Endocrinology Flashcards
Thyrotoxicosis (signs)
Easy fatigability = Fine tremor
Heat intolerance = Warm, sweaty extremities
Excessive sweating = Proximal myopathy/atrophy
Palpitations = Tachy/ arrythmias
Weight loss, increased appetite = Dyspneoa
Diarrhoea
Target organs =heart, muscle etc)
Thyrotoxicosis (Atypical)
weight loss, slow AF, severe depression
Primary presentation with heart involvement
Tachy-arrythmias (resistant AF)
Young women: infertility, menstrual abnormalities
Thyrotoxicosis (Typical)
Elderly: Apathetic thyrotoxicosis: small goitre
Severe muscle weakness, Associated HPP
(> older patient > 60yrs)
High output failure
Thyrotoxicosis (common causes)
- Grave’s disease (Diffuse, smooth, vascular)
Toxic multinodular goitre (multi nodular)
Toxic adenoma (single nodule)
Subacute thyroiditis (de Quervain’s) (extremely tender to touch)
Drugs: Amiodarone, Thyroid hormone replacement
Grave’s disease
Common form of thyrotoxicosis
F>M, 20-40 yrs
Auto-immune dx
stimulate antibodies against TSH receptor
Thyroidal (bruit), Extrathyroidal
Graves:
Ophthalmopathy = Inflammation vs Infiltration (Proptosis, muscle, vision)
Dermopathy = anterior aspect of shin (Fibrosis), itchy
Acropachy
Grave’s (more info)
Suspected hyperthyroidism
TSH + free T4
High TSH and low T4/T3 = Primary hyperthyroidism
Ultrasound (Anat)
(Functional) = Thyroid uptake scan, NIS
Treatment:
-Neomercazole (Relapse graves)
-Radio-active iodine (very effective, contra = grave’s eye dx, pregnancy)
-Surgery (refuse RAI, large goitre, pregnancy, failed medical px, single adenoma, very young, comsetic eye dx)
-Supportive / anti-inflammatory therapy : Thyroiditi
When to request TSH-R antibodies?
To confirm Grave’s disease if no extrathyroidal signs and patient keen to be treated medically
When to do free T3?
Free T4 normal, TSH suppressed
Free T3:
High “T3 toxicosis” = Grave’s, Toxic nodular goitre
Normal = Subclinical toxicosis
Low = Euthyroid sick syndrome, Non-thyroidal illness
Primary hypofunction
Low T4 and T3
High TSH level
Clinically hypo
Hypo-thyroidism (COMMONEST CAUSES)
HASHIMOTO’S disease (Most common)
Iatrogenic damage to thyroid gland
Drugs: Amiodarone, Lithium
Hypothyroidism (symptoms and signs)
Face, puffy
Skin cold, dry, rough, yellow discoloration
Voice hoarse
Bradycardia
Slow mentation
Concentration difficulties
Slow reflexes
Elderly
Macrocytic anaemia
Depression
Infertility, menstrual abnormalities
Apathy and withdrawal in elderly
HASHIMOTO’S disease
(Most common cause of hypothyroidism)
F>M, any age
Auto-immune dx
Lymphocytic/chronic thyroiditis
Antibodies: TPO/microsomal
High TSH and low T4/T3 = Primary hyperthyroidism =>Iatrogenic damage to thyroid 9Prev surge./radio-active iodine, Hashimoto’s thyroiditis
What should you do if there is a strong clinical suspicion of hypo-thyroidism?
But TSH is normal
Do free T4
If low – then secondary hypothyroidism (pituitary hypofunction)
Patient should be referred to endocrinologist for further evaluation
Hypothyroidism treatment
-Levo-Thyroxine (Eltroxin, Euthyrox) T4
-replacement dose 50– 200ug/d (age, weight)
-TSH only stabilize on therapy after 4 – 6 weeks
-once daily (long half-life) - Give in morning on empty stomach.
-Absorption may be affected by concomitant use of calcium / Fe-supplements / estrogen / anti-acids / proton pump inhibitors
-Primary care level; Life-long replacement = T4 converted to T3, no need to give T3
-Carefully and slowly in the elderly and in patients with known heart disease
- Thyroxine in elderly / heart disease ( Start low & go slow!!!) ( 25ug daily, incr. 25ug 2-4 weeks, continue on 50-75ug for 6weeks) Only increase dose = if TSH still elevated
Subclinical hypothyroidism
- Elevated TSH ; normal free T3 and T4 levels in a clinically euthyroid patient
- If TSH level above 10mIU/l, consider treatment as for overt hypothyroidism
- If TSH level less than 10mIU/l, repeat functions after 3-6 months - see proposed algorithm
