Endocrinology Flashcards
1
Q
Where is GH produced?
A
Anterior pituitary gland
2
Q
What is the action of GH?
A
Stimulates cell reproduction and growth of organs, muscles, bones and height
Stimulates release of insulin-like growth factor
3
Q
Where is IGF-1 released from and what is its action?
A
Released by the liver and promotes growth
4
Q
What is congenital GH deficiency a result of?
A
Disruption of the growth hormone axis at the hypothalamus or pituitary gland
5
Q
What are some causes of congenital GH deficiency?
A
Genetic mutations (e.g. GH1, GHRGHR) Empty sella syndrome (underdeveloped pituitary gland) Hypopituitarism/ multiple pituitary hormone deficiency
6
Q
What are some causes of acquired growth hormone deficiency?
A
Secondary to infection, trauma or surgery
7
Q
How may GH deficiency present in neonates?
A
Micropenis
Hypoglycamia
Severe jaundice
8
Q
How may older children present with GH deficiency?
A
Poor growth
Short stature
Slow development of movement/ strength
Delayed puberty
9
Q
What test is done to look for GH deficiency?
A
Growth hormone stimulation test: measuring response to medications that normally stimulate the release of GH.
10
Q
What other investigations are done when looking at GH deficiency?
A
Test for thyroid and adrenal deficiency
MRI brain (pituitary or hypothalamic abnormalities)
Genetic testing
Xray for bone age
11
Q
How is GH deficiency managed?
A
Daily subcutaneous injections of GH
Treat other hormone deficiencies
Close monitoring of height and development
12
Q
What is the pathophysiology of T1DM?
A
Pancreas stops being able to produce insulin (unknown why), meaning cells can’t use glucose, causing hyperglycaemia
13
Q
What is the ideal blood glucose concentration?
A
4.4-6.1 mmol/ L
14
Q
Where is insulin produced?
A
Beta cells in the Islets of Langerhans in the pancreas
15
Q
What kind of hormone is insulin?
A
Anabolic (builiding)
16
Q
What are the 2 ways insulin reduces blood sugar?
A
Causes cells to absorb glucose from the blood and use it as fuel.
Causes muscle and liver cells to absorb glucose and store it as glycogen.
17
Q
What kind of hormone is glucagon and where is it produced?
A
Catabolic hormone produced by the alpha cells in the Islets of Langerhans in the pancreas
18
Q
What occurs during ketogenesis?
A
When there is insufficient supply of glucose and glycogen stores are exhausted, the liver converts fatty acids to ketones to be used as fuel
19
Q
What percentage of new T1 diabetics present in DKA?
A
25-50%
20
Q
What is the triad of symptoms that T1 diabetes presents with?
A
Polyuria
Polydipsia
Weight loss
21
Q
What are some less typical potential presentations of T1 diabetes?
A
Secondary enuresis (bedwetting in a previously dry child) Recurrent infections
22
Q
What bloods should be taken on a new T1 diabetes diagnosis?
A
FBC U&E's Lab glucose Blood cultures HbA1c TFT's + TPO anti-TTG antibodies Insulin, anti-GAD and Islet cell antibodies
23
Q
Why are TFT’s and TPO’s done in a newly diagnosed T1 diabetes?
A
To test for autoimmune thyroid disease
24
Q
Why are anti-TTG antibodies looked for in new T1 diabetes diagnosis?
A
TO test for coeliac disease
25
Why are Insulin antibodies, anti-GAD antibodies and islet cell antibodies tested for on new T1 diabetes diagnosis?
To test for antibodies associated with the destruction of the pancreas and the development of T1 diabetes
26
What are the different components of T1 diabetes management?
Insulin regimes
Monitoring carbohydrate intake
Monitoring blood sugar
Monitoring/ managing complications
27
When should T1 diabetics check their blood sugar levels?
On waking
At each meal
Before bed
28
What are the different insulin regimes available?
Basal- bolus
| Insulin pump
29
What can injecting insulin in the same spot cause?
Lipodystrophy- where the subcutaneous fat hardens and prevents normal absorption of insulin
30
Why should patients cycle their injection sites?
To prevent lipodystrophy and ensure effective absorption of insulin
31
What is the basal part of the basal-bolus regime?
Injection of long acting insulin once a day to give constant background insulin
32
What is the bolus part of the basal-bolus regime?
Injection of short acting insulin before meals, and according to the number of carbohydrates consumed with each snack
33
How do insulin pumps work?
Continuously infuse insulin at different rates through a cannula inserted under the skin
34
How often is the cannula repalced on an insulin pump?
Every 2-3 days
35
What is the criteria needed to qualify for an insulin pump on the NHS?
>12
| Have difficulty controlling HbA1c
36
What are the advantages of an insulin pump?
Better blood sugar control
More flexibility with eating
Fewer injections
37
What are the disadvantages of an insulin pump?
Difficulties learning to use it
Having it attached at all times
Blockages in the infusion set
Small risk of infection
38
What are the two types on insulin pump?
Tethered pump
| Patch pump
39
What are tethered pumps?
Devices with replaceable infusion sets and insulin. Pump usually has all controls on it and can attach to belt/ pocket ect.
40
What is a patch pump?
Patch attached directly onto body and works via remote. Whole thing needs changing (not just infusion set and location)
41
What are the short term complications of T1 diabetes?
Hypoglycaemia
| Hyperglycaemia (& DKA)
42
What causes hypoglycaemia in diabetes?
Too much insulin
Not enough carbohydrates
Not processing carbohydrates properly (malabsorption, diarrhoea, vomiting, sepsis)
43
What are the typical symptoms of hypoglycaemia?
```
Hunger
Tremor
Sweating
Irritability
Dizziness
Pallor
```
44
How is hypoglycaemia treated?
Combination of rapid acting glucose (e.g. lucozade) and slower acting carbohydrates
45
What are the signs of severe hypoglycaemia?
Reduced consciousness
Coma
Death
46
How is severe hypoglycaemia treated?
IV dextrose
| IM glucagon
47
What are other causes of hypoglycaemia?
```
Hypothyroidism
Glycogen storage disorder
GH deficiency
Liver cirrhosis
Alcohol
Fatty acid oxidation defects
```
48
When does hypoglycaemia commonly occur in T1 diabetics and how is this managed?
Nocturnal hypoglycaemia
| Treat by altering basal-bolus regime and have snacks at bedtime
49
How is hyperglycaemia managed?
Increase insulin dose
50
What are the different types of long term complications that can occur with T1 diabetes?
Macrovascular
Microvascular
Infections
51
What does chronic exposure to hyperglycaemia do to blood vessels?
Damages endothelium, leading to leaky malfunctioning vessels that are unable to regenerate
52
What does chronic hyperglycaemia to to the immune system?
Suppresses it, and creates optimal environment for infectious organisms to thrive
53
What are the macrovascular complications of T1 diabetes?
Coronary artery disease
Peripheral ischaemia (poor healing, ulcers, diabetic foot)
Stroke
Hypertension
54
What are the microvascular complications of T1 diabetes?
Peripheral neuropathy
Retinopathy
Nephropathy
55
How is T1 diabetes monitored?
HbA1c
Capillary blood glucose
Flash glucose monitoring
56
What is measured on HbA1c?
Glycated haemoglobin- reflects average blood glucose over last 3 mnths
57
How often is HbA1c measured in T1 diabetics?
Every 3-6 months to track average blood sugar and assess effectiveness of interventions
58
What is Flash glucose monitoring?
Using a sensor on the skin to measure the glucose level of the interstitial fluid in the subcutaneous tissue
59
What is the FreeStyle Libre system?
Device that sits on upper arm and continuously monitors blood glucose
60
What is the time lag when using flash glucose monitoring?
5 minutes
61
What are ketones?
Water soluble fatty acids that can be used as fuel
62
How can ketone levels be measured?
Urine dipstick
| Blood using ketone meter
63
What does hyperglycaemic ketosis do to the blood?
Causes metabolic acidosis
64
When does DKA occur?
When the patient is not producing adequate and not injecting adequate insulin to compensate
65
What are the key problems in DKA?
Ketoacidosis
Dehydration
Potassium imbalance
66
Why do you get dehydrated in DKA?
Hyperglycaemia overwhelms the kidneys and causes glucose to be filtered into the urine. This draws water out (osmotic diuresis), resulting in severe dehydration
67
Why do you get potassium imbalance in DKA?
Insulin usually drives potassium into cells. Therefore without it potassium stays in the blood
68
What happens to serum potassium in DKA and why?
It is either high (due to no insulin driving it into cells) or normal due to kidneys balancing the levels with the amount excreted in the urine
69
What happens to total body potassium in DKA?
It is low as none of it is being stored in the cells
70
What can happen when insulin treatment starts in patients with DKA/
They can develop severe hypokalaemia, which can lead to fatal arrhythmias
71
What are children with DKA at high risk of developing?
Cerebral oedema
72
Why does DKA increase the risk of cerebral oedema?
Dehydration + hyperglycaemia cause water to move from the intracellular space in the brain to the extracellular space, causing brain cells to shrink and become dehydrated. Then, the correction with fluids and insulin causes a rapid shift back to the intracellular space, causing the brain to become oedematous
73
What should be monitored closely to look for signs of cerebral oedema when treating DKA?
GCS
| Headaches, altered behaviour, bradycardia
74
How is cerebral oedema managed?
Slowing IV fluids, IV mannitol and IV hypertonic saline
75
How dose DKA present?
```
Polyuria
Polydipsia
N&V
Weight loss
Acetone breath
Dehydration + hypotension
Altered consciousness
Symptoms of underlying trigger (e.g. sepsis)
```
76
What is the criteria for diagnosing DKA?
Hyperglycaemia (>11mol/l)
Ketosis (>3mmol/l)
Acidosis (ph<7.3)
77
What are the 2 principles of DKA management?
1. Correct dehydration over 48 hours
| 2. Give fixed rate insulin infusion
78
What other factors should be considered when managing DKA?
- Avoid fluid boluses
- Treat underlying triggers (Abx for sepsis)
- Prevent hypoglycaemia with IV dextrose
- Monitor potassium and add to fluids if needed
- Monitor for signs of cerebral oedema
- Monitor glucose, ketones and pH to assess progress
79
What is adrenal insufficiency?
Where the adrenal glands don't produce enough steroid hormones
80
What are the main steroid hormones produces by the adrenal glands?
Cortisol and aldosterone
81
What is Addison's disease?
Primary adrenal insufficiency- condition where the adrenal glans have been damaged causing reduction in cortisol and aldosterone secretion
82
What is the most common cause of primary adrenal insufficiency?
Autoimmune
83
What is secondary adrenal insufficiency?
When there inadequate ACTH stimulating the adrenal glands, resulting in low levels of cortisol being released
84
What is the causes of secondary adrenal insufficiency?
```
Loss or damage to pituitary gland:
Congenital underdevelopment
Surgery
Infectino
Radiotherapy
Loss of blood flow
```
85
What is tertiary adrenal insufficiency?
The result of inadequate CRH release by the hypothalamus
86
What is the most common cause of tertiary adrenal insufficiency?
Long term oral steroids causing suppression of the hypothalamus
87
Why should long term steroids be tapered slowly?
If they are withdrawn suddenly, the hypothalamus does not wake up fast enough to produce adequate endogenous steroids.
88
What are the features of adrenal insufficiency in babies?
```
Lethargy
Vomiting
Poor feeding
Hypoglycaemia
Jaundice
Failure to thrice
```
89
What are the features of adrenal insufficiency in older children?
```
Nausea and vomiting
Weight loss/ poor weight gain
Anorexia
Abdominal pain
Muscle weakness/ cramps
Developmental delay
Bronze hyperpigmentation in Addison's
```
90
Why do you get bronze hyperpigmentation in Addison's?
High ACTH levels stimulate melanocytes
91
What investigations should be done with suspected adrenal insufficiency?
U&E's
Blood glucose
Cortisol, ACTH, aldosterone and renin levels
Short synacthen test
92
What will be the results of tests in Addisons disease?
Low cortisol
High ACTH
Low aldosterone
High renin
93
What will be the results of tests in secondary adrenal insufficiency?
Low cortisol
Low ACTH
Normal aldosterone
Normal renin
94
What is the short synacthen test?
Synacthen (synthetic ACTH) given in the morning. Blood cortisol taken at baseline, 30 and 60 minutes after administration.
95
What is a normal result of the short synacthen test?
Cortisol level should at least double
96
What does a failure of cortisol to rise indicate in a short synacthen test?
Primary adrenal insufficiency
97
How is adrenal insufficiency managed?
Replacement steroids
98
What steroid hormones are given to manage adrenal insufficiency?
Hydrocortisone to replace cortisol
| Fludrocrotisone to replace aldosterone
99
What should patients on steroid hormone be given?
Steroid card and emergency ID tag to inform emergency services they are dependent on steroids for life
100
What should be monitored in patients with adrenal insufficiency?
```
Growth & development
BP
U&E's
Glucose
Bone profile
Vitamin D
```
101
What should patients on steroids do during acute illness? (Sick day rules)
Increase dose of steroids until illness has resolved
Blood sugar monitoring
IM steroid if have diarrhoea or vomiting
102
What is an adrenal crisis?
An acute presentation of severe Addisons
103
How does an adrenal crisis present?
Reduced consciousness
Hypotension
Hypoglycaemia, hyponatraemia and hyperkalamia
104
When might adrenal crisis occur?
First presentation of Addison's disease,
Triggered by infection, trauma or other acute illness
Abrupt stopping of long term steroids
105
How do you manage Addisonian crisis?
Intensive monitoring
Parenteral steroids
IV fluids
Hypoglycaemia
106
What is congenital adrenal hyperplasia?
Underproduction of cortisol and aldosterone, and overproduction of androgens
107
What causes CAH?
Autosomal recessive condition causing deficiency of 21-hydroxylase enzyme
108
What type of hormone is testosterone?
Androgen
109
What is the action of glucocorticoid hormones?
Help body deal with stress, raise blood glucose, reduce inflammation and suppress immune system
110
What is the main glucocorticoid hormone?
Cortisol
111
When are cortisol levels higher?
In the morning
| During times of stress
112
What is cortisol released in response to?
ACTH from the anterior pituitary
113
What is the action of mineralocorticoid hormones?
Act on the kidneys to control the salt and water balance in the blood
114
What is the main mineralocorticoid hormone?
Aldosterone
115
What is aldosterone released in response to?
Renin
116
What is the action of aldosterne?
Acts on the kidneys to increase sodium reabsorption in the blood and increase potassium secretion into the urine
117
What is the action of 21-hydroxylase?
Enzyme responsible for converting progesterone into aldosterone and cortisol (NOT testosterone)
118
What is progesterone converted into?
Aldosterone
Cortisol
Testosterone
119
What is the pathophysiology of congenital adrenal hyperplasia?
Defect in 21-hydroxylase enzyme means that there is extra progesterone that cannot be converted to aldosterone or cortisol, so is instead converted to testosterone
120
What are the aldosterone, cocrtisol and testosterone levels in CAH?
Low aldosterone & cortisol
| High testosterone
121
How does severe CAH present at birth in females?
Virilised genitalia
122
What is virilised genitalia?
Ambiguous genitalia- enlarged clitoris
123
How do patients with more severe CAH present shortly after birth?
Hyponatraemia
Hyperkalaemia
Hypoglycaemia
124
What are the signs and symptoms of severe CAH?
```
Poor feeding
Vomiting
Dehydration
Arrhythmias
Virilisation
```
125
When do patients with severe CAH usually present?
At birth
126
When do patients with mild cases of CAH usually present?
During childhood or after puberty
127
What do the symptoms of mild CAH tend to be related to?
High androgen (testosterone) levels
128
How do females with mild CAH usually present?
```
Tall for age
Facial hair
Absent periods
Deep voice
Early puberty
Hyperpigmentation
```
129
How do male patients with mild CAH usually present?
```
Tall
Deep voice
Large penis
Small testicles
Early puberty
Hyperpigmentation
```
130
Why do you get hyperpigmentation in CAH?
Pituitary gland responds to low levels of cortisol by producing more ACTH/ A byproduct of ACTH is melanocyte simulating hormone.
131
How is CAH managed?
Cortisol replacement with hydrocortisone
Aldosterone replacement with fludrocortisone
Corrective surgery for virilisation
132
What is congenital hypothyroidism?
Where the child is born with an underactive thyroid gland or gland that does not produce enough hormone
133
What is dysgenesis?
Underdeveloped thyroid gland
134
What is dyshormonogenesis?
Fully developed gland that does not produce enough hormone
135
Where is congenital hypothyroidism screened for?
Newborn blood spot screening test
136
How may patients with congenital hypothyroidism present if not picked up at screening test?
```
Prolonged neonatal jaundice
Poor feeding
Constipation
Increased sleeping
Reduced activity
Slow growth and development
```
137
What is acquired hypothyroidism?
Where a child develops an underactive thyroid gland that was previously functioning normally
138
What is the most common cause of acquired hypothyroidism?
Autoimmune thyroiditis (Hashimoto's)
139
What antibodies is Hashimoto's associated with?
anti-TPO and antithyroglobulin
140
What symptoms do you get with Hashimoto's?
```
Fatigue
Poor growth
Weight gain
Poor school performance
Constipation
Dry skin/ hair loss
```
141
How is hypothyroidism investigated?
Thyroid function tests
Thyroid USS
Thyroid antibodies
142
How is hypothyroidism managed?
Levothyroxine once daily
