bitemedicine lecture 9 (acromegaly and prolactinoma) slides

Endocrinology

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Lecture 9

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@bitemedicine

Dr Azeem Alam, MBBS BSc (Hons)Surgical AFPGuy’s and St. Thomas’ Hospital

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Content reviewed on the 23/04/2020.

Learning objectives• 2 endocrinology topics: Acromegaly and Prolactinoma

• Case-based discussion(s) to identify the top differentials and why

• Theory to cover pathophysiology, diagnostic criteria, investigations and

management

• Quiz (Mentimeter and multi-step SBAs)

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Case 1

History

A 41-year-old male presents to his GP with profuse sweating and visual disturbance. He has also noticed numbness in his right hand. He has been feeling very tired due to difficulty sleeping.

On examination, thick skin is noted and he has course facial features.

Observations

HR 96, BP 148/102, RR 18, SpO2 98%, Temp 37.0°C.



Acromegaly: Pathophysiology Definition: a multi-systemic and progressive condition caused by excessive secretion of growth hormone (GH)

Aetiology• Most common cause is pituitary somatotroph adenoma (95-99% of cases) • Rarely because of ectopic secretion from neuroendocrine tumours

Risk factors• MEN 1: pituitary adenomas, primary hyperparathyroidism, and pancreatic

neuroendocrine tumours• McCune-Albright syndrome

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Pathophysiology


Clinical featuresSymptoms SignsVisual disturbance Bitemporal hemianopia

Headaches Facial features:• Prominent jaw and supra-orbital ridge • Prognathism• Splaying of teeth • Macroglossia

Rings and shoes are tight Spade-like hands

Tingling in hands (carpal tunnel) Deep, husky voice

Polyuria/polydipsia (T2DM) Sweaty palmsHypertension


Clinical features

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DifferentialsAcromegaly Gigantism

Definition Oversecretion of growth hormone

Oversecretion of growth hormone before the fusion of growth plates

Age Onset in adulthood Onset in childhoodFacial features Large lips, tongue

and protruding jawProminent forehead and jaw

Height Unaffected Increased for age of child

Onset of puberty Unaffected DelayedGonadal development

Unaffected Reduced (hypogonadal)


InvestigationsBedside• ECG: acromegaly can cause cardiomyopathy and heart failure

Bloods• Insulin-like growth factor 1: first line investigation and raised in disease • Oral glucose tolerance test: a glucose load should cause suppression of GH

normally. In acromegaly, there is failure of GH suppression

Imaging• Pituitary MRI: visualisation of pituitary adenoma• CT chest, abdomen and pelvis: very rarely can be due to an ectopic source

Special tests• Visual field testing


ManagementFirst line• Surgery: trans-sphenoidal resection of the pituitary

Second line• Medical: dopamine agonists (e.g. cabergoline) in mild disease and somatostatin

analogues (e.g. octreotide) in severe disease• Pegvisomant is a GH antagonist which is sometimes used, although very expensive

Third line• Radiotherapy: reserved for patients who are refractory to medical and surgical

treatment


ComplicationsAcromegaly Gigantism

Cardiac • Cardiomyopathy• Heart failure• Hypertension

Respiratory • Obstructive sleep apnoea

Neurological • Carpal tunnel syndrome• Proximal myopathy

Endocrine • T2DM• Panhypopituitarism

Gastrointestinal • Colorectal cancer


Recap• Acromegaly is most commonly caused by a pituitary somatotroph adenoma leading to

a state of GH excess

• First line investigations include IGF-1 and OGTT

• First line management is with trans-sphenoidal surgery

• Medical therapy includes somatostatin analogues, dopamine agonists, and growth hormone antagonists

• Radiotherapy is reserved for refractory cases


Top decile question

Case 2

History A 21-year-old female presents to the GP with visual disturbance and irregular menstrual periods. She has been taking a combined oral contraceptive pill for the last 2 years.

She has no known past medical history.

Observations

HR 85, BP 125/85, RR 17, SpO2 97%, Temp 37.5°C


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PathophysiologyDefinition: a benign lactotroph adenoma that secretes prolactin

Aetiology• Prolactin-secreting pituitary adenomas• Most occur sporadically • Genetic causes (5% of cases)

• MEN-1• Carney complex• Familial isolated pituitary adenoma syndrome

Risk factors• Female gender• 20-50 years of age• Genetic predisposition

PathophysiologyPituitary size• Microadenomas: ≤ 10 mm • Macroadenomas: > 10 mm

• With suprasellar extension may result in bitemporal hemianopia

Functional pituitary adenoma (60%)• Secretory pituitary adenomas • Associated with hormone secretion and therefore hyperpituitarism • Commonly one hormone secretion• Prolactinoma is associated with excessive prolactin secretion

Non-functional pituitary adenoma (40%)• Typically gonadotroph adenomas account for 80-90%• Chromophobic

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Pathophysiology

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Clinical featuresSymptoms SignsVisual changes Bitemporal hemianopia

Galactorrhoea Gynecomastia: males

Amenorrhoea or oligomenorrhoeaInfertility

Loss of libido

Erectile dysfunction: males


Differentials

Drug-induced hyperprolactinaemia

Aetiology • Antipsychotics• Antidepressants• Opiates• Anti-emetics• Oestrogens• H2 blockers• Verapamil

Features • Prolactin levels drop after stopping the drugs


Investigations

Bloods• Serum prolactin: > 400 mU/L• Macroprolactin: assess in asymptomatic patients

Imaging• Pituitary MRI

Special tests• Visual field testing

Consider alternative causes• Pregnancy• Antipsychotics• Primary hypothyroidism


ManagementMedical• Dopamine agonist: cabergoline is preferred; dose increased for larger tumours• COCP: consider for patients with amenorrhoea and a microadenoma

Surgical• Transphenoidal surgery: if unresponsive or unable to tolerate medical therapy

Pregnancy: addendum to webinar presentation• Discontinue dopamine agonist as soon as possible (most patients)• Selected patients with macroadenomas may continue therapy• Bromocriptine is not technically teratogenic but does cross the placenta during the first

4 weeks of development, which is a critical period for early organogenesis• For more information visit: JCEM. Diagnosis and Treatment of Hyperprolactinemia: An

Endocrine Society Clinical Practice Guideline. https://academic.oup.com/jcem/article/96/2/273/2709487

https://academic.oup.com/jcem/article/96/2/273/2709487


Recap• A prolactinoma is a benign pituitary adenoma secreting prolactin

• Commonly associated with young women

• Bitemporal hemianopia is usually secondary to a macroadenoma. Other features include amenorrhoea, galactorrhoea, loss of libido and erectile dysfunction

• Prolactin levels and an MRI are useful investigations

• Dopamine agonists are your first line management


Top decile question

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References1. Shutterstock. https://www.shutterstock.com/image-vector/structure-hypothalamicpituitary-thyroid-axis-hpt-

11476051822. Shutterstock. https://www.shutterstock.com/image-vector/growth-hormone-somatotropin-secreted-by-

pituitary-3148733663. Philippe Chanson and Sylvie Salenave / CC BY (https://creativecommons.org/licenses/by/2.0)4. Philippe Chanson and Sylvie Salenave / CC BY (https://creativecommons.org/licenses/by/2.0).

https://upload.wikimedia.org/wikipedia/commons/1/1a/Acromegaly_prognathism.JPEG5. Offices of Kenneth Yamanaka, DDS / Public domain.

https://upload.wikimedia.org/wikipedia/commons/1/1f/Acromegalyteethgapping.jpg6. Ceridwen commonswiki. https://commons.wikimedia.org/wiki/File:Pilule_contraceptive.jpg#globalusage7. National Endocrine and Metabolic Diseases Information Service, NIH. / Public domain.

https://upload.wikimedia.org/wikipedia/commons/7/7f/Prolactinoma-art.jpg8. US Government / Public domain.

https://upload.wikimedia.org/wikipedia/commons/9/9d/Illu_endocrine_system_New.png

34Buy our textbook at www.bitemedicine.com

https://www.shutterstock.com/image-vector/structure-hypothalamicpituitary-thyroid-axis-hpt-1147605182

https://www.shutterstock.com/image-vector/growth-hormone-somatotropin-secreted-by-pituitary-314873366

https://creativecommons.org/licenses/by/2.0

https://creativecommons.org/licenses/by/2.0

https://upload.wikimedia.org/wikipedia/commons/1/1a/Acromegaly_prognathism.JPEG

https://upload.wikimedia.org/wikipedia/commons/1/1f/Acromegalyteethgapping.jpg

https://commons.wikimedia.org/wiki/File:Pilule_contraceptive.jpg

https://upload.wikimedia.org/wikipedia/commons/7/7f/Prolactinoma-art.jpg

https://upload.wikimedia.org/wikipedia/commons/9/9d/Illu_endocrine_system_New.png

bitemedicine lecture 9 (acromegaly and prolactinoma) slides

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