Nephrology & Urology Archer Online USMLE Reviews www.ccsworkshop.com All rights reserved Archer Slides are intended for use with Archer USMLE step 3 video lectures. Hence, most slides are very brief summaries of the concepts which will be addressed in a detailed way with focus on High-yield concepts in the Video lectures. These slides are only SAMPLES
The diagnosis of HRS iS of exclusion and depends mainly on serum creatinine level, as no specific tests establish the diagnosis of HRS.
Serum creatinine level is a poor marker of renal function in patients with cirrhosis. But no other reliable noninvasive markers exist for monitoring renal function in these patients.
Diagnosis of HRS depends on the presence of a reduced GFR in the absence of other causes of renal failure in patients with chronic liver disease.
Major criteria ( All major criteria are required to diagnose HRS .)
Low GFR, indicated by a serum creatinine level higher than 1.5 mg/dL or 24-hour creatinine clearance lower than 40 mL/min
Absence of shock, ongoing bacterial infection and fluid losses, and current treatment with nephrotoxic medications
No sustained improvement in renal function (decrease in serum creatinine to <1.5 mg/dL or increase in creatinine clearance to >40 mL/min) after diuretic withdrawal and expansion of plasma volume with 1.5 L of plasma expander
Proteinuria less than 500 mg/d and no ultrasonographic evidence of obstructive uropathy or intrinsic parenchymal disease
Additional criteria (Additional criteria are not necessary for the diagnosis but provide supportive evidence.)
Urine volume less than 500 mL/d
Urine sodium level less than 10 mEq/L
Urine osmolality greater than plasma osmolality , Urine red blood cell count of less than 50 per high-power field & Serum sodium concentration greater than 130 mEq/L
Urinary indices are not considered major criteria because a subset of patients with HRS may have high urine sodium levels and low urine osmolality (similar to acute tubular necrosis [ATN]), while other patients with cirrhosis and ATN may have low urine sodium levels and high urine osmolality.
) A 25 y/o male comes to your office with complaints of dark red colored urine and pain in the legs that started this morning. He has been working out at the local gym excessively for the past three days. He does consume alcohol on weekends but reports having involved in a binge drinking episode that included 10 beers yesterday. On physical examination, he weighs 70kg and he has some tenderness in his calf muscles which he attributes to the excessive squats he performed yesterday. Urine dipstick reveals large blood. If this patient develops acute renal failure , the most likely mechanism would be: A) Interstitial nephritis due to pigment B) Glomerulonephritis C) Acute Tubular necrosis due to pigment deposition D) Acute Tubular Necrosis due to Ischemia E) Alcohol related direct toxic injury 1b) Lab studies revealed normal electrolytes and normal creatinine but a CPK of 50,000. His Urine output has been at 70 ml/hr for the past 6 hours. Your first step in the management to prevent development of patient's Acute Renal Faliure : A) Intravenos Fluids B) Furosemide C) Calcium Gluconate D) No treatment because serum creatinine is normal D) Sodium Bicarbonate
A 7-year-old boy is brought to the emergency department by his mother because of "tea-colored urine" for the last several days. He has also had some nausea and vomiting, and his eyes appear swollen when he wakes up in the morning. The eye swelling tends to resolve over the course of the day. He is generally very healthy and there is no family history of any chronic diseases. His temperature is 36.7 C (98.0 F), blood pressure is 130/90 mm Hg, pulse is 96/min, and respiratory rate is 16/min. Physical examination is unremarkable. A urinalysis shows red cell casts. At this time the most appropriate study to confirm your diagnosis is A. antinuclear antibody B. antistreptolysin O antibody C. renal biopsy D. renal ultrasound E. urine culture
1c) The above patient has been adequately treated but his repeat CPK after 2 days is still elevated at 48,000. He complains of increasing pain in his left leg and some tingling and pricking sensations. On examination his left leg was mildly swollen and there was pain on passive stretching of the leg muscles. Dorsalis pedis and posterior tibial pulses are intact. The most likely diagnosis at this time: A) Deep Vein Thrombosis B) Cellulitis C) Compartment Syndrome D) Edema due to renal failure E) Congestive Heart Failure 1d) The immediate course of treatment in this condition would be : A) Anticoagulation with Heparin B) Antibiotics C) Emergency Fasciotomy D) Loop diuretics E) Elevation of the leg
Q1) A 12 y/o boy is brought to you by his mother for skin rash and complaints of intermittent abdominal pain, joint pains for past 2 days. He did have an upper respiratory infection about 2 days ago. On physical exam, his vitals are normal. Abdomen is benign with out any tenderness or rigidity. However, you notice patchy purple discolorations on his extremities and the back. Lab studies are obtained that revealed WBC: 6.6 , HGB: 15.3 , MCV: 88 , Platelets: 290,000 ( normal 180k to 400k) BUN: 11 , Creatinine : 0.6 ( normal) , Anti streptolysin O titer : negative Streptozyme : negative ,Urine dipstick : normal without any blood Urinalysis : normal/ no rbcs/ no protein
The mother is very anxious and asks about the long term prognosis of her son. Your response : A) Reassure the mother that boys disorder is self limiting and does not require any follow up B) Tell her the boy needs to be admitted and treated vigorously to prevent renal failure C) Tell her that renal failure develops 100% of such cases and hence needs very cautious follow up D) Tell her that 50% of such cases progress to end stage renal disease. E) Tell her that the boy requires follow up monthly urinalysis for at least 3 months in order to make sure there is no heamaturia/ renal dysfunction. If the boy presented with Renal failure in the above case, the most likely underlying pathology would be : A) IgA mediated vasculitis B) Post streptococcal glomerulonephritis C) Anti GBM disease D) Acute tubular necrosis E) Interstitial Nephritis.
A 46 y/o woman who is a school bus driver by occupation presents to your office for regular follow up. She has a history of ADPKD. Her blood pressure is well controlled at 120/70 on enalapril. She has no other problems. She denies any headache. There is no family history of intracranial or subarachnoid hemorrhage. However, she is concerned that her head might explode because her sister who also has ADPKD was recently diagnosed of having a berry aneurysm. She wants to be screened for berry aneurysm as soon as possible. Her physical examination is benign and does not reveal any focal neurological deficits. Which of the following suggests the necessity for screening in her case? A. Family history of berry aneurysm B. Polycystic kidneys C. School bus driving D. Cysts in the liver E. No screening necessary in her case
High risk jobs ( pilot, bus driver etc) is one of the indications to screen for berry aneurysm in asymptomatic ADPKD patients.
Family hx of berry aneurysm alone does not warrant screening for berry aneurysm in asymptomatic ADPKD patients. Asymptomatic ADPKD patients must be screened if there is a family history of “ Ruptured” berry aneurysm ( history of SAH in the family etc)
E. is not the answer because this patient is a school bus driver by occupation and needs to be screened
A 76 YO DEBILITATED MALE, In extended care facility , develops every 6 months mild fever, frequency of micturation with urinary incontinence. USUALLY E.COLI count is >100,000. What is the appropriate treatment? A. CYSTOSCOPY and IVP B. Continuous low dose antibiotics C. Catheterize and irrigate the Bladder daily D. Treat only the acute episode of infection E. No need of treatment as this is colonization
Grossly Reddish or Tea colored urine, dipstick positive for blood and urine microscopy shows RBCs.
Any patient with gross hematuria should always be referred for urological evaluation unless this is secondary to an infection .
If a woman has gross hematuria but the urine dipstick also reveals leucoesterase or nitrite or if the woman has symptoms of UTI ( dysuria etc) or if the cultures are growing bacteria, this can be treated as UTI ( cystitis) with antibiotics with out referring for further evaluation. A repeat urinalysis should be obtained after resolution of the infection. Even in this setting of infection, if there are risk factors for urological malignancy the patient should still be referred for further evaluation ( since hematuria from cancer can also be intermittent).
Runner's hematuria or March hematuria is another benign condition that presents as gross hematuria after a severe physical activity. In such cases, patients may be observed for resolution. However, if the hematuria is persistent or if the patient has any risk factors for having a urological malignancy, must be referred to a urologist
Microscopic hematuria is defined as three or more red blood cells per high-power field on microscopic evaluation of urinary sediment from two of three properly collected urinalysis specimens. ( >3rbc/hpf on 2 or more occassions).
Always confirm on repeat testing. Repeat urinalyses to establish whether significant hematuria is present must be done within 3 to 6 months of the initial test.
Look for glomerular origin of hematuria – If urinalysis reveals Red cell casts/ dysmorphic RBCs or Renal function is compromised/ new onset HTN, combined with mild proteinuria consider glomerulonephritis or renal parenchymal disease in such cases, next step is referral to a nephrologist and renal biopsy.
Some benign causes of Microhematuria : A) Exercise B) Sexual activity C) Menstruation D) UTI If UTI is present ( symptoms and dipstick for leucoesterase are clues that point towards infection) - treat it with antibiotics and repeat urinalysis after the infection has cleared. E) Benign Prostatic Hypertrophy F) Prostatitis
Recurrent painless Hematuria consider IgA nephropathy
1. Consider strongly CA.Bladder in the elderly and in smokers
2. R/O benign causes like BPH ( Ask for symptoms of BPH)
3. R/O Prostate Ca in the elderly and in those with family history
DO NOT NEGLECT POSSIBILITY OF BLADDER CA IN Patients WITH HEMATURIA
Symptomatic Microhematuria : If the microhematuria is associated with classic flank pain next step is Non Contrast CT scan to rule out renal calculus. In pregnant women do ultrasound to avoid radiation.
Asymptomatic MicroHematuria : Patients without the classic flank pain of urolithiasis should be evaluated extensively. Once benign causes such as infection and the kidney ( glomerular) origin are ruled out, further approach should be defined based on the patient's risk profile.
For patients with low risk of urological disease, a less extensive work-up may be appropriate ( First do upper tract imaging and if this is negative, add urine cytology+cystoscopy).
If the patient is a high risk of having a urological malignancy, extensive work-up is needed ( see the risk factors below) --> Upper tract imaging + cystoscopy+ urine cytology all are needed. Urine cytology should be obtained in all patients with asymptomatic hematuria since it is an easy and non invasive step. Sensitivity of urine cytology is only 48% but remember that if it is positive it is highly specific for urological cancer ( 94% specificity)
What imaging studies should be done as initial step in evaluating Asymptomatic Hematuria?
For both high risk and low risk patients, upper tract imaging must be performed as an initial step.
For upper tract imaging, CT urography ( i.e; non-contrast CT followed by contrast CT imaging from kidney to bladder) is best recommended initial test now to evaluate asymptomatic hematuria. CT urography is less affected by overlying bowel gas and is more sensitive for detecting small tumors and calculi than the IVP.
IVP used to be the best preferred test for upper tract imaging in hematuria evaluation but now CT urogram is becoming the preferred method. IVP and ultrasound are good to image the urinary tract but they do not completely assess the renal parenchyma. If you order an IVP, you may eventually need to order a CT urogram again to image the parenchyma better - so, in order to avoid ordering multiple studies, CT urogram is recommended as the best initial test.
Upper tract imaging – preferred modality is Helical CT or CT Urogram ( If you do not find CT Urogram in the choices or if you want to reduce radiation exposure such as in pregnant women, you can choose IVP+renal ultrasound for upper tract imaging remember IVP is more invasive and we are not using now. So, where available, CT urogram is first choice for imaging the upper tract. But if IVP is used it must be combined with renal ultrasound because IVP only images the tract but does not look at the kidney itself).
In patients with high risk of bladder ca, Helical CT followed by urine cytology and cystoscopy must all be performed.
In patients with low risk for bladder ca, you may choose step-wise approach. First step then is upper tract imaging. Then urine cytology or cystoscopy.
Do not routinely screen but however, if you find Hematuria ( even microscopic) on routine urinalysis that was done for another purpose do not neglect this finding. ABNORMAL LAB always need to be addressed pursue further w/u for this hematuria ( BPH, Ca.Bladder, ca.prostate, cystitis, r/o glomerulonephritis)
Remember Micro-HEMATURIA is the most common manifestation of bladder cancer.
IMPORTANT Refer all patients ( especially those at high risk) presenting with unexplained hematuria for cystoscopy, even if their hematuria is intermittent , and regardless of the findings on history and physical exam.
Cystoscopy and exam under anesthesia with biopsies
Additional diagnostic evaluations, based on findings from the cystoscopy and pathologic evaluation of the tumor, to assess the upper urinary tract or to look for metastatic disease lfts, ivp, cxr, ct scan of abd/pelvis, bone scan.
Criteria for surgery in primary hyperparathyroidism
Sestamibi scan only if surgery is planned/indicated
Hypercalcemic crisis management – ivf + lasix after volume repletion only
Indications for corticosteroids : are useful for treating hypercalcemia caused by vitamin D toxicity, certain malignancies (eg, multiple myeloma, lymphoma), sarcoidosis, and other granulomatous diseases
Cinacalcet (Sensipar) -- Directly lowers parathyroid hormone (PTH) levels by increasing sensitivity of calcium sensing receptor on chief cell of parathyroid gland to extracellular calcium. Also results in concomitant serum calcium decrease Indicated for hypercalcemia with parathyroid carcinoma.
Do not lower Calcium too much Serum calcium reduction may cause lowered seizure threshold, paresthesia, myalgia, cramping, and tetany;
Criteria for Surgery – Primary hyperparathyroidism
Serum total calcium level >12 mg per dL (3 mmol per L) at any time
Hyperparathyroid crisis (discrete episode of life-threatening hypercalcemia )
Marked hypercalciuria (urinary calcium excretion more than 400 mg per day)
Impaired renal function
Osteitis fibrosa cystica
Reduced cortical bone density (measure with dual x-ray absorptiometry or similar technique)
Bone mass more than two standard deviations below age-matched controls (Z score less than 2)
Classic neuromuscular symptoms
Proximal muscle weakness and atrophy, hyperreflexia , and gait disturbance
Demands an understanding of physiology and pathophysiology
pH is a major determinant of enzymatic reactions – Acedemia denatures the enzymes, decreases threshold for ventricular fibrillation and increases respiratory drive. Alkalemia suppresses respiratory drive, can cause myocardial ischemia, coronary vasospasm etc
Calculate Anion Gap : Na - (Cl + HCO 3 ) - Normal 3 - 10 meq/L
Given entirely by Unmeasured anions are related to (-) charge on albumin One gram albumin = 2.5 meq/L anion
i.e. Albumin of 4 gm/L, baseline anion gap would be 10 meq/L which is Normal. Correct Gap for Albumin!!! If albumin is 2gm%, the baseline anion gap should be 5 in which case 10 should be assumed as increased Anion gap.
Delta Gap : Delta AG / Delta HCO3:
1:1 = Anion gap acidosis
>1 = Anion gap acidosis plus metabolic alkalosis
< 1 = Increased Anion gap acidosis plus normal anion gap acidosis
If measured Pco2 is less than expected pco2 as calculated by this equation – suspect a primary respiratory alkalosis. If it is more than expected suspect primary respiratory acidosis. This is how you diagnose mixed disorders!!!
Sam is a 35 y/o alcoholic who is brought to the ER in a comatose state. Sam’s wife tells you that she had an argument in the evening about 5 hrs ago over Sam’s alcohol habits. Sam apparently got mad over the discussion, drove his car and returned an hour ago in a very intoxicated state. Wife called the EMS and rushed him to the ER. On examination Sam is disoriented and hallucinating , Pulse 120 Tm 99, RR 26 BP 126/76. The rest of the physical exam is normal except for stuporos state and alcohol smell. Lab studies revealed Na 130 k 3.4 cl- 95 Hco3 16, Glucose 90 Creatinine 1.6 BUN 45. Blood Ethylalcohol level was 180. Serum osmolarity was 360mg%. ABGs revealed 7.28, Pco2 28, Po2 76 Sao2 93. The next best step in management ?
A) Endotracheal intubation in view of severe acidosis
B) Hemodialysis because this is an acute renal failure causing acidosis
C) Fomepizole because of suspicion of ethylene glycol intoxication
D) Supportive treatment for now because this is an ethylalcohol induced lactic acidosis
E) Bicarbonate drip to reverse the acidosis because this is renal tubular acidosis
Treatment : Consider Antidote ( Fomepizole or Ethanol ) if Level > 20mg% or if you suspect ethylene glycol intake with 2 or more – a) arterial ph < 7.3, Hco3 <20, osmolar gap>10, calcium oxalate crystals in urine.
Antidote blocks Alcohol dehydrogenase and prevents the Glycolic acid formation. In case of methanol, toxic meatbolite is formic acid
A 26 year old woman presents to the ER with generalized weakness associated with perioral numbness. She is moderately built and looks slightly depressed. On physical exam, she has mild pallor. She denies use of any medications. BP 120/88 mmHg and physical exam is normal. Lab data: Cr 1.2mg/dL, BUN 15mg/dLNa 136 , K 2.8 , Cl 88 , HCO3 38. Urine Na 45 meq/L, Urine K 35 meq/L, Urine Cl 8 meq/L, Urine specific gravity 1.010, Urine pH 7