Endocrine Flashcards
1
Q
What is the definition of diabetes mellitus?
A
A disease in which the body’s ability to produce or respond to the insulin is impaired, resulting in abnormal metabolism of carbohydrates and elevated levels of glucose in the blood
2
Q
Briefly outline the pathology of type 1 diabetes
A
An insulin deficiency disease characterised by loss of beta cells due to autoimmune destruction
3
Q
Briefly outline the pathology of type 2 diabetes
A
Inappropriately low insulin secretion and peripheral insulin resistance
4
Q
Name 3 examples of endocrine causes of secondary diabetes.
A
Acromegaly
Cushing’s syndrome
Drug-induced diabetes
5
Q
Give 3 subacute presentations of diabetes
A
Thirst, polyuria, weight loss and fatigue, hunger, blurred vision
6
Q
Give 3 acute presentations of diabetes
A
Diabetic ketoacidosis - polyuria and polydipsia, abdominal pain, hyperventilation, hypotension, coma
7
Q
What investigations are carried out for the diagnosis of diabetes?
A
Fasting plasma glucose >7mmol/L
HbA1c 48mmol/mol
C peptide decreases in type 1
8
Q
How do we screen for neuropathy?
A
Sensation - 10mg monofilament
Vibration perception (tuning fork)
Ankle reflexes
9
Q
What is a serious consequence of missing a type 1 diabetes diagnosis?
A
Formation of ketone bodies:
Reduced insulin leads to fat breakdown and formation of glycerol and free fatty acids.
These impair glucose uptake and are transported to the liver, providing energy for gluconeogenesis.
Oxidised to form ketone bodies which dissolve in the blood and release H+, causing acidosis
10
Q
What are the complications of diabetes?
A
Diabetic retinopathy, nephropathy, peripheral vascular disease, stroke, CVD, diabetic peripheral neuropathy
11
Q
What is a hyperglycaemic hyperosmolar state and how does it present?
A
Hyperglycaemic hyperosmolar state - a diabetic emergency glucose >30mmol/L
Dehydration, severe hyperglycaemia, weakness, leg cramps, vision problems, altered level of consciousness
LMWH prophylaxis, then rehydrate with IV saline
12
Q
What is hypoglycaemia and how does it present?
A
Endocrine emergency - plasma glucose <3mmol/L
Sweating, anxiety, hunger, tremor, palpitations, dizziness, confusion, drowsiness, visual trouble, seizures, coma
Treat with quick-acting carb snack
13
Q
How is type 1 diabetes managed?
A
BD Biphasic regimen - twice daily premixed insulins by pen
QDS regimen - before meals ultra-fast insulin + bedtime long-acting analogue
Once-daily before bed long-acting insulin
Awareness of blood glucose lowering effect of exercise
DAFNE - dose adjustment for normal eating
14
Q
How is type 2 diabetes managed?
A
Lifestyle Modification - weight loss and exercise
Ramipril - control BP, statins control cholesterol
1st line - metformin - increases cell sensitivity to insulin (SE: diarrhoea, nausea, weight loss)
HbA1c > 53 add a sulfonylurea
HbA1c > 57 add isoprene insulin
DDP4 inhibitors - prevent breakdown of incretins
15
Q
What are the 3 mechanisms for increased levels of thyroid hormone?
A
- Overproduction of thyroid hormone
- Leakage of preformed hormone from thyroid
- Ingestion of excess thyroid hormone
16
Q
What are some causes of hyperthyroidism?
A
Grave’s disease, congenital, thyroiditis, toxic adenoma
17
Q
Name 4 symptoms of hyperthyroidism
A
Weight loss, tachycardia, anxiety, heat intolerance, sweating, diarrhoea, menstrual disturbance
18
Q
How is hyperthyroidism diagnosed?
A
Thyroid function tests
Diagnosis of underlying cause
Clinical history, physical signs
Thyroid antibodies
19
Q
How is hyperthyroidism treated?
A
Antithyroid drugs e.g. thionamides
Radioiodine
Surgery (partial/ subtotal thyroidectomy)
20
Q
Describe the pathology of Graves’ disease
A
Increased levels of TSH receptor stimulating antibody which causes excess thyroid hormone secretion
21
Q
What is Graves’ disease?
A
An autoimmune disease affecting the thyroid that causes hyperthyroidism and results in an enlarged thyroid
22
Q
Give 4 symptoms of Graves’ disease.
A
Bulging eyes - Graves' ophthalmopathy Thick, red skin on shins/top of feet - Graves' dermopathy Heat sensitivity Weight loss Fine tremor of hands
23
Q
How is Graves’ disease diagnosed?
A
Physical exam - eye exam or enlarged thyroid gland
Blood sample - low TSH and high thyroid hormones
Ultrasound - to identify enlarged thyroid gland
24
Q
How is Graves’ disease managed?
A
Radioactive iodine therapy to destroy the overactive thyroid cells over time
Beta blockers - provide rapid relief of irregular heartbeats, tremors, heat tolerance and muscle weakness
Thyroidectomy
25
What is primary hypothyroidism?
Absence/dysfunction of the thyroid gland - most cases due to Hashimoto's thyroiditis
26
What is secondary hypothyroidism?
Pituitary/ hypothalamic dysfunction with isolated TSH deficiency
27
What are the causes for hypothyroidism in children?
Neonatal hypothyroidism
Resistance to thyroid hormone
Isolated TSH deficiency
28
Describe the pathophysiology of primary hypothyroidism
Disease associated with the thyroid - Antibodies bind and block TSH receptors leading to inadequate thyroid hormone production and secretion
29
Describe the pathophysiology of secondary hypothyroidism
Disease associated with the pituitary or hypothalamus - reduced release or production of TSH leading to reduced T3/T4 release
30
Describe the pathophysiology of tertiary hypothyroidism
Disease associated with treatment withdrawal - thyroid overcompensates until it can re-establish correct concentrations of thyroid hormone
31
Name 3 symptoms of hypothyroidism
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Fatigue, lethargy
Weight gain
Cold intolerance
Menstrual disturbances
Decreased perspiration
Dry skin
```
32
Name 3 signs of hypothyroidism
Weight gain, jaundice, slowed speech, pallor, loss of scalp, axillary or pubic hair, bradycardia, pericardial effusion
33
What is a differential diagnosis for hypothyroidism?
Chronic fatigue syndrome
34
How is hypothyroidism diagnosed?
Bloods - increased TSH, usually decreased T3/T4 (secondary/tertiary - TSH low)
Low pulse pressure and sinus bradycardia
35
How is hypothyroidism managed?
Replacement of thyroid hormone - levothyroxine
| Requirements vary according to cause, dose is tired until TSH normalises
36
What is Hashimoto's thyroiditis?
Hypothyroidism due to aggressive autoimmune destruction of thyroid cells
37
What are the risk factors for Hashimoto's?
```
Sex - women
Age - middle age
Hereditary - family history
Other autoimmune disease
Radiation exposure
```
38
What can trigger Hashimoto's?
Iodine, infection, smoking
39
Describe the pathophysiology of Hashimoto's?
Antibodies bind and block TSH receptors leading to inadequate thyroid hormone production and secretion
40
How does Hashimoto's present?
Fatigue, increased sensitivity to cold, constipation, dry skin, brittle nails, hair loss, muscle weakness, unexplained weight gain
41
How is Hashimoto's diagnosed?
Based on signs and symptoms
Blood tests - low thyroid hormone but raised TSH
Antibody test - antibodies against thyroid peroxidase (TPO antibodies)
42
How is Hashimoto's managed?
Synthetic hormones - synthetic thyroid hormone levothyroxine
| Resection of obstructive goitre
43
What are the 4 types of thyroid cancer?
Papillary, follicular, medullary, anaplastic
44
How do thyroid cancers present?
Painless, palpable, solitary thyroid nodule
45
How is thyroid cancer diagnosed?
Fine-needle aspiration biopsy (FNAB)
Indirect laryngoscopy
Elevated serum calcitonin suggests medullary thyroid carcinoma
46
How is thyroid cancer managed?
Malignancies require surgical intervention
47
How is papillary thyroid cancer treated?
Total thyroidectomy to remove non-obvious tumour
| Give levothyroxine to suppress TSH
48
How is follicular thyroid cancer treated?
Total thyroidectomy, T4 suppression, radioiodine ablation
49
How is medullary thyroid cancer treated?
Thyroidectomy and node clearance
50
How is anaplastic thyroid cancer treated?
Excision and radiotherapy - poor response to any treatment
51
How is lymphoma treated?
Chemotherapy
52
What is Cushing's syndrome?
An abnormal condition caused by chronic excess levels of corticosteroids in the body due to hyper function of the adrenal gland
53
What is Cushing's disease?
A TUMOUR on the pituitary gland that CAUSES the gland to produce too much ACTH, leading to high levels of cortisol production
54
What are the symptoms of Cushing's?
Weight gain, mood change, proximal weakness, gonadal dysfunction, acne
55
What are the signs of Cushing's?
Central obesity, skin and muscle atrophy, purple abdominal striae, osteoporosis
56
How is Cushing's diagnosed?
Overnight dexamethasone suppression test - 1mg dexamethasone at midnight, take serum cortisol at 8am. Normally should suppress to 50nmol/L, no suppression indicates Cushing's syndrome
Test for plasma ACTH - if undetectable, a tumour is likely
57
How is Cushing's managed?
Iatrogenic - stop causative medications
| Cushing's disease - selective removal of pituitary adenoma
58
What is the main cause of Cushing's syndrome?
Corticosteroid medication
59
What is acromegaly?
The abnormal growth of hands, feet and face due to overproduction of growth hormone
60
Describe the pathophysiology of acromegaly?
Growth hormone stimulates growth of bone and soft tissue, through secretion of insulin-like growth factor-1
61
Name 3 symptoms of acromegaly
Acral enlargement, arthralgias, maxillofacial changes, excessive sweating, headache, backache, hypogonadal symptoms, acroparaesthesia, amenorrhoea
62
Name 3 signs of acromegaly
Coarsening face - wide nose, macroglossia, puffy lips, eyelids and skin, obstructive sleep apnoea
63
Name a differential diagnosis of acromegaly
Gigantism
64
How is acromegaly diagnosed?
GH >0.4ng/ml, 75mg glucose tolerance test, abnormal IGF-I
65
How is acromegaly managed?
Trans-sphenoidal surgery 1st line
| Radiotherapy/ somatostatin analogues
66
What is Conn's syndrome?
Excess aldosterone production (primary hyperaldosteronism) due to a solitary aldosterone-producing adenoma
67
What is primary hyperaldosteronism?
A disease of the adrenal glands involving excess production of aldosterone. (It can cause high BP)
68
What are the symptoms of Conn's syndrome?
Often asymptomatic
| Symptoms of hypokalaemia - weakness, cramps, paraesthesia, polyuria, polydipsia
69
What are the signs of Conn's syndrome?
High blood pressure - causes headaches, blurred vision, dizziness
Low potassium - causes fatigue, increased urination and thirst
70
How is Conn's syndrome diagnosed?
Investigate for suppressed renin and increased aldosterone, adrenal vein sampling, U&E - potassium may be low or normal
71
How is Conn's syndrome managed?
Laparoscopic adrenalectomy
72
What is adrenal insufficiency?
A condition in which the adrenal glands do not produce adequate amounts of steroid hormone (cortisol)
73
Describe the pathophysiology of adrenal insufficiency
Autoimmune destruction of the entire adrenal cortex. Loss of cortex leads to reduction in ability to produce cortisol and/or aldosterone.
74
What is primary adrenal insufficiency and what are the causes?
Addison's disease - destruction of the adrenal cortex leads to glucocorticoid (cortisol) and mineralocorticoid (aldosterone) deficiency
Caused by adrenal antibodies, very long chain fatty acids, genetics
75
What is secondary adrenal insufficiency and what are the causes?
Hypopituitarism/ long-term steroid therapy leading to suppression of the pituitary-adrenal axis
Caused by any steroids, imaging, genetic
76
What are the symptoms of Adrenal insufficiency?
Fatigue, weight loss, dizzy, faints, poor recovery from illness, headache, abdominal pain, diarrhoea, constipation
77
What is as an adrenal crisis?
Hypotension and cardiovascular collapse, fatigue, fever, hypoglycaemia, hyponatraemia and hyperkalaemia
78
What are the signs of adrenal insufficiency?
Pigmentation (primary) and pallor (secondary), hypotension
79
How is adrenal insufficiency diagnosed?
Family history of autoimmunity, any previous use of steroids
| Low Na, high K, anaemia, borderline elevated TSH
80
How is adrenal insufficiency managed?
Replace aldosterone with fludrocortisone
Hydrocortisone 2/3 times daily
Mineralocorticoids to correct postural hypertension
81
What is diabetes insipidus?
A rare metabolic disorder in which the patient produces large quantities of dilute urine and is constantly thirsty
82
Describe the pathology of diabetes insipidus
it is due to a deficiency of the pituitary hormone vasopressin (ADH), which regulates reabsorption of water in the kidneys. This means that the body can't make enough concentrated urine and too much water is passed
83
What is cranial diabetes insipidus?
Not enough AVP in the body to regulate urine production. Caused by damage to the hypothalamus/ pituitary gland e.g. after infection, operation, tumour, injury
84
What is nephrogenic diabetes insipidus?
When there is enough AVP in the body, but the kidneys fail to respond to it. Caused by kidney damage or inherited as a problem
85
What are the symptoms of diabetes inspidus?
Polydipsia, polyuria, tiredness, irritability, difficulty concentrating
86
How is diabetes insipidus diagnosed?
Water deprivation test - no liquid for 8 hours - in DI the body will still pass large amounts of dilute urine instead of small amount of concentrated urine.
Vasopressin test - inject small dose AVP and if it stops urine production it's cranial DI, if urine production continues it's nephrogenic
87
How is cranial diabetes insipidus managed?
Desmopressin can be used to replicate the functions of AVP
88
How is nephrogenic diabetes insipidus managed?
Thiazide diuretics, which reduce the amount of urine the kidneys produce
89
What is syndrome of inappropriate secretion of ADH?
The hyponatraemia and hypo-osmolality resulting from inappropriate, continued secretion or action of the ADH arginine vasopressin (AVP) despite normal or increased plasma volume, which results in impaired water excretion
90
What are the causes of syndrome of inappropriate secretion of ADH?
Malignancy (lung small cell, pancreas, prostate, thymus, lymphoma)
CNS disorders - abscess, stroke
Chest disease - TB, pneumonia
91
Describe the pathophysiology of syndrome of inappropriate secretion of ADH
Ectopic production increases the amount of ADH produced, beyond mechanisms of control. This secretion results in enhanced water reabsorption, leading to hyponatreamia
92
What are the clinical presentations of syndrome of inappropriate secretion of ADH?
Nausea, irritability and headache with mild dilution hyponatraemia, fits and coma with severe hyponatraemia
93
Name a differential diagnosis of syndrome of inappropriate secretion of ADH
Cerebral salt-wasting syndrome (CSW) - excessive ADH secretion caused by stimulation of the hypothalamus after trauma or ischaemia
94
How is syndrome of inappropriate secretion of ADH diagnosed?
Diagnose by serum concentrations of sodium, potassium, chloride and bicarbonate
Hyponatraemia (>20mmol/L) with corresponding hypo-osmolality (>100mOsmol/kg)
95
How is syndrome of inappropriate secretion of ADH managed?
Treat the cause and restrict the fluid
Consider salt +/- loop diuretic if severe
Vasopressin receptor antagonists
96
Describe the clinical chemistry of syndrome of inappropriate secretion of ADH
Decreased sodium and plasma osmolality
| Increased urine osmolality and urine sodium
97
What is hyperparathyroidism?
Excessive secretion of parathyroid hormone, usually due to a small tumour in one of the parathyroid glands.
98
What causes primary hyperparathyroidism?
A solitary adenoma, or occasionally hyperplasia of all glands
99
What causes secondary hyperparathyroidism?
Decreased vitamin D intake or chronic renal failure
100
What causes tertiary hyperparathyroidism?
Occurs after prolonged secondary hyperparathyroidism, causing glands to act autonomously after undergoing hyper plastic or adenomatous change
101
Briefly outline the pathophysiology of PTH.
Parathyroid hormone is normally secreted in response to low ionised Ca2+ levels, by 4 parathyroid glands situated posterior to the thyroid. The glands are controlled by negative feedback via Ca2+ levels
102
What are the symptoms of primary hyperparathyroidism?
Often asymptomatic, bones (osteoporosis), stones (kidney), groans (confusion), moans (abdominal - constipation)
103
What are the symptoms of secondary hyperparathyroidism?
Kidney disease, with skeletal or cardiovascular complications
104
What are the symptoms of tertiary hyperparathyroidism?
Bones (osteoporosis), stones (kidney), groans (confusion), moans (abdominal - constipation)
105
Name a differential diagnosis of hyperparathyroidism
Cancers producing parathyroid hormone
106
How is hyperparathyroidism diagnosed?
Primary - raised Ca2+, PTH and ALP (bone resorption
Secondary - low Ca2+, raised PTH
Tertiary - raised Ca2+ and PTH
107
How is hyperparathyroidism managed?
Primary - surgical removal of adenoma
| Secondary - calcium correction (underlying cause)
108
What is hypoparathyroidism?
Subnormal activity of the parathyroid glands, causing a fall in the blood concentration of calcium and muscular spasms
109
What are the causes of hypoparathyroidism?
Genetics, autoimmune, infiltration of the parathyroid glands by iron overload, surgery
110
Describe the pathology of hypoparathyroidism
PTH stimulates the activation of vitamin D, which facilitates intestinal calcium absorption, renal reabsorption of calcium as well as calcium release from bone
111
What are the symptoms of hypoparathyroidism?
```
Increased excitability of muscles and nerves.
Numbness around the mouth/ extremities
Cramps
Tetany
Convulsions
```
112
What is Chvostek's sign (hyperparathyroidism)?
The twitching of the facial muscles in response to tapping over the area of the facial nerve
113
What is Trousseau's sign (hyperparathyroidism)?
Carpopedal spasm caused by inflating the blood-pressure cuff to a level above systolic pressure for 3 minutes
114
What is pseudohypoparathyroidism?
A genetic defect that causes lack of response to parathyroid hormone.
115
What are the symptoms of pseudohypoparathyroidism?
Short stature, obesity, round faces, mild learning difficulties, short fourth metacarpals
116
What is hypercalcaemia of malignancy?
A higher-than-normal level of calcium in the blood due to a malignancy secreting parathyroid hormone-related protein
117
Which malignancies can cause hypercalcaemia and how?
Lung, oesophagus, skin, cervix, breast and kidney
| The tumour secretes parathyroid hormone-related protein which results in increased calcium levels
118
How does hypercalcaemia of malignancy present?
Bones (osteoporosis), stones (kidney), groans (confusion), moans (abdominal - constipation)
Weight loss, anorexia, nausea, polydipsia, polyuria, constipation, abdo pain
119
What effect can a hypercalcaemia of malignancy seizure have on an ECG?
Short QT interval
120
How is hypercalcaemia of malignancy diagnosed?
Raised calcium and phosphate, decreased albumin, chloride and potassium
Alkalosis
121
How is hypercalcaemia of malignancy managed?
Aggressive rehydration, bisphosphonates, control of underlying malignancy
122
Whats is hypocalcaemia?
An abnormally low calcium concentration in the blood
123
What are the causes of hypocalcaemia?
```
HAVOC
Hypoparathyroidism
Acute pancreatitis
Vit D deficiency
Osteomalacia
CKD
```
124
How does hypocalcaemia present?
SPASMODIC
Spasms, paraesthesiae, anxious, seizures, muscle tone increase, orientation impaired, dermatitis, impetigo herpetiformis, Chvostek's sign
125
What effect can a hypocalcaemia seizure have on an ECG?
QT prolongation
126
Name 2 differential diagnoses of hypocalcaemia
Hypoparathyroidism, acute kidney injury
127
What are the complications of hypocalcaemia?
Dysphagia, wheezing, syncope, congestive heart failure, angina
128
How is hypocalcaemia diagnosed?
Measure serum albumin levels (rule out hypoalbuminaemia)
Chvostek's/Trousseau's sign
eGFR to look for CKD
PTH and vit D levels
129
How is hypocalcaemia managed?
Treat with calcium (oral/IV)
CKD - alfacalcidol
Respiratory alkalosis - correct alkalosis
130
What is hyperkalaemia?
An abnormally high concentration of potassium in the blood, usually due to a failure of the kidneys to secrete it
131
What are the causes of hyperkalaemia?
Renal impairment, metabolic acidosis, Addison's disease, burns
132
How does hyperkalaemia present?
Dyspnoea, paraethesia, a fast, irregular pulse, chest pain, weakness, palpitations
133
What is a differential diagnosis for hyperkalaemia?
Rhabdomyolysis (muscle injury- death of muscle fibres that release their contents into the bloodstream)
134
How is hyperkalaemia diagnosed?
Plasma potassium >6.5mmol/L
| ECG: tall tented T waves, small P waves, wide QRS complex and ventricular fibrillation
135
How is hyperkalaemia managed?
Treat underlying cause, polystyrene sulfonate resin - binds K+ in the gut preventing absorption and bringing K+ levels down over a few days
Dietary potassium and loop diuretic
136
What is hypokalaemia?
Abnormally low levels of potassium in the blood (occurs in dehydration)
137
Describe the pathology of hypokalaemia
Gi fluid loss -> less chloride -> increase in aldosterone -> decreased potassium reabsorption
138
How does hypokalaemia present?
Muscle weakness, hypotonia, hyporeflexia, cramps, tetany, palpitations, light-headedness, constipation
139
Name a differential diagnosis for hypokalaemia
Bartter syndrome (inherited defect that causes low potassium levels)
140
How is hypokalaemia diagnosed?
ECG: T wave inversion, prominent U wave
Serum potassium levels
Urine potassium, sodium and osmolality
141
How is hypokalaemia managed?
Potassium (oral/ IV)
| Withdraw harmful medication, normalise magnesium and potassium
142
What are the 3 vital signs of presentation for diagnosing tumours?
1. Pressure on local structure e.g. optic nerves
2. Pressure on normal pituitary - hypopituitarism
3. Functioning tumour e.g. prolactinoma
143
Which inherited conditions increase your chance of developing a neuroendocrine tumour/
Multiple endocrine neoplasia type 1
Neurofibromatosis type 1
Von Hippel-Lindaeu syndrome
144
What is a prolactinoma?
Lactotroph cell tumour of the pituitary
145
How do proclactinomas present?
Local effect of tumour - headache, visual field defect
Effect of prolactin - amenorrhoea
Loss of libido
146
How are prolactinomas diagnosed?
Ultrasound, CT, MRI, PET
147
How are prolactinomas managed?
Dopamine agonists e.g. cabergoline
148
What is a pheochromocytoma?
A catecholamine (adrenaline) secreting tumour - tumours of the chromaffin cells of the medulla (these produce catecholamine)
149
How do pheochromocytomas present?
Episodic, headaches, palpitations, sweating, tremor, anxiety and nausea, hypertension, tachycardia, pallor
150
How are pheochromocytomas diagnosed?
24 hour urine collection for urinary catecholamines and metabolites
151
How are pheochromocytomas managed?
Surgery preceded by alpha and beta blockers to stagger adrenaline loss
152
What is a carcinoid tumour?
Neuroendocrine tumours that particularly affect the small bowel, large bowel or appendix.
Common sites: appendix, ileum, rectum
153
Describe the pathophysiology of carcinoid tumours
Carcinoid tumours are a group of tumours of enterochromaffin cell origin, capable of producing 5HT. They secrete bioactive compounds e.g. serotonin and Kallikrein which cause carcinoid syndrome
(only with liver metastasis)
154
How do bowel tumours present?
Stomach pain, diarrhoea, constipation, nausea, vomiting, rectal bleeding
155
How do lung tumours present?
Cough, wheezing, SOB, chest pain, tiredness
156
How do stomach tumours present?
Pain, weight loss, tiredness, weakness
157
What is carcinoid syndrome?
The collection of symptoms some people get when a neuroendocrine tumour (usually hepatic involvement) releases hormone such as serotonin into the blood stream
158
How does carcinoid syndrome present?
Bronchoconstriction, diarrhoea, skin flushing, carcinoid crisis
159
What is a carcinoid crisis and how is it treated?
When a tumour outgrows its blood supply, mediators flow out causing life threatening vasodilation, hypotension, tachycardia and bronchoconstriction.
Treated with octreotide and management of fluid balance
160
How are carcinoid tumours diagnosed?
CXR + chest/pelvis MRI/CT to locate primary tumours
Echocardiography - carcinoid heart disease
Liver ultrasound - confirm metastasis
161
How are carcinoid tumours managed?
Loperamide for diarrhoea
| Tumour resection is only cure for carcinoid tumours - vital to find primary site
