Endocrine system Flashcards
What is an endocrine?
Substance released from endocrine gland into blood stream and affects distal organs.
Name 2 pituitary problems
Acromegaly
Cushing’s syndrome
Which hormones are released from the anterior pituitary gland? (5)
- LH/FSH (luteinizing hormone/follicle stimulating hormone)
- TSH (thyroid stimulating hormone)
- ACTH (adrenocorticotropic hormone)
- GH (growth hormone)
- Prolactin
Which hormones are released from posterior pituitary hormone? (2)
- Vasopressin
2. Oxytocin
Name 4 consequences of pituitary pathology
- Hormonal deficiencies
- Hormone over production due to functioning tumours e.g. acromegaly, Cushing’s, prolactinomas
- Systemic disease (e.g. infiltrative, metastatic)
- Local pressure effects (laterally cranial nerve palsies, superiorly optic chiasm involvement.
GH production
What does GH do?
What mediates GH?
What other effects does GH have?
- secreted in pulses
- amount secreted per day much higher in children than adults.
- stimulates growth and cell division in childhood
- effects mediated by IGF-1 released from liver.
other reported effects: - decreased body fat - increased muscle mass - increased bone density = increased energy levels - improved skin tone - improved immune system function
What is acromegaly?
- Adult onset - growth hormone excess after the completion of linear growth
- overgrowth of soft tissues
- in children = gigantism
- pituitary adenoma - GH secreting cells
- usually benign
What are the symptoms of acromegaly?
- sweating
- skin change
- snoring
- arthritis
- carpal tunnel syndrome
- headache
- visual changes
- change in hand or foot size
- ask about rings and shoes
- change in TEETH
- change in APPEARANCE ‘COARSE FEATURES’
- amenorrhoea
- impotence
What are the clinical signs of acromegaly?
macroglossia - enlarged tongue
prognathism - protrusion of jaw
increased inter-dental spacing
soft tissue enlargement
- hypertension
- diabetes
- sleep apnoea
= bitemporal hemianopia
What is gigantism?
Excess GH in childhood
How do you investigate and diagnose acromegaly?
- confirm the presence of growth hormone excess:
> IGF-1 elevated
> abnormal GH response e.g. lack of suppression on OGTT
> measure other pituitary hormones - then find the source with MRI pituitary
- visual fields
How do you treat acromegaly?
gold standard = pituitary surgery
other options
- Dopamine agonist therapy
- Somatostatin analogues
- Pegvisomant (GH receptor antagonist)
- RT
What dental relevance does acromegaly have?
Pt complaining of trouble with teeth
> increased interdental spacing
> dentures may not fit
> macroglossia
Snoring
Change in appearance - course features
Insidious onset
What is HPA axis?
Hypothalamic Pituitary Adrenal Axis (ACTH)
Hypothalamus produces Corticotropin Releasing Hormone (CRH)
>
Anterior pituitary gland produces Adrenocorticotropic Hormone (ACTH)
>
Adrenal cortex produces cortisol
(then negative feedback)
What does cortisol do?
involved in response to stress and anxiety
Increases BP (vascular tone) and blood sugar
Affects the immune response
Axis abnormal in depression, stress, severe illness etc
What is Cushing’s Syndrome?
Causes? (4)
Excess cortisol
Pituitary adenoma
> ACTH secreting cells (Cushing’s disease)
Adrenal tumour: adenoma or carcinoma
Ectopic ACTH production
>Bronchial NET, small cell lung cancer, more weird rare suff…
Iatrogenic
> excess steroid
What are the symptoms and signs of Cushing’s syndrome?
Change in appearance - Abdominal adiposity - Muscle wasting in limbs Thin skin Easy bruising Acne Hirsutism Poor wound healing
Diabetes
Hypertension
Lemon-on-sticks appearance Moon face Buffalo hump Osteoporosis Psychiatric illness > Euphoria > Depression > Psychosis
How do you investigate and diagnose Cushing’s syndrome?
Screening
- 24 hr urinary free cortisol
Further tests involve confirming the diagnosis and the site of excess hormone production.
Imaging of adrenals (CT) or pituitary (MRI) depending on results.
How do you manage Cushing’s syndrome?
- referral to an endocrinologist
- temporary medical control of hormone excess?
- surgical resection of the lesion -adrenalectomy -transphenoidal hypophysectomy
- nasty disease, difficult to cure long-term
- Pt may be on steroid replacement post-operatively
What is the relevance of cushing’s to dental practice?
- Poor wound healing, thin skin, easy bruising
- Psychiatric manifestation
- Immunocompromised - may be more prone to infection
- complex if on replacement steroids after treatment…
- look out for moon face..although some ppl look cushingoid but aren’t
What is hypoadrenalism?
- Loss of glucocorticoid production
- Possible loss of mineralocorticoid production
- Primary: adrenal (Addison’s Disease)
- Secondary: pituitary disease
- Iatrogenic: pts on long term steroid who stop suddenly
Important role in maintaining circulating volume and blood pressure
What are the clinical features of addison’s disease?
- non-specific, complains of malaise, tiredness and weakness
- weight loss
- abdominal pain
- vomiting
- postural hypotension
- may have increased pigmentation
- can be associated with other autoimmune diseases e.g. hypothyroidism, type 1 diabetes, vitiligo
How do you investigate and diagnose Addison’s disease?
Short synacthen test with ACTH measurement
How do you manage addison’s disease?
- Glucocorticoid replacement
> cortisol deficiency
> hydrocortisone 10mg/5mg/5mg
> cortisone acetate/prednisolone/dexamethasone - Mineralocorticoid replacement
> aldosterone deficiency
> fludrocortisone 100mcg - Secondary insufficiency
> review all other pituitary hormones
What do you do to dose of glucocorticoid doses when using LA?
GA?
Double dose on morning of procedure
GA: iv steroids requires peri-op and while nbm
What is the dental relevance of addison’s disease?
- look for characteristic pigmentation on gums and buccal mucosa.
- Onset often insidious and vague
- patients may need increased steroid cover for procedures
- a major operation on a pt with undiagnosed adrenal insufficiency may precipitate an ‘Addisonian crisis’ with circulatory collapse.
name 2 thyroid problems
hyperthyroidism
hypothyroidism
Describe the hypothalamic pituitary thyroid axis
Hypothalamus secretes TRH (thyrotropin-releasing hormone)
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This stimulates pituitary gland to secrete TSH (thyroid-stimulating hormone)
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This stimulates thyroid gland to secrete T3 and T4 (thyroxine)
What does thyroxine do?
T4 and T3:
Increase metabolic rate in all cells.
Regulate cell O2 and heat generation.
In adults also play a role in protein, fat and CHO metabolism, nerve function, muscle function, gone health, skin health and reproductive function.
In fetus and neonate, thyroid hormones are responsible for growth and development of all tissues including brain.
What are the commonest causes of Hyperthyroidism/ Thyrotoxicosis: (2)
- Graves disease
: autoimmune
: associated with eye disease
: often young and female - Toxic multinodular goitre
: commoner in older pts
: may have an obvious goitre
What are the clinical features of hyperthyroidism? SYMPTOMS
> Weight loss > Increased appetite > heat intolerance > irritability > diarrhoea > amenorrhoea > change in hair and skin
> swelling in neck > eye symptoms --prominence --dryness --pain --grittiness > tiredness > palpitations
What are the signs of an overactive thyroid?
fine tremor warm clammy palms lid retraction, proptosis chemosis sinus tachycardia or atrial fibrillation goitre - enlarged thyroid gland > may have stridor > may have dysphagia
How do you investigate and diagnose hyperthyroidism? (2)
- Biochemistry
> suppressed TSH and elevated free T4 and T3 - Imaging
> ultrasound scan: nodule(s)
> isotop scan - diffuse or nodular uptake
How do you manage hyperthyroidism? (3)
- Medical
> anti-thyroid medication - carbimazole or propylthiouracil
side effect - agranulocytosis - Radio-iodine
3 Surgery
What is the dental relevance of hyperthyroidism? (3)
- pathology may be visible in head and neck
- uncontrolled pts at risk of a ‘thyroid storm’ peri-operatively
- agranulocytosis/neutropenia as a side effect of the medication
> often manifests as mouth ulcers or sore throat
> stop medication and urgent full blood count
What are the causes of hypothyroidism? (3)
lack of thyroxin
- Primary hypothyroidism - autoimmune
- Following treatment for hyperthyroidism
> medical overtreatment
> radioiodine
> surgery - Secondary to pituitary disease
What are the symptoms of hyperthryoidism?
> Weight gain > cold intolerance > tiredness > constipation > menorrhagia > thinning hair > women>men
> puffy face > macroglossia (rarely) > goitre > bradycardia > loss of outer third of eyebrow > slow relaxing reflexes
How do you investigate and diagnose hypothyroidism?
Biochemistry:
High TSH with low/normal free T4 and low/normal free T3
No imaging necessary
How do you treat hypothyroidism?
Typically lifelong hormone replacement
- Levothyroxine at about 1.5mcg/kg
- Average dose 100mcg od
What is the dental relevance of hypothyroidism?
No need to change doses around time of procedures?
Defer procedures if untreated or significantly under-treated.
Absorption of thyroxine
> drugs
> calcium, iron supplements
> caffeine, soya milk
