Thyroid Examination Flashcards
Explain the function of T3
Thyroid hormone (T3)
Thyroid hormone (T3) plays an essential role in the normal functioning of cells and therefore excessive or low levels can cause a broad range of symptoms and clinical signs which can be identified on clinical assessment. High levels of circulating T3 significantly increases metabolism resulting in weight loss and potentiates the effects of catecholamines such as adrenaline resulting in excessive sympathetic output (e.g. tachycardia, tremor, anxiety). Low levels of circulating T3 have the opposite effect, causing weight gain, low mood, constipation, poor memory and hyporeflexia.
Describe the connection between weight changes and thyroid dysfunction
Weight: weight loss is typically associated with hyperthyroidism (increased metabolism), whilst weight gain is associated with hypothyroidism (decreased metabolism).
Anxiety is connected with which thyroid condition and why?
anxiety and hyperactivity are associated with hyperthyroidism (due to sympathetic overactivity).
Low mood is associated with which thyroid condition?
Hypothyroidism is more likely to be associated with low mood.
What may the patients clothing be able to tell you?
Clothing: may be inappropriate for the current temperature. Patients with hyperthyroidism suffer from heat intolerance whilst patients with hypothyroidism experience cold intolerance.
Explain the vocal changes that occur in a patient with thyroid malignancy
Hoarse voice: caused by compression of the larynx due to thyroid gland enlargement (e.g. thyroid malignancy).
What is the following clinical sign and what does it indicate?
Thyroid acropachy: similar in appearance to finger clubbing but caused by periosteal phalangeal bone overgrowth secondary to Graves’ disease.
What is the following clinical sign and what does it indicate?
Onycholysis: painless detachment of the nail from the nail bed associated with hyperthyroidism.
What is the following clinical sign and what does it indicate?
Palmar erythema: reddening of the palms associated with hyperthyroidism, chronic liver disease and pregnancy.
What does a peripheral tremor indicate in the context of a thyroid pathology?
Peripheral tremor is a feature of hyperthyroidism reflecting sympathetic nervous system overactivity.
Describe the connection between pulse and thyroid dysfunction
A pulse <60 bpm is known as bradycardia and has a wide range of aetiologies (e.g. healthy athletic individuals, hypothyroidism, atrioventricular block, medications, sick sinus syndrome).
A pulse of >100 bpm is known as tachycardia and also has a wide range of aetiologies (e.g. hyperthyroidism, anxiety, supraventricular tachycardia, hypovolaemia).
An irregular rhythm is most commonly caused by atrial fibrillation which can be associated with hyperthyroidism.
Dry skin and sweating is associated with which thyroid conditions?
Dry skin: associated with hypothyroidism.
Excessive sweating: associated with hyperthyroidism.
Eyebrow loss: the absence of the outer third of the eyebrows is associated with which thyroid condition?
Eyebrow loss: the absence of the outer third of the eyebrows is associated with hypothyroidism (although this is a rare sign).
What is the following clinical sign and what does it indicate?
Upper eyelid retraction is the most common ocular sign of Graves’ disease however it can be present in other thyrotoxic states (e.g. toxic multinodular goitre). Eyelid retraction is thought to occur due to sympathetic hyperactivity causing excessive contraction of the superior tarsal and levator palpebrae superioris muscles.
What is the following clinical sign and what does it indicate?
Exophthalmos is bulging of the eye anteriorly out of the orbit. Bilateral exophthalmos develops in Graves’ disease, due to oedema and lymphocytic infiltration of orbital fat, connective tissue and extraocular muscles.
List 3 eye conditions associated with graves disease aside from lid retraction and exopthalmos
Due to lid retraction and exophthalmos, the eye is more prone to dryness and the development of conjunctival oedema (chemosis), conjunctivitis and in severe cases corneal ulceration.
What abnormal eye movements occur in Grave’s disease?
ophthalmoplegia (e.g. restricted eye movement, diplopia) and pain during eye movement caused by Graves’ disease (lymphocytic infiltration of orbital fat, connective tissue and extraocular muscles):
Lid lag refers to a delay in the descent of the upper eyelid in relation to the eyeball when looking downward. Lid lag is most commonly associated with Graves’ disease although it can be present in other thyrotoxic states (e.g. toxic multinodular goitre). Lid lag is thought to occur secondary to a combination of lid retraction and exophthalmos.
Explain how the movements of thyroid lumps during swalling and tounge protrusion can guide diagnosis
Swallowing
Ask the patient to swallow some water and observe the movement of the mass:
Thyroid gland masses (e.g. a goitre) and thyroglossal cysts typically move upwards with swallowing.
Lymph nodes will typically move very little with swallowing.
An invasive thyroid malignancy may not move with swallowing if tethered to surrounding tissue.
Tongue protrusion
Ask the patient to protrude their tongue:
Thyroglossal cysts will move upwards noticeably during tongue protrusion.
Thyroid gland masses and lymph nodes will not move during tongue protrusion.
What may cause a unilateral enlargement of the thyroid lobes?
Symmetry: assess for any evidence of asymmetry between the thyroid lobes (unilateral enlargement may be caused by a thyroid nodule or malignancy).
What would a widespread irregular consistency of the thyroid gland suggest?
Consistency: assess the consistency of the thyroid gland tissue, noting any irregularities (e.g. a widespread irregular consistency would be suggestive of a multinodular goitre).
What may a thrill in the thyroid gland suggest?
Palpable thrill: assess for evidence of a palpable thrill caused by increased vascularity of the thyroid gland due to hyperthyroidism (suggestive of Graves’ diseas
What is a thyroglossal cyst?
Thyroglossal cysts are the most common congenital abnormality of the neck and arise as a result of the persistence of the thyroglossal duct. The thyroglossal duct is the tract by which the thyroid gland descends during embryological development to its final position in the front of the neck. The tongue is attached to the thyroglossal duct, which is why thyroglossal cysts rise during tongue protrusion.
Describe are the different types of goitres and give some underlying causes
Types of goitre
There are several different subtypes of goitre which include:
Diffuse goitre: the whole thyroid gland is enlarged due to hyperplasia of the thyroid tissue.
Uninodular goitre: the presence of a single thyroid nodule which may be active (toxic) autonomously producing thyroid hormones (causing hyperthyroidism) or inactive.
Multinodular goitre: the presence of multiple thyroid nodules which may be active or inactive. Active multinodular goitres are often referred to as a toxic multinodular goitre.
What does lymphadenopathy in a thyroid examination suggest?
local lymphadenopathy may indicate the metastatic spread of primary thyroid malignancy.
Why would you percuss the sternum in a thyroid exam?
Percuss the sternum moving downwards from the sternal notch to assess for retrosternal dullness.
Retrosternal dullness may indicate a large thyroid mass extending posteroinferiorly to the manubrium.
What would a bruit in the thyroid gland indicate?
Auscultate each lobe of the thyroid gland for a bruit using the bell of the stethoscope.
A bruit indicates increased vascularity, which typically occurs in Graves’ disease.
How would hypothyroidism affect reflexes?
Reflexes
Reflexes are assessed to screen for hyporeflexia, which is associated with hypothyroidism. The most commonly tested reflexes are the biceps reflex or the knee jerk reflex (you only need to assess one).
What is the following sign and what does it suggest?
Pretibial myxoedema is a form of diffuse mucinosis in which there is an accumulation of excess glycosaminoglycans in the dermis and subcutis of the skin. It usually presents itself as a waxy, discoloured induration of the skin on the anterior aspect of the lower legs (pre-tibial region). Pretibibial myxoedema is a rare complication of Graves’ disease.
What is the proximal myopathy a sign of in the context of a thyroid abnormality?
Proximal myopathy is a potential complication of both multinodular goitre and Graves’ disease. Patients develop wasting of their proximal musculature causing difficulties in tasks such as standing from a sitting position.
What further assessments/investigations would you do upon completing a thyroid examintion?
Further assessments and investigations
Thyroid function tests: these include TSH, T3 and T4.
ECG: should be performed if an irregular pulse was noted to rule out atrial fibrillation.
Further imaging: an ultrasound scan of the neck to further assess any thyroid lumps.
