Chapter 6 Endocrine Flashcards
1
Q
Where is the Thyroid gland located?
A
Wraps around trachea, just below thyroid cartilage
2
Q
What is the function of thyroid gland?
A
Produces thyroid hormones (T3 and T4)
3
Q
What is T4?
A
- Thyroxine
- Most abundant thyroid hormones but largely inactive
- less metabolic effect
4
Q
where is T4 activate to T3?
A
tissues and liver
5
Q
What is T3?
A
- Triidothyroxine
- Active form, greater metabolic effect
6
Q
What is the tissue in the body that only uses iodine?
A
Thyroid Gland
7
Q
How many Iodines does T4 and T3 have?
A
- T4 = 4 iodine 2 tyrosine amino acids
- T3 = 3 iodine 2 tyrosine amino acids
8
Q
What feedback does thyroid gland regulate to?
A
Negative feedback
9
Q
What does hypothalamus release?
A
Thyrotropin releasing hormone (TRH)
10
Q
what does release of TRH causes?
A
causes the anterior pituitary to release TSH
11
Q
What does Thyroid stimulating hormone (TSH) do?
A
Causes thyroid to produce and secrete Thyroxin (T4)
12
Q
Who/what releases TSH?
A
Anterior pituitary gland
13
Q
Activated T3 acts on what? and causes what?
A
Activated T3 acts on cells to increase metabolism
14
Q
what causes the hypothalamus to stop releasing TRH?
A
When there is an increased levels of thyroid hormones
15
Q
Explain the regulation of the thyroid gland (Negative feedback)
A
- Hypothalamus releases TRH which causes the anterior pituitary to release TSH
- TSH causes thyroid to release T4
- Activated T3 acts on cells to increase metabolism
- Increased levels of thyroid hormones cause hypothalamus to stop releasing TRH
16
Q
TSH is used as a marker for what?
A
TSH is easiest to measure, and used as a marker for thyroid function
17
Q
Continuum of Thyroid dysfunction (Hyper to Hypo)
A
-Hyper- Thyrotoxicosis Hyperthyroidism Euthyroid Hypothyroidism Myxedema coma -Hypo-
18
Q
What is goitre?
A
An enlargement of thyroid gland
19
Q
What is nodule
A
A localized growth of thyroid gland
20
Q
Is goitre result from hyper or hypo thyroidism?
A
- Both
- Thyroid cells are stimulated to grow, which may result in hyper or hypo
21
Q
What causes goitre? (3)
A
- Elevated levels of TSH ( endemic goitre)
- Toxic goitre (thyroid grows without TSH stimulation tumour)
- Goitrogen drugs
22
Q
What causes elevated TSH ( endemic goitre)?
A
- Iodine Deficiency
- Thyroid needs iodine to make T4 and without it the T4 level drops. The Hypothalamus will sense that there is low T4 and will release TRH to try to stimulate the anterior pituitary gland. Anterior pituitary then releases TSH and will continue to release it in order to try to get more T4.
- too much TSH is the result
23
Q
What causes toxic goitres?
A
- Benign tumours in the thyroid gland causing the gland to grow uniformly or through nodules
- Thyroid grows without TSH stimulations
24
Q
How do goitrogen drugs cause goitre?
A
They interfere with gland uptake of iodine and can cause low levels of T4 which results in elevated TSH and eventually form goitre.
25
Goitrogen drugs (4)
- Sulphonamides
- Salicylates
- Lithium
- Amiodarone
26
Does goitre indicates whats going on with thyroid glands?
- NO
| - Needs further assessment
27
how do we identify if the thyroid nodule is benign or cancerous?
Biopsy of tissue is taken
28
2 types of thyroid nodules
- Functional nodules ( caused by increase TSH)
| - Benigh tumours
29
What is the risk factor of thyroid cancer? and how do we prevents it?
- Radiation is risk factor
- Thyroid is really sensitive to radiation therefore, we have to wear vest with collar on neck to protect thyroid glands.
30
What is thyroiditis?
Thyroiditis is an inflammation of the thyroid gland
31
what causes thyroiditis? (4)
- Autoimmune - can lead to hypothyroidism (hashimoto's thyroiditis)
- Viral infection
- Bacterial infection
- Postpartum thyroiditis
32
Which of the causes of thyroiditis can people usually recover from?
- Viral infection
- Bacterial infection
- Postpartum thyroiditis
33
What is Hashimoto's thyroiditis
- Thyroid tissues is replaced by fibrous functional tissues
| - Permanently changed and can no longer or barely make any thyroid hormones
34
What is Hyperthyroidism
Higher than normal levels of thyroid hormone circulating in blood
35
What is thyrotoxicosis
A group of symptoms caused by excess levels of thyroid hormone (hyper-metabolism)
36
What causes Hyperthyroidism (5)
- Auto-immune (Graves disease)
- Toxic nodular goitres/ Thyroid cancer
- Pituitary tumours
- Thyroiditis
- Exogenous iodine ( treatment for endemic goitre)
37
What is Graves Disease? How does it cause hyperthyroidism?
- Auto-immune
| - Antibody mimics TSH and it binds to the TSH receptors causing the thyroid to produce large amount of thyroid hormones
38
Graves disease is characterized by?
Remission and exacerbations, with or without treatment
39
How does toxic nodular goitre/ thyroid cancer cause hyperthyroidism?
Nodule or lump grows on the thyroid gland causing it to become enlarged and produce excess thyroid hormones.
- this is independent of TSH
40
How does pituitary tumours cause hyperthyroidism?
Nodule or lump grows on the pituitary causing it to produce excess TSH which stimulates the thyroid to create more T4 hormones.
41
How does thyroiditis cause hyperthyroidism?
Thyroiditis can cause excess production of hormones.
42
how does exogenous iodine cause hyperthyroidism
- Too large of dose can increase excess production of hormones.
- More iodine available to make T4
43
Clinical manifestations of Hyperthyroidism - CNS (7)
Anxiety, very alert, nervous, depression, insomnia, irritable, heat intolerance
44
Clinical manifestations of Hyperthyroidism - CVS (6)
- increase CO
- Increase HR
- Afib
- SVT (supra ventricular tachycardia)
- PVCs ( premature ventricular contractions)
- Cardiac hypertrophy
45
What does fast metabolism do in sympathetic system?
- SNS is sensitive to fast metabolism
46
Clinical manifestations of Hyperthyroidism - respiratory (2)
- Tachypnea
| - Eventually muscle wasting can cause dyspnea
47
Clinical manifestations of Hyperthyroidism - GI (4)
- increase appetite
- weight loss
- increase BS (bowel sounds)
- Diarrhea
48
Clinical manifestations of Hyperthyroidism - musculoskeletal (3)
- fatigue
- muscle weakness
- osteoporosis ( rapid bone reabsorption)
49
Clinical manifestations of Hyperthyroidism - others (2)
- exophthalmos - autoimmune
| - Goitre - due to high TSH
50
What is exophthalmos?
Autoimmune attack which affects soft tissue behind eyes causes inflammation and edema which pushes the eyes forward
-> risk of injury due to eyelids cannot protect bulging eyes
51
What is the complication of Hyperthyroidism?
Thyroid Crisis ( Thyroid Storm)
52
When is thyroid crisis most likely to occur?
Most likely to happen in chronic or untreated hyperthyroidism
53
What is Thyroid Crisis
- It is a rare complication where hyperthyroidism symptoms are intensified
54
Thyroid Crisis is triggered by? (3)
- illness
- Trauma
- Surgery
55
Thyroid Crisis is characterized by (14)
- Severe tachycardia
- heart failure
- shock
- fever
- agitation
- delirium
- nausea
- vomiting
- diarrhea
- hyperthermia
- restlessness
- seizure
- abdominal pain
- coma
56
During thyroid crisis, why is the heart and nerve more sensitive to SNS?
due to more binding sites for epinephrine and norepinephrine are present
57
What is the treatment for Thyroid Crisis?
Thyroid levels must be reduced and other symptoms managed with medical therapy
58
Does thyroid Crisis requite immediate medical treatment?
yes
59
What are the treatment of hyperthyroidism (4)
- Drug therapy
- Radioactive iodine therapy
- Surgical therapy
- Nutritional Therapy
60
What is Radioactive iodine therapy?
- Treatment for hyperthyroidism
| - ingested capsule that Destroys part of the thyroid tissue and cells
61
What is Surgical Therapy? When is it done?
- Treatment for hyperthyroidism
- Removing part of thyroid gland
- Done when patient no longer respond to drugs
62
Nutritional Therapy
- Treatment for hyperthyroidism
- Increase calorie diet, high in protein, mineral and vitamins
- avoid high fibre foods because it can stimulate GI more
63
What is the difference between goitre and nodule?
- Goitre is enlargement of the thyroid gland while nodule is localized growth of thyroid gland.
64
Why does a person with hyperthyroidism complain of fatigue?
Due to high metabolism. The body works extra to reach demand therefore it results in fatigue. SNS is also sensitive so our body goes into SNS stimulation which causes more fatigue
65
Hypothyroidism
Lower than normal levels of thyroid hormone circulating in the blood
66
what are the causes of hypothyroidism? (7)
- Congenital hypothyroidism
- Auto-immune ( Hashimotos Thyroiditis)
- Pituitary disease
- Hypothalamic dysfunction
- Iodine deficiency
- After surgical removal of thyroid gland
- Medications: Amiodarone, Lithium
67
What is congenital hypothyroidism
Born without the ability to produce adequate amounts of thyroid hormones
68
What is Autoimmune (Hashimoto's Thyroiditis)
Antibodies attack on thyroid gland which results in functional thyroid tissue replaced by fibrous tissue that is not capable of sensitizing hormones.
69
How does pituitary disease and hypothalamic dysfunction cause hypothyroidism?
Both affects the negative feedback loop affecting thyroid from getting stimulated normally = low TSH
70
How does Iodine deficiency cause hypothyroidism?
Cannot make T4 without iodine
71
How does surgical removal of thyroid gland cause hypothyroidism
If too much is removed then the thyroid gland is unable to produce adequate amount of hormones.
72
How does medications such as Amiodarone and Lithium cause hypothyroidism?
Amiodarone - Contains iodine which causes thyroid to make less T4 ( Thyroid gland get used to high levels of iodine that normal amount of iodine is not going to work anymore then it will result in low production)
Lithium - Blocks hormone production
73
Clinical Manifestations of Hypothyroidism - CNS (6)
- Fatigue
- lethargy
- Depression
- memory loss
- cold intolerance
- Slow speech
74
True or false: Onset of hypothyroidism symptoms is noticed right away
false: onset of symptoms may be unnoticed for months to years
75
Clinical Manifestations of Hypothyroidism - CVS (4)
- bradycardia
- Heart blocks
- Anemia
- increase LDL (risk for cardiovascular)
76
Clinical Manifestations of Hypothyroidism - Respiratory(3)
- lower respiratory rate
- Sleep apnea
- SOB on exertion
77
Clinical Manifestations of Hypothyroidism - GI (3)
- Loss of appetite
- Weight gain
- constipation
78
Clinical Manifestations of Hypothyroidism - Musculo (2)
- muscle fatigue
| - muscle cramps
79
Clinical Manifestations of Hypothyroidism - renal
- low GFR due to decrease in renal blood flow ( fluid retention)
80
Clinical Manifestations of Hypothyroidism - others (2)
- myxedema
| - goitre due to increase in TSH
81
what is myxedema?
due to accumulation of polysaccharides in the connective tissue of the skin which draws water
- puff face, periorobital edema, mask expression
82
what is the complication of hypothyroidism?
Myxedema Coma ( extremely low metabolic state)
83
When can myxedema coma occur?
Can occur due to chronic, untreated hypothyroidism
84
What are the triggers for myxedema coma? (4)
- drugs ( opioids, barbiturates, tranquilizers)
- infection
- exposure to cold
- trauma
85
Myxedema coma is characterized by? (5)
- lethargy
- coma
- hypothermia
- hypotension
- hypoventilation
86
What to do dor myxedema coma?
- Medical emergency
- vital signs must be supported
- thyroid hormones replaced ( IV )
87
How does amiodarone cause problems with thyroids?
Amiodarone can lead to inhibition of T4 and T3 entry into the peripheral tissues. Both amiodarone and its principle metabolite may have direct cytotoxic effects on the thyroid follicular cells, leading to a destructive thyroiditis
88
Adrenal glands consist of?
Medulla and cortex
89
Medulla secretes what?
Catecholamines
90
what are the example of catecholamines
Epinephrine and noripheneprine
91
What does cortex secretes
Secretes >50 steroid hormones, collectively known as "corticosteroids"
92
what are the 3 corticosteroids? and give examples
1) glucocorticoids - cortisol
2) mineralcorticoids - aldosterone
3) Androgen
93
what is the function of glucocorticoids? (3)
- Helps maintain blood glucose
- Anti-inflammatory that suppress the immunity
- Support of action that helps body respond to stress
94
what is the function of mineralcorticoids
- maintenance of fluid and electrolyte balance.
| - Acts on renal tubules to increase reabsorption of sodium and excretion of potassium
95
What is the function of androgen (2)
- Secrete in small amounts to stimulate pubic and hair axillary hair growth
- Controls sex drive in females
96
Regulation of adrenal gland is through what feedback?
Negative feed back
97
Adrenal gland regulation is controlled by?
Hypothalamus - anterior pituitary
98
How does Regulation of the adrenal glands work?
1) Hypothalamus releases corticotropin releasing hormone (CRH) which stimulates anterior pituitary
2) anterior pituitary releases adrenocorticotropic hormone (ACTH)
3) Adrenals produce corticosteroids
99
Difference between physiological effect vs pharmacologic effect
Physiological - occurs at low levels
| Pharmacologic - occurs at high levels
100
what is physiologic effect of glucocorticoids
- Occurs at low levels
- release of cortisol from normal adrenal glands
- Admin of low dose
101
what is pharmacologic effect of glucocorticoids
- Occurs at high levels
- Excessive secretion of cortisol (Cushing's syndrome)
- admin of large doses to treat disorders unrelated to adrenal dysfunction ei. inflammation, cancer, asthma etc.
102
What is Cushing's syndrome?
A group of symptoms caused bu excess levels of corticosteroids (particularly glucocorticoids)
103
what are the causes of Cushing syndrome?
- Causes are divided in to two groups: ACTH independent and ACTH dependent
104
what are 2 causes of ACTH dependent Cushing Syndrome
1) Pituitary adenoma (Secretes ACTH) - 68% of non-iatrogenic
2) Non-pituitary tumour (Secretes ACTH) - 15% of non-iatrogenic
105
what does non-iatrogenic means?
not related from taking medications
106
How does Pituitary adenoma secrete ACTH and cause cushings
Pituitary have an abnormal growth which can cause increase in ACTH to be secreted which causes increase in cortisol
107
How does Non-pituitary tumour secrete ACTH and cause cushing's
Tumour outside pituitary gland that increase the secretion of ACTH causes rise in cortisol level. Common spots are in the lungs
108
what are 2 causes of ACTH independent Cushing Syndrome
1) adrenocortical tumour (secretes cortisol) - 17% of non-Iatrogenic
2) Iatrogenic administration of exogenous glucocorticoids (for inflammation) ( most common)
109
How does adrenocortical tumour cause cushing's syndrome
adrenal glands have tumour which causes it to secrete excess amounts of corticosteroids (cortisol)
110
How does iatrogenic administration of exogenous glucocorticoid cause cushings?
High intake of exogenous glucocorticoids increase levels of cortisol in blood
111
Clinical manifestations of Cushing syndrome -Glucocorticoids (9)
- Moon face
- Buffalo hump
- Supraclavicular fat pad
- Thin extremities with muscle atrophy (catabolic effect)
- Thin skin and subcutaneous tissues ( catabolic effect)
- Purple striae ( catabolic effect)
- Pendulous abdomen
- Ecchymosis resulting from easy bruising
- slow wound heal
112
Clinical manifestations of Cushing syndrome - Mineral corticosteroids
- Increase in BP
| - Weight gain
113
Clinical manifestations of Cushing syndrome - Androgen
- acne
- thinning of hair
- Increased body and facial hair
114
Cushing syndrome according to cause - effects of cortisol
- Central obesity
- muscle wasting and fatigue
- hyperglycaemia/ insulin resistance
- osteoporosis
- Thin skin with striae, easily bruised
- Impaired immune response and opportunist infection.
115
Cushing syndrome according to cause - effects of mineral corticoids (2)
- hypokalemia
| - hypertension
116
Cushing syndrome according to cause - effects of androgens(4)
- Increase body hair/ masc hair line
- acne
- menstrual irregularities/ infertility
- Hirsutism ( abnormal hair growth in women)
117
Name 3 things that are "broken down" by high levels of cortisol in cushing's syndrome(3)
- muscle
- bones
- skin
118
Why would we be concerned about a skin tear in a patient with cushings syndrome?
because they are immunosuppressive therefore, skin tear can increase the risk for infection.
119
What is adrenal insufficiency?
a rare condition caused by decreased levels of corticosteroids.
120
What does PRIMARY adrenal insufficient cause means? list 4
- primary means that the problem is in the adrenal glands and the negative feedback is still working ( low cortisol, Increase ACTH)
1) auto-immune - Addison's disease
2) tuberculosis
3) CMV infection
4) Adrenal Tumour
121
What does SECONDARY adrenal insufficient cause means? list 2
- Pituitary gland is the problem ( low cortisol, low ACTH)
1) Pituitary disease
2) Administration of exogenous corticosteroids
- Body detects corticosteroids so pituitary gland doesn't make as much ACTH to prompt the adrenal gland to make more.
122
Addison's disease clinical manifestations- symptoms causes: Increased levels of ACTH
- Hyperpigmentation to face, hands, over joints and in skin folds
123
Addison's disease clinical manifestations- symptoms causes: Reduced aldosterone level
- Hyponatremia
- Dehydration and hypotension
- Hyperkalemia
- Metabolic Acidosis
124
Addison's disease clinical manifestations- symptoms causes: reduced cortisol levels
- decrease blood sugar between meals ( hypoglycemia)
- weakness and fatigue
- Decrease tolerance to stress
125
What is addisonian crisis?
life threatening emergency caused by insufficient adrenal hormones or a sudden sharp decrease in these hormones.
126
What are the causes of Addisonian crisis?(5)
Stressors like:
- infection
- trauma
- surgery
- Psychological distress
- sudden withdrawal of corticosteroid hormone therapy.
127
What are the symptoms of addisonian crisis? (10)
- hypotention
- hypoglycemia
- hyponatremia
- hyperkalemia
- fever
- weakeness
- confusion
- nausea
- vomiting
- diarrhea
128
What to do on addisonian crisis?
- Support vitals
| - Give corticosteroids IV
129
Compare and contrast cushing syndrome to addison's disease
Cushing - too much cortisol
| Addisons - too little
130
Explain why hyperpigmentation occurs in Addison's
- Increase in ACTH binds to melanocytes receptors causing hyperpigmentation
131
Why can we never discontinue exogenous glucocorticoids suddenly?
Because it can result in addisonian crisis due to decrease size of adrenal glands
132
Where is the posterior pituitary gland?
This gland is an extension of the hypothalamus
133
what hormones does posterior pituitary gland release
1) oxytocin
| 2) Antidiuretic Hormone (ADH)
134
What does ADH do?
ADH (vasopressin) regulates fluid volume by stimulating water reabsorption in renal tubules
135
What is Syndrome of Inappropriate ADH (SIADH)
ADH released despite low or normal serum osmolality
136
what does low osmolality or high osmolality means?
```
Low = Blood is more diluted
High= blood is more concentrate
```
137
What is the cause of SIADH (4)
- brain injury/ tumours
- infections (meningitis)
- small cell lung ca ( secretes ADH)
- Drug induced ( seizure meds, antidepressants, opiates)
138
SIADH clinical manifestations (1 others) ( brain 5) , ( GI 3) , (Muscles 3)
- Fluid retention = decrease urine output and increase body weight
- Symptoms are primary related to decrease in NA+
1) Muscle cramps, twitching and weakness
2) Vomiting, abdominal cramping, anorexia ( GI related)
3) Lethargy, confusion, headache, seizure, coma (Brain)
139
What is Diabetes Insipidus?
group of conditions associated with a deficiency in production or secretion of ADH or with a decreased renal response to ADH
140
What causes Diabetes insipidus (3)
1) Central (neurogenic) - Problem with brain
2) Nephrogenic - ADH acts on kidneys/ kidneys not responding
3) Primary ( psychogenic) - excess water intake
141
Clinical Manifestations of DI (9)
- "dying of Thirst"
- Polydipsia
- Abrupt Polyuria
- Fatigue
- Constipation
- Weight loss
- Dehydration
- Decreased LOC, seizure, shock, coma
- Hypernatremia
142
What is the role of ADH in the body?
Reabsorb water in the renal Tubes
143
When is ADH released normally?
When osmolality is high ( blood is concentrated)
144
How do kidneys respond to ADH?
By reabsorbing water at the renal tubes
145
What are the symptoms of hyponatremia
- Changes in LOC - confusion, seizure, coma, lethargic
- Muscle cramps, twitching, weakness
- Vomiting, abdominal cramp and anorexia
146
What are symptoms of hypernatremia (4)
- Decrease LOC
- seizure
- Shock
- coma
