Acromegaly

Learning objectives

Acromegaly is a chronic, progressive, hormone hypersecretion syndrome caused by an excess of growth hormone (GH) after the growth plates have closed (i.e., puberty)
The hypersecretion of GH is the result of oversecretion of growth hormone-releasing hormone (GHRH) from the hypothalamus or oversecretion of the hormone itself from a pituitary adenoma

Affected area	Signs and symptoms
Face	Increase in size of skull and supraorbital ridges; enlarged lower jaw; increase in spacing between teeth/malocclusion
Hands and feet	Spade-shaped; carpal tunnel syndrome
Mouth/tongue	Macroglossia; thickened pharyngeal and laryngeal soft tissues; thickened vocal cords; reduction in the size of the laryngeal aperture; obstructive sleep apnea
Soft tissue	Thick skin; doughlike feel to palm
Skeleton	Vertebral enlargement; osteoporosis; kyphosis
Cardiovascular	Hypertension; cardiomegaly; impaired left ventricular function
Endocrine	Impaired glucose tolerance; diabetes
Other	Arthropathy; proximal myopathy

Surgery: Preferred treatment; to remove the pituitary tumor
Drugs:
- Somatostatin analogs: Drugs that reduce GH production
- Dopamine agonists: Drugs to lower hormone levels
- GH receptor antagonists: Drugs to block the action of GH
Radiation therapy: Both used alone or in combination with surgery or drugs

Four grades of airway involvement have been described in acromegaly:

Grade	Airway involvement
1	No significant involvement
2	Nasal and pharyngeal mucosa hypertrophy but normal cords and glottis
3	Glottic involvement including glottic stenosis or vocal cord paresis
4	Combination of grades 2 and 3: Glottic and soft tissue abnormalities

Ventilation with a bag and mask is straightforward in acromegalic patients but an oral airway may be required
Laryngoscopy and tracheal intubation prove more difficulty due to a combination of macrognathia, macroglossia, and expansion of the upper airway soft tissues
Tracheostomy is recommended for grades 3 and 4, however, fiberoptic laryngoscopy is a safe alternative
Tracheal intubation is feasible with standard techniques (i.e., external laryngeal pressure and the use of a gum elastic bougie or airway exchange catheter)
Awake fiberoptic intubation is the technique of choice in case of anticipated difficult intubation in these patients
Preoperative transthoracic echocardiography is useful to assess left ventricular size and performance, and to estimate pulmonary pressures due to associated cardiopulmonary complications

About one-quarter of acromegalic patients have an enlarged thyroid, which may compress the trachea
Preoperative assessments help the anesthesiologist to understand the possibility of difficulties with airway management and tracheal intubation
Difficult airway
- Macroglossia and enlarged epiglottis: Difficult bag-mask ventilation and direct laryngoscopy
- Recurrent laryngeal nerve palsy, narrow glottic opening, subglottic narrowing (stridor)
- Nasal turbinate enlargement: Caution with nasal intubation and consider a smaller endotracheal tube