Endocrinology and Dermatology Flashcards
Define Endocrine
Pour secretions into blood stream
e.g. thyroid, adrenal and beta cells of pancreas
Define Exocrine
Glands pour secretions into a duct to the site of action
e.g. pancreas - amylase+lipase
Define Endocrine
Acts on distant cells
Define Paracrine
Acting on adjacent cells
Define Autocrine
Feedback on same cell that secreted the hormone
What are 5 ways to control hormone action?
- Metabolism
- Receptor induction
- Receptor down regulation
- Synergism e.g. Glucagon + adrenaline
- Antagonism e.g. Glucagon + insulin
What is the function of Oxytocin?
Milk secretion and uterine contraction
What is the function of Theca Cells?
Stimulated by LH to produce androgens that diffuse into granulosa cells to be converted into oestrogen.
What is the function of Sertoli cells?
Sertoli cells produce MIF and inhibin and activin which acts on the pit gland to regulate FSH
What is the function of granulosa cells?
Granulosa cells are stimulated by FSH to convert androgen’s into oestrogen using aromatase
What is the function of Leydig Cells?
Stimulated by LH to produce testosterone
What does LH act on?
In ovaries - Theca cells
In testes - Leydig Cells
What does FSH act on?
In ovaries - Granulosa cells
In Testes - Sertoli cells
What is the LH/FSH axis?
Hypothalamus –> GnRH –> AP –> FSH/LH –> Ovaries/testes
What does FSH do to granulosa cells?
Produces Oestrogen
What does FSH do to Sertoli cells?
Induces spermatogenesis
What does LH do to Theca cells?
Produces androgens to diffuse to the granulosa cells to be converted to oestrogen.
What does LH do to Leydig Cells?
Produce testosterone.
What are some characteristics of Water soluble hormones?
Unbound and binds to surface receptor, short half-life and fast clearance e.g. peptide (receptors in cell membrane)
What are the characteristics of fat soluble hormones?
Protein bound and diffuses into cell, long half life and slow clearance e.g. Thyroid hormone + cortisol (receptors in cytoplasm)
What is a prolactinoma?
A condition where an adenoma causes excess production + release of prolactin.
What are 2 causes of prolactinoma?
Pituitary adenoma
Anti-dopaminergic drugs
What are 5 signs of prolactinoma?
Infertility Amenorrhoea Libido loss Visual field effects (bitemporal hemianopia) Headaches.
What is the treatment for prolactinoma?
Dopamine agonist e.g. Cabergoline
This causes a negative feedback –> promoting dopamine and preventing the release of prolactin.
What does prolactin act on?
The mammary glands to produce milk –> + feedback mechanism, breast sucking = less dopamine.
What is the mechanism of prolactin release?
Hypothalamus –> dopamine (-) –> AP –> Prolactin
What would happen if you block the AP’s ability to produce dopamine?
Levels of prolactin would increase.
What are the consequences of too much prolactin?
Galactorrhoea
Low libido and testosterone
Infertility
Menstrual irregularity
What is acromegaly?
Hormonal disorder resulting from too much GH
What is the cause of acromegaly?
Benign adenoma on the pit gland.
What comorbidities are seen in Acromegaly?
T2 Diabetes, arthritis, Cerebrovascular events, hypertension + HD, sleep apnoea
What are the symptoms of Acromegaly?
- Bigger hands and feet
- Excessive sweating
- Headache
- Tiredness
- Weight gain
- Deep voice
- Amenorrhoea
- Change in appearance
What signs might someone with acromegaly present with?
Bi-temporal hemianopia, spade like hands and feet, large tongue, jaw protrusion, interdental separation .
What investigations might you do on a patient with suspected acromegaly?
Plasma GH levels can exclude acromegaly
Serum IGF-1 level raised
Oral glucose tolerance test failure of glucose to suppress serum GH and thus IGF-1
MRI of pituitary
What is the treatment for acromegaly?
Trans-sphenoidal surgical resection
Radiotherapy
Medical therapy –> dopamine agonists, somatostatin analogues
Give an advantage and disadvantage of Trans-sphenoidal surgical resection.
Advantage - Complete removal of the tumour
Disadvantage - many complications are possible e.g. Haemorrhage, CNS injury and hypopituitarism
Give an advantage and disadvantage of dopamine agonists in the treatment of acromegaly.
Advantage - no risk of hypopituitarism
Disadvantage - maybe ineffective.
How do dopamine agonists and somatostatin analogues work in the treatment of acromegaly?
They look to control IGF and GH levels.
What two drugs can be used to treat acromegaly?
Cabergoline - dopamine agonist
Octreotide - somatostatin analogue - v effective.
What is the main reason for diabetic complications?
Poor glycaemic control
What can acute hyperglycaemia cause?
DKA and Hyperosmolar coma
What can chronic hyperglycaemia cause?
Micro/macrovascular complications
What are 3 microvascular complications of diabetes?
- Diabetic retinopathy
- Diabetic nephropathy
- Diabetic peripheral neuropathy
What are 2 macrovascular complications of diabetes?
CV Disease
Stroke
What is the most common type of diabetic neuropathy?
Distal symmetrical polyneuropathy
What are 5 signs of autonomic neuropathy?
- Hypotension
- HR affected
- Diarrhoea/constipation
- Erectile dysfunction
- Dry skin
- Incontinence
What is a consequence of insensitivity?
Foot ulceration –> failure to heal –> infection and amputation.
How is neuropathy distributed?
Glove and stocking - starts at the toes and moves proximally.
What are the risk factors for diabetic neuropathy?
- Poor glycaemic control
- Hypertension
- Smoking
- HbA1c
- Overweight
- Long duration of DM
What is the treatment for diabetic neuropathy?
- Improve glycaemic control
- Pain relief
- Antidepressants
What are the consequences of diabetic neuropathy?
- Pain - burning and triggered nocturnally
- Autonomic neuropathy – damage to nerves that supply structures that reg HR, BP, emptying
- Insensitivity
Would you have a decreased or increased pulse in a diabetic neuropathic foot?
Increased.
What is diabetic retinopathy?
Complication of diabetes caused by damage to light sensitive tissue in the retina.
What is the pathophysiology of diabetic retinopathy?
Micro-aneurysm –> pericyte loss + protein leakage –> occlusion = ischaemia.
What are the risk factors for diabetic retinopathy?
- Long term DM
- Poor glycaemic control
- Pregnancy
- Hypertension
- High HbA1c
- Insulin treatment
What can diabetic retinopathy be subdivided into?
Proliferation - evidence of neovascularisation
Nonproliferation
What are the 3 stages of diabetic retinopathy?
R1 Retinopathy grade – non-proliferative – interretinal hemorrhages, exudate and micro-aneurysms
R2 Retinopathy grade – Pre proliferative – venous beading, growth of new vessels
R3 Retinopathy grade – Proliferative – new blood vessel on disk
What is the treatment of diabetic retinopathy?
People with diabetes are offered regular screening
Laser therapy treats neovascularisation
Give 3 signs of acute ischaemia in someone with PVD
- Pulseless
- Pale
- Cold
- Pain
- Paralysis
- Paraesthesia
How can you avoid amputation in patients with diabetes?
- Screening for insensitivity
- Education
- MDT Food clinics
- Podiatry
- Revascularisation
- Pressure relieving footwear
What is diabetic nephropathy?
Chronic loss of kidney function in those with DM.
What is the hallmark of diabetic nephropathy?
Development of proteinuria and progressive decline in renal function.
What happens to the glomerular basement membrane in Diabetic nephropathy?
It thickens.
How does microalbuminuria present in Type 1 and Type 2 DM?
Type 1 - 5-10 years post diagnosis
Type 2 - Immediately
How can you treat diabetic nephropathy?
Glycaemic control BP Control ACEi Cholesterol control Proteinuria
What controls serum calcium levels?
The parathyroid.
What two hormones does the Parathyroid release to modify calcium levels.
PTH
Calcitonin
When is PTH triggered and what is its action?
Low serum Ca2+ triggers release of PTH –> increases
When is Calcitonin triggered and what is its action?
High serum Ca2+ triggers c-cells to release calcitonin
What is the action of PTH?
Increases bone resorption
Increases calcium reabsorption at the kidney
Activates vit D –> acts on the intestine to increase calcium absorption
What does hyperparathyroidism cause?
Hypercalcaemia
What does hypoparathyroidism cause?
Hypocalcaemia
What are the causes of hyperparathyroidism?
- Primary – Parathyroid adenoma PTH and Ca up, phosphate down (Most common)
- Secondary – Physiological hypertrophy to correct low Ca
- Tertiary – Renal failure, can’t activate Vit D
- Prolonged uncorrected hypertrophy
What are the symptoms of hyperparathyroidism?
Renal/biliary stones Bone pain Abdo Pain Polyuria Depression, anxiety and malaise
Stones, bones, groans, thrones, moans.
What is the treatment for hyperparathyroidism?
- High fluid intake, low calcium diet.
- Excision of adenoma
- Correct underlying cause
- Parathyroidectomy
What investigations would you do for hyperparathyroidism?
ECG
Thyroid function tests
What ECG changes would you see in hyperparathyroidism?
Tall T waves
Short QT waves
What is hypercalcaemia?
High serum Ca2+ levels.
What are 3 causes of hypercalcaemia?
- Hyperparathyroidism
- Hypercalcaemia of malignancy
- Vit D toxicity
- Myeloma
How could you establish the cause of hypercalcaemia?
PTH test for hyperparathyroidism
What are the symptoms of hypercalcaemia?
- Constipation
- Vomiting
- Depression
- Confusion
- Increased thirst and frequent urination
What is the treatment of hypercalcaemia?
- IV normal saline
- Iv Furosemide
- IV calcitonin
What are the symptoms of hypoparathyroidism?
- Spasm
- Anxious/irritable
- Seizures
- Increased muscle tone
- Confusion
- QT prolongation
- Paraesthesia around lips
- Tetany and increased reflexes
- QT elongation
What are the causes of hypoparathyroidism?
- AI disease e.g. Addison’s disease
- Injury to Parathyroid gland
- Low blood magnesium levels
What ECG changes would you see in hypoparathyroidism?
- Small T waves
- Long QT interval
What is the treatment of hypoparathyroidism?
Calcium supplements
Resolve underlying cause
What is the cause of hypocalcaemia?
- Dietary insufficiency
- Anticonvulsant therapy
- CKD
- Vit D deficiency
- Osteomalacia
- Hypoparathyroidism
What are the symptoms of hypocalcaemia?
- Muscle cramps and spasms
- Bradycardia
- Muscle weakness
- Seizures
- Facial twitching
What is the treatment for hypocalcaemia?
- Calcium supplements
- Treat underlying cause
What metabolic changes are associated with pregnancy?
- Increased EPO, Cortisol, Nad
- High CO
- High Cholesterol + TG
- Pro thrombotic and inflammatory state
- Insulin resistance
When does the thyroid gland start to develop?
Foetal thyroid follicles and thyroxine synthesis starts at week 10
What condition is common in pregnancy?
Hypothyroidism
What is the treatment for hypothyroidism?
Levothyroxine
Give 5 gestational syndromes
- Pre-eclampsia
- Gestational diabetes
- Obstetric Cholestasis
- Gestational thyrotoxicosis
- Transient Diabetes insipidus
- Postnatal depression
- Postpartum thyroiditis
What are some of the complications post pregnancy from untreated hypothyroidism?
- Gestational hypertension
- Placental abruption
- Post-partum haemorrhage
- Low birth weight
- Neonatal goitre
- Pre-eclampsia
- Risk of miscarriage
Why can hCG activate TSH receptors and cause hyperthyroidism?
HCG and TSH are glycoprotein hormones –> very similar structures so hCG can activate TSH receptors
Is hypothyroidism or thyrotoxicosis more commin pregnancy?
Hypothyroidism
How can you differentiate between grave’s disease and gestational thyrotoxicosis?
Graves - symptoms predate pregnancy and get more severe during it –> Goitre + TSH-R antibodies present
Gestational thyrotoxicosis - symtpoms do not predate pregnancy –> No goitre or TSH-R antibodies
Consequences of untreated hypothyroidism in pregnancy?
- Gestational hypertension
- Placental abruption
- Post-partum haemorrhage
- Low birth weight
- Neonatal goitre
- Pre-eclampsia
- Risk of miscarriage
Consequences of untreated hyperthyroidism in pregnancy?
Intra-uterine growth restriction
Low birth weight
pre-eclampsia
risk of still birth/miscarriage.
What disease is described as a disorder of carb metabolism characteristed by Hyperglycaemia
DM
What is the most common cause of hyperthyroidism in Pregnancy?
Graves
What is the management for hyperthyroidism?
Carbimazole - can harm foetus so given later
Propylthiouracil
What are the different types of hypothyroidism?
- Primary - Thyroid gland dysfunction
- Secondary – Pituitary (TSH not being made)
- Tertiary – Hypothalamic dysfunction - not making TRH
What are 5 causes of hypothyroidism?
AI Thyroiditis e.g. Hashimoto’s
Post-partum thyroiditis
Iatrogenic – thyroidectomy + radioiodine therapy
Drug induced – carbimazole, amiodarone and lithium
Iodine deficiency
What are the signs of hypothyroidism?
- Mental slowness
- Bradycardia
- Anaemia
- Loss of eyebrows
- Dry thin hair
- Cold peripheries
- Hypertension
What is the management of hypothyroidism?
Levothyroxine
What would be the investigations you would order in suspected hypothyroidism?
- TFT – serum TSH high, T4 low
- Thyroid antibodies –> TPO, TG, TRAb
What is thyrotoxicosis?
Excess thyroid hormone production due to any cause
What are 5 causes of thyrotoxicosis?
- Increase production e.g. Graves, toxic adenoma
- Leakage of t3/4 due to follicular damage
- Ingestion
- Thyroiditis
- Drug induced
What is the pathophysiology of graves disease?
Autoimmune disease - TSH receptor antibodies stimulate thyroid hormone production causing hyperthyroidism.
Give 5 symptoms of Grave’s disease that doesn/t include opthalmopathy signs
weight loss, increased appetite, irritable, tremor, palpitations, goitre diarrhoea malaise vomiting muscle spasm tachycardia, Tachycardia, arrhythmias, heat intolerance
Give 5 signs of Graves that dont include opthalmopathy signs.
- Tachycardia
- Arrythmia e.g. AF
- Warm peripheries
- Muscle spasm
- Pre-tibial myxoedema
- Thyroid acropach (clubbing and swollen fingers)
Give 5 opthalmology signs of Grave’s
exophthalmos (bulging eyes), redness, conjunctivitis, pre-orbital oedema, extra-ocular swelling
What histology would you see in someone with grave’s disease?
lymphocyte infiltration and thyroid follicle destruction
What is the treatment for Grave’s disease?
Surgery –> partial thyroidectomy
Radioiodine drugs – emit beta particles that destroy thyroid follicles, so TH production goes down.
Ant-thyroid drugs e.g. carbimazole.
How does carbimazole work in treating Grave’s disease?
Targets TPO so prevents T3/T4 formation.
What is a serious side effect of Carbimazole?
Agranulocytosis
How do radioiodine drugs treat Grave’s disease?
Radioiodine drugs emit B particles that destroy Thyroid follicles so TH production goes down.
What are 3 potential complications of a partial thyroidectomy?
hypothyroidism, hypocalcaemia, recurrent laryngeal palsy, bleed