Nephrology Flashcards
Renal blood flow normally drains ___ of the cardiac output
~20%
The most common clinical course of contrast nephropathy is characterized by a rise in SCr beginning ____ following exposure, peaking within ____ , and resolving within
24–48 h
3–5 days
1 week
Definition of AKI
AKI is currently defined by a rise from baseline of at least 0.3 mg/dL within 48 h or at least 50% higher than baseline within 1 week, or a reduction in urine output to < 0.5 mL/kg per h for longer than 6 h.
Diseases that may present with eosinophilluria (5)
Allergic interstitial nephritis
Atheroembolic dse
Pyelonephritis
Cystitis
Glomerulonephritis
Diseases that may present with RBC casts (4)
Glomerulonephritis
Vasculitis
malignant Hypertension
Thrombotic Microangiopathy
Diseases that may present with WBC casts (5)
Interstitial Nephritis
Glomerulonephritis
Plyelonephritis
Allograft Rejection
Malignant Infiltration of the kidney
Diseases that may present with RTE casts (5)
ATN
Tubulointerstitial nephritis
Acute cellular allograft reaction
Myoglobulinuria
Hemoglobinuria
Diseases that may present with granular casts (4)
ATN
GN
Vasculitis
TIN
Diseases that may present with crystalluria
Acute uric acid nephropathy
Caox
Drugs or toxin (acyclovir, indinavir, sulfadiazin, amoxicillin)
Fe Na of pre renal AKI
< 1%
Dose for furosemide challenge
1-1.5 mg/kg
UO of ________ after IV furosemide may identify patients at higher risk of progression to more severe AKI, and the need for renal replacement therapy
< 200 mL over 2 h a
Molecule can be detected shortly after ischemic or nephrotoxic injury in the urine and, therefore, may be an easily tested biomarker in the clinical setting
KIM-1
_____ is highly upregulated after inflammation and kidney injury and can be detected in the plasma and urine within 2 h of cardiopulmonary bypass– associated
NGAL
patients with AKI should achieve a total energy intake of ____ kcal/kg per day.
20–30 kcal/kg per day
Protein intake in AKI
_____ g/kg in noncatabolic AKI without the need for dialysis;
_____ g/kg per day in patients on dialysis;
and up to a maximum of ____ per day if hypercatabolic and receiving continuous renal replacement therapy
0.8–1.0 g/kg per day
1.0–1.5 g/kg
1.7 g/kg
Alkali supplementation may attenuate the catabolic state and possibly slow CKD progression and is recommended when the serum bicarbonate concentration falls below ____ mmol/L.
20–23
These PTH FGFR3 changes start to occur when the GFR falls below ___ mL/min.
60 mL/min
_____ is a devastating condition seen almost exclusively in patients with advanced CKD. It is heralded by livedo reticularis and advances to patches of ischemic necrosis, especially on the legs, thighs, abdomen, and breasts
Calciphylaxis
Blood thinner that is considered a risk factor for calciphylaxis
Warfarin
Warfarin is commonly used in HD patients in whom most direct oral anticoagulants (DOACs) are contraindicated, and one of the effects of warfarin therapy is to decrease the vitamin K–dependent regeneration of matrix GLA protein which is important in preventing vascular calcification
Target PTH level for CKD
150 and 300 pg/mL
_______ is leading cause of morbidity and mortality in px at every stage of CKD
Cardiovascular disease
First line therapy for CKD to reduce BP
Salt restriction
In CKD patients with diabetes or proteinuria >1 g per 24 h, blood pressure should be reduced to ______ , if achievable without prohibitive adverse effects.
< 130/80 mmHg
normocytic, normochromic anemia is observed as early as stage ___ CKD and is almost universal by stage __
3,4
Target Hb for CKD
10-11.5 g/dl
Peripheral neuropathy usually becomes clinically evident after the patient reaches stage __ CKD, although electrophysiologic and histologic evidence occurs earlier.
4
P-eripheral neuropathy, P-or
Class of drugs that do not require dose reduction when EGFR is less than 50% of normal
SGLT 2 inhibitors
A skin condition unique to CKD patients called _____ consists of progressive subcutaneous induration, especially on the arms and legs.
nephrogenic fibrosing dermopathy
The condition is seen very rarely in patients with CKD who have been exposed to the magnetic resonance contrast agent gadolinium.
Current recommendations are that patients with CKD stage 3 (GFR 30–59 mL/min) should minimize exposure to gadolinium, and those with CKD stages 4–5 (GFR < 30 mL/min) should avoid the use of gadolinium agents unless it is medically necessary
Diseases where kidney size may be normal in the face of CKD (3)
diabetic nephropathy, amyloidosis, and HIV nephropathy
Discrepancy ___ cm in kidney length suggests either unilateral developmental abnormality or dse process or renovascular dse with arterial insufficiency affecting 1 kidney more than the other
> 1 cm
The most important complication of arteriovenous grafts is _______
thrombosis of the graft and graft failure
due principally to intimal hyperplasia at the anastomosis between the graft and recipient vein
_______ is the most common acute complication of hemodialysis, particularly among patients with diabetes mellitus.
Hypotension
Peritonitis in peritoneal dialysis is defined as _____
elevated peritoneal fluid leukocyte count (100/mm3 , of which at least 50% are polymorphonuclear neutrophils
_____ is the procedure of choice to rule out urinary obstruction or to confirm the presence of perirenal collections of urine, blood, or lymph.
Diagnostic ultrasound
The first rejection episode is usually treated with IV administration of
methylprednisolone, 500–1000 mg daily for 3 days.
Failure to respond is an indication for antibody therapy, usually with antithymocyte globulin.
Greater than ____mg/day of albuminuria represents frank proteinuria and more advanced renal disease
300 mg/24 h
___________ glomerulonephritis demonstrates hypercellularity of mesangial and endothelial cells, glomerular infiltrates of PMNs, granular subendothelial immune deposits of IgG, IgM, C3, C4 , and C5–9, and subepithelial deposits
PSGN
In PSGN In the first week of symptoms, ____ % of patients will have a depressed CH50 and decreased levels of C3 with normal levels of C4
90%
Treatment for PSGN
Treatment is supportive, with control of hypertension, edema, and dialysis as needed.
Antibodies that that fix complement correlate best with the presence of renal disease in lupus nephritis
Anti-dsDNA
Hypocomplementemia is common in patients with acute lupus nephritis (70–90%) and declining complement levels may herald a flare.
Class of Lupus nephritis that presents with mesangial hypercellularity with expansion of the mesangia matrix
Class II
Class of Lupus nephritis that presents with focal endocapillary and extracapillary proliferation with focal subendothelial immune deposits and mild mesangial expansion
Class III
Class of Lupus nephritis that presents with diffuse endocapillary and extracapillary proliferation with diffuse subendothelial immune deposits and mesangial alterations
Class IV
Class of Lupus nephritis that presents with thickened BM with diffuse subepithelial immune deposits
V
Class of lupus nephritis with Global sclerosis of nearly all glomerular capillaries
VI
Class of lupus nephritis with the most varied course
III
Henoch-Schönlein purpura is distinguished clinically from IgA nephropathy by (4).
prominent systemic ssx, a younger age (<20 years old), preceding infection, and abdominal complaints
Type I MPGN is associated with Hepatiti __ infection
C
Primary responders are patients who have a complete remission ( of____ proteinuria) after a single course of prednisone; steroid-dependent patients relapse as their steroid dose is tapered.
<0.2 mg/24 h
Response to steroids
Frequent relapsers have ____ relapses in ___ months following taper, and steroid-resistant patients fail to respond to steroid therapy.
two or more relapses in the 6 months
Adults are not considered steroid-resistant until after ___ months of therapy.
4
First line therapy for MCD
Prednisone
Treatment of patients with primary FSGS should include
inhibitors of the renin-angiotensin system
The treatment of secondary FSGS typically involves
treating the underlying cause and controlling proteinuria.
GN that has the highest reported incidences of renal vein thrombosis, pulmonary embolism, and deep-vein thrombosis.
MGN AKA membranous nephropathy
Therapy with immunosuppressive drugs is also recommended for patients with primary MGN and persistent proteinuria ____ g/day
(>3.0 g/24 h).
What microscopic finding is a sensitive indicator for the presence of diabetes but correlates poorly with the presence or absence of clinically significant nephropathy.
Thickening of the GBM
Microalbuminuria appears ____ years after the onset of diabetes.
5–10
More than ___% of patients with type 1 diabetes and nephropathy have diabetic retinopathy
90%
so the absence of retinopathy in type 1 patients with proteinuria should prompt consideration of a diagnosis other than diabetic nephropathy
There is a significant correlation between the presence of retinopathy and the presence of __________ nodules .
Kimmelstiel-Wilson
Characteristic lesion of HIVAN
The lesion in HIVAN is FSGS, characteristically revealing a collapsing glomerulopathy
Hydronephrosis may be absent on ultrasound when obstruction is less than ____ in duration or associated with volume contraction, staghorn calculi, retroperitoneal fibrosis, or infiltrative renal disease.
48 h
Type of stone not influenced by pH
Calcium Oxalate
Uric acid stones form only when the urine pH is consistently _____ , whereas calcium phosphate stones are more likely to form when the urine pH is _____ .
≤5.5 or lower
≥6.5or higher
Size of stone with low probability of spontaneous passage
> = 6mm
The “gold standard” diagnostic test is ____ for urolithiasis
helical CT without contrast.
Urine volume needed to lessen risk of stone formation
> 2L/day
______ also known as infection stones or triple-phosphate stones, form only when the upper urinary tract is infected with urease-producing bacteria such as Proteus mirabilis, Klebsiella pneumoniae, or Providencia species.
Struvite stones
Cystine stones may be treated with medication that covalently binds to cystine like ______ and a medication that raises urine pH.
eg tiopronin or penicillamine
Preferred alkalinizing agent for cystine stones
The preferred alkalinizing agent to achieve a urine pH of 7.5 is potassium citrate or bicarbonate as sodium salts may increase cystine excretion
Pentad for TTP
MAHA, thrombocytopenia, neurologic symptoms, fever, and renal failure.
Which has deficiency of ADAMST13? HUS or TTP?
TTP
Antibody that may identify young patients at risk for scleroderma renal crisis
Anti-U3-RNP may identify young patients at risk for scleroderma renal crisis.
Antibody that is a negative predictor of scleroderma renal crisis
Anticentromere antibody, in contrast, is a negative predictor of this disorder.
First line therapy for scleroderma renal crisis
ACE-inhibition
____ and _____ account for ~90% of cases of acute intrinsic renal failure
Ischemic and toxic Acute tubular necrosis (ATN)
BUN: crea ratio of prerenal azotemia
> 20:1
Fe Na of prerenal azotemia
< 1%
Causes of hypercoagulable state in nephrotic syndrome
urinary losses of antithrombin III
reduced proteins S and C
hyperfibrinogenemia
enhanced platelet aggregation.
Cause of hyperlipidemia in nephrotic syndrome
inc hepatic lipoprotein synthesis.
Hematuria with dysmorphic RBCs, RBC casts, and protein excretion > ____mg/day is virtually diagnostic of glomerulonephritis.
> 500 mg/d
1st test when evaluating polyruia
urine osmolality
Recommended as the best method for distinguishing between central and nephrogenic diabetes insipidus.
plasma AVP level
AVP secretion is stimulated as systemic osmolality increases above a threshold level of ____
~285 mOsm/kg
Serum uric acid is often low (<_____) in patients with SIAD
4 mg/dL
in contrast, patients with hypovolemic hyponatremia will often be hyperuricemic, due to a shared activation of proximal tubular Na+-Cl– and urate transport
Most common malignancy associated with SIADH
small cell lung CA
Overly rapid correction of hyponatremia (>________ in 24h and ____ in 48h) is also associated with a disruption in integrity of the bloodbrain barrier, allowing the entry of immune mediators that may contribute to demyelination.
> 8–10 mM in 24 h or 18 mM in 48 h
_______ has long been a cornerstone of the therapy of chronic hyponatremia.
Water deprivation
The urine-to-plasma electrolyte ratio (urinary [Na+] + [K+]/plasma [Na+]) can be exploited as a quick indicator of electrolyte-free water excretion;
o patients with a ratio of >1 should be more aggressively restricted _______
o those with a ratio of ~1 should be restricted to _______,
o those with ratio <1 should be restricted to _____
(<500 mL/d)
500–700 mL/d
1 L/d
________ is perhaps most appropriate for the management of significant and persistent SIAD (e.g., in small-cell lung carcinoma) that has not responded to water restriction and/or oral furosemide and salt tablets
Oral tolvaptan
Many patients with SIAD respond to combined therapy with oral furosemide, 20 mg twice a day (higher doses may be necessary in renal insufficiency), and oral salt tablets; furosemide serves to inhibit the renal countercurrent mechanism and blunt urinary concentrating ability, whereas the salt tablets counteract diuretic-associated natriuresis.
Treatment of acute symptomatic hyponatremia should include hypertonic 3% saline (513 mM) to acutely increase plasma Na+ concentration by _____ to a total of ____; this modest increase is typically sufficient to alleviate severe acute symptoms
1–2 mM/h
4–6 mM
__________ is the most frequent manifestation of hypernatremia
Altered mental status
ranging from mild confusion and lethargy to deep coma.
Patients with NDI will fail to respond to DDAVP, with a urine osmolality that increases by __% or < ____mOsm/kg from baseline, in combination with a normal or high circulating AVP level
<50%
< 150 mOsm/kg
A rare exception to the slow correction of hypernatremia is patients with acute hypernatremia (<48 h) due to sodium loading, who can safely be corrected rapidly at a rate of _____
1 mM/h
Class of diuretics that may reduce polyuria due to NDI, ostensibly by inducing hypovolemia and increasing proximal tubular water reabsorption.
Thiazides
Random testing of plasma renin activity (PRA) and aldosterone is a helpful screening tool in hypokalemic and/or hypertensive patients, with an aldosterone:PRA ratio of ____ suggestive of primary hyperaldosteronism.
> 50
Critical diagnostic test in Giterlman vs Barter syndrome
urinary calcium excretion
Patients with GS are uniformly hypomagnesemic and exhibit marked hypocalciuria (hece hypercalcemic), rather than the hypercalciuria typically seen in BS
ECG findings are most marked when serum K+ is <_____
2.7mmol/L
Urine K value that will differentiate extrarenal from renal losses
< 15 mmol / day for extrarenal losses
TTKG in hypokalemia level that connotes inc K secretion
> 4
TTKG level in hypokalemia that connotes inc tubular flow
< 2
2bular
Urine calcium/crea for Barters
> 0.20
B for bente
Urine calcium/crea for Gitelman
< 0.15
Classically, the ECG manifestations in hyperkalemia progress from tall peaked T waves (_____), to a loss of P waves (____) to a widened QRS complex (____), and, ultimately, a to a sine wave pattern ( )
5.5–6.5 mM (t wave)
6.5–7.5 mM (loss of p wave)
7.0–8.0 mM ( QRS)
>8.0 mM (sine)
Electrolyte imblances that may potentiate digoxin
Hypokalemia and hypercalcemia
In hyperkalemic patients with glucose concentrations of ≥ _____mg/dL, insulin should be administered without glucose, again with close monitoring of glucose concentrations
200–250
TTKG level in hyperkalemia that connotes reduced tubular flow
> 8
TTKG level in hyperkalemia that connotes decreased distal K secretion
< 5
Drug that you should give if TTKG < 5 in hyperkalemia to test for tubular resistance
Fludrocortisone
F-ive, F-ludrocortisone
Hypercalcemia associated with granulomatous disease (e.g., sarcoidosis) or lymphomas is caused by ___________
enhanced conversion of 25(OH)D to the potent 1,25(OH)2 D.
The first step in the diagnostic evaluation of hyper- or hypocalcemia is to ensure that ____________
the alteration in serum calcium levels is not due to abnormal albumin concentrations
When serum albumin concentrations are reduced, a corrected calcium concentration is calculated by adding 0.2 mM (0.8 mg/dL) to the total calcium level for every decrement in serum albumin of 1.0 g/dL below the reference value of 4.1 g/dL for albumin, and, conversely, for elevations in serum albumin
Chronic hypercalcemia is most commonly caused by __________ , as opposed to the second most common etiology of hypercalcemia, an underlying ______.
primary hyperparathyroidism
malignancy
Initial therapy of significant hypercalcemia begins with ________
volume expansion because hypercalcemia invariably leads to dehydration
4–6 L of IV saline may be required over the first 24 h, keeping in mind that underlying comorbidities may require the use of loop diuretics to enhance Na and Ca excretion
In patients with 1,25(OH)2 D-mediated hypercalcemia, ______ are the preferred therapy, as they decrease 1,25(OH)2 D production.
glucocorticoids
Formula for plasma osmolality
Plasma osmolality is calculated according to the following expression: Posm = 2Na + Glu + BUN (all in mmol/L), or, using conventional laboratory values in which glucose and BUN are expressed in milligrams per deciliter: Posm = 2Na+ Glu/18 + BUN/2.8.
Type of RTA that is most often due to generalized proximal tubular dysfunction manifested by glycosuria, generalized aminoaciduria, and phosphaturia
Proximal RTA (type 2 RTA)
Type of RTA with the typical findings including hypokalemia, a non-AG metabolic acidosis, low urinary NH4 + excretion (positive UAG, low urine [NH4 +]), and inappropriately high urine pH (pH > 5.5).
classic distal RTA (type 1 RTA)
Remember low urinary NH4 exretion!!!
Most patients have hypocitraturia and hypercalciuria, so nephrolithiasis, nephrocalcinosis, and bone disease are common.
bONE (b1)
Type of RTA in which hyperkalemia is disproportionate to the reduction in (GFR) because of coexisting dysfunction of potassium and acid secretion.
distal RTA (type 4 RTA)
______ syndrome results from an inherited gain of function mutation of genes that regulate the collecting duct Na+ channel (ENaC).
Liddle’s
most common acid-base disturbance in critically ill patients and, when severe, portends a poor prognosis
Chronic respiratory alkalosis
the most common cause of drug-induced respiratory alkalosis as a result of direct stimulation of the medullary chemoreceptor
Salicylates
mechanism that predominantly
mediates potassium balance in CKD
Aldosterone dependent secretion in the
distal nephron
complication is prevented by
supplemental bicarbonate in CKD
protein catabolism
Target blood pressure for
patients with CKD and concomitant proteinuria?
<130/80
most common organisms implicated in peritonitis in px undergoing peritoneal dialysis
G+ cocci
main feature distinguishing
pyelonephritis from cystitis?
fever
What is the threshold for diagnosing asymptomatic bacteriuria in urine culture expressed in bacterial CFU/mL?
10^5
type of AKI caused by cyclosporine
pre-renal
portion of the kidney is particularly
susceptible to ischemic damage?
outer medulla
PSGN usually develops
After _____ weeks post impetigo/skin infection
After _____weeks post strep pharyngitis
2-6 weeks
1-3 weeks
Most common cause of nephrotic syndrome in the elderly
MGN
Biopsy: uniform thickening of the basement
membrane along the peripheral capillary loops on light microscopy, diffuse granular deposits of IgG and C3 on IF and subepithelial electron-dense deposits on EM
urine osmolality of pre renal AKI
> 500
urine crea/ plasma crea ratio of pre renal AKI
> 40
Vomiting, nausea, confusion, and seizures, usually at plasma Na+ concentration _____
<125 mM
The ultimate “gold standard” for the diagnosis of hypovolemic hyponatremia is __________
the demonstration that plasma Na+ concentration corrects after hydration with normal saline
Causes of low FeNa aside from pre-renal AKI
Rhabdomyolysis
Sepsis
Hemolysis
CIN
-sis + CIN
Myeloma light chains can also cause AKI
by
Binding to Tamm-Horsfall protein to form obstructing intratubular
casts
The presence of hematuria and RBC casts on urinalysis in the setting of azotemia, oliguria, edema and hypertension point to the possibility of which major renal syndrome?
Acute nephritis
If BM thickening is a sensitive indicator of DM but does not corrrelate with nephropathy, what histologic finding correlates well with DM nephropathy?
Mesangial expansion
Peripheral neuropathy usually becomes clinically evident after the patient reaches Stage ___ CKD
4
P-eripheral neuropathy P-or
Formula for corrected anion gap
CorrectedAnionGap=MeasuredAnionGap+2.5×(4.0−SerumAlbumin(g/dL))
*some sources use 4.5 as normal value for albumin
In IgA nephropathy what provides the greatest predictive power for adverse renal outcomes
Monitoring of persistent proteinuria
The primary mechanism mediating potassium balance in a patient with chronic kidney disease is ___
aldosterone-dependent secretion in the distal nephron
What possible complication is prevented by bicarbonate supplementation in CKD
Protein catabolism
What is the mechanism of Vancomycin in causing acute kidney injury?
Intratubular obstruction
What is the osmotic threshold for AVP release?
More than 285 mOsm/kg
In a patient with milk alkali syndrome, what is the likely mechanism for metabolic alkalosis?
exogenous bicarb loads
What is the mechanism of hypokalemia in magnesium deficiency?
Intracellular block of K efflux through the secretory K channel
how do you treat PSGN?
Treatment is mainly supportive, and directed towards control of hypertension, oedema, and dialysis, if necessary.
Vitamin C supplementation increases risk for what kind of stone formation
CaOx
What is the recommended urine pH for uric acid stones
6.5
Most common cause of nephrotic syndrome in the elderly
Mebranous nepropathy/ MGN
What are the containdications to kidney biopsy?
Contraindications for kidney biopsy
Not advisable for patients with bilaterally small
kidneys:
* Technically difficult and higher chances of bleeding
* Scarred tissue will not show underlying disease
* Disease-specific therapy no longer useful
Other contraindications:
* Uncontrolled hypertension
* Active UTI
* Bleeding diathesis (including anticoagulation)
* Severe obesity
A urine osmolality <___mOsm/kg is suggestive of polydipsia
100
from the earliest stages of microalbuminuria, it usually takes ___ years to reach ESRD.
10–20
GNs that presents with hypocomplementenemia (3)
MPGN
Lupus nephritis
PSGN
Type of cast seen in pre renal AKI
granular/hyaline
