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Flashcards in Diagnostic Testing Deck (42)
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1

Sxs of testosterone deficiency in adult males?

- decreased: energy, libido, muscle mass, body hair
- hot flashes, gynecomastia, infertility

2

Source of testosterone? Negative feedback loop?

- produced in testes by Leydig cells
- LH stimulates production
- negative feedback loop: testosterone inhibits production of LH and FSH
- single most impt dx test for male hypogonadism

3

What tests should be ordered if you suspect hypogonadism? Diff in causes of increased and decreased SHBG?

- 1st: serum total testosterone (Normal range: 300-800 ng/dl)
- abnormal testosterone binding to sex hormone bidning globulins ( may need free testosterone test) - if SHBG increased then less free testosterone - aging, hyperthyroidism, increased estrogen, liver disease, HIV, anti-seizure drugs
- if SHBG decreased then more free testosterone - obesity, insulin resistance, T2DM, hypothyroidism, increased GH, exogenous androgens, glucocorticoids, nephrotic syndrome

4

When should testosterone be drawn? Results?

- collect sample at 8am when testosterone levels are highest
- if normal - stop testing
- if abnormal - repeat 1-2 more times to confirm

5

What should be done if testosterone is low on 2 tests?

- check LH and FSH
- if testosterone low and FSH and LH high = primary hypogonadism - ex: klinefelter, cryptorchidism, varicocele. glucocorticoids
- testosterone low and LH and FSH not elevated = secondary hypogonadism - ex: T2DM, liver or kidney disease, aging

6

What is PSA? Where can it be found? Fxn?

- prostate specific antigen
- secreted by epithelial cells of the prostate
- present in low levels in the serum
- present in the semen
- fxn is to liquify semen in seminal coagulum to allow sperm to swim freely

7

Causes of an elevated PSA?

- BPH
- prostate cancer
- prostatic inflammation or infection
- perineal trauma:
rarely DRE
bike riding
sexual activity (persists for 48-72 hrs post)
- indirect measure of prostate glandular size in men w/o cancer
- normal values increase w/ age
- values can vary by race: blacks have higher PSA levels than whites

8

Causes of decreased PSA?

- obesity: elevated BMI levels may cause lower PSA levels
- delayed early detection may partially explain worse outcomes in obese men with early prostate cancer
- meds that reduce PSA:
5-alpha-reductase inhibitors: 50% or greater reductions
NSAIDs
statins (17.4%)
thiazides (26%)

9

Use of PSA for prostate cancer?

- determine extent of cancer
- response to tx
- screening method for detection:
controversial
lacks sensitivity and specificity

10

Why are normal values of PSA controversial?

- in past a value of less than 4 ng/ml was normal
- men with prostate cancer were found to have values of less than 4
- men w/o prostate cancer were found to have values greater than 4
- impt to follow trend - how much has PSA increased over the last yr?

11

Diff studies of PSA?

- age specific reference ranges
- free vs total PSA: lower portion of free PSA may be correlated w/ more aggressive forms of cancer
- PSA velocity and PSA doubling time: rate of change in PSA values over time, time it takes to double PSA
- pro-PSA: more strongly assoc w/ prostate cancer than BPH

12

Research on PSA screening?

- for q 1000 men ages 55-69 that get screening PSAs yearly for a decade- 100-120 get positive results leading to prostate bx
- 110 get prostate cancer - and of these at least 60 have tx complication, 4-5 die from prostate cancer and 5 die who weren't screened
- 0-1 deaths from prostate cancer are avoided by screening - causes more harm than good

13

What is PSA density (PSAD)?

- PSA levels are higher in men with BPH
- PSAD is sometimes used for men with BPH to try to adjust for this - amt of PSA should be proportional to size of prostate
- it measures volume (size) of prostate w/ TRUS and divides PSA number by prostae volume
- a higher PSAD indicates greater likelihood for cancer

14

Use of PSA velocity?

- PSAV
- rate of change in PSA over time
- PSA that is rising quickly is more suspicous for cancer
- however a PSA that is already high or quickly rises to a concerning level will quickly lead to further eval
- usually with transrectal prostate bx

15

What is Free/total PSA (PSAII)? BPH vs cancer findings?

- percentage of free PSA decreases as total PSA increases in serum of men with prostate cancer
- ratio of f/t PSA, especially in men w/ normal PSA values can be helpful in dx those w/ possible CA
- only useful when PSA 4-10 ng/dl

- if free PSA is elevated in respect to bound PSA - then PSA is probably being produced by BPH
- if there is high level of bound PSA then it is likely to be manufactured by prostate cancer cells

16

USPSTF statement on PSA testing?

- small pontential benefit and significant potential harms - don't screen pt with PSA test unless individual being screened understands what is known about PSA screening and makes personal decision that even a small possibility of benefit outweighs known risk of harms

17

Impt of semen analysis? What needs to be done?

- remains mainstay in investigating male fertility potential
- abstain from coitus 2-3 days
- collect all ejaculate
- analyze w/in 1 hr
- obtained by masturbation
- provides immediate information

18

What are the diff parts to semen analysis?

- macroscopic:
viscosity, volume and pH
- microscopic:
spem concentration/count
motility
morphology
viability (supravital stain)
leukocyte count
search for immature germ cells

19

Normal semen analysis?

- volume: over 1 cc
- concentration: over 20 mill/cc
- initial forward motility: over 50%
- normal morphology: over 60%

20

What is azospermia? oligospermia?

- azospermia: no measurable sperm in semen
- oligospermia: less than 15 mill/ml

21

Causes of azospermia?

- klinefelters (1/500)
- hypogonadotropic-hypogonadism
- ductal obstruction (absence of vas deferens)

22

Causes of oligospermia?

- anatomic defects
- endocrinopathies
- genetic factors
- exogenous (heat)

23

Causes of abnormal volume of semen?

- retrograde ejaculation
- infection
- ejaculatory failure
- meds

24

How is dx of chronic prostatitis made?

- analyzing specimens obtained following prostatic massage
- first periurethral area is cleaned and pt allowed to void
- initial 5-10 ml and midstream specimen are obtained for quantitative culture
- the pt should stop voiding b/f bladder is empty and prostate should be massaged - any prostatic secretions that are expressed should be cultured as well as first 5-10ml of subsequently voided urine

25

When should a prostatic massage be avoided?

- in acute bacterial prostatits
- risk for induction of bacteremia or sepsis

26

How is a UTI dx?

- in adults and older kids - mid stream urine sample usually reliably represents the urine in bladder (clean catch)
- samples collected from urinary bags, pedi-bags or bedpans shouldn't be used to dx UTI as they are most likely contaminated
- most reliable sample is obtained via cath or or suprapubic aspiration in infants (often less traumatic than cath - do if unable to cath)

27

Traditional gold std for sig bacteriuria, test used for what pts?

- urine culture and sensitivity - over 100,000 cfu/ml of urine
- some argue criteria for bacteriuria is only 100 cfu/ml of uropathogen in sx females or 1,000 in symptomatic males
- bacterial identification from urine C&S - key in males and females w/ complicated UTIs

28

Methods of urine sensitivity?

- measurement of sensitivity of bacteria to abx
methods:
-agar diffusion:
kirby-bauer - discs
Etest - strips
-broth dilution

- solid media: disc diffusion technique
- liquid media: minimum inhibitory concentration (MIC) test

29

Presentation of bladder cancer? What tests do you want to run?

- pts usually present w/ painless hematuria (hallmark)
- Will get UA and some cytology
- real dx test: cystoscopy
(gold std: cystoscopy and bx)

30

How do you dx bladder cancer w/ cytology?

- microscopic cytology of urinary sediment or saline bladder wash to detect malignant cells ( saline bladder washes more accurate)
- microscopic cytology is more sensitive in high grade tumors or carcinoma in situ but can be falsely negative in 20% of cases