The Medical and Surgical Management of Thyroid, Pituitary and Adrenal disorders Flashcards
Endocrine glands
Ductless
Release a product into bloodstream for transport to target organs
Hormones
Chemical signals produced by endocrine glands
Affect target organs a distance from release site
Targets
Mechanism of interaction
Organs, tissues and cells capable of responding to hormone
Presence of receptor which binds to hormone
Thyroid gland
Physiology
Biochem
Why is it unique
Largest of all endocrine glands
Produces
- T4 and T3 which regulate basal metabolic rate
- calcitonin which regulates blood Ca2+ levels
Stores large amount of inactive hormone within extracellular follicles
Thyroid gland - surface anatomy
Where are parathyroids located
Which major vessels surround it
Shields anterior and lateral surfaces of lower respiratory tract
Between posterior border of thyroid gland and its sheath (2 on each side)
Internal jugular vein and common carotid lie postero-lateral
Measurement of thyroid hormone
Which types are important
Thyroxine - T4
Free triodothyronine - T3
Thyroid stimulating hormone - TSH
Autoimmune Hypothyroidism
3 causes and hormone concs
Do they produce goitre?
Primary failure of thyroid gland - less T3 and T4 but TSH up
Secondary failure to hypothalamic or pituitary failure - less T3, T4, less TSH (and or TRH)
Dietary iodine deficiency - less T3 and T4 but TSH XS
Goitre - Yes, No, Yes
Clinical features of hypothyroidism
Weight gain Lethargy Increased fatigue Cold intolerance Hair loss Dry skin Deafness Muscle weakness Facial puffiness Goitre Bradycardia Delayed reflexes
Causes of hypothyroidism
Primary
Secondary and tertiary
Dyshormonogenesis Iodine deficiency Autoimmunity Post radioactive iodine Post thyroidectomy Iodine excess
Pituitary tumours Pituitary granulomas Empty sella Isolated TRH deficiency Hypothalamic disorders
Indications for hypothyroidism screening
Methods of investigation
Congenital hypothyroidism Tx for hyperthyroidism Neck irradiation Pituitary surgery/irradiation Lithium or amidoarone tx
Thyroid fx test
thyroid antibodies
levothyroxine
Dental complications in hypothyroidism
Delayed eruption Enamel hypoplasia macroglossia Micrognathia thick lips Dysgeusia
Hyperthyroidism - causes
3 causes
Hormone concs
Goitre?
Abnormal thyroid stimulating immunoglobulin e.g Grave’s disease - XS T3 and T4 but less TSH
Secondary to XS hypothalamic or pituitary secretion - Increased T3 and T4, increased TSH and/or TRH
Hypersecreting thyroid tumour - increased T3 and T4, less TSH
No, yes, no (not in traditional sense)
Causes of hyperthyroidism
Common and rare
Autoimmune thyroid disease - graves - postpartum thyroiditis Toxic nodular goitre Toxic adenoma - one nodule producing XS thyroid hormone
Amiodarone induced
De Quervain’s thyroiditis
Thyrotroph adenoma
hCG hyperthyroidism
Clinical features of hyperthyroidism
Weight loss Heat intolerance Anxiety Increased sweating and appetite Palpitations Loose bowels
Goitre Tremor Warm moist skin Tachycardia Eye signs Thyroid murmur Muscle weakness Atrial fibrillation
Grave’s disease
Clinical features
Investigations
Diffuse goitre Eye signs - diplopia, exophthalmos Myxoedema (swelling of skin) Vitiligo Family history of thyroid disease
TSH receptor antibody checks
Thyroglobulin antibodies
Thyroid radioisotope
Mechanism of action of TSH receptors
TSH binds to receptor and regulatory protein is stimulated
Cascade reaction intracellularly
Treatment of hyperthyroidism
Side effects of medical tx
Medical - nausea, vomiting, leukopenia –> agranulocytosis, aplastic anaemia, drug fever and cholestatic jaundice
Surgical
Radioactive iodine
Dental complications of hyperthyroidism
Accelerated dental eruption
Mx or md osteoporosis due to increased turnover of bone
Increased caries risk
Periodontal disease
Increased sensitivity to epinephrine –> arrhythmias or palpitations
Surgery, oral infection + stress may trigger crises
Referral criteria for thyroid nodules
New onset Increase in size Pain onset Associated speech disturbance Lymphadenopathy Patient/doctor concern
Pituitary disorders - causes
Investigations
Empty sella
Hormone XS
Hormone deficiency
Tumour mass effects - can affect optic chiasm and reduce periphery vision
Hormonal tests
If abnormal –> MRI of pituitary
Local effects of pituitary mass
Headaches
Visual field defects
CSF rhinorrhoea - can get fluid leakage via nasal cavity
Cranial nerve palsy and temporal lobe epilepsy
Hormone deficiency of GH
and Tx
Growth hormone
- short stature
- abnormal proportions
- reduced muscle mass
- poor QoL
Tx - growth hormone
Hormone deficiency of LH/FSH
Tx
LH and FSh usually feed back to GnRH to inhibit production
Luteinising hormone/follicle stimulating
- hypogonadism
- reduced sperm count
- infertility
- menstruation problems
Testosterone for males
Progesterone for females
Hormone deficiency of TSH
Tx
Thyrotropin stimulating hormone
Hypothyroidism
Levothyroxine
Hormone deficiency of ACTH
Tx
Adrenocorticotropic hormone
- adrenal failure
- decreased pigment
hydrocortisone
Hormone deficiency of ADH
Tx
Anti-diuretic hormone
- diabetes insipidus
- decreased water absorption therefore polyuria and polydipsia
DDAVP
Hypopituitarism causes
Tumours Radiotherapy Trauma Infarction Infiltration of pituitary Infection of pituitary e.g syphilis Sheehan's syndrome (post partum pituitary necrosis)
Acromegaly
Pituitary disorder
XS GH secretion
4/million per year
equal sex incidence
Clinical features of acromegaly
Head
Other areas
Coarse facial features Enlarged supraorbital ridges Separation of teeth Prognathism Macroglossia
Headaches Spade-like hands Joint pain XS sweating Hypertension Impaired glucose tolerance
Treatment of acromegaly
Investigations: IGF1, dynamic tests, MRI pituitary
Surgical resection – Transphenoidal surgery, Transfacial Surgery
- biochemical control
80% microadenomas
50% macromore than 10mm adenomas
Somatostatin analogues – 40% complete responders - inhibits GH production
Pegvisomant reduces IGF-1 to levels > 90% - growth hormone receptor antagonist - inhibitor
Radiotherapy in unsuccessful surgery
Dental complications of acromegaly
Jaw Malocclusion Difficulty in speech due to macroglossia Teeth mobility Missing teeth Teeth separation Thickening of alveolar processes Enlarged posterior roots In 50% upper airways obstruction caused by pharyngeal hypertrophy and macroglossia with obstructive sleep apnoea.
Adrenal disorders
CAUSES OF CUSHING SYNDROME
Adrenal tumour = XS Cortisol decreased ACTH
Pituitary tumour = XS ACTH and XS cortisol
Cushing’s syndrome
XS glucocorticoids
corticotropin releasing hormone released from hypothalamus –. ACTH release from pituitary
CORTISOL RELEASED ON A RHYTHM Pit tumour Adrenal tumour Ectopic ACTH tumour Iatrogenic
Clinical features of Cushing’s
Weight gain Menses problems Moon face Acne Bruising Glucose intolerance Hyper pigmentation Muscle weakness Plethora Hirsutism Oedema Can result from long term steroid use
Management of Cushing’s syndrome
Investigations
Treatment
Hormonal tests
Radiological tests - MRI, CT chest and adrenal
Surgery, drugs, radiotherapy
Disease involving adrenal insufficiency
Addison’s disease
Causes of adrenal insufficiency
Primary
Secondary
Autoimmune Tuberculosis Fungal infections Adrenal haemorrhage Congenital adrenal hypoplasia Sarcoidosis Amyloidosis Metastatic neoplasia
After exogenous glucocorticoids
After treatment for Cushing’s (EXCESS ACTH)
Hypothalamic or pituitary tumours
Clinical features of adrenal insufficiency
Weakness Skin and mucous membrane pigmentation Loss of weight, emaciation, anorexia, vomiting, diarrhoea Hypotension Salt craving - loss of salt in urine Hypoglycaemic episodes
Management of adrenal insufficiency
Investigations
Tx
Hormonal tests
- measuring cortisol, ACTH and adrenal antibodies
Radiological
- MRI pituitary
CT or MRI adrenals
Tx - hydrocortisone replacement treatment
Primary adrenal insufficiency
Adrenal gland is insufficient and not producing enough cortisol
ACTH will increase
Pigmentation due to ACTH secreted with melanin stimulating hormone which binds to skin
Secondary adrenocortical insufficiency
Low ACTH therefore cortisol not stimulated
Glucocorticoid cover for dental procedures
Need to prevent patient from undergoing steroid crisis
On treatment therapy e.g asthma, rheumatoid arthritis ◦ Prednisolone > 7.5mg
◦ Hydrocortisone > 30mg
◦ Dexamethasone > 0.75mg
On replacement therapy
◦ Addison’s e.g. Hydrocortisone 20/10mg - own production is not sufficient
◦ ACTH deficiency 10/5/5mg
Simple Procedures - when giving LA : double dose one hour before surgery, double dose oral medication for 24 hours
Major Procedures/GA: hydrocortisone 100mg im at induction and double dose oral medication for 24 hours
Surgery and other endocrine disorders
Hyperthyroidism
Pheochromocytoma
Cushing’s - avoid infections and pathological fractures
Refer to endocrinologist
Endocrine causes of hypertension
Primary aldosteronism Phaechromocytoma Acromegaly Cushing's syndrome Hypothyroidism Hyperthyroidism
Calcium homeostasis
10000mg excreted in kidney
9800mg reabsorbed into body
Role of calcium
Ionised
- cofactor in coagulation
- skeletal mineralisation
- membrane stabilisation – neuronal conduction
Parathyroid hormone action
Kidney
- increase Ca reabsorption
- reduced phosphate reabsorption
- increased hydroxylation of 25-oh bit D
Bone
- increased bone remodelling
Gut
- no direct effect
- increased ca absorption
calcium homeostasis is
an example of negative feedback
Abnormalities in PTH
May be appropriate - to maintain calcium balance
May be inappropriate as it can cause calcium imbalance
Hypocalcaemia
Low serum albumin
Low total serum calcium
but NOT low ionised calcium
e.g serum calcium = 2.08 mol/L
corrected calcium = 2.28 mmol/L
Causes of hypocalcaemia
vit D deficiency
Hypoparathyroidism
– post surgery, radiation, autoimmune disease
– Hereditary (Autosomal dominant
hypocalcaemia)
– Syndromes (Di George, HDR [hypopara, deafness, renal dysplasia] etc)
– Infiltration (Wilson’s disease, haemochromatosis)
Chronic renal failure
Magnesium deficiency -> linked to vitamin D deficiency
Pseudohypoparathyroidism
Acute pancreatitis
Multiple citrated blood transfusions
Consequences of hypocalcaemia
Parasthesia Muscle spasm - hands and feet, larynx and premature labour Seizures Basal ganglia classification Cataracts Dental hypoplasia ECG abnormalities
Signs of hypocalcaemia
- History of neck surgery
- Presence of other autoimmune conditions
- History of congenital defects and immunodeficiency
- Family history to suggest genetic cause
- Drug history e.g antiepileptics
- Neck scar, candidiasis, vitiligo, generalized bronzing
- Growth failure, hearing loss
Vit D deficiency
Calcium reduced
Decreased PTH –>
Decreased serum calcium
Management of hypocalcaemia
Mild and severe
Mild
- oral calcium supplements
- cholecalciferol (active form) if vitamin D deficiency
- post-thyroidectomy –> calcium supplements
- hypomagnesaemia –> magnesium supplements
Causes of hypercalcaemia
• Malignancy – bone mets, myeloma, PTHrP, lymphoma • Primaryhyperparathyroidism • Thiazides • Thyrotoxocosis • Sarcoidosis • Familial hypocalciuric / benign hypercalcaemia • Immobilisation • Milk-alkali • Adrenal insufficiency • Phaeochromocytoma 90%
Symptoms of hypercalcaemia
- Thirst, polyuria
- Nausea
- Constipation
- Confusion coma
- Pancreatitis
- Gastric ulcer
- Renal stones
- ECG abnormalities
- Short QT
Hypercalcaemia - signs
- Confusion, hypotonia, hyporeflexic
- Dehydration
- Signs of malignancy (enlarged liver, clubbing, thyroid mass, breast lump, lymph nodes)
- Faecal impaction
- Irregular pulse (arrhythmia,
Approach to hypercalcaemia
Low CA –> first thing to check is PTH
- if PTH normal then urine test used
• Identify any drugs that may cause hypercalcaemia (thiazides, lithium, Vitamin D)
• Identify whether presence of renal failure ? Tertiary hyperparathyroidism
• Check serum PTH and if high or normal perform 24-hour urine calcium
excretion (Urine Calcium/Urine Creatinine x Plasma Creatinine)
- If PTH high or normal and urine calcium excretion > 0.01 mmol/l – Primary Hyperparathyroidism
- If PTH high or normal and urine calcium excretion < 0.01 mmol/l – FHH
- If PTH low or suppressed – exclude malignancy, hyperthyroidism, Addison’s, sarcoidosis, granulomatous disorders
Hypercalcaemia of malignancy
reduced bone resorption
calcium reabsorption and calcium absorption from gut
• About 20 to 30% of patients with cancer
• 80% are due to bony metastases (breast, thyroid , kidney,
lung, prostate)
• 20% due to PTHrP release (others secrete Vitamin D, ectopic PTH)
• Osteoclastic Hypercalcaemia
Consequences of primary hyperparathyroidism
Management
• Bones
– Osteitisfibrosacystica – Osteoporosis
- erosions of bone
- osteitis and cysts
• Kidney stones
• Psychic groans
– confusion
• Abdominal moans – Constipation
– Acute pancreatitis
Indications for surgery
• Serum calcium > 0.25 mmol/l from upper limit
• Creatinine clearance < 60 ml/min
• T-score < -2.5 at any site and/or previous fragility fracture at spine, hip, radius, femoral neck
• 24 hour urine calcium >400mg/day (>10mmol/day) • Nephrocalcinosis or nephrolithiasis
• < 50 years
Tertiary hyperparathyroidism
Renal failure –> nodular hyperplasia and autonomy
Management of hypercalcaemia
• Intravenous fluids Normal 0.9% saline
• Loop diuretic if risk of overload ONLY
• Intravenous bisphosphonates e.g pamidronate,
zoledronic acid (make sure PTH sample taken)
• Corticosteroids e.g Vitamin D intoxication, sarcoidosis
SUMMARY
PTH controls calcium balance to keep serum calcium in a narrow normal range
• High or low PTH may be appropriate or inappropriate
• Symptoms and causes of calcium imbalance
• Think about how changes affect the feedback loop
