Ch7: Thyroid Flashcards
(83 cards)
1
Q
what is T4
A
thyroxine
2
Q
what is T3
A
triiodothyronine
3
Q
what is the function of T3 and T4
A
these hormones act as cellular energy release catalysts and influence the function and health of every cell in the body
4
Q
most common thyroid disorder encountered in primary care
A
hypothyroidism
5
Q
MOMS SO TIRED mnemonic for hypothyroidism presentation
A
Memory loss Obesity Menorrhagia Slowness Skin/hair dry Onset gradual Tiredness Intolerance to cold Raised BP Energy levels fall Depression/delayed relaxation phase of all reflexes (especially patellar, Achilles)
6
Q
what is the natural history of weight gain with hypothyroidism?
A
modest weight gain of <10lbs that is mostly fluid, will pee off this fluid when adequately treated
7
Q
DTRs with hypothryoidism
A
delayed relaxation of DTRs - slow arc out and an even slower arc back
“hung up patellar reflex”
most noticeable in patellar and achilles DTRs
8
Q
most common cause of hypothyroidism in the USA
A
chronic autoimmune hypothyroidism
aka Hashimotos thyroiditis
9
Q
classic patient characteristics of someone with Hashimotos thyroiditis
A
> 50yo
female
10
Q
causes of hypothyroidism
A
- autoimmune (Hashimotos)
- post-radioactive iodine treatment (e.g., after Graves dx)
- select medications (Lithium, amiodarone, interferon)
11
Q
medications that can cause HYPOTHYROIDISM
A
- lithium (up to 1/3)
- amiodarone
- interferon
12
Q
SWEATING mnemonic for hyperthyroidism
A
Sweating Weight loss Emotional lability Appetite increased but losing weight Tremor/tachycardia Intolerance of heat/irregular menstruation/irritability Nervousness Goiter, GI problems (diarrhea)
13
Q
what is a goiter
A
descriptor for thyroid enlargement
14
Q
most common cause of hyperthyroidism
A
Grave’s disease (autoimmune)
15
Q
cluster of autoimmune conditions to keep on your radar if someone has autoimmune thyroid disease (5)
A
- rheumatoid arthritis
- lupus SLE
- vitiligo
- celiac dz
- T1DM
16
Q
exophthalmos, suspect….
A
Grave’s hyperthyroidism
17
Q
What is a toxic adenoma
A
benign (non-malignant) metabolically-active thyroid nodule that causes typical hyperthyroid symptoms but with palpable unilateral thyroid mass and NO exophthalmos
18
Q
what is thyroiditis
A
inflammation of the thyroid
usually transient
can be caused by a viral infection, autoimmune condition, postpartum, drug-induced, etc.
typically has a milder symptom presentation with thyroid tenderness but without exophthalmos
19
Q
medications that can cause hyperthyroidism (2)
A
- amiodarone
- interferon
20
Q
hyper or hypothyroid: dry skin
A
hypothyroid
21
Q
hyper or hypothyroid: fine tremor
A
hyperthyroid
22
Q
hyper or hypothyroid: hypoactive DTRs (delayed relaxation)
A
hypothyroid
23
Q
hyper or hypothyroid: mood changes
A
both
24
Q
hyper or hypothyroid: menorrhagia
A
hypothyroid
25
hyper or hypothyroid: exophthalmos
hyperthyroid
26
normal range for TSH
0.4-4.0 mIU/L
27
what is the single most reliable test to diagnose all common forms of hypo and hyperthyroidism
TSH
thyroid-stimulating hormone
28
TSH is released by the.....
anterior pituitary
29
when TSH results are normal, can you rule out thyroid disease?
yes, very good sensitivity and specificity
30
normal range for free T4
10-27 pmol/L
31
normal range for thyroid peroxidase antibody (anti-TPO ab)
<35 IU/mL
32
second most helpful test for diagnosing hypo or hyperthyroidism
*FREE*T4
| not total
33
% of all T4 that is free
0.025%
majority of T4 is protein-bound
34
anti-TPO antibodies are used to detect....
Hashimoto's thyroiditis
35
dx: TSH 84, free T4 3
high TSH
low free T4
untreated hypothyroidism
36
levothyroxine replacement doses for hypothyroidism
based on ideal body weight if obese, actual body weight if BMI WNL or underweight
- 1.6 mcg/kg/day in most adults
- 1.0 mcg/kg/day in elderly
37
check TSH after ____ weeks after starting levothyroxine for hypothyroidism
q6-8 weeks until euthyroid, then in 4-6 months, then yearly if stable
she says 8 WEEKS and any earlier can lead to errors in clinical decision-making
38
weight based dosing for levothyroxine: most adults
1.6 mcg/kg/day
| ranges 50-200mcg for adults, typically
39
weight based dosing for levothyroxine: elderly
1.0 mcg/kg/day
40
T4/T3 combination medication?
Armour Thyroid
use is not recommended by the AACE due to variable pharmcokinetics
41
instructions for patient administration of levothyroxine
levothyroxine should be taken with plain water on an empty stomach, same time every day
should not be taken within 2 hours of cation such as calcium, iron, aluminum, magnesium , or others due to chelation effect with reduced drug absorption
42
dx: TSH 0.15, free T4 79
low TSH, high free T4
hyperthyroidism
43
treatments for hyperthyroidism
- non-cardioselective beta blockers (propanolol, nadolol) for counteracting tachycardia and tremor
- thyroid-ablative therapies (e.g., methimazole, PTU, RAI)
44
thyroid ablative therapy options in hyperthyroidism
- methimazole PO (Tapazole)
- PTU (Propylthiouracil)
- radioactive iodine
use the PO methimazole or PTU first to reduce thyroxine production to become euthyroid. Once euthyroid from antithyroid medications, use radioactive iodine with the goal of thyroid ablation with resulting hypothyroidism
**usually treated in conjunction with endocrinology consult**
45
do you want cardioselective or non-cardioselective beta blockers for hyperthyroidism?
non-cardioselective beta blockers
most commonly, propanolol
46
priority risk of methimazole and PTU
acute hepatic failure even in the absence of liver disease risk factors (e.g., alcohol use)
can happen to anyone
47
dx: TSH 8.9, total T4 15, TPO-ab 76
subclinical hypothyroidism
48
treatment for subclinical hypothyroidism?
recommend treatment if TSH >5 and presence of a goiter or TPO-antibodies, symptomatic, infertility/pregnant/trying to conceive
49
what range should you treat TSH to ideally with levothyroxine
0.5-2 uIU/mL
50
If you start levothyroxine, they come back in 6-8 weeks later and the TSH is still elevated (>4) -- Dose titration?
increase levothyroxine dose by 12.5mcg to 25mcg
51
If you start levothyroxine, they come back in 6-8 weeks later and the TSH is now low (<0.5) -- Dose titration?
decrease levothyroxine dose by 12.5 - 25mcg
52
follow-up interval for checking TSH after levothyroxine adjustments
q6-8 weeks until euthyroid, then 6 months, then annually
53
risk that any given thyroid nodule is malignant?
5%
54
role of a NP primary care provider in pt with a thyroid nodule
initiate evaluation, refer to specialist
55
what is a thyroid nodule
a palpable thyroid mass, not a term specific to a diagnosis. is clinically evident, typically >1cm in diameter
presentation of benign and malignant tends to be the same
5% risk of being malignant
56
findings most consistent with a MALIGNANT thyroid nodule?
- h/o head or neck irradiation
- size >4cm
- firmness, nontender on palpation
- relatively fixed position (nonmobile)
- persistent non-tender cervical lymphadenopathy
- dysphonia
- hemoptysis
57
pt presents with clinically evident thyroid nodule >1cm, next step?
labs: TSH
imaging: thyroid US
58
pt presents with clinically evident thyroid nodule >1cm. you order TSH and a thyroid US. lab results return low TSH. what is your next step?
refer for nuclear medicine thyroid scan to determine the nodule function and structure
will determine "hot" (releasing T4) aka toxic or non-toxic (not releasing excess T4) nodules
59
pt presents with clinically evident thyroid nodule >1cm. you order TSH and a thyroid US. lab results return low TSH. nuclear medicine thyroid scan reveals a "hot" nodule, diagnosed with toxic nodular goiter. what is the next step?
radioiodine ablation or surgery to remove it
60
pt presents with clinically evident thyroid nodule >1cm. you order TSH and a thyroid US. lab results return low TSH. nuclear medicine thyroid scan reveals a non-toxic goiter, nodule is not releasing excess T4. what is the next step?
FNA biopsy
(fine needle aspiration)
this is very unusual for it to be not "hot", non-toxic
61
pt presents with clinically evident thyroid nodule >1cm. you order TSH and a thyroid US. Lab results return a normal TSH. what is the next step?
refer for FNA biopsy (fine needle aspiration)
62
one of the most common causes of asymptomatic hypercalcemia in an otherwise well adult?
primary hyperparathyroidism
63
hypothalamic-pituitary-thyroid axis
hypothalamus releases TRH (thyroid hormone releasing hormone) --> stimulates anterior pituitary to release TSH (thyroid stimulating hormone) --> stimulates the thyroid to produce T3 and T4
64
TSH production requires which nutritional components (3)
- protein
- magnesium
- zinc
65
T4 production requires which nutritional components (3)
- iodine
- vitamin C
- vitamin B2
66
T3 production requires which nutritional and body system requirements
- selenium
- healthy liver function
- healthy adrenal gland function
67
hyper vs. hypothyroid: which can you treat as NP in primary care vs. which do you refer out?
NP can treat hypothyroid (levothyroxine replacement)
refer out hyperthyroid for consultation
68
what is deQuervein's thyroiditis?
aka subacute granulomatous thyroiditis
transient thyroid inflammation (hyperthyroidism, transient) usually s/t a viral infection
69
possible physical exam findings indicative of hyperthyroidism
- thyroid bruit
- exophthalmos
- hyperactive DTRs
- tachycardia
- proximal muscle weakness
- lid lag
- atrial fibrillation
70
world-wide most common cause of hypothyroidism
iodine-deficiency (uncommon in US)
71
% of hypothyroidism that is caused by Hashimoto's autoimmune thyroiditis?
90-95%
72
(3) most common causes of hypothyroidism
- autoimmune Hashimoto's
- ablative therapy for hyperthyroidism treatment
- iodine deficiency
73
role of PTH (parathyroid hormone) in the body
increases serum calcium
| opposite of calcitonin
74
what is primary hyperparathyroidism
elevated level of parathyroid hormone (PTH)
excess PTH = hypercalcemia
caused by overactivity of one or more of the four parathyroid glands, via enlargement (hyperplasia), adenoma (benign tumor), or malignant tumor
75
clinical presentation of primary or secondary hyperparathyroidism
variable
"moans, groans, stones, and bones with psychic overtones"
common s/s include:
- loss of energy
- poor concentration or memory
- depression
- OSTEOPOROSIS/OSTEOPENIA
- insomnia
- GERD
- decreased libido
- hair loss
- bone and joint aches
other s/s:
- kidney stones
- hypertension
- arrhythmias, atrial fibrillation
- liver dysfunction
- abnormal blood protein levels
76
diagnostic evaluation of primary hyperparathyroidism
elevated serum calcium found on labs without other obvious cause
confirmed by elevated PTH level
additional test could include a 24-hour urine calcium to determine disease severity -- specialty consult advised
77
priority sequelae of primary hyperparathyroidism
osteoporosis
78
what is secondary hyperparathyroidism
elevated PTH as a result of another condition that lowers serum calcium levels, thus causing the parathyroid glands to overproduce PTH
causes include:
- severe calcium deficiency
- severe vitamin D deficiency
- chronic kidney disease
79
most common causes of secondary hyperparathyroidism (3)
- calcium deficiency
- vitamin D deficiency
- chronic kidney disease
80
diagnostic evaluation of secondary hyperparathyroidism
low-normal serum calcium
elevated PTH on labs
presence of severe renal dysfunction (often on dialysis or have significant kidney problems over several years)
81
treatment options for hyperparathyroidism
- surgery to remove the problematic gland is curative 95% of the time for primary hyperparathyroidism, only considered as last resort in secondary
- cinacalcet (Sensipar) is a calcimimetic used to treat hyperparathyroidism in CKD or parathyroid cancer, causes less parathyroid hormone to be released
- bisphosphonates and/or hormone replacement therapy for post-menopausal women should be considered to prevent bone loss
- phosphate binders and/or vitamin D analogs can be used in secondary hyperparathyroidism if vitamin D deficiency or calcium deficiency is the cause
- ensure adequate intake of vitamin D and calcium
- stop use of lithium or thiazide diuretics which may exacerbate
82
avoid use of (2) medications in someone with hyperparathyroidism as these can elevate levels of both PTH and calcium, exacerbating the condition
- thiazide diuretics
| - lithium
83
if a patient is taking either of these (2) medications when hyperparathyroidism is found on labs, they should stop medications and have calcium levels reassessed after a medication-free interval to confirm the diagnosis
lithium or thiazide diuretics (e.g., HCTZ)
