Lab Study Guide- Endocrine Flashcards
What labs would you check in primary testicular failure? (primary hypogonadism)
LH, FSH, testosterone, semen analysis
Decreased sperm count
Decreased LH
Decreased FSH
Decreased testosterone
Hypothalamic-pituitary abnormality
What should you measure next with hypothalamic-pituitary abnormality?
Measure prolactin
MRI of hypothalamic pituitary region
Decreased sperm count
Increased LH or FSH
Decreased or normal testosterone
Primary testicular abnormality
Decreased sperm count
Normal testosterone and LH
Normal or increased FSH
Sperm Present
Acquired Primary Hypogonadism
Decreased sperm count Normal testosterone and LH Normal or increased FSH Sperm Absent Absent Seminal Fluid frutose
Congenital absence of seminal vesicles and vas deferans
Decreased sperm count Normal testosterone and LH Normal or increased FSH Sperm Absent Present Seminal Fluid frutose Normal testicular biopsy
Ductal obstruction
Decreased sperm count Normal testosterone and LH Normal or increased FSH Sperm Absent Present Seminal Fluid frutose Abnormal testicular biopsy
Spermatogenic failure
Decreased sperm count Increased LH or FSH Decreased or normal testosterone No testes Increased testosterone on hCG stimulation
Cryptorchidism
Decreased sperm count Increased LH or FSH Decreased or normal testosterone No testes No increased testosterone on hCG stimulation
Anorchia
Decreased sperm count
Increased LH or FSH
Decreased or normal testosterone
Small, firm Testes present
Klinefelter’s
Decreased sperm count
Increased LH or FSH
Decreased or normal testosterone
Postpubertal size testes (normal and soft)
Acquired primary hypogonadism
Normal OGTT 2 hours postprandial
<140mg/dl
OGTT 2 hours postprandial diagnostic of DM
> or equal 200mg/dl
Diagnosis of impaired glucose tolerance if 2 hour postload OGTT
> or equal 140 and <200
If a nodule is “hot” after radionuclide scan, what should you do?
clinical follow-up with or without treatment depending on whether the patient is euthyroid or thyrotoxic
If a nodule is warm or cold after radionuclide scan and has suspicious cytology, what should you do?
raises question of cancer and necessitates surgical excision
What is a cold nodule?
Cold nodules are nonfunctioning; malignancy is associated with a cold nodule
What are warm or hot nodules?
Functioning thyroid nodules
Normal total T4
4.5-10.9 mcg/mL
Normal free T4
0.8-2.7 ng/dL
Normal total T3
60-181 ng/dL
Normal TSH
.5-4.7 ng/dL
Elevated total T4, elevated free T4, elevated T3, decreased TSH
Hyperthyroidism
What will labs look like for hypothyroidism?
Low Total T4
Low Free T4
Low total T3
High TSH
What is the most definitive test for thyroid cancer?
serum thyroglobulin measurements
What is diagnostic for diabetes insipidus?
DDAVP (synthetic vasopressin) intranasally that causes a 50% greater increase in urine osmolality
When you are diagnosed with DI by DDAVP what test should be done?
Evaluation of the pituitary and hypothalamus via MRI
Urine osmolality < plasma osmolality and <45% increase in urine osmolality for ____________ diabetes insipidus
nephrogenic DI
What are the parameters for diagnosis of neurogenic DI?
Urine osmolality > plasma osmolality
>50% increase in urine osmolality
What would you expect to see on labs if a DM patient is having nephropathy?
Proteinuria and HTN
_______ is inaccurate guide to degree of GFR impairment when screening for diabetic nephropathy
Measurement of SCr
In diabetic nephropathy, screening for proteinuria should be performed __________, starting at time of diagnosis for Type 2 and ________ after diagnosis in Type 1
Annually
5 years after dx
What is the simplest method for screening microalbuminuria?
Ratio of protein (albumin) to Cr in random spot urine specimen (measurement correlates closely with 24 hour urinary protein estimates)
What would microalbuminuria be in 24 hours urinary protein estimates?
<300gm/24hours
What is the best tests to measure hypopituitarism?
IGF-1, plasma testosterone, TSH, Free T4, plasma cortisol response to synthetic ACTH
Diagnosis of pituitary tumors is confirmed by
MRI
What is Fine needle aspiration the initial evaluation of choice for?
Thyroid nodule patients
After FNA, you should do what for cystic and solid thyroid masses?
Ultrasound- assists in evaluating for size and cystic components
Thyroid nuclear scans- to confirm functional state
Metastatic and follicular tumors associated with ______ serum thyroglobulin
Increase
Medullary tumors show what on labs?
increased serum calcitonin
CEA antigen
Thyroid US is useful for?
differentiating solid nodules vs cystic nodules (may help guide FNA as well)
FNA is useful for?
used to obtain thyroid cells for cytologic evaluation (differentiate benign vs. malignant disease)
What is the testing sequence for thyroid nodule?
FNA (if cytology is malignant- surgery)
If benign- observe x1 year and follow up US
If suspicious on US- radionucleotide scan of nodule uptake
Metformin is C/I with what 2 lab findings?
Cr >1.5
Hepatic insufficiency
When can someone not be on Rosiglitazone and Pioglitazone (TZDs)?
ALT >2.5x ULN
What drug needs dose adjustments for CrCl?
DDP-4 Inhibitors (sitagliptin, saxagliptin)
If triclycerides >500mg/dL, what drug is C/I?
Colesevelam (WelChol)
With GLP-1 (Exenatide), you should use precaution if CrCl is what?
<30
Who should you never give TZD (rosiglitazone, pioglitazone) to?
NYHA class III or IV HF
When do you need to be on a statin if DM?
If HDL < 40 or high LDL
What is the goal BP of a diabetic?
130/80
Treat with ARB or ACEI
What is goal BP of DM patient with renal insufficiency and proteinuira >1g/24hours?
125/75
What labs should you get for premature menopause?
Elevated FSH
Elevated serum gonadotropin
Low serum estradiol
Estrogen deficiency symptoms (hot flashes, dry vagina)
