Acromegaly OSCE Examination

Contents

1. Introduction
2. General Inspection
3. Hand Examination
4. Arms and Blood Pressure
5. Facial Examination
6. Visual Fields and Eyes
7. Neck Examination
8. Cardiovascular and Respiratory Assessment
9. Lower Limbs and Joints
10. Completing the Examination
11. Quiz

Introduction

Wash your hands and don personal protective equipment if appropriate.

Introduce yourself to the patient and ensure to mention your grade e.g. 3rd year medical student/junior doctor/consultant.

Confirm the patient's details taking 3 points of identification usually; full name, date of birth and NHS/hospital number.

Briefly explain the examination and obtain consent, for example: "I would like to look at your hands and face, check your vision, and examine your pulse and blood pressure. Is that alright?"

Ask the patient if they are in any pain anywhere before you begin, as joint pain is common in acromegaly.

Position the patient seated on the edge of the bed or in a chair, and ensure their hands, forearms and face are exposed and accessible.

General Inspection

Begin by standing back and observing the patient from the end of the bed. The diagnosis of acromegaly is frequently apparent from the general inspection alone, so take time to build an overall impression before touching the patient.

Look for the characteristic coarsening of the facial features, large hands and feet, and an increase in overall body size. Patients often report that their rings no longer fit and that they have had to buy larger shoes or gloves, which is a useful clue to the gradual soft-tissue overgrowth.

Note the patient's height and habitus. Acromegaly developing in adulthood does not increase height, but if excess growth hormone was present before the epiphyses fused (in childhood) the patient would have gigantism and be unusually tall.

If the patient is mobile, watch how they walk. A broad-based, rolling gait may be seen, reflecting the degenerative joint disease and any varus (bow-legged) deformity that the acromegalic arthropathy causes at the knees.

Scan the bedside for clues such as a blood glucose monitor or insulin (suggesting associated diabetes mellitus), a visual field chart, or walking aids (reflecting the arthropathy that acromegaly causes). A deepened or husky voice may also be noticeable when the patient speaks, caused by thickening of the vocal cords and enlargement of the laryngeal soft tissues and sinuses.

Hand Examination

Inspect the hands first. In acromegaly the hands are typically large, broad and "spade-like", with thickened, doughy soft tissue and an increase in the size of the fingers. This is due to overgrowth of soft tissue, cartilage and bone driven by GH and IGF-1, rather than any swelling of the joints themselves. A simple way to gauge the degree of acral enlargement is to hold your own hand against the patient's, palm to palm, and compare the overall span; the patient's hand often noticeably overlaps your own.

Assess the skin thickness by gently pinching the skin over the third metacarpophalangeal joint and comparing it with the equivalent skin on your own hand. Excessively thick skin supports the diagnosis and reflects the generalised soft-tissue expansion seen throughout the body. The skin may also feel oily and sweaty, as acromegaly increases the activity of sweat and sebaceous glands, producing hyperhidrosis.

Inspect the fingertips for capillary blood glucose testing marks. Excess growth hormone is a counter-regulatory (anti-insulin) hormone, so it promotes insulin resistance and around one in three patients develops diabetes mellitus or impaired glucose tolerance.

Image - The broad, enlarged "spade-like" hands seen in acromegaly, caused by soft-tissue and bony overgrowth

Creative commons source by Philippe Chanson and Sylvie Salenave [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]

Acromegaly is a common cause of carpal tunnel syndrome. The soft-tissue overgrowth within the wrist compresses the median nerve as it passes through the carpal tunnel, producing pain, tingling and numbness in the thumb, index, middle and radial half of the ring finger. Look for wasting of the thenar eminence (the muscle bulk at the base of the thumb) as a sign of long-standing median nerve compression.

Two bedside tests can provoke the symptoms of carpal tunnel syndrome:

• Tinel's test – tap firmly over the carpal tunnel on the palmar aspect of the wrist. A positive test reproduces tingling or paraesthesia in the median nerve distribution.
• Phalen's test – ask the patient to hold their wrists in full flexion (back-to-back) for around 60 seconds. A positive test again reproduces the median nerve symptoms.

Finally, palpate the radial pulse, assessing the rate and rhythm. A normal rate is 60–100 bpm. This begins to assess the cardiovascular complications of acromegaly, which are an important cause of excess mortality in these patients.

Arms and Blood Pressure

Move up the arms and inspect the axillae and skin. Acromegaly is associated with multiple skin tags (acrochordons), which are small benign outgrowths of skin that are particularly common in the axillae and neck. They are clinically relevant because their presence has been linked with an increased risk of colonic polyps, part of the recognised association between acromegaly and colorectal neoplasia.

While inspecting the axillae and neck, also look for acanthosis nigricans – velvety, thickened, darkened skin in the flexures. This is a marker of the insulin resistance that growth hormone produces, and ties in with the impaired glucose handling seen in many patients.

You may also note proximal muscle weakness, as a chronic myopathy can develop in long-standing disease. A quick bedside screen is to ask the patient to stand from a seated position with their arms folded across their chest; difficulty doing so without pushing up on the arms of the chair suggests proximal weakness.

Offer to measure the blood pressure. Hypertension is common in acromegaly and arises from a combination of sodium and fluid retention (growth hormone has an anti-natriuretic effect on the kidney) and increased vascular tone. Hypertension contributes substantially to the cardiovascular morbidity of the condition, so its identification is an important part of the examination.

Facial Examination

Inspect the face carefully, as it carries some of the most recognisable features of acromegaly. Look for coarse facial features overall, with thickened skin and accentuated facial creases.

Specific features to look for include:

• Frontal bossing – prominence of the forehead and brow caused by overgrowth of the frontal bones and the underlying frontal sinuses.
• Prognathism – protrusion of the lower jaw (mandible) due to bony overgrowth, often producing an underbite (malocclusion) where the lower teeth sit in front of the upper teeth.
• Interdental separation – widening of the gaps between the teeth, as the jaw enlarges but the number of teeth stays the same.
• Enlarged nose and lips – broadening of the nose and thickening of the lips from soft-tissue overgrowth.

Ask the patient to open their mouth and inspect the tongue for macroglossia (an enlarged tongue). This is significant beyond appearance: enlargement of the tongue and the soft tissues of the upper airway predisposes patients to obstructive sleep apnoea, a very common and important complication of acromegaly.

If you have not already done so, note any deepening of the voice, which results from thickening of the vocal cords and enlargement of the laryngeal cartilages and paranasal sinuses.

Image - The coarse facial features of acromegaly, including frontal bossing, an enlarged nose and prominent jaw, caused by bony and soft-tissue overgrowth

Creative commons source by Philippe Chanson and Sylvie Salenave [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]

Image - Prognathism in acromegaly, with protrusion of the lower jaw produced by overgrowth of the mandible

Creative commons source by Philippe Chanson and Sylvie Salenave [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]

Visual Fields and Eyes

Assessment of the visual fields is one of the most important parts of the acromegaly examination, because it tests for the local effects of the pituitary tumour. The pituitary gland sits in the sella turcica, directly beneath the optic chiasm. As a pituitary adenoma enlarges upwards (supra-sellar extension), it compresses the chiasm.

The fibres that cross within the optic chiasm are those carrying information from the nasal half of each retina, which correspond to the temporal (outer) half of each visual field. Compression from below therefore affects these crossing fibres first, producing the classic bitemporal hemianopia – loss of the outer halves of the visual field in both eyes.

Test the visual fields using confrontation: sit roughly one metre opposite the patient at the same eye level, ask them to cover one eye while you cover your opposite eye, and bring a moving finger or red hatpin in from the periphery in each quadrant, comparing the patient's field with your own. Always test each eye separately. A defect that respects the vertical midline and affects the temporal fields of both eyes strongly suggests chiasmal compression.

Image - Patterns of visual field loss. Compression of the optic chiasm from below by a pituitary adenoma classically produces a bitemporal hemianopia, with loss of the outer half of the field in both eyes

SimpleMed original image, credit 'SimpleMed original'

Offer to complete the eye assessment by testing visual acuity, examining the eye movements (a large tumour may compress the cranial nerves in the cavernous sinus), and performing fundoscopy to look for optic atrophy from chronic compression.

A large pituitary adenoma can also disturb the surrounding gland. If the tumour compresses the pituitary stalk it disinhibits prolactin release, and roughly a quarter of GH-secreting adenomas co-secrete prolactin. The resulting hyperprolactinaemia may cause galactorrhoea (inappropriate milk production), menstrual disturbance or reduced libido, so offer to ask about these symptoms and, with a chaperone, to inspect for galactorrhoea.

Neck Examination

Examine the neck, paying particular attention to the thyroid gland. Acromegaly can cause a diffuse or multinodular goitre, as growth hormone and IGF-1 stimulate the growth of thyroid tissue. Inspect the neck from the front, ask the patient to swallow a sip of water (a thyroid swelling will move upwards with swallowing), and then palpate the gland from behind to assess its size, symmetry and any nodules.

Although most patients remain euthyroid, the increased prevalence of thyroid nodules is relevant because of the recognised association between acromegaly and thyroid neoplasia.

Image - A visible goitre. Growth hormone and IGF-1 stimulate thyroid tissue, so a diffuse or nodular goitre may be found on examining the neck in acromegaly

SimpleMed original image, credit 'SimpleMed original'

Cardiovascular and Respiratory Assessment

Cardiovascular disease is the leading cause of premature death in untreated acromegaly, so a focused cardiovascular assessment is essential. Chronic exposure to growth hormone and IGF-1 promotes growth of the heart muscle, leading to a specific acromegalic cardiomyopathy with biventricular hypertrophy, diastolic dysfunction and, in advanced disease, heart failure.

Auscultate the praecordium for any murmurs, as valvular thickening and regurgitation can occur. Listen for added heart sounds and, at the lung bases, for crackles that might indicate pulmonary oedema from heart failure. Check the ankles for peripheral oedema.

The combination of hypertension, cardiomyopathy, diabetes mellitus and obstructive sleep apnoea explains why cardiovascular risk is so markedly increased in these patients, and why each component should be actively sought during the examination.

Lower Limbs and Joints

Inspect the feet, which, like the hands, become large and broad due to soft-tissue and bony overgrowth; an increase in shoe size is a common historical clue.

Assess the joints for signs of osteoarthritis, which is a frequent and disabling complication. Excess GH causes overgrowth of cartilage, but this new cartilage is mechanically inferior and wears unevenly, leading to early degenerative change and joint pain in the knees, hips and spine. Look for joint swelling, reduced range of movement and any walking aids that suggest significant arthropathy.

Inspect the back as well, as degenerative change in the spine can produce a kyphosis and contribute to the rolling gait noted on general inspection.

You may also note a proximal myopathy in the legs, contributing to weakness and difficulty rising from a chair.

Completing the Examination

Thank the patient and wash your hands.

Summarise your findings and offer a differential, clearly stating whether the clinical picture is consistent with acromegaly.

To complete the examination, suggest the following further assessments and investigations:

• A full set of observations, including a formal lying and standing blood pressure.
• Capillary blood glucose and a urine dip to screen for diabetes mellitus.
• A formal examination of the eyes and visual fields (ideally with formal perimetry) and fundoscopy.
• Comparison of the patient's appearance with old photographs, which helps demonstrate the slow change in features over time.
• Biochemical confirmation: a raised serum IGF-1 is the best screening test, with the diagnosis confirmed by failure of growth hormone to suppress during an oral glucose tolerance test (OGTT).
• MRI of the pituitary to identify and characterise the adenoma, together with assessment of the remaining pituitary hormone axes (including thyroid function and serum prolactin, which may be co-secreted) for hypopituitarism or co-secretion.
• Screening for complications, including an ECG and echocardiogram, HbA1c, assessment for obstructive sleep apnoea, and colonoscopy given the increased risk of colorectal neoplasia.

Quiz

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