PATH - General

Question 1

Potter sequence (syndrome)

Answer 1

Oligohydramnios–>compression of
developing fetus–>limb deformities, facial anomalies (eg, low-set ears and
retrognathia, flattened nose), compression of chest and lack of amniotic fluid aspiration into fetal lungs–>pulmonary hypoplasia (cause of death).

POTTER sequence associated with:
Pulmonary hypoplasia
Oligohydramnios (trigger)
Twisted face
Twisted skin
Extremity defects
Renal failure (in utero)

“Babies who can’t “Pee” in utero develop Potter sequence”

Question 2

Multicystic cystic dysplastic kidney

Answer 2

Ureteric bud fails to induce differentiation of metanephric mesenchyme–>nonfunctional kidney consisting of cysts and connective tissue.

Often diagnosed prenatally via ultrasound.

Question 3

Renal tubular acidosis

Answer 3

A disorder of the renal tubules that leads to normal anion gap (hyperchloremic) metabolic acidosis.

Question 4

Distal renal tubular acidosis (type 1)

Answer 4

Urine pH > 5.5

Defect in ability of α intercalated cells to secrete H+–>no new HCO3− is
generated–>metabolic acidosis

Associated with *hypokalemia, INC risk for calcium phosphate kidney stones

Question 5

Proximal renal tubular

acidosis (type 2)

Answer 5

Urine pH INC excretion of HCO3− in urine and
subsequent metabolic acidosis

Associated with *hypokalemia,  risk for hypophosphatemic rickets.

Question 6

Hyperkalemic renal tubular acidosis (type 4)

Answer 6

Urine pH *hyperkalemia–>DEC NH3 synthesis in PCT–>DEC NH4+

excretion.

Question 7

Casts in urine

Answer 7

Presence of casts indicates that hematuria/pyuria is of glomerular or renal tubular origin

Question 8

RBC casts

Answer 8

Glomerulonephritis, malignant hypertension.

Question 9

WBC casts

Answer 9

Tubulointerstitial inflammation, acute pyelonephritis, transplant rejection

Question 10

Fatty casts (“oval fat
bodies”)

Answer 10

Nephrotic syndrome.

Associated with “Maltese cross” sign.

Question 11

Granular (“muddy brown”) casts

Answer 11

Acute tubular necrosis

Question 12

Waxy casts

Answer 12

End-stage renal disease/chronic renal failure

Question 13

Hyaline casts

Answer 13

Nonspecific, can be a normal finding, often seen in concentrated urine samples

Question 14

Hydronephrosis

Answer 14

Distention/dilation of renal pelvis and calyces

Usually caused by urinary tract obstruction, other causes include retroperitoneal fibrosis,
vesicoureteral reflux

Serum creatinine becomes
elevated only if obstruction is bilateral or if patient has only one kidney

Leads to compression and
possible atrophy of renal cortex and medulla

Question 15

Stress incontinence

Answer 15

Outlet incompetenceŽ–>leak with INC intra-abdominal pressure (sneezing, lifting)

Question 16

Urgency incontinence

Answer 16

Overactive bladder–>leak with urge to void immediately

Question 17

Mixed incontinence

Answer 17

Features of both stress and urgency incontinence

Question 18

Overflow incontinence

Answer 18

Incomplete emptying–>leak with overfilling

INC postvoid residual (urinary retention) on catheterization or ultrasound

Question 19

Urinary tract infection

acute bacterial cystitis

Answer 19

Inflammation of urinary bladder.

Presents as suprapubic pain, dysuria, urinary frequency, urgency.

Systemic signs are usually absent

-E coli (most common).
ƒ-Staphylococcus saprophyticus—seen in sexually active young women
-Klebsiella.
ƒ-Proteus mirabilis—urine has *ammonia scent.

Question 20

Acute pyelonephritis

Answer 20

Affects *cortex with relative sparing of glomeruli/vessels.

Neutrophils infiltrate renal interstitium

Presents with fevers, flank pain (costovertebral angle tenderness), nausea/vomiting, chills

Complications include chronic pyelonephritis, renal papillary necrosis, perinephric abscess,
urosepsis.

Question 21

Chronic pyelonephritis

Answer 21

result of recurrent episodes of acute pyelonephritis

Coarse, asymmetric corticomedullary scarring, blunted calyx.

Tubules can contain eosinophilic casts resembling thyroid tissue (thyroidization of kidney).

Question 22

Diffuse cortical necrosis

Answer 22

Acute generalized cortical infarction of *both kidneys.

Likely due to a combination of vasospasm and DIC.

Associated with obstetric catastrophes (abruptio placentae), septic shock

Question 23

Renal osteodystrophy

Answer 23

Hypocalcemia, hyperphosphatemia, and failure of vitamin D hydroxylation associated with chronic renal disease–>2° hyperparathyroidism

Causes subperiosteal thinning of bones

Question 24

Acute kidney injury

acute renal failure

Answer 24

an abrupt decline in renal function as measured by INC creatinine and INC BUN.

Question 25

Prerenal azotemia (AKI)

Answer 25

Due to DEC RBF (eg, hypotension)–>DEC GFR

INC BUN/creatinine ratio
DEC FENa.

Question 26

Intrinsic renal failure (AKI)

Answer 26

Generally due to acute tubular necrosis or ischemia/toxins

DEC BUN/creatinine ratio

Urine has *epithelial/granular casts

Question 27

Postrenal azotemia (AKI)

Answer 27

Due to outflow obstruction (stones, BPH, neoplasia, congenital anomalies).

Develops only with
*bilateral obstruction

Question 28

Acute interstitial nephritis

tubulointerstitial nephritis

Answer 28

Acute interstitial renal inflammation

Pyuria (classically eosinophils) and azotemia occurring after administration of drugs that act as haptens, inducing hypersensitivity

Associated with fever, rash, hematuria, and
costovertebral angle tenderness, but can be
asymptomatic

Remember these P’s:
ƒ-Pee (diuretics)
ƒ-Pain-free (NSAIDs)
ƒ-Penicillins and cephalosporins
ƒ-Proton pump inhibitors
ƒ-RifamPin

Question 29

Acute tubular necrosis

Answer 29

Most common cause of acute kidney injury in hospitalized patients

**Key finding: granular (“muddy brown”) casts

Can be fatal, especially during initial *oliguric phase. 

INC FENa

-Ischemic—2° to DEC renal blood flow. Results
in death of tubular cells that may slough into tubular lumen (*PCT and thick ascending limb
are highly susceptible to injury).
-Nephrotoxic—2° to injury resulting from toxic substances, crush injury (myoglobinuria), hemoglobinuria. *PCT is particularly susceptible to injury.

Question 30

Renal papillary necrosis

Answer 30

Sloughing of necrotic renal papillae–>gross
hematuria and proteinuria

May be triggered by recent infection or immune stimulus.

Associated with sickle cell disease or trait, acute pyelonephritis, NSAIDs, diabetes mellitus.

SAAD papa with papillary necrosis:
Sickle cell disease or trait
Acute pyelonephritis
Analgesics (NSAIDs)
Diabetes mellitus