Renal/GU Flashcards
Difficult to control HTN w increase in Creatinine after adding ACE-I. DX?
Hypertension that is difficult to control, hypokalemia, and an increase in creatinine > 30% after adding an ACE inhibitor are characteristic of renal artery stenosis. Decreased renal perfusion in renal artery stenosis activates the renin-angiotensin-aldosterone system, which causes efferent arteriole constriction and increased sodium and water retention. This autoregulatory process maintains glomerular capillary hydrostatic pressure and GFR, but the increased elimination of potassium (caused by aldosterone) would result in hypokalemia, while systemic vasoconstriction caused by angiotensin II and Na+/H2O retention would result in hypertension. The administration of ACE inhibitors (e.g., lisinopril) to patients with renal artery stenosis inhibits the autoregulatory mechanism, resulting in a decrease in GFR and an increase in creatinine, as seen here. The use of a diuretic (hydrochlorothiazide) in this patient also contributes to a decrease in glomerular filtration pressure and GFR.
Most common cause of urinary tract obstruction in male newborns? Dx/Tx?
This patient presents with urosepsis, a palpable bladder (midline lower abdominal mass), and a history of oligohydramnios, all of which are features of urinary tract obstruction due to posterior urethral valves. Urethral valves are present in about 1/8,000 live births, making them the most common cause of urinary tract obstruction in newborn boys. The treatment of choice is cystoscopy with primary valve ablation.
Kid with edema, proteinuria and casts in urine. Dx? What type of casts?
Minimal change dz. Fatty casts are very common in the urinary sediment of patients with nephrotic syndrome. Massive proteinuria (> 3.5 g/24 h) results in low serum albumin, which reduces capillary oncotic pressure, thereby causing edema secondary to fluid leaking into tissue. Consequently, the liver increases all synthetic activity (involving albumin as well as other macromolecules, such as lipids) to compensate. Some of these excess lipids are reabsorbed by the proximal tubular epithelial cells. Once the cytoplasm becomes engorged, chunks of the cell can slough off into the tubular lumen, leading to the classic fatty casts on urinary sediment.
Kids 2-24 months w first presentation of UTI. First line imaging?
Renal and bladder u/s. In children between 2 and 24 months of age, voiding cystourethrography (VCUG) is only recommended if the first-line imaging modality revealed ureteric dilation, hydronephrosis, and/or renal scarring. In this age group, VCUG is also indicated as an adjunct to the first line of imaging if any of the following are present: a previously confirmed UTI, failure to respond within 48 hours of appropriate antibiotic therapy, poor urine flow, flank or suprapubic mass, organisms other than E. coli on urine culture, and increased creatinine levels. Since this child does not meet any of these criteria, VCUG is not the most appropriate next step. In any case, VCUG cannot be performed during an active UTI (as seen here) and should only be performed once the infection clears and bladder irritability subsides.
You suspect nephrolithiasis in pt w gout. what will urine pH be?
In patients with urolithiasis, a low urine pH (<5.5) is characteristic for calcium oxalate, uric acid, or cystine stones. The stones are formed from organic acids that are less soluble when protonated and therefore tend to form crystals in an acidic environment. Of these, only uric acid forms radiolucent stones that cannot be detected on plain x-ray, as seen in this patient. Persistently acidic urine is the most common risk factor for uric acid stones, which are also associated with gout and other states of hyperuricemia such as increased cell turnover, e.g., myelodysplastic syndrome. Gout is likely the reason for this patient’s history of toe pain and swelling (podagra). Gouty stone is “rhomboid”
young woman w fbromuscular dysplasia, causing bilateral renal artery stenosis. Tx?
An ACE inhibitor such as ramipril is indicated for the control of hypertension in patients with renal fibromuscular dysplasia. In patients with severe bilateral disease, as seen here, PTA without stent placement is also indicated and is indeed the first-line revascularization procedure. Stent placement is avoided because it does not confer any additional benefit, and might in fact make subsequent aortorenal bypass grafting much more difficult, should PTA prove ineffective.
Urinary stone in diatal ureter and 10 mm. Tx?
Ureterorenoscopy (URS) with stone removal is the first-line therapy for patients with urinary stones in the middle or distal ureter ≥ 10 mm, and – unlike shock wave lithotripsy – it is effective even in morbidly obese patients and, therefore, recommendable in this patient. It is also the suggested treatment in patients with ureteral stones who decide against or fail a trial of spontaneous stone passage. Overall, URS is the intervention with the greatest stone-free rate.
Kidney stone < 5mm. Tx?
IVF and analgesia
Kidney stone <7mm. Tx?
CCB or tamsulosin (alpha-blocker)
Kidney stone <1.5 cm and proximal. Tx?
Lithotripsy
Kidney stone >1.5 cm. Tx?
Surgery.
Kidneystone + infxn. Tx?
Nephrostomy if proximal. Stent if distal.
RTA associated w abnormal H+ secretion and nephrolithiasis. High urine pH. Low serum K+
RTA Type I (distal)
TA associated with abnormal HCO3- reabsorption and rickets. Low serum K+
RTA Type II (proximal)
RTA associated w low aldosterone state. Low urine pH.
RTA Type IV (distal)
Treat of hypernatremia
NS if unstable VS. D5W or 1/2 NS to replace free water loss
DDX for hypotonic hypervolemic hyponatremia
CHF, Cirrhosis, Nephrotic syndrome, AKI, CKD
T-wave flattening and U waves. Etiology?
HypoKalemia
Peaked T waves and wide QRS
Hyperkalemia
Treatment of Hyperkalemia
C BIG K Calcium gluconate Bicarb Insulin Glucose Kayexalate
First line treatment for moderate hypercalcemia
IV hydration
FeNA less than 1%. Type of AKI?
Prerenal
