Clinical Chemistry VI Flashcards

1
Q

Endocrinology

A

Consists of several glands that secrete hormones directly into the blood rather than into a duct system

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2
Q

Amines

A

Single amino acids

-T3, T4

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3
Q

Peptide and protein

A

Pituitary gland hormones

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4
Q

Steroid

A

Converted from cholesterol

-Glucocorticoids, estrogens

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5
Q

Professor Nowak’s Endocrinology Rule

A

95% of endocrinology disorders are due to primary gland dysfunction

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6
Q

Glands in endocrinology

A
Hypothalamus 
Pituitary
Thyroid
Adrenals
Parathyroid
Pancreas
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7
Q

Hypothalamus

A

Synthesizes hormones
Stimulate or inhibit the secretion of pituitary hormones
Controls body temp, hunger, attachment behaviors, thirst, fatigue, sleep, and circadian rhythms

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8
Q

Anterior pituitary hormones

A
Growth hormone (GH)
Thyroid-stimulating hormone (TSH)
Adrenocorticotropic hormone (ACTH)
Prolactin (PRL)
Luteinizing hormone (LH)
Follicle-stimulating hormone (FSH)
Melanocyte-stimulating hormone (MSH)
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9
Q

Posterior pituitary hormones

A

Oxytocin- uterine contractions, lactation
Vasopressin (antidiuretic hormone, ADH)
Kidney water reabsorption and excretion

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10
Q

Acromegaly and giantism

A

Too much growth hormone (GH) usually from pituitary adenoma

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11
Q

Sx of acromegaly and giantism

A

Overgrowth of skeleton and soft tissues

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12
Q

Lab of acromegaly and giantism

A

Increased growth hormone
Increased serum insulin-like growth factors (IgF-1)
-IgF-1 circulates in much higher plasma concentrations than GH and is a good screening test of suspected GH abnormalities and for monitoring therapy in pts
-Single measurements of GH are not often reliable because GH secretion is episodic and diurnal

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13
Q

Hyperprolactinemia

A

Too much prolactin usually due to pituitary adenoma (pregnancy, chronic renal failure, medications)

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14
Q

Sx of hyperprolactinemia

A
Infertility
Anovulation
Menstrual irregularity
Amenorrhea
Oligospermia
Impotence
Gynecomastia
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15
Q

Labs of hyperprolactinemia

A

Elevated prolactin level

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16
Q

Tx for hyperprolactinemia

A

Dopamine agonists (cabergoline, bromocriptine)

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17
Q

Central diabetes insipidus

A

Deficiency of ADH (diuretic effect)

18
Q

Sx of central diabetes insipidus

A

Dehydration (urinates up to 20L per day)
Normal-high serum sodium and osmolality
Low urine sodium and osmolality

19
Q

Labs for central diabetes insipidus

A

Hypernatremia

Decreased ADH

20
Q

Tx for central diabetes insipidus

A

Desmopressin

21
Q

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

A

Too much ADH (tumors that secrete ADH)

-MDMA, sarcoidosis, pulmonary disease, medications

22
Q

Sx of SIADH

A
Muscle weakness
Ataxia
Tremor
Lethargy
Confusion
Delirium
Seizures
23
Q

Thyroid gland

A

Produce hormones that affect body metabolism

  • Triiodothyronine (T3)
  • Thyroxine (T4)
  • Calcitonin
24
Q

Triiodothyronine (T3)

A

Minority, but more active hormone

25
Thyroxine (T4)
Majority, prohormone Both T3 and T4 contain iodine and are transported to tissues by plasma proteins Thyroxine-binding globulin (TBG)- 70% Transthyretin (10-15%) and albumin (15-20%)
26
Calcitonin
Related to calcium homeostasis | Also a tumor marker for medullary thyroid carcinoma
27
Thyroid stimulating hormone (TSH) lab test
``` Pituitary hormone that stimulates the thyroid gland to produce T4 and then T3 Nl range: 0.3-3.0 Increased: Primary hypothyroidism -Secondary hyperthyroidism Decreased: Primary hyperthyroidism -Secondary hypothyroidism ```
28
Total T3 and/or T4
Measures amt that is bound to thyroxine-binding globulin (TBG) Less useful with protein abnormalities
29
Free T3 (0.3%) or T4 (0.03%)
May need to be ordered after TSH reviewed | More expensive test compared to TSH
30
Antithyroid antibodies
Antimicrosomal/antithyroid peroxidase antibodies (anti-TPO) Antithyroglobulin antibodies TSH receptor antibodies
31
Antimicrosomal/antithyroid peroxidase antibodies (anti-TPO)
Directed against the protein enzyme TPO | Seen in Hashimoto thyroiditis (99%) and Graves disease (85%)
32
Antithyroglobulin antibodies
Hashimoto thyroiditis (85%) and Graves disease (30%)
33
TSH receptor antibodies
Immunoglobulins that bind to TSH receptors and influence their action (usually stimulate thyroid like in Graves disease)
34
Radioactive iodine uptake and thyroid scan
Nuclear imaging scan of administered radioactive iodine Low uptake suggests thyroiditis High uptake suggests Graves disease Unevenness in uptake suggests the presence of a nodule
35
Thyroglobulin
Stored in the follicular colloid of the thyroid as a prohormone Used to monitor tx in thyroid cancer
36
Hyperthyroidism (thyrotoxicosis)
Too much T3/T4 is being made - Primary- thyroid gland makes too much T3/T4 - -Pituitary then decreases the amt of TSH - -95% of all hyperthyroidism - Secondary- pituitary makes too much TSH - -Acts on the nl thyroid to make too much T3/T4 - Tertiary- hypothalamus makes too much TRH - -Acts on the nl pituitary to then make too much TSH
37
Sx of hyperthyroidism
``` Hypermetabolic features Nervousness Palpitations Muscle weakness Increased appetite Diarrhea Heat intolerance Warm skin Weight loss Perspiration Exopthalmous Emotional changes Menstrual changes Fine tremor ```
38
Graves disease
Autoimmubne disease caused by TSH receptor antibodies that bind to and stimulate TSH receptors resulting in autonomous production of thyroid hormone
39
Labs: Graves disease
High T3/T4 Low TSH Diffuse radioactive iodine uptake + TSH receptor antibodies
40
Tx for Graves disease
Radioiodine therapy Medications Thyroid surgery
41
Subacute thyroiditis
Secondary to viral infection, lasts for months
42
Labs: subacute thyroiditis
High T3/T4 Low TSH High ESR No radioactive uptake