Clinical Chemistry VI

Question 1

Endocrinology

Answer 1

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

Question 2

Amines

Answer 2

Single amino acids

-T3, T4

Question 3

Peptide and protein

Answer 3

Pituitary gland hormones

Question 4

Steroid

Answer 4

Converted from cholesterol

-Glucocorticoids, estrogens

Question 5

Professor Nowak’s Endocrinology Rule

Answer 5

95% of endocrinology disorders are due to primary gland dysfunction

Question 6

Glands in endocrinology

Answer 6

Hypothalamus 
Pituitary
Thyroid
Adrenals
Parathyroid
Pancreas

Question 7

Hypothalamus

Answer 7

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

Question 8

Anterior pituitary hormones

Answer 8

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

Question 9

Posterior pituitary hormones

Answer 9

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

Question 10

Acromegaly and giantism

Answer 10

Too much growth hormone (GH) usually from pituitary adenoma

Question 11

Sx of acromegaly and giantism

Answer 11

Overgrowth of skeleton and soft tissues

Question 12

Lab of acromegaly and giantism

Answer 12

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

Question 13

Hyperprolactinemia

Answer 13

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

Question 14

Sx of hyperprolactinemia

Answer 14

Infertility
Anovulation
Menstrual irregularity
Amenorrhea
Oligospermia
Impotence
Gynecomastia

Question 15

Labs of hyperprolactinemia

Answer 15

Elevated prolactin level

Question 16

Tx for hyperprolactinemia

Answer 16

Dopamine agonists (cabergoline, bromocriptine)

Question 17

Central diabetes insipidus

Answer 17

Deficiency of ADH (diuretic effect)

Question 18

Sx of central diabetes insipidus

Answer 18

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

Question 19

Labs for central diabetes insipidus

Answer 19

Hypernatremia

Decreased ADH

Question 20

Tx for central diabetes insipidus

Answer 20

Desmopressin

Question 21

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Answer 21

Too much ADH (tumors that secrete ADH)

-MDMA, sarcoidosis, pulmonary disease, medications

Question 22

Sx of SIADH

Answer 22

Muscle weakness
Ataxia
Tremor
Lethargy
Confusion
Delirium
Seizures

Question 23

Thyroid gland

Answer 23

Produce hormones that affect body metabolism

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

Question 24

Triiodothyronine (T3)

Answer 24

Minority, but more active hormone

Question 25

Thyroxine (T4)

Answer 25

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%)

Question 26

Calcitonin

Answer 26

Related to calcium homeostasis | Also a tumor marker for medullary thyroid carcinoma

Question 27

Thyroid stimulating hormone (TSH) lab test

Answer 27

``` 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 ```

Question 28

Total T3 and/or T4

Answer 28

Measures amt that is bound to thyroxine-binding globulin (TBG) Less useful with protein abnormalities

Question 29

Free T3 (0.3%) or T4 (0.03%)

Answer 29

May need to be ordered after TSH reviewed | More expensive test compared to TSH

Question 30

Antithyroid antibodies

Answer 30

Antimicrosomal/antithyroid peroxidase antibodies (anti-TPO) Antithyroglobulin antibodies TSH receptor antibodies

Question 31

Antimicrosomal/antithyroid peroxidase antibodies (anti-TPO)

Answer 31

Directed against the protein enzyme TPO | Seen in Hashimoto thyroiditis (99%) and Graves disease (85%)

Question 32

Antithyroglobulin antibodies

Answer 32

Hashimoto thyroiditis (85%) and Graves disease (30%)

Question 33

TSH receptor antibodies

Answer 33

Immunoglobulins that bind to TSH receptors and influence their action (usually stimulate thyroid like in Graves disease)

Question 34

Radioactive iodine uptake and thyroid scan

Answer 34

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

Question 35

Thyroglobulin

Answer 35

Stored in the follicular colloid of the thyroid as a prohormone Used to monitor tx in thyroid cancer

Question 36

Hyperthyroidism (thyrotoxicosis)

Answer 36

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

Question 37

Sx of hyperthyroidism

Answer 37

``` Hypermetabolic features Nervousness Palpitations Muscle weakness Increased appetite Diarrhea Heat intolerance Warm skin Weight loss Perspiration Exopthalmous Emotional changes Menstrual changes Fine tremor ```

Question 38

Graves disease

Answer 38

Autoimmubne disease caused by TSH receptor antibodies that bind to and stimulate TSH receptors resulting in autonomous production of thyroid hormone

Question 39

Labs: Graves disease

Answer 39

High T3/T4 Low TSH Diffuse radioactive iodine uptake + TSH receptor antibodies

Question 40

Tx for Graves disease

Answer 40

Radioiodine therapy Medications Thyroid surgery

Question 41

Subacute thyroiditis

Answer 41

Secondary to viral infection, lasts for months

Question 42

Labs: subacute thyroiditis

Answer 42

High T3/T4 Low TSH High ESR No radioactive uptake