E2 - Thyroid disorders Flashcards
What is thyreotoxicosis?
biochemical reactions and pathophysiological changes triggered by overproduction of thyroid hormone
What are the diseases of hyperthyreodism?
- Graves disease
- nodular autonomous hormone-producing adenomas
- thyroid inflammations
- well differentiated thyroid tumor
What are the general symptoms of hyperthyroidism?
- hot intolerance
- sweating
- agitation
What are the skin symptoms of hyperthyroidism?
- hair loss, hair thinning
- “Plummer’s nails” (softening and become detached)
- pigment disorders
What are the muscular system symptoms of hyperthyroidism?
- weakness
- fatigue
- proximal myopathy
What are the cardiac symptoms of hyperthyroidism?
- accelerated circulation: resting tachycardia, systolic, hypertension, agina pectoris
- 10-20% afib
- mitral prolapse becomes more pronounced
- cardiomyopathy may develop
What are the respiratory symptoms of hyperthyroidism?
- tracheal constriction
- difficulty breathing
- weakness of resp. muscles
What are the gastrointestinal symptoms of hyperthyroidism?
- weight loss with good appetite
- frequent, softer stools
- in sever disease: nausea, vomiting, liver enzyme elevation
What are the skeletal symptoms of hyperthyroidism?
- accelerated bone metabolism
- coritcal bone detachment, fragility
- moderate hypercalcemia may develop
What are the hematological symptoms of hyperthyroidism?
- RBC production increases
- increase in plasma volume
What are the hormonal changes in case of hyperthyroidism?
FSH/LH changes resulting in oligoraro menorrhea, loss of libido, impotence, infertility
What are the metabolic changes in hyperthyroidism?
- cholesterol decreases, HDL increases
- insulin secretion and resistance increases (impaired glucose tolerance)
What are the nervous system symptoms of hyperthyroidism?
- agitated, restless, anxious
- depression
- insomnia
- rapid/erratic thinking
- deterioration of cognitive functions
- hypermotile but fatigable
- hand, body-wide fine wave tremors
- increased risk of developing dementia
- in sever cases: psychosis-like clinical picture
What are the opthalmological symptoms of hyperthyroidism?
- shiny and dilated eyes
- stiff eyes
- slow blinking
What is Graves disease?
- autoimmune disease: antibody against TSH receptor is produced
- predisposing factors: female; genetic; infection (yersinia enterocolica); psychological stress; good iodine supply; smoking
- its course is extremely erratic!!
clinical picture:
- diffuse goitre
- TSH is very low, increased fT3 and fT4
- consistent enrichment on scintigram
What are the specific symptoms for Graves disease?
- skin: vitiligo, alopecia, pretibial infiltrative dermopathy
- eye: exophthalmos, eye movement disorder, periorbital and conjunctival edema
- gastrointestinal: achlorhydria, celiac disease
- muscular: 1% of patients w/ myasthenia gravis
- hematology: relative lymphocytosis (low WBC count)
What is toxic nodular goitre?
- somatic mutation of TSH receptor or Gs subunit
- predisposing factors: >40 years, iodine deficiency
clinical picture:
- nodular goitre (one or more nodules)
- TSH is very low, very high fT3, and high fT4
- nodular enrichment on scintigraphy
What is iodine-induced hyperthyroidism?
- high doses of iodine intake with autonomous thyroid function
- common causes: contrast agent administration, amiodarone treatment
clinical picture in case of contrast agent
- TSH is very low, fT3 and fT4 are high
- iodine uptake <5%
clinical picture in case of amiodarone
- 6mg iodine from one 200mg amiodarone tablet
- inhibits 5’-monodeiodinase (catalyst of thyroid inactivation)
- direct toxic effect
What are the causes of non-thyroid thyrotoxicoses?
- diet
- psychiatric illness
- consumption of animal thyroid gland
- ovarian cyst teratoma
What are the causes of TSH-induced hyperthyroidism?
- pituitary adenoma
- T3 resistance syndrome (general or central)
What are the therapeutic options for hyperthyroidism?
- Tireostatics
- Radiojod treatment
- surgical
What are the advantages and disadvantages of tireostatics?
advantages
- easily accessible
- reversible
- cheap
disadvantages
- rarely curative
- daily treatment
- side effects
What are the advantages and disadvantages of Radiojod treatment?
advantages:
- rare side effects
- effective outside the TG
- fast effect
disadvantages:
- hospitalization (sometimes)
- irreversible efect
- expensive
What are the disadvantages of surgical intervention in hyperthyroidism?
- expensive
- surgical complications
- irreversible effect
What are the drug therapies for hyperthyroidism?
- Tireostatics
- Lithium carbonate: rapid effect (risk of intoxication!!) (3x250-500mg/day)
- Iodine: Lugol solution, contrast agents
- Beta-blockers: inhibits T4-T3 conversion (ie. propanolol)
- Dexamethasone: inhibits T4-T3 conversion (4x2mg/day)
What are the Tireostatics?
- first line therapy for Graves
- thionamides: methimazole, propylthiouracil
- methimazole: max. 40mg/day
- propylthiouracil: 150-900mg/day
- side effects: leukocytopenia, granulocytopenia, agranulocytosis
What to be cautious of in case of radioiodine treatment?
- Tionamide drugs should be stopped 1 wk before
- 24-hour iodine uptake measurement before treatment
- side effect restrictions:
- hypothyroidism
- orbitopathy can worsen
- pregnancy should be avoided for 6-12 months
- possibly suppressed TSH with normal fT3 and fT4
What is a Tireotoxic crisis?
- fever
- profuse sweating
- tachycardia; frequent arrythmias; cardiac decompensation
- tense nervousness psychosis
- apathy stupor coma
- nausea, vomiting, diarrhea
- abdominal pain
What is the intensive treatment for Tyreotoxic crisis?
- fluid replacement
- circulatory support
- hydrocortisone (2-4 x150mg/day iv.)
further inhibition of hormone production/secretion
What are the causes of hypothyroidism?
- thyroid diseases of inflammatory/autoimmune origin
- injury: preventative therapeutic effect on the thyroid gland
- drugs affecting thyroid function
- chromosomal abnormalities or gene mutations
- diseases of pituitary-hypothalamus
What are the symptoms/complaints of hypothyroidism?
- sleepiness
- weakness/fatigue
- memory problems
- cold intolerance
- weight gain
- constipation
- infertility
- menstrual cramps
- loss of libido
- hair loss, dry skin
- vitiligo
- slow movement
- bradycardia
- diastolic hypertension
- hypercholesterolemia, hyperprolactinemia
Treatment of hypothyroidism based on TSH levels
- TSH >10mU/L: must be treated
- TSH >6 mU/L (w/ ↑ lipid, ↑ CV risk): consider treatment
- TSH>3.5mU/L (w/ anti-TPO): treatment recommended if trying to get pregnant
What is the treatment for hypothyroidism?
Levothyroxine substitution treatment
- 50-150µg/day
- TSH monitoring 4-6wks after last L-T4 dose change
What is myxedematous coma?
- severe hypothyroidism
- intensive unit treatment necessary!!
causes
- cold infection: trauma
- sedatives: sleeping pills
complications
- heart, lung, kidney failure
symptoms:
- heart failure - pericardial effusion
- hyponatremia - resp. failure
- ileus - drug sensitivity
- hypothermia
- adrenocortical insufficiency
- coagulopathy
What are the types of thyroiditis?
- acute thyreoditis: infective
- subacute thyreoiditis: De Quervain, Silent, post-partum
- chronic thyroiditis: Hashimoto, Riedel
- iatrogenic thyroiditis
What is De Quervain thyreoiditis?
-
prevalence: 12/100,000 per year
- female:male = 5:1 - causes: viral - usually upper resp. infection (ie. Coxackie, mumps, adenovirus); associated w/ HLA-B35 haplotype
- symptoms: upper resp. infection, neck pain/tenderness, enlarged thyroid gland
-
treatment:
- NSAID, steroid (ie. prednisone if no improvement)
- symptomatic treatment of hyperthyroidism (beta blocker, thionamides are ineffective)
- hypothyroidism should not be treated
What is Hashimoto thyroiditis?
- high genetic influence: HLA D3, CTLA-4
- immune mechanism: similar to Grave’s disease
