Endocrinology Flashcards
1
Q
What is endocrinology?
A
The study of hormones, their receptors, the intracellular signalling pathways and associated diseases
2
Q
What are the three types of hormone action?
A
- Endocrine - blood-borne, acting at distant sites
- Paracrine - acting on adjacent cells
- Autocrine - feedback on same cell that secreted hormone
3
Q
What is an endocrine gland?
A
Secretes into the blood stream
- Examples are thyroid, adrenal, beta cells of pancreas
4
Q
What is an exocrine gland?
A
Secretes through a duct
- Examples include pancreas amylase and lipase
5
Q
What is synergism?
A
The combined effect of two hormones amplified
6
Q
What is permissiveness?
A
A hormone needed for another full potential effect
7
Q
Function of thyroid hormone? (5)
A
- Accelerates food metabolism
- Increases protein synthesis
- Enhances fat metabolism
- Increase in ventilation rate, cardiac output
- Growth rate accelerated
8
Q
Function of growth hormone?
A
- Stimulates production of IGF-1. This induces metabolic changes
- Decreases adipose
- Increases liver function/muscle
- Increases protein synthesis and lipolysis
9
Q
What hormone stimulates GH?
A
GHRH
10
Q
What hormone inhibits GH?
A
Somatostatin
11
Q
What is acromegaly? (2)
A
- Overgrowth of all organ systems, bones, joints, soft tissues
- Due to excessive GH secretion after epiphyseal plate fusion
12
Q
What is hyperprolactinaemia?
A
- A condition with elevated serum prolactin
13
Q
What is satiety?
A
The feeling of fullness - disappearance of appetite after a meal
14
Q
Which part of the brain plays a central role in appetite regulation?
A
Hypothalamus
15
Q
What are the main ‘players’ in appetite regulation?
A
- Peripheral factors e.g. leptin and insulin
- Gut peptides
- Hypothalamus
- Central areas
- Brain stem
16
Q
What is the role of leptin?
A
- Binds to leptin receptor
- Switches off appetite and is immune-stimulatory
17
Q
Why is diabetes a public health issue?
A
- Mortality
- Disability
- Co-morbidity
- Reduced quality of life
18
Q
What is an ‘obesogenic’ environment?
A
- Physical environment - TV remote controls, lifts, cars
- Economic environment - cheap TV watching, expensive fruit and veg
- Sociocultural environment - safety fears, family eating patterns
19
Q
What is different about the anterior pituitary blood supply?
A
- Has no arterial blood supply
- Receives blood through portal venous circulation from the hypothalamus
20
Q
Would the removal of the thyroid cause an increase or decrease in TSH?
A
Increase
21
Q
Would an overreactive thyroid cause an increase or decrease in TSH?
A
Decrease
22
Q
What are two examples of diseases of the pituitary?
A
- Benign pituitary adenoma
- Craniopharygioma
- Trauma
- Apoplexy
- Sarcoid/ TB
23
Q
What can a tumour of the pituitary cause?
A
- Pressure on local structures e.g. optic nerves
- Pressure on normal pituitary
- Functioning tumour
24
Q
What can pressure on local structures of a pituitary tumour cause?
A
- Headaches
- Visual field defects
- Cranial nerve palsles
- Rhinorrhoea
25
What is bitemporal hemianopia?
- affects peripheral view
| - lose colour vision first
26
What are examples of functioning pituitary tumours?
- Prolactinoma
- Acromegaly/giantism
- Cushing's Disease
27
What are the symptoms of prolactinoma?
- present with galactorrhoea (excessive production of milk) and/or infertility
- Loss of libido
- visual field defect
28
What is the treatment for prolactinoma?
- Dopamine agonist = cabergoline
29
What are the symptoms of acromegaly?
- thick skin, greasy, sweating, prognathism, frontal bossing
| - ABCDEFGHIJ
30
What are the symptoms of Cushings?
Central obesity, red face, proximal myopathy, short stature, thin skin, brusing
31
What is mean age of diagnosis of acromegaly?
44
32
What are the co-morbidities related to acromegaly?
- hypertension
- Sleep apnoea
- Arthritis
- Type 2 diabetes
33
How can acromegaly be diagnosed?
- Clinical features - includes facial enlargement, maxfax changes, excessive sweating and headaches
- Increasaed GH and IGF-1
34
What therapy is used for treating acromegaly?
- Restore basal GH and IGF-1 to normal levels (surgery
- Relieve symptoms
- Prevent further skeletal deformities
35
What surgery can be used in acromegaly
- Pituitary surgery
| - success dependent on size of tumour and surgeon
36
What medication is used for acromegaly? (3)
- Cabergoline (dopamine agonist)
- Somatostain analogue
- GH receptor antagonist
37
What symptoms would occur with prolactinoma?
- Effect of tumour = headache, visual field defect
| - menstrual irregularity, infertility, low libido, galactorrhoea
38
What is the main type of treatment for acromegaly?
- Pituitary surgery is the main therapy
| - Medical management is improving
39
What is the main type of treatment for prolactinoma?
- Medication rather than surgery
| - Unlike other pituitary tumour management
40
What medication is used in prolactinoma?
- Cabergoline - dopamine agonist
41
What part of the body can determine circadian rhythm?
- The eyes (cells)
42
What are the symptoms of Addison's Disease?
- Fatigue
- Lethargy
- Muscle weakness
- Mild depression
- Loss of appetite/dehydration
- Can go on to develop other common symptoms
43
What is the pathology of Addison's Disease?
- Primary adrenal insufficiency
| - Disruption of production of the steroid hormones aldosterone and cortisol
44
What are the symptoms are hypopituitarism?
- Fatigue
- Weight Loss
- Decreased sex drive
- Decreased appetite
- Anaemia
- Infertility
45
What is the treatment for Addison's and hypopituitarism?
- Hydrocortisone 2-3x
| - Also in primary adrenal insufficiency replace aldosterone with fludrocortisone
46
What is the common presentation of adrenal crisis?
- Hypotension
- Fatigue
- Fever
- Hypoglycaemia
- Hyponatraemia/ hyperkalaemia
47
How can you manage adrenal crisis?
- Immediate hydrocortisone
48
Name two types of thyroid autoimmunity.
- Postpartum thyroiditis
- Hashimoto's thyroiditis
- Atrophic thyroiditis
- Graves' disease
49
What is Graves' Disease?
- Autoimmune condition
| - Body attacks thyroid so it is overreactive
50
What can predispose someone to thyroid autoimmunity?
- Genetic factors
- Female, especially post-partum
- Environmental factors e.g. stress, iodine intake and smoking
51
What is a goitre?
A palpable and visible thyroid enlargement
52
What can hyperthyroidism be due to?
- Overproduction of thyroid hormone
- Leakage of preformed hormone from thyroid
- Ingestion of excess thyroid hormone
53
What are the features of a patient with hyperthyroidism?
- Weight loss
- Tachycardia
- Hyperphagia
- Heat intolerance/sweating
- Menstrual issues
54
How would you investigate hyperthyroidism?
- Thyroid function test
55
What is the treatment for hyperthyroidism?
- Anti-thyroid drugs = thionamides
- carbimazole
- Radioiodine
- Surgery
56
What is the common side effect of thionamides?
- Rash
57
What is the medication used for hyperthyroidism?
- Carbimazole
| - Thionamides
58
What are two causes of hypothyroidism?
- Hashimoto's thyroiditis
- Iodine therapy
- Drugs
- Pituitary disease
- Hypothalamic disease
59
What are the features of hypothyroidism?
- Fatigue
- Weight gain
- Cold intolerance
- Constipation
- muscle cramps
- dry, rough skin
- oedema
60
How would you investigate hypothyroidism?
- levels of TSH (would be increased)
61
What is the treatment for hypothyroidism?
- synthetic L-thyroxine
62
What is Hashimoto's thyroiditis?
The immune system attacks the thyroid gland so that it swells and becomes damaged
- Symptoms include tiredness, weight gain and dry skin
63
What are the consequences of hypocalcaemia?
- parasthesia
- muscle spasms
- seizures
- cataracts
64
What is puberty?
The physiological, morphological and behavioural changes as the gonads switch from infantile to adult
65
What are the secondary sex characteristics that occur at puberty for girls and boys?
- Girls = ovarian oestrogens - growth of breast and female genitalia. Ovarian and androgens control pubic hair and axillary hair
- Boys = testicular androgens - genitalia and pubic hair growth. Also enlargement of larynx
66
What do you stage male/female genitalia/characteristics with?
- Tanner stages
67
What can delayed puberty lead to?
Reduced peak bone mass and osteoporosis
68
What is delayed puberty?
- delayed activation of the hypothalamic pulse generator (idiopathic)
- hypogonadotrophic hypogonadism
- hypergonadotrophic hypogonadism
69
What can delayed puberty lead to?
- Delay in secondary sex charactertistics
- psychological problems
- defects in reproduction
- reduced peak bone mass
70
What is primary hypogonadism?
- ovary and testis failing
- Female = oestrogen decreases, lack of feedback and LH and FSH increase
- Males = testosterone goes down, lack of feedback so LH and FSH increase
71
What is secondary hypogonadism?
- hypothalamus/ pituitary failing
- female = LH and FSH low, no response to feedback and oestrogen decreases
- Male = LH and FSH low so testosterone decreases
72
What are the symptoms of diabetes insipidus?
- polyuria
- polydypsia
- no glycosuria (excess sugar in urine)
73
How can you diagnose DI?
- measure urine volume
- check renal function/serum calcium
- water deprivation test
- serum osmo >300 AND urine osmo <200
74
What are some causes of cranial diabetes insipidus?
- lack of vasopressin
- acquired - idiopathic, tumours, trauma, infections
- genetic = DIDMOAD, autosomal dominant
75
What are some causes of nephrogenic diabetes insipidus?
- resistance to vasopressin action
- Acquired = diabetes mellitus, drugs, renal failure
- Familial = X-linked, or autosomal recessive
76
How can you manage cranial diabetes insipidus?
- Treat any underlying condition
| - Desmopressin
77
How can you manage nephrogenic diabetes insipidus?
- Try and avoid precipating drugs
- high dose of desmopressin
- hydrochlorothiazide or indomethacin
78
What is hyponatraemia?
- Serum sodium <135mmol/l
| - low sodium
79
What are some symtpoms of hyponatraemia?
- headache
- lethargy
- anorexia and abdominal pain
- weakness
- agitation
- decreased conscious level
- fitting/coma
80
What is the difference between acute vs chronic hyponatraemia?
- Acute - 48 hours. Rapid correction safer and may be necessary
- Chronic - CNS adapts. Correction must be slow
81
How can you investigate hypomataemia?
- Plasma osmolality
- Urine osmolality
- Plasma glucose
- Urine sodium
- others
82
What are the different types of causes of hyponatraemia?
- Fluid overload
- Normovolaemic
- Dehydrated
83
What is Rathke's Cyst?
- derived from remnants of Rathke's pouch
- single layer of epithelial cells
- present with headache, amenorrhoea and hypopituitarism
84
What is the most common and 2nd most common tumour region?
1. pituitary adenoma
| 2. meningioma
85
What is meningioma associated with?
- visual disturbance and endocrine dysfunction
| - presents with loss of visual acuity and visual field defects
86
What are effects of a local mass on pituitary?
- visual field defects
- CSF rhinorrhoea
- headaches
- cranial nerve palsy
87
How would you investigate a non-functioning tumour?
- There would be absence of hormone secretion
| - Test normal pituitary function
88
What can prolactin levels be raised due to?
- Stress
- Drugs: anti-psychotics
- Stalk pressure
- Prolactinoma
89
Why use an MRI compared to CT for studying the pituitary?
- better visualisation of soft tissues and vascular structures
- no exposure to ionizing radiation
- can see fat e.g. fatty marrow and orbital fat
90
When is a CT preferred over an MRI?
- better at visualising bony structures and calcifications within soft tissue
- diagnose tumours with calcification
91
If a patient has low GH, how would they present?
- short stature
- abnormal body composition
- reduced muscle mass
- poor quality of life
92
If a patient has low LH/FSH, how would they present?
- reduced sperm count
- infertility
- menstration problems
93
If a patient has low ACTH, how do they present?
- Adrenal failure
| - decreased pigment
94
Who would you give thyroxine replacement to?
Patients with low TSH
95
What are the presenting features of diabetes?
- Thirst
- Polyuria
- Weight loss and fatigue
- Hunger
- Pruritis vulvae
- blurred vision
96
What are some suggestive features of type 1 diabetes?
- onset in childhood
- lean body habitus
- prone to ketoacidosis
97
What are some suggestive features of type 2 diabetes?
- Usually presents in over 30s
- Onset is gradual
- FH is often positive
98
What is ketoacidosis?
- Absence of insulin and rising counter-reg hormones leading to increased hyperglycaemia
- Ketones cause anorexia and vomiting
99
What is the definition of diabetic ketoacidosis (DKA)?
- Hyperglycaemia
| - Raised plasma ketones
100
What are the symptoms of DKA?
- develop over days
- polyuria/polydipsia
- nausea and vomiting
- weight loss
- abdominal pain
101
What are the signs of DKA?
- hyperventilation
- dehydration
- hypotension
- tachycardia
- coma
102
How can you manage DKA?
- rehydration
- insulin
- replacement of electrolytes
103
What are the aims of treatment for T1D?
- relieve symptoms and prevent ketoacidosis
| - prevent microvascular and macrovascular complications
104
What are the consequences of diabetic neuropathy?
- Pain
- insensitivity - includes foot ulceration, infection
- Autonomic - orthostatic hypotension, incontinence, erectile dysfunction
105
How can you treat diabetic neuropathy?
- glycaemic control
- anti-depressants/ SSRIs
- IV lignocaine
- psychological interventions/hyponosis
106
What is diabetic foot ulceration?
- occurs in 15% of people with DM during their lifetime
| - most people won't show symptoms until the ulcer has become infected
107
What can occur with DFU?
- sensory nerve damage
- motor nerve damage
- localised callus
- autonomic nerve damage
108
How would you screen for diabetic peripheral neuropathy?
- test sensation
- vibration perception
- ankle reflexes
109
How does peripheral vascular disease present?
- Intermittent claudication (cramping in leg induced by exercise)
- rest pain
- diminished pedal puses
- coolness of feet and toes
- poor skin and nails
- absence of hair on feet and legs
110
What is the treatment for peripheral vascular disease
- quit smoking
- walk through pain
- surgical intervention
111
What is the cause of diabetic amputation?
- Neuropathy occurs
- Trauma
- Leads to ulcer
- failure to heal
- infection leads to amputation
112
What is the best way to detect early diabetic retinopathy?
- Eye screening
113
What is the treatment for diabetic retinopathy?
- Laser therapy
| - treatment does not improve sight, just stabilise the changes
114
What are the risks of laser treatment?
- difficulty with night vision
| - loss of peripheral vision
115
What is the treatment for diabetic nephropathy?
- blood pressure control
- glycemic control
- ARB
116
What is the pathogenesis of T1D?
- Insulin deficiency with a loss of beta cells due to autoimmune destruction
117
What does the failure of insulin secretion lead to?
- Continued breakdown of liver glycogen
- increase in hepatic glucose output
- suppression of peripheral glucose uptake
118
What does the reduction insulin lead to?
- fat breakdown
| - formation of glycerol and FFA
119
What is ketoacidosis?
- absence of insulin and rising hormones
| - leasds to hyperglycaemia and rising ketones
120
What can ketones cause?
- Anorexia and vomiting
121
What is the pathogenesis of T2D?
- impaired glucose tolerance
| - due to a combination of genetic predisposition and environmental factors
122
If there is impaired insulin secretion in T2D, what does this lead to?
- Hepatic insulin resistance
- Muscle/fat insulin resistance
- leads to hyperglycaemia
123
What is hypoglycaemia?
- low plasma glucose
| - causes impaired brain function
124
What are the symptoms of hypoglycaemia?
- trembling/palpitations
- sweating
- difficulty concentrating, confusion
- weakness, dizziness
125
What is the treatment for hypoglycaemia?
- Recognise symptoms
- treat with 15g fast-acting carbohydrate
- retest in 15 mins
126
Why does hypoglycaemia occur?
- due to the inability of insulin therapy to mimic the physiology of the beta cell
