Flashcards in Diagnostic Testing Deck (42)
Sxs of testosterone deficiency in adult males?
- decreased: energy, libido, muscle mass, body hair
- hot flashes, gynecomastia, infertility
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
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
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
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
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
Causes of an elevated PSA?
- prostate cancer
- prostatic inflammation or infection
- perineal trauma:
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
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
Use of PSA for prostate cancer?
- determine extent of cancer
- response to tx
- screening method for detection:
lacks sensitivity and specificity
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?
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
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
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
Use of PSA velocity?
- 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
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
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
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
What are the diff parts to semen analysis?
viscosity, volume and pH
viability (supravital stain)
search for immature germ cells
Normal semen analysis?
- volume: over 1 cc
- concentration: over 20 mill/cc
- initial forward motility: over 50%
- normal morphology: over 60%
What is azospermia? oligospermia?
- azospermia: no measurable sperm in semen
- oligospermia: less than 15 mill/ml
Causes of azospermia?
- klinefelters (1/500)
- ductal obstruction (absence of vas deferens)
Causes of oligospermia?
- anatomic defects
- genetic factors
- exogenous (heat)
Causes of abnormal volume of semen?
- retrograde ejaculation
- ejaculatory failure
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
When should a prostatic massage be avoided?
- in acute bacterial prostatits
- risk for induction of bacteremia or sepsis
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)
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
Methods of urine sensitivity?
- measurement of sensitivity of bacteria to abx
kirby-bauer - discs
Etest - strips
- solid media: disc diffusion technique
- liquid media: minimum inhibitory concentration (MIC) test
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)