Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Jorge ENI > Hypothyroidism physiology > Flashcards

Hypothyroidism physiology Flashcards

1
Q

What is primary hypothyroidism and what types are there?

A

Lack of functional thyroid tissue
Acquired
Iatrogenic
Congenital

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the causes of acquired primary hypothyroidism?

A

Lymphocytic thyroiditis
Idiopathic follicular atrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the causes of iatrogenic primary hypothyroidism?

A

surgery
radioactive iodine therapy
Anti-thyroid meds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is secondary hypothyroidism?

A

Impaired secretion of TSH from pituitary gland
Acquired:
- neoplasia
- pituitary suppression
- illness, malnutrition
Congenital:
- cystic rathke’s pouch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is tertiary hypothyroidism?

A

lack of TRH in hypothalamic supraoptic and paraventricular nuclei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what breeds are predisposed to canine hypothyroidism?

A

Golden retrievers
Cocker spaniels
Terriers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the clinical signs of canine hypothyroidism?

A

Gradual onset of:
- dullness
- lethargy
- exercise intolerance
- obesity without history of polyphagia
- cold intolerance
- skin changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is there a gradual onset of clinical signs due to hypothyroidism?

A

due to store of thyroid hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the effect of hypothyroidism on development

A

reduced development and maturation of brain cells in foetus and young

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the effect of hypothyroidism on growth

A

Required for normal growth:
- growth retardation
- smaller
- shorter bones
- delayed closure of physes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the metabolic actions of hypothyroidism

A

Decreases carb and fat metabolism
Decreased BMR (basal metabolic rate)
Increased body weight
=> weight gain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the effects of hypothyroidism on the MSK system

A

reduced muscle tone and changes in fibre type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the effects of hypothyroidism on the cardiovascular system

A

Brachycardia, weak apex beat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the normal physiological effects of T3 and T4 on the cardiovascular system?

A

increase blood flow and cardiac output
Increase HR
Increase contractility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the effect of hypothyroidism on the nervous system

A

Neurological anomalies
Neuropathy:
- knuckling and paresis (weak limbs)
- hearing impairment
- slower reflexes
Myopathy:
- paresis
- slow gait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are thyroid hormones needed for in the nervous system?

A

normal development
enhances SNS (increase epinephrine receptors)
optimal nerve conduction

17
Q

What is the effect of hypothyroidism on the CNS?

A

lethargic and requires more sleep

18
Q

What is the effect of hypothyroidism on the repro system?

A

Male:
- infertile
- testicular atrophy
- reduced sperm production
Female:
- infertility
- shortened oestrus
- prolonged oestrual bleeding
- prolonged anoestrus

19
Q

What is effect of hypothyroidism on the GIT?

A

decreases motility and secretion of pancreatic enzymes => constipation

20
Q

Describe the effects of hypothyroidism on integument

A

Arrests hair growth, hair retained in telogen
Alopecies or failure to regrow hair after clipping

21
Q

What is the action of thyroid hormone on integument?

A

initiates and maintains anagen phase

22
Q

What skin changes can be seen in canine hypothyroidism?

A

Bilateral symmetrical alopecia
Seborrhea
Lichenification
Comedones
Hyperpigmentation on alopecic areas
Recurrent infections

23
Q

what can be seen here?

A

comedones

24
Q

What can be seen here?

A

alopecia
hyperpigmentation

25
Q

What is myxedema in hypothyroidism?

A

tragic facial expression due to excess mucopolysaccharides and hyaluronic acid in dermis

26
Q

Describe the complete blood count found in hypothyroidism

A

Normocytic, normochromic anaemia
Leukocytosis if there is an infection

27
Q

Describe the biochemistry profile in hypothyroidism

A

Increased parameters of lipid metabolism - cholesterol, lipids, triglycerides
Increased hepatic enzymes

28
Q

What baseline thyroid hormones are used in endocrine testing

A

Total T4
Free T4
TSH

28
Q

Describe the use of measuring tT4 in endocrine testing

A

Measures protein bound and free T4
Good sensitivity/screening test
Normal total T4 can exclude hypothyroidism

29
Q

What reasons other than hypothyroidism can cause a low total T4 result?

A

daily fluctuations
Non-thyroid illness/euthyroid sick syndrome
Drugs - glucocorticoids, antibiotics

30
Q

Describe euthyroid sick syndrome

A

Non-thyroidal illnesses suppress T4 and T3 but patient is not hypothyroid
Mechanisms:
- decreased binding of T4 and T3
- decreased T4 to T3 conversion
- decreased TSH release
Low total T4 with low-normal TSH

31
Q

Describe use of free T4 in diagnosing hypothyroidism

A

Conc of fT4 reflects thyroid status at tissue level
Higher specificity/diagnostic test
less affected by external factors

32
Q

Describe the use of baseline TSH in diagnosis of hypothyroidism

A

Primary hypothyroidism => low T4 and high TSH levels
High specificity if interpreted with tT4 or fT4 results
Low sensitivity - some hypothyroid dogs have normal TSH levels

Jorge ENI (81 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions