USMLE Step III/Nephro, electrolyte
What is ileus associated with?
Abdominal surgeries, opiates, hypokalemia, sepsis
At what age should you consider bladder and kidney US on febrile kids presenting with UTI's?
After a first-time febrile urinary tract infection, children age <24 months should undergo renal and bladder ultrasound to evaluate for anatomic abnormalities. Those with recurrent infections or abnormal ultrasound findings should also undergo a voiding cystourethrogram.
What should all children under the age of 24mo undergo when they are febrile and test positive for a UTI on UA?
All children age <24 months with a febrile UTI should undergo renal and bladder ultrasound to evaluate for hydronephrosis and ureteral dilation, which may suggest an underlying anatomic abnormality.
What is the mainstay therapy for hyponatremia in the setting of CHF?
Angiotensin II and the presence of low cardiac output also stimulate thirst, leading to increased water intake and worsening hyponatremia. Water intake restriction is the mainstay of initial therapy for hyponatremia in patients with CHF.
Which antibodies do NOT correlate with nephritic SLE disease?
Anti-double stranded DNA and complement levels can be used to monitor for active renal involvement in patients with systemic lupus erythematosus. Antinuclear antibody titers do not correlate with renal disease activity.
When should you consider prophylactic abx in recurrent UTI patients?
Antibiotic prophylaxis can be considered in women who have had more than two UTIs in six months or more than three UTIs in a year. Prophylaxis can be used either continuously for up to several years or solely after intercourse in women whose UTIs occur only after sexual activity. Fluoroquinolones, sulfamethoxazole-trimethoprim, and nitrofurantoin are the most commonly used agents. An additional option is providing female patients with antibiotics in advance, and allowing the patient to self-diagnose and treat her UTIs.
What are the first line abc treatment for UTI in pregnant women?
Augmentin Cephalexin Fosfomycin Treatment of asymptomatic bacteriuria during pregnancy decreases the risk of maternal (eg, pyelonephritis) and fetal complications (eg, preterm birth, low birth weight, perinatal mortality). First-line antibiotics during pregnancy include cephalexin, amoxicillin-clavulanate, or fosfomycin.
What is the initial diagnostic approach for ADPKD?
Autosomal dominant polycystic kidney disease is an inherited disorder characterized by multiple bilateral renal cysts. Patients are often asymptomatic, but many develop hypertension, hematuria, proteinuria, renal insufficiency, and/or flank pain. Diagnosis is usually made by renal ultrasound
What is Chvostek sign? Trousseau sign?
Both are signs for hypocalcemia 1. Chvostek sign- tapping angle of jaw elicits facial muscle contraction 2. Trousseau- BP cuff elicits hand (carpopedal) spasms
Which complement will be low in post-streptococcal glomerunolenphrits? which will be normal?
C3 Normal C4 complement levels
What are some causes of SIADH?
CNS disturbance (eg, stroke, hemorrhage, trauma) Medications (eg, carbamazepine, SSRIs, NSAIDs) Lung disease (eg, pneumonia) Ectopic ADH secretion (eg, small cell lung cancer) Pain &/or nausea
Which calcium form is decreased during hypoalbuminemia states?
Calcium homeostasis involves blood transport as albumin-bound calcium (45%), ionized calcium (40%), or calcium bound to inorganic and organic anions (15%). Patients with hypoalbuminemia can have decreased total plasma calcium. However, the ionized serum calcium (physiologically active form) is hormonally regulated and remains stable.
What are the extra renal presentation of ADPKD?
Cerebral aneurysms Hepatic & pancreatic cysts MVP, aortic regurgitation Colonic diverticulosis Ventral & inguinal hernias
What is the though pathophysiology mechanism of contrast induced nephropathy ?
Contrast-induced renal vasoconstriction is thought to cause contrast-induced nephropathy (CIN) Some theorized that free radicals may have a inflammatory response to to aid in damaging directly
How do you correct for calcium when you have hypoalbuminemia?
Corrected Ca = Measured Ca + 0.8 x [Measured Alb -4]
How do corticosteroids cause HTN?
Corticosteroids cause hypertension by stimulating sodium and water retention.
What is the approach of ureteral stones ?
Depends on size, if <10mm supportive and DC unless pain and or nausea is not controlled, if >10mm consult urology from the ED
How does Dextrose help in AKA?
Dextrose leads to an increase in insulin secretion, which leads to the metabolism of ketone bodies to bicarbonate. Almost all alcoholics are likely to be thiamine-deficient unless proven otherwise.
Why do TCA's work for refractory nocturnal enuresis ?
Efficacy results from the anticholinergic effect of urinary retention
Definition of enuresis
Enuresis is defined as urinary incontinence at age >5
What is the treatment for AKA?
Fluids which include dextrose and thiamine
What abx can you consider for prophylaxis of recurrent UTI's?
Fluoroquinolones, sulfamethoxazole-trimethoprim, and nitrofurantoin are the most commonly used agents. An additional option is providing female patients with antibiotics in advance, and allowing the patient to self-diagnose and treat her UTIs.
What Is a long term complication of kidney donation childbearing female age?
Gestational complications such as pre-eclampsia, gestational HTN, DM and fetal loss.
What is the presentation of hypermagnasemia?
Hypermagnesemia, on the other hand, results in loss of the deep tendon reflexes.
Which electrolyte can cause ileus?
Hypokalemia Diuretic-induced hypokalemia is a common complication of antihypertensive/congestive heart failure therapy, especially with loop diuretics. Dysfunctional bowel, as in paralytic ileus, and cardiac and neurologic complications are indications for prompt parenteral potassium replacement.
What is a common consequence as far as electrolyte when refeeding occurs?
Hypophosphatemia. Patients with severe alcoholism often have chronic depletion of phosphate secondary to decreased vitamin D and phosphate intake along with decreased intestinal uptake in those with chronic diarrhea. Urinary phosphate excretion may also be increased because of secondary hyperparathyroidism from decreased vitamin D intake as well as a proximal tubular reabsorption defect from alcohol abuse itself. Despite the depletion of phosphate, serum levels are often maintained (extracellular shift) Once the patient is fed or receives intravenous fluids with glucose, insulin secretion is increased which results in shifting of phosphate intracellularly and unmasking of the previously compensated phosphate depletion. A respiratory alkalosis occurs in many of these patients as well, which can further shift phosphate into cells and out of the serum. Patients may develop weakness thus should raise concern for the development of rhabdomyolysis from hypophosphatemia and the CPK should be rechecked. Patients with alcoholism frequently have an underlying myopathy, and the addition of hypophosphatemia on top of the myopathy can lead to symptomatic rhabdomyolysis.
What is the approach for gross hematuria eval?
If hx of trauma or stone get CT vs US but if lack of those then obtain UA or even with those still obtain UA and then based on results follow up for glomerular disease, infection or malignancy
What are important risks factors for contrast induced nephropathy?
Impaired renal function (estimated glomerular filtration rate <40 mL/min/1.73 m2 or Serum creatinine >1.5 mg/dL) and volume depletion are important risk factors.
In pregnancy, what I the first line treatment abc for a UTI?
In pregnancy, the first-line antibiotics for acute cystitis include cephalexin, fosfomycin, and amoxicillin-clavulanate, all of which provide broad-spectrum coverage and are not teratogenic.
What are the indications for removal of ureteral stones?
Indications for removal are stones >10 mm - persistent pain - AKI - Signs of sepsis.
Wha is the treatment of mixed cryoglobulinemia syndrome
Initial immunosuppressive therapy - stabilizes end-organ damage (eg, glomerulonephritis) using rituximab plus prednisone Treatment of underlying disease - targeted therapy against the condition that triggered the cryoglobulinemia Mixed cryoglobulinemia syndrome is typically treated with immunosuppressive therapy (eg, corticosteroids and rituximab) followed by targeted therapy against the underlying condition that triggered the disease. Patients with underlying hepatitis C virus (the most common trigger) should receive antiviral treatment.
When do you require iron supplementation ESRD pts?
Iron supplementation is recommended for ESRD patients with transferrin saturation <30% and ferritin <500 ng/mL
How does hypocalcemia manifest ?
It May manifest as hyperactive deep tendon reflexes, muscle cramps and, rarely,
What mutation causes polycythemia vera?
JAK2 which is present in 97% of patients
What does mixed cry-globulinemia typical present in labs as?
Laboratory examination typically reveals elevated rheumatoid factor and hypocomplementemia
What is the treatment of hepatorenal syndrome?
Liver transplantation. Seen in patients with cirrhosis who develop acute renal failure. This is due to increased production of NO which causes systemic vasodilation and reduced renal perfusion. The renal failure resembles pre-renal azootemia BUT it is NOT responsive to fluid replacement. Liver transplantation is the definitive management. Hepatorenal syndrome is a common cause of acute renal failure in patients with cirrhosis but should be considered a diagnosis of exclusion. A fluid bolus is needed to confirm that the renal failure is not secondary to intravascular volume depletion. A combination of midodrine and octreotide along with albumin is the treatment of choice after the diagnosis is confirmed.
What is the treatment for orthostatic proteinuria?
Long-term studies have shown that orthostatic proteinuria in adolescents is a benign condition that usually resolves spontaneously and does not have a significant effect on renal function. As a result, patients do not require further diagnostic workup or treatment
What is the management of postoperative urinary retention ?
Management includes urinary catheter placement, which is both diagnostic and therapeutic.
What is the management of nephrolithiasis during pregnancy ?
Management of nephrolithiasis in pregnancy is generally supportive with pain control as needed. Nephrolithiasis that is complicated by persistent obstruction, intractable pain, or urinary tract infection may require surgical management.
What is the treatment for primary nocturnal enuresis ?
Management of nocturnal enuresis begins with behavior modifications (eg, limiting fluid intake before bedtime) and motivational therapy (eg, reward system). Continued enuresis after institution of these measures for 3-6 months warrants enuresis alarm therapy
Function of Methylnaltrexone?
Methylnaltrexone selectively blocks mu opioid receptors on the gut mucosa without reversing the analgesic effect of opioids. It is used to reverse opioid-induced constipation.
What kind of hypercalcemia (mild, moderate or high) do patients with familial hypocalciuric hypercalcemia have?
Mildly elevated with no treatment necessary
What is the presentation of mixed cryoglobulinemia ?
Mixed cryoglobulinemia syndrome most commonly develop a triad of manifestations - Altrhalgias - Palpable purpura - Weakness
Most cases of mixed cryogloboulinemia arises from what risk factor?
Most cases arise in those with chronic hepatitis C virus
What is the clinical presentation on PE of patients w/ ADPKD?
Most patients asymptomatic until age 30-40 - Flank pain, hematuria - Hypertension - Palpable abdominal masses (usually bilateral) Chronic kidney disease (CKD)
Why is nitrofurantoin not a good choice for UTI in the first trimester of pregnancy?
Nitrofurantoin can also be used in the second and early third trimesters, but is avoided in the first trimester due to a risk of orofacial clefts and in the late third trimester due to an association with neonatal hemolytic anemia.
What is the most common cause of proteinuria in adolescents?
Orthostatic proteinuria is the most common cause of proteinuria in adolescents (60%-75% prevalence) and rarely occurs after age 30
What should you give to a pt receiving many pRBC units?
Packed red blood cells are preserved and anticoagulated using sodium citrate. Patients who receive massive transfusions or those with certain underlying conditions (eg, liver or renal failure, hypothermia, shock) can fail to adequately clear citrate. As citrate binds ionized calcium, these patients are at risk for symptomatic hypocalcemia due to ionized calcium deficiency. An ionized calcium level is required for diagnosis, as serum calcium is often normal. Should receive calcium gluconate and Calcium chloride
What is the approach of a positive ADPKD pt's progeny when it comes to evaluation of the disease?
Patients age ≥18 with a family history of autosomal dominant polycystic kidney disease (ADPKD) should be screened for the disorder using renal ultrasound.
What is the classical triad seen in RCC? renal per carcinoma?
Patients classically develop the triad of flank pain, hematuria, and palpable abdominal mass; however, all 3 features are present in <9% of cases Paraneoplastic syndromes such as constitutive erythropoietin production (erythrocytosis) are also quite common.
When dealing w/ CKD pts who have normocytic, normochromic anema, what is the first step in treating it prior to starting them on erythropoietin stimulating agents ESA?
Patients with advanced chronic kidney disease or end-stage renal disease commonly develop a normocytic anemia due to underproduction of erythropoietin by the failing kidneys. Vigorous hematopoiesis after administration of erythropoiesis-stimulating agents (ESAs) can lead to rapid depletion of iron stores; therefore, all patients who require ESAs should have iron levels checked prior to initiation and at scheduled intervals while on therapy.
What other test should follow up in pts <24mo of age who undergo renal US for evaluation of UTI and have a positive abnormality or recurrent febrile UTI's?
Patients with an abnormal ultrasound or recurrent, febrile UTIs should undergo a voiding cystourethrogram (VCUG) in addition to renal ultrasound.
What is the approach for urosepsis 2/2 nephrolithiasis?
Patients with obstructing ureterolithiasis associated with infection, acute kidney injury, or severe pain that has failed initial measures require decompression of the upper urinary tract with percutaneous nephrostomy or ureteral stent placement.
What is the volume for post void residual volume concerning for acute urinary retention ?
Post-void residual of 150-200 cc is particularly concerning
What are some of the causes of post operative SIADH?
Postoperative SIADH is common due to prominent nonosmotic stimuli for ADH secretion (eg, pain, nausea, physical and emotional stress).
How does anesthesia cause Postoperative urinary retention ?
Postoperative urinary retention, the inability to void after a procedure. This surgical complication occurs due to the combination of anesthesia and the administration of a large volume of intravenous fluid. The anesthesia causes bladder stretch-receptor dysfunction and decreased detrusor contractility, which, along with large fluid volumes, results in rapid overdistension
What is the definition of primary nocturnal enuresis ?
Primary nocturnal enuresis is the inability to achieve nighttime dryness in healthy patients age >5 without additional urinary tract symptoms (eg, dysuria, daytime incontinence)
What is the approach for treatment and diagnosis of lupus induced nephritis when it comes to initial evaluation?
Prompt diagnosis is critical for patients with lupus nephritis. Urgent renal biopsy is indicated in patients with rapidly declining renal function or new nephrotic syndrome and should be performed prior to immunosuppression to maximize yield and to aid in appropriately tailoring therapy.
Marked increase in serum creatinine after initiation of ACE inhibitor therapy is highly suggestive of what?
RAS
What should suspect in a pt who is s/p renal transplant presenting with HTN and post initiation of ACE inhibitors AKI develops?
RAS Renal hypoperfusion due to renal artery stenosis stimulates the renin-angiotensin-aldosterone system that in turn causes hypertension and maintains the glomerular capillary pressure and glomerular filtration rate (GFR). In patients with bilateral renal artery stenosis or renal artery stenosis in a solitary kidney (eg, patients with transplant), administration of ACE inhibitors lowers the angiotensin II level acutely, leading to a significant decrease in GFR (by >30%) and acute kidney injury
How do you monitor nephritic disease in SLE pts ?
Renal involvement in systemic lupus erythematosus (SLE) is due to immune complex-mediated glomerular injury. These immune complexes are composed primarily of anti-double stranded DNA (anti-dsDNA) antibodies and are deposited in the mesangial, subendothelial, or subepithelial space, with resultant influx of neutrophils and mononuclear cells. The titers of anti-dsDNA correlate well with the disease activity of lupus nephritis. Of note, anti-dsDNA is also highly specific for SLE. Immune complex deposition within the glomerulus induces complement fixation, leading to low circulating complement levels. Complement activation occurs during active disease, so low levels correlate well with disease activity. antidouble stranded DNA and compliment level correlate well with disease severity
What is the most common cause of correctable secondary HTN?
Renovascular hypertension is the most common correctable cause of secondary hypertension and should be suspected in patients with clinical clues suggestive of renovascular disease
What is the definition of resistanT HTN?
Resistant hypertension, which is defined as persistent hypertension in spite of the concurrent use of 3 or more antihypertensive agents of different classes, including a diuretic at maximal tolerated dose
What is the treatment once ADPKD diagnosis has been made?
Rigorous control of blood pressure with ACE inhibitors has been shown to reduce the rate of renal decline. Aggressive control of lipid levels using statins is also recommended to limit risk of cardiovascular disease.
What is the approach for enuresis ?
Rule out secondary cause by obtaining UA. If glycosuria then perhaps DM If + LE & Nitrites then UTI A normal urinalysis is reassuring that the diagnosis is likely primary nocturnal enuresis and spontaneous resolution is expected. For motivated families, such as this family, modification of evening behavior, such as limiting fluid intake and voiding before bedtime, is initial management. If that all fails then you can try to recommend enuresis alarm
When is nephrolithiasis most common during pregnancy as far as trimester?
Second and third trimesters
What are the electrolyte presentations on SIADH?
Serum hypotonicity (<275 mOsm/kg H2O) High urine osmolality(>100 mOsm/kg H2O) Clinical euvolemia; High urine sodium concentration (>40 mEq/L) as the kidneys do not aggressively retain salt in the setting of euvolemia.
What is one major risk factor for renal cell carcinoma?
Smoking
What is a confirmatory test for orthostatic proteinuria?
Split 24-hour urine collection divided between the daytime (after morning void until bedtime) and nighttime periods. Orthostatic proteinuria is confirmed in patients with a significant elevation in daytime protein excretion but a normal nighttime rate.
What is the approach for diagnosis of RAS, renal artery stenosis?
Such patients should have noninvasive assessment with renal duplex Doppler ultrasonography or CT or MR angiography (MRA) for the diagnosis of RAS. Renal Doppler ultrasound is the initial preferred modality in patients with renal insufficiency due to risk of contrast-induced nephropathy (with CT angiography) and nephrogenic systemic fibrosis (with gadolinium-enhanced MRA). Noncontrast MRA may be performed when available.
What stage of RCC can you offer a partial nephrectomy?:
Surgical management is the only chance of cure for patients with renal cell carcinoma. If the renal mass is confined within the renal capsule (stage I), partial nephrectomy can be offered. If the process extends through the renal capsule but not beyond Gerota's fascia (stage II), radical nephrectomy is the best treatment option.
What stage of RCC can you offer a pt a radical nephrectomy?
Surgical management is the only chance of cure for patients with renal cell carcinoma. If the renal mass is confined within the renal capsule (stage I), partial nephrectomy can be offered. If the process extends through the renal capsule but not beyond Gerota's fascia (stage II), radical nephrectomy is the best treatment option.
What is the mechanism by which CHF with low EF causes dilution hyponatremia?
The presence of low cardiac output and decreased perfusion pressure at the baroreceptors and renal afferent arterioles leads to neurohumoral activation with the release of renin and norepinephrine, and secretion of antidiuretic hormone (ADH). ADH (vasopressin) binds to V2 receptors in the renal collecting ducts and promotes water reabsorption; renin (via angiotensin II) and norepinephrine increase proximal sodium and water reabsorption and limit water delivery to the distal tubules. These actions promote free water retention and lead to dilutional hyponatremia. Angiotensin II and the presence of low cardiac output also stimulate thirst, leading to increased water intake and worsening hyponatremia. Angiotensin II and the presence of low cardiac output also stimulate thirst, leading to increased water intake and worsening hyponatremia. Water intake restriction is the mainstay of initial therapy for hyponatremia in patients with CHF.
What risk is increased following renal transplant?
The risk of new-onset diabetes mellitus (DM) is increased following renal transplant and highest within the first few months. Likely secondary to high doses of corticosteroids mediated decreased insulin sensitivity, and calcineurin inhibitors cause reversible toxicity to pancreatic islet cells, leading to impaired insulin secretion. Improved renal function: The healthy, transplanted kidney causes increased insulin excretion and is capable of increased gluconeogenesis.
How much does calcium decrease for every 1g/dl of albumin ?
The serum calcium concentration decreases by 0.8 mg/dL for every 1 g/dL decrease in serum albumin concentration.
How many subtypes of lupus nephritis are there?
Total of 6 - Classes I and II are typically mild and often do not require therapy unless the disease progresses. - Classes III and IV require immunosuppression with glucocorticoids (eg, methylprednisolone, prednisone) and cyclophosphamide or mycophenolate mofetil (Choices D and E). - Class V (membranous) may require immunosuppression if proliferative lesions or nephrotic syndrome is present. Class VI is an advanced sclerosing disease, and immunosuppression is not recommended.
Why do you have to treat asymptomatic pregnant women with UTI's?
Treatment of asymptomatic bacteriuria during pregnancy decreases the risk of maternal (eg, pyelonephritis) and fetal complications (eg, preterm birth, low birth weight, perinatal mortality). First-line antibiotics during pregnancy include cephalexin, amoxicillin-clavulanate, or fosfomycin. untreated asymptomatic bacteriuria is associated with fetal complications, including preterm birth, low birth weight, and perinatal mortality.
What is the treatment for RCC?
Treatment with nephrectomy is usually curative
How does myoglobinuria present in UA?
Urinalysis often reveals blood with no red blood cells, indicating myoglobinuria.
What are the 3 types of urinary incontinence categories ?
Urinary incontinence Type Symptoms Treatment Stress Leakage with coughing, sneezing, laughing, lifting Lifestyle modification Pelvic floor exercises Pessary Urethral sling surgery Urge Sudden, overwhelming, or frequent need to urinate Lifestyle modification Bladder training Antimuscarinic medications Overflow Constant dribbling of urine, incomplete bladder emptying Intermittent catheterization Correct underlying etiology
What are the usual causes of hypocalcemia during or after surgery?
Usually, hypocalcemia occurs due to volume expansion and hypoalbuminemia, and is therefore asymptomatic; however, sometimes it may manifest as hyperactive deep tendon reflexes, muscle cramps and, rarely,
What is the pathophysiology of mixed cryoglobulinemia?
Vasculitis due to the deposition of immune complexes (polyclonal IgG and IgM rheumatoid factor) within the vascular wall of small- and medium-size vessels.
IF a pt is symptomatic 2/2 hyponatremia, what could be considered instead of water intake restriction?
Vasopressin receptor antagonists (eg, tolvaptan) may be considered in patients with chronic heart failure and symptomatic hyponatremia to raise the serum sodium above 120 mEq/L when other treatment options have been unsuccessful.
Can pneumonia cause SIADH?
Yes
What is familial hypocalciuric hypercalcemia ?
familial hypocalciuric hypercalcemia (FHH), an autosomal dominant disorder due to inactivating mutations of the calcium-sensing receptor. Normally, high-normal calcium levels suppress parathyroid hormone (PTH) secretion, but in FHH, higher calcium concentrations are required to suppress PTH release. Concurrently, the defective calcium-sensing receptor causes increased reabsorption of calcium in renal tubules.
How does myoglobinuria present on UA?
+ blood in urine but lack of visualization of RBC's Therefore if Myoglobinuria from rhabdomyolysis is excluded by the visualization of RBCs on urine microscopy.
What is the amount of WBC that is accounted for in the definition of a UTI?
A urinary tract infection (UTI) is defined by the presence of pyuria (leukocyte esterase on dipstick analysis, white blood cell count of >5/hpf on microscopy) and bacteriuria.
