregular, triangular 2. Orientation: parallel, not parallel. (Taller than wider= malignant //wider than taller= benign) 3. Margins: well circumscribed, and distinct, angular, micro-lobulated, spiculated “starburst appearance” 4. Echo patter.: anechoic, hyper, echoic, hypoechoic, complex, cyst, or solid, isoechoic, heterogeneous. 5. Posterior features: enhancement, shadowing, combined.

is a non-invasive form of breast cancer where abnormal malignant cells are confined within the breast ducts and have not yet invaded surrounding breast tissue. Pre-cancerous or Stage 0 breast cancer limited to the ducts. Can progress to invasive ductal carcinoma if untreated. Common in women aged 40–60, but can occur younger/older. Often asymptomatic – usually found on screening mammogram “In Situ = hasn’t invaded”

Ductal Carcinoma In Situ

also called Infiltrating Ductal Carcinoma — is the most common type of breast cancer, accounting for about 70–80% of all invasive breast cancers. It originates in the milk ducts and invades the surrounding breast tissue. Mostly in women, but can occur in men too.

Invasive ductal carcinoma

is an aggressive subtype of breast cancer that lacks three key receptors commonly found in other types: -Estrogen receptor (ER) – ❌ Negative -Progesterone receptor (PR) – ❌ Negative -HER2 (human epidermal growth factor receptor 2) – ❌ Negative Most breast cancers are treated by targeting one or more of these receptors. Since TNBC lacks all three, hormonal therapy and HER2-targeted therapy won’t work, making it more challenging to treat. More common in younger women (<50), especially premenopausal, Black women and BRCA1 mutation carriers.

Triple-Negative Breast Cancer (TNBC)

Kidney’s Flashcards

(156 cards)