Thyroid status Flashcards
What is thyroid hormone and what is its role in the body?
T3
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.
What equipment do you need for the thyroid exam
Stethoscope
Glass of water
Tendon hammer
Piece of paper
How should the patient be positioned in the thyroid exam
Adequately expose the patient’s neck and upper sternum.
Ask the patient to sit on a chair for the assessment.
What should you look for in the initial assessment of the patient in the thyroid exam (4)
And objects?
Weight: weight loss is typically associated with hyperthyroidism (increased metabolism), whilst weight gain is associated with hypothyroidism (decreased metabolism).
Behaviour: anxiety and hyperactivity are associated with hyperthyroidism (due to sympathetic overactivity). Hypothyroidism is more likely to be associated with low mood.
Clothing: may be inappropriate for the current temperature. Patients with hyperthyroidism suffer from heat intolerance whilst patients with hypothyroidism experience cold intolerance.
Hoarse voice: caused by compression of the larynx due to thyroid gland enlargement (e.g. thyroid malignancy).
Mobility aids: patients with hyperthyroidism can develop proximal myopathy.
Prescriptions (e.g. levothyroxine).
What are the stages of the thyroid exam
WIPERQQ
Inspection
Hands
Face
Thyroid + Auscultation
Lymph nodes
Trachea
Sternum
Further tests
What do you inspect for on the hands during the thyroid exam
Thyroid acropachy: similar in appearance to finger clubbing but caused by periosteal phalangeal bone overgrowth secondary to Graves’ disease.
Onycholysis: painless detachment of the nail from the nail bed associated with hyperthyroidism.
Palmar erythema: reddening of the palms associated with hyperthyroidism, chronic liver disease and pregnancy.
What do you assess for after inspecting the hands in the thyroid exam?
What do you do next?
Peripheral tremor
a feature of hyperthyroidism reflecting sympathetic nervous system overactivity.
To assess for evidence of a subtle peripheral tremor:
- Ask the patient to stretch their arms out in front of them.
- Place a piece of paper across the back of the patient’s hands.
- Observe for evidence of a peripheral tremor (the paper will quiver).
Assess radial pulse
What do you look for when inspecting the in the face thyroid exam
Dry skin: associated with hypothyroidism.
Excessive sweating: associated with hyperthyroidism.
Eyebrow loss: the absence of the outer third of the eyebrows is associated with hypothyroidism (although this is a rare sign).
Eye signs
What eye signs should you look for in the thyroid exam
eye pathology associated with thyrotoxicosis (e.g. Graves’ disease) including
lid retraction,
eye inflammation,
exophthalmos (also known as proptosis),
eye movement abnormalities
lid lag
How do you assess lid retraction in the thyroid exam
What might you see and what does this mean
inspect the eyes from the front and note if sclera is visible between the upper lid margin and the corneal limbus (this indicative of lid retraction).
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 do you do to assess exophthalmos
inspect the eye from the front, the side and from above.
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
Why might you look for eye inflammation in the thyroid exam
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.
How and why do you assess for ophthalmoplegia in the thyroid eye exam
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):
- Ask the patient to keep their head still and follow your finger with their eyes.
- Move your finger through the various axes of eye movement (“H” shape).
- Observe for restriction of eye movements and ask the patient to report any double vision or pain.
What is lid lag
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.
How do you check for lid lag in the thyroid exam
- Hold your finger superiorly and ask the patient to follow it with their eyes, whilst keeping their head still.
- Move your finger in a downwards direction whilst observing the patient’s upper eyelids as the patient’s eyes follow your finger. If lid lag is present, the upper eyelids will be observed lagging behind the eyes’ downward movement, with the sclera being visible between the upper lid margin and the corneal limbus.
How do you inspect the thyroid?
Inspect the midline of the neck from the front and the sides noting any masses (e.g. goitre) or scars (e.g. previous thyroidectomy). The normal thyroid gland should not be visible.
If a mass is present, perform a swallowing test and a tongue protrusion test
Describe the swallow and tongue protrusion tests in the thyroid exam
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.
How do you palpate the thyroid
Palpate each of the thyroid’s lobes and the isthmus:
- Stand behind the patient and ask them to tilt their chin slightly downwards to relax the muscles of the neck to aid palpation of the thyroid gland.
- Place the three middle fingers of each hand along the midline of the neck below the chin.
- Locate the upper edge of the thyroid cartilage (“Adam’s apple”) with your fingers.
- Move your fingers inferiorly until you reach the cricoid cartilage. The first two rings of the trachea are located below the cricoid cartilage and the thyroid isthmus overlies this area.
- Palpate the thyroid isthmus using the pads of your fingers.
- Palpate each lobe of the thyroid in turn by moving your fingers out laterally from the isthmus.
- Ask the patient to swallow some water, whilst you feel for the symmetrical elevation of the thyroid lobes (asymmetrical elevation may suggest a unilateral thyroid mass).
- Ask the patient to protrude their tongue (if a mass represents a thyroglossal cyst, you will feel it rise during tongue protrusion).
What should you feel for when palpating the thyroid
Size: note if the thyroid gland feels enlarged.
Symmetry: assess for any evidence of asymmetry between the thyroid lobes (unilateral enlargement may be caused by a thyroid nodule or malignancy).
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).
Masses: note if there are any distinct palpable masses within the thyroid gland’s tissue (e.g. solitary thyroid nodule or thyroid malignancy). If a thyroid mass is noted assess its position, shape, consistency and mobility (i.e. is it tethered to underlying tissue).
Palpable thrill: assess for evidence of a palpable thrill caused by increased vascularity of the thyroid gland due to hyperthyroidism (suggestive of Graves’ disease)
What is the most common congenital abnormality of the neck
Thyroglossal cysts
arise as a result of the persistence of the thyroglossal duct.
The tongue is attached to the thyroglossal duct, which is why thyroglossal cysts rise during tongue protrusion.
What are the 3 key subtypes of goitre
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 do you do after palpating the thyroid in the thyroid exam
Auscultate the thyroid
Then palpate lymph nodes and assess tracheal position
Then move on to sternum
What do you do with the sternum in the 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.
How do you auscultate the thyroid
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.
