Transcript Statistics for the board

Board Review
05/18/2010
Statistics for the board
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Statistics questions : 2 -3 / modules
Cardiology question 31 total questions
GI questions 28 questions
Heme-onc questions 27 questions
• Renal 18-20 Questions
For the board
Test +
Test -
Disease
Positive
Disease
Negative
A
C
B
D
• Sensitivity : (A) /(A+C)
• Specificity :( D) / (D+ B)
Classical Board question
• A new screening test is being developed by Amgar .
Inc for early detection of CKD. Which of the following
assays would be preferable?
A- Sensitivity 90 % Specificity 20 %
B- Sensitivity 80 % Specificity 50%
C- Sensitivity 70 % Specificity 60 %
D- Sensitivity 60 % Specificity 90 %
• Amgar inc. is developing a test to confirm HIV
status in patients with a positive ELISA test.
Which assay should be used?
A- Sensitivity 90 % Specificity 20 %
B- Sensitivity 80 % Specificity 50%
C- Sensitivity 70 % Specificity 60 %
D- Sensitivity 60 % Specificity 90 %
• A few years ago the AUA decided to change the threshold for
Abnormal PSA value from >10 to >4 . What happened to the
sensitivity and the specificity of the test ?
A-They were not affected
B-They both increased
C-The specificity increased and the sensitivity increased
D- We need the prevalence of the disease
E-The sensibility increased and the specificity decreased
Normal
Disease
4
10
• Screening test : high sensitivity
• Confirmatory test : high specifity.
For the board
Test +
Test -
Disease
Positive
Disease
Negative
A
C
B
D
• Positive predictive Value : (A) /(A+B)
• Negative predictive value :( D) / (D+ C)
Classical Board question :
• As the prevalence of a disease decreases in a
population what happens to the Positive predictive value:
A- Stays the same and the Sensibility decreases
B-Increases and the Negative predictive values decreases
C-Decreases and the Negative predictive value increases
D-Neither the Positive or the negative predictive values are
affected
Relative risk
Disease +
Exposure
Non
exposed
A
C
B
D
No disease
• Relative Risk : A/B
<1 the exposure is protective
>1 the exposure is a risk factor
ARR/NNT
Disease +
No disease
No treatment
Treatment
A
C
B
D
• Relative risk reduction: A-B / (A)
• Absolute risk reduction :A-B ( in percent )
• Number needed to treat
(Favorite board question ) 1/ ARR
Classical Board question
• A new treatment for terminal heart failure is tried in a
phase III trial . Mortality at 2 years is 60 % with traditional
medication and 35 % with this new drug .
-What is the NNT?
A-4
B-5
C-25
D-35
Classical Board question
• A new experimental chemotherapy drug is being tested
for metastatic pancreatic Aden carcinoma. Patient who
receive the drug have a 35 % survival rate at 1 year
those who don’t have a 15 % survival rate.
What is the NNT?
A- 4
B-20
C-5
D-15
Classical Board question
• A new treatment for breast cancer is being tested . In
Population A 180 receives the treatment and 72 survive
at 5 years . Of the 240 patients who do not receive the
treatment 48 survive . What is the NNT for this
treatment?
A- 20
B-30
C-50
D-5
E- need more information can not calculate.
• 300 subjects are randomized to trial for a drug . Placebo
group had a mortality of 90%. Treatment group 75 % . How
many patients need to be treated to save a life?
A-15
B-75
C-6
D-90
E-we need to know the exact number of patients in each group.
Classical Board Question
A metanalysis is just published an the benefits of
Nacetylcysteine in patients undergoing cardiac
catheterisation . The risk of developing Contrast
Nephropathy with NAC is found to be 0.7 [ 0.5-1.1] p value
0.05.
What can you say about the effect of NAC and cardiac
catheterization?
A- There is no proven effect
B- it is protective
C-It is a risk
D- We need more information on the type of contrast used
Concept of CI
• Confidence interval (CI) is the interval within which exists
a high probability of finding the true value .
• Eg : Odds-ratio : 2.0 (CI 95 % : [1.5-3])
• On a question with a CI that encompasses 1 for a risk or
0 for an effect there is no statistically significant
relationship even is p <0.05.
Important Type of studies
• Observational /Retrospective
• For rare disease : case-series.
• Intent to treat : is a method of adjusting for
bias caused by participants leaving the
study because of treatment.
• Randomized – controlled trials
• Multicenter trial refers to the number of
centers not the type of study.
• Systematic review (Cochrane)
• Meta-analysis: quantitative combination of
multiple studies.
• The best level of evidence is Systematic
reviews or RCT.
• Evidence of Class A or I is considered to
be supported by good EBM evidence
• Evidence of class D or IV : expert opinion
is BOGST
Case #1
• 24 yo man with Hx of seizures, presents with fever and
recent convulsions. He was recently discharged from
another hospital. You are seeing him in the ED he is
agitated and confused, complains of shortness of breath
and headaches.
• PMHx: Seizure, appendectomy
• Medications: Keppra
• Physical examination reveals: Temp 101 HR 110 BP
160/95 he is confused- rest of examination
unremarkable.
• His lab work reveals : WBC 15 Hgb 15 PLT 150 , BUN 65 creatinine
5.0 mg/dl. Na 134 K 4.9 Cl 101 Bic 19 Calcium 7.3 His previous
creatinine 1 month ago from his PCP’s office was 0.9mg/dl
• UA 1.020/pH 5.5 /trace protein/3+ blood / no esterase/ rest
unremarkable. What would you do next for this patient ?
A)Check a lactic acid level – start antibiotics: vancomycin+gent
B)Check C3,C4
C)Check CK , start NS at 150cc/H
D)Check a renal ultrasound
E)Give Calcium gluconate 1gm and check a PTH for low calcium
Rhabdomyolysis: Key points
• Always when UA shows + blood but no RBC’s
• Think about it with history IVDA, Recent seizures, statins,
Antipsychotic
• Pattern of Hyperkalemia,Hyperphosphatemia,low calcium
high CK
• Key is volume repletion NS equivalent to Bicarbonate
• You do not get renal damage without volume depletion
probably also not below 10,000-16,000.
Case #2
• 82 male Sent form NH for Change in mental status .
• PMHx: HTN, OA, hemorroidectomy.
• On Admission found to be disoriented ,and short of breath. Temp 101.
examination showed a left lower extremity cellulitis. CT scan of chest with
contrast showed no infiltrates .
• BUN 26 Creatinine 1.1 Na 138 K 4.3 Cl 102 Bic 25 . WBc 12 Hgb 14 PLT
170 . Blood culture grew Staph epi- started on dicloxacillin.
• Discharge 5 days later with creatinine 0.7, comes back one week later
with low grade temp, weakness. Creatinine 5.2 , BUN 64 , Na 138,K 5.0,
Cl 100 Bic 18 . WBC 9 Hgb 13.2 PLT 190. Examination 100.8 HR 89 Pox
98%- UA shows 1.010/pH 5/ 30-40 WBC/ no casts or bacterias and has a
positive Hansel stain.
• What is the diagnosis?
A)Acute prostatitis
B)Contrast induced nephropathy from CT
scan
C)Acute interstitial nephritis
D)Prerenal azotemia from early sepsis
E)MPGNI
Acute interstitial nephritis: Key points
• Triad of Eosinophiluria, rash ,fever occurs
in 15 to 20 % of cases.
• Medications to suspect: dicloxacillin,
methicillin, NSAIDS , Bactrim.
• Hansel Stain positive, has to have pyuria.
• Can occur from one week up to few years
after starting medication.
• Treat by withdrawal of medication .
Steroids data is controversal.
Case #3
• 41 year old AAM presents to your office for regular visit.
He has no complains and has not seen a doctor in years.
He had a cholecystectomy at age 32 , and previously
used Heroin IV.
-His Height 170 cm weight 130 kg-VS: 150/90 -65-98%98.2 .
-Remaining of examination unremarkable. Creatinine 1.8
BUN 40 –UA 1.015/pH 6/4+ protein/ no WBC/no RBC. 24
urine protein reveals 6gm protein.
• What is the renal lesion that he most likely
has?
A)Focal segmental glomerulosclerosis
B)Minimal change disease
C)Hypertensive nephrosclerosis
D)Membranous nephropathy
E)Amyloid
FSGS: key points
• Most commonly in African american
• Other risk factors : morbid obesity, Reflux,
HIV,heroin use, sickle cell disease.
• In HIV , has a particular form collapsing
FSGS.
• Treatment with >6months of steroids
idiopathic
Case #4
• 18 year old Asian Man presents to the office for hematuria. He has
not been feeling well the last few days and has been taking Motrin®
for a sore throat that started 4 days ago. He has no fever ,chills or
dysuria. His past medical history is remarkable for tooth abscess at
age 15- and he smokes marijuana occasionally. On Examination VS
100 HR 98 his tonsills are slightly red , slight diffuse bronchial
sounds, rest normal.
• BUN 8 Creat 0.9 – UA 1.030/2+ protein/4+ blood/30-40 RBC’s .
• What is the most likely diagnosis ?
A)Post-steptococcal nephritis
B)IGA nephropathy
C) Alport syndrome
D)Thin membrane disease
E)Nephrolithiasis
IGA nephropathy: Key points
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Occurs 3 to 5 days after URI
Most common cause of GN
Occurs very commonly in young Asians
It manifests with hematuria
Complements are normal – IGA is not
diagnostic
• 1 to 2 % progresses to ESRD
• ACE I to slow worsening
Case #5
• 32 yo male presents with left flank pain that radiates to
groin with hematuria and dysuria. All symptoms started
few hours ago and are unbearable. She also report
nausea , but not vomiting.
• His PMH/PSH: Crohn disease, s/p termianl ileum
resection.
• PE : VS 110/65 –HR 108 Temp 99
• Positive CVA tenderness
• UA shows 1.020/pH 7/ 3+ blood and 30-50 RBC’s
• What is the most probable type of
nephrolithiasis this patient has?
A)Calcium oxalate
B)Calcium phosphate
C)Uric acid
D)Struvite
Case #6
• 25 yo patient come to you with recurrent attacks of renal
colic- he brought one of the stones that passed and it
was found to be calcium Phosphate.
• What type of dietary advice would you want to give him?
A) A lot of water and Salt- Restrict Ca and Phos
B) A lot of water- restrict Salt
C) A lot of water- restrict only Ca
D) Avoid Meats.
Case #7
• 65 yo patient comes to you with second episode of
kidney stones in 3 years. He has a PMHx HTN, DM and
seizures. Medications : HCTZ, Topamax , lisinopril and
Glipizide.
• What would you do for this patient?
A)Dietary advice
B)Stop HCTZ – start Lasix-perform stone profile
C)Stop Topamax – perform stone profile
D)Perform stone profile
Nephrolithiasis : Key points
• Risk factors include low fluid intake- hypercalciuria
(idiopathic or secondary: PTH, Type I RTA) hyperoxaluria
(Steatorrhea) hypocitraturia, and hyperuricemia.
• Check family history – Rule out secondary causes after
second stone in 3 years
• CT scan test of choice
• All stone hydration- low salt diet – normal calcium diet
• If stone less than 5mm will pass alone - > 1 cm refer to
urology
Case #8
• 70 year old man has fever , dysuria and urinary
frequency . On physical examination his prostate is
enlarged . He is diagnosed with prostatitis and treatment
is started with Bactrim®. One week later he sees you in
the office and you check a chemistry basic , his Na 137 K
4.0 Cl 101 Bic 22 BUN 7 Creat 1.9. UA shows Sg
1.020/pH 5 / no cells
• What is the most probable cause of his
elevated creatinine?
A)Bactrim competing with tubular secretion
of creatinine
B)Bactim induced Acute interstitial nephritis
C)Pre-renal azotemia from pyelonephritis
D)Obstructive uropathy from prostatitis
E)The intern on night float
Key points Bactrim
• Can induce acute interstitial nephritis
• Can induce hyperkalemia and type IV RTA
• Competes with tubular secretion of
creatinine and increases level without
affecting BUN
• Metabolites can precipitate as crystals.
Case #9
• 28 yo male presents to you for SOB, and lower extremity
edema . His PMH includes DM(dx 3 years
ago),HTN(diagnosed 15 years ago), recurrent folliculitis
and non hodgkin lymphoma diagnosed 3 months ago .
He takes Norvasc, and lisinopril for BP and glipizide for
DM.
• His PE shows normal lungs and you obtain the following
labs : ABG 7.56/20/62- Na 134 K 3.8 Cl 101 Bic 22 UA
1.020 / 4+ edema/ no cells. 24 h urine collection 4 gm/24
hours.
• What is the most likely cause of his edema?
A)The medication norvasc since it was started about 4
months ago
B)Diabetic nephropathy
C)Minimal change disease
D)Membranous nephropathy
E)MRSA-related nephritis
Minimal change – key points
• 90 % in children – 10 % in adults
• Mostly idiopathic , secondary causes
include NSAIDS, lithium, Hodgkin
lymphoma, leukemia.
• Treatment with steroids.
Case # 10
• A 28 year old Female with a history of
IVDA presents to the ED for fever and
chills. Lab work and blood cultures are
drawn and she signs out AMA. 1 day later
she comes back with the same symptoms
– the cultures drawn the day before grew
MRSA- and because of her shortness of
breath the MAR orders a CT cans with IV
contrast. Her WBC was 19 her creatinine
0.9
• She had no PE . She was started on
Vancomycin(1500 mg )+ gentamycin(120
mg) –
• Her Creatinine 2 days later is 1.9 BUN 48
Na 140 k 4.9 Cl 102 Bic 18 – WBC 15
/Hgb 10 /PLT 77– Vanco through 29
gentamycin rd 8
• What is the most likely etiology of her AKI?
A)Contrast-induced nephropathy
B)ATN secondary to gentamicin
C)Post-infectious GN
D)Vanomycin-induced renal failure
E)The intern on night float
Contrast nephropathy : key points
• Occurs 24 to 48 hours after contrast
• Risk factors include : volume depletion ,
CHF, DM , CKD, amount of contrast .
• For “prevention” you should give IV fluids ±
NAC
• Minimal progression to ESRD
• Resolves in 10 to 14 days.
Case # 11
• 40 yo male goes to the ED for chest pain and shortness
of breath. He is examined by the ED intern who orders a
RUQ ultrasound which turned out to be negative but
revealed the presence of “cysts” in the kidney.
• His PMH : HTN, Osteoarthritis . His father died from a
stroke at 75 years old
• Medication : motrin and tylenol prn
• PE unremarkable.
• He gets a formal U/S of his kidney 2 days later which
shows a 10 cm right kidney 10.8 cm left kidney and tow
cysts (2 and 3 cm of the right) .
• Creat is 0.8
• In you opinion this patient:
A)Should undergo a genetic test screening for Polycystic
kidney disease since he has two cysts and father died
from stroke
B)Should both get the Genetic test for PKD and rule out
Berry aneurysms by MRA
C)Should be screened for RAS since discrepancy of size of
two kidneys
D)‘s cyst are secondary to chronic motrin intake
E)Go to the movies and relax a bit
PKD : key points
• ADPKD is caused by abnormal gene on chrom 16 in 85
% of patients
• The presence of : two cysts – age <30
two cysts in each kidney -30 to 59
four cysts in each kidney >60
• You only screen for Berry aneurysm : family history,
personnal history and high-risk profession
Case #12
• 70 yo patient presents with CHF
exacerbation to the ED . He has been
vomiting for 7 days now and is in
respiratory distress. On PE BP 70/30 HR
102 Pox 87%
• We send labs and ABG before intubation –
the results come back:
• Na 140 Cl 70 Bic 20 k 2.3 BUN 79 Creat
4.8 ABG 7.58/22/59
• What is the acid base disorder in this patient ?
A)Mixed HAGA and non gap acidosis
B)Mixed HAGA and Respiratory alkalosis
C)HAGA, Respiratory Alkalosis and metabolic alkalosis
D)HAGA, non gap acidosis ,respiratory alkalosis
E)No clue consult Renal ,ICU, Cards,…. And podiatry
Case # 14
• 75 elderly homeless man found by EMS comatous and
intubated in the field.no information is available about his
medical history. He is treated with Naloxone,thiamine
glucose with minimal response.
• In the ED his temperature is 99.3 Bp 86/54 . His na 140 k
5.2 Cl 105 Bicar 23 ,BUN 18 creat 1.2 Glucose 156 ,
osmolarity 331 , serum ketone positive . ABG pH
7.37/38/392 .
• Which is the most likely diagnosis ?
A)Methanol ingestion
B) Ethylene glycol ingestion
C)Isopropyl alcohol ingestion
D)Alkoholic ketoacidosis
E)Glue sniffing
F) He was an intern on night float
Case #15
• 25 yo patient presents with Diarrhea , nausea and
vomiting for the last week. She seems volume depleted.
On PE 84/66- HR 109
• PMH: anxiety disorder, migraine
• Medications : xanax,ativan,topamax
• Na 129 Cl 110 Bic 15 BUN 28 Creat 0.8 ABG 7.31/29/99
• WBC 9 Hgb 11 PLT 205 – lactic acid 0.9
• UA 1.020/pH 6.8/no cells
• Urine electrolytes : Na 77 Cl 22 K 19
• What is her most likely diagnosis?
A)Non anion gap acidosis from diarrhea
B)Non gap acidosis with inadequate
respiratory compensation since the pH is
acid
C)Non gap acidosis secondary to RTA
D)Respiratory acidosis and metabolic
acidosis
E)Who cares-consult Renal anyway
Case # 16
• You are on medicine consult with Glenn
Newell and you are called for a patient who
is about to get surgery the next day for an
acute cholecystitis. His VS 101 temp – HR
99 BP 99/57 – WBC 18 Hgb 9.7 PLT208
Creatinine 1.8 His urine analysis from this
morning shows yeast.
• What is your recommendation to the team?
A)Cancel the surgery
B)Give fluconazole and proceed with surgery
C)Proceed with surgery
D)Give betablocker and proceed with surgery
E)Inform the patient of risk of dialysis and proceed with
surgery
F)We have no clue what to do consult Cardio, Renal and
ID
Thank You