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Thyroid

Key Points

• Thyroid disease is common and has major peri-operative implications for cardiovascular, respiratory, metabolic and neuromuscular function.
• Aim to render all elective surgical patients clinically and biochemically euthyroid.
• Large goitres rarely cause impossible intubation, but distorted anatomy and tracheomalacia increase the risk of peri-extubation airway failure and neck haematoma.
• High-flow nasal oxygen (HFNO/THRIVE) improves apnoeic oxygenation during induction and extubation but does not replace a secured airway.
• Intra-operative nerve monitoring (IONM) should be considered for redo surgery, malignancy, bilateral dissection or pre-existing vocal-cord palsy. Continuous IONM requires avoidance of neuromuscular blockade after initial mapping.

Thyroid Physiology

Synthesis and Regulation

Step	Process	Key enzyme/transport	Notes
1	Iodide trapping	Na⁺/I⁻ symporter	Blocked by perchlorate/thiocyanate
2	Oxidation & organification	Thyroid peroxidase (TPO)	Forms monoiodotyrosine (MIT) & di-iodotyrosine (DIT)
3	Coupling	TPO	DIT + DIT → T4; DIT + MIT → T3
4	Storage	Thyroglobulin in colloid	Months of reserve
5	Release	Endocytosis & lysosomal cleavage	TSH-dependent
6	Peripheral conversion	5ʹ-deiodinase types 1 & 2	Converts ~80 % of circulating T3

• Feedback axis: Hypothalamic TRH → pituitary TSH → thyroid; negative feedback by free T4/T3. Iodine deficiency, illness, drugs (amiodarone, steroids) and pregnancy alter this axis.

T3 versus T4

Hormone	Fraction of glandular output	Degree of protein binding	Relative potency	Plasma half-life
T3	≈ 10 %	Lower than T4 (binds mainly to albumin & transthyretin)	3–5 × T4	≈ 24 h
T4	≈ 90 %	~75 % bound to thyroxine-binding globulin	Pro-hormone (precursor to T3)	≈ 7 d

Physiological Effects of T3

• Increased_=: β-adrenergic receptor density, myocardial α-myosin heavy chain, basal metabolic rate, thermogenesis, ventilation, bone turnover, neuromuscular excitability.
• Critical for: fetal brain myelination, linear growth, reproductive function.

Interpretation of Thyroid Function Tests

• Euthyroid:
  • TSH: 0.4–4.5 mU l⁻¹; Free T4: 9–25 pmol l⁻¹; Free T3: 3.5–7.8 pmol l⁻¹

Pattern	Likely diagnosis
↑TSH, normal FT4	Subclinical hypothyroidism
↓TSH, normal FT4/FT3	Subclinical hyperthyroidism, exogenous T4
↑TSH, ↓FT4/FT3	Primary hypothyroidism (autoimmune, post-radio-iodine, post-surgery)
↓/normal TSH, ↓FT4/FT3	Secondary (pituitary) hypothyroidism, severe illness (“euthyroid sick”)
Normal/↑TSH, ↑FT4/FT3	TSH-secreting adenoma, thyroid hormone resistance, amiodarone effect
↓TSH, ↑FT4/FT3	Primary hyperthyroidism (Graves’, toxic MNG, adenoma, thyroiditis)

Anaesthesia for Thyroidectomy

Pre-operative Assessment

1. Thyroid status–ensure euthyroid; if hyperthyroid postpone 6–8 weeks or optimise with β-blocker ± thionamide ± iodine ± steroid.
2. Goitre assessment
   • Duration > 5 y or tracheal diameter < 8 mm → suspect tracheomalacia.
   • Positional dyspnoea, orthopnoea, dysphagia or voice change mandate CT neck/chest and nasendoscopy.
   • Pemberton’s sign or venous congestion → consider SVC obstruction; site IV access below diaphragm.
3. Airway imaging–CT provides accurate tracheal calibre and tube size prediction; CXR overestimates diameter.
4. Cardiorespiratory–ECG, echocardiography if AF, heart failure or pulmonary hypertension.
5. Laboratory–TFTs, FBC, electrolytes, Ca²⁺, Mg²⁺, PO₄³⁻; add calcitonin & metanephrines for suspected medullary carcinoma.

Intra-operative Management

Aspect	Best practice
Induction	Standard IV or inhalational; pre-oxygenate with HFNO > 40 l min⁻¹ to prolong safe apnoea time.
Intubation	Video-laryngoscopy is first-line. Awake fibre-optic reserved for severe compression, fixed obstruction or previous failure. Recent multicentre data show failed asleep intubation in mediastinal goitre is < 1 %.
Backup	Rigid bronchoscopy with jet ventilation; CPB/ECMO for invasive malignancy crossing carina.
Maintenance	TIVA or volatile. Avoid sustained neuromuscular block if continuous IONM used–give ≤ 0.3 mg kg⁻¹ cisatracurium after V1 mapping, then infuse remifentanil/propofol.
Haemodynamics	Esmolol 50–300 µg kg⁻¹ min⁻¹ blunts sympathetic surges; titrate fluids to avoid venous engorgement.
Position	Head-up 15°, neck neutral to slight extension; protect eyes and ulnar nerves.
Adjuncts	Dexamethasone 8 mg IV (anti-emetic, reduces airway oedema). Tranexamic acid 10 mg kg⁻¹ IV may reduce bleeding.
Extubation	Fully awake, head-up. Perform leak test; consider cuff-down fibre-optic inspection. If doubtful, leave ETT or exchange catheter and observe in HDU.

Post-operative Concerns

• Neck haematoma (0.3–1 %)–any airway compromise → open wound immediately.
• Hypocalcaemia–check ionised Ca²⁺ at 6 h; symptomatic or Ca²⁺< 1.0 mmol l⁻¹ → 10 ml 10 % CaCl₂ IV.
• Recurrent laryngeal nerve (RLN) palsy–temporary 1–5 %, permanent < 1 %; higher with re-do surgery or malignancy.
• Tracheomalacia–high suspicion with long-standing goitre; may require staged extubation or tracheostomy.

Hyperthyroidism

Summary

Pathogenesis and Clinical Findings

View or edit this diagram in Whimsical.

Causes

• Graves’ disease (autoimmune), toxic multinodular goitre, toxic adenoma, TSH-secreting pituitary adenoma, iodine-induced (amiodarone, contrast), gestational trophoblastic disease, excess thyroid hormone ingestion.

Diagnosis

• Suppressed TSH with elevated free T4 ± T3. T3-toxicosis (isolated high T3) is common in Graves’.

Optimising the Surgical Patient

• Timing of Surgery:
  • Surgery is postponed until the patient is clinically and chemically euthyroid with normal T3 and T4 levels and no resting tachycardia.
  • Elective Surgery: Defer if hyperthyroid (6-8 weeks). If urgent, manage with β-blockers, iodide, propylthiouracil (PTU) via nasogastric tube (NG), and glucocorticoids (dexamethasone).

Drug	Typical dose	Comments
Carbimazole	15–40 mg day⁻¹ PO	Pro-drug for methimazole; block TPO.
Propylthiouracil	50–100 mg 8-hourly PO	Also blocks peripheral T4→T3; preferred in first-trimester pregnancy & thyroid storm.
Potassium iodide (Lugol’s 5 %)	5 drops (≈ 50 mg) 8-hourly PO	Start ≥ 1 h after thionamide; blocks release (“Wolff–Chaikoff”).
Propranolol	40 mg PO 6-hourly or 1 mg IV every 5 min	Controls HR, reduces T4→T3.
Hydrocortisone	100 mg IV 8-hourly	Inhibits T4→T3; cover for adrenal insufficiency.

• Radio-iodine (I-131) is contraindicated in pregnancy and uncontrolled thyrotoxicosis. Sub-total or total thyroidectomy is definitive when medical therapy fails or malignancy/goitre size dictates

Thyroid Storm (Thyrotoxic Crisis)

Recognition

• Hyperpyrexia (> 38.5 °C), tachyarrhythmia, CNS agitation or coma, heart failure, gastrointestinal upset. Burch-Wartofsky score > 45 suggests storm

Management (ABC-“5 B’s”)

1. Block sympathetic–Esmolol 250–500 µg kg⁻¹ IV bolus then 50–100 µg kg⁻¹ min⁻¹.
2. Block synthesis–Propylthiouracil 500–1000 mg PO/NG.
3. Block release–Lugol’s solution 10 drops PO 1 h later.
4. Block conversion–Hydrocortisone 100 mg IV 8-hourly.
5. Supportive–Cool, monitor glucose & electrolytes, treat precipitant, admit ICU.

Complications of Thyroidectomy

Immediate (0–24 h)	Early (24 h–2 w)	Late
Airway obstruction from haematoma	Temporary RLN palsy	Permanent RLN palsy
Laryngeal oedema/tracheomalacia	Hypocalcaemia/parathyroid stunning	Hypothyroidism
Vocal-cord dysfunction	Chyle leak (if thoracic duct injured)	Keloid, hypertrophic scar
Superior laryngeal nerve injury (voice pitch change)	Seroma, wound infection	Voice fatigue

View or edit this diagram in Whimsical.

Hypothyroidism

• Hypothyroidism is common (female > male, peak incidence 40–60 yr) and ranges from sub-clinical disease to the life-threatening state of myxoedema coma.
• Thyroid hormone deficiency slows metabolism in every organ system, producing bradycardia, hypoventilation and impaired drug clearance–all highly relevant to anaesthesia.
• Elective surgery should be deferred until patients are clinically and biochemically euthyroid unless urgency outweighs risk.
• In emergencies, intravenous thyroid hormone plus stress-dose steroids restore cardiovascular stability within hours and permit safe anaesthesia.

Summary

Pathogenesis and Causes

• Primary (≈ 95 %)—autoimmune (Hashimoto thyroiditis), thyroidectomy, radio-iodine, external neck irradiation, antithyroid drugs, iodine deficiency or excess, infiltrative disease, congenital biosynthetic defects.
• Secondary / Tertiary—hypothalamic-pituitary failure (tumour, surgery, trauma, infiltrative disorders).
• Drug-induced—lithium, amiodarone, interferon-α, tyrosine-kinase inhibitors.
• Neonatal—maternal iodine deficiency/endemic cretinism, dyshormonogenesis.

Severity Classification

Severity	Typical biochemistry	Predominant clinical features	Peri-operative plan
Sub-clinical	TSH 4.5–10 mU l⁻¹, normal FT₄	Often asymptomatic	Proceed with routine care
Overt (moderate)	TSH ≥ 10 mU l⁻¹ and/or low FT₄	Lethargy, weight gain, bradycardia, effusions	Optimise with oral levothyroxine before elective surgery
Severe / Myxoedema	Marked ↑TSH (if primary) with very low or unmeasurable FT₄, hyponatraemia, hypoglycaemia	Hypothermia, hypotension, ventilatory failure, coma	ICU, IV thyroid hormone ± T₃, hydrocortisone; postpone surgery

Clinical Manifestations

• General: cold intolerance, weight gain, dry skin, periorbital oedema, myxoedema facies.
• Cardiovascular: sinus bradycardia, ↓stroke volume & cardiac output, pericardial effusion, diastolic hypertension.
• Respiratory: hypoventilation, impaired response to hypoxia/hypercapnia, sleep-disordered breathing.
• Neuromuscular: fatigue, myalgia, delayed tendon reflexes.
• Gastro-intestinal: constipation, ileus, delayed gastric emptying.
• Haematological / Metabolic: normocytic anaemia, hyponatraemia, hypoglycaemia, hypercholesterolaemia.

Diagnosis

Pattern	Interpretation
↑TSH, ↓FT₄	Primary hypothyroidism
Normal/low TSH, ↓FT₄	Secondary/tertiary hypothyroidism
Normal TSH, low T₃ ± low T₄	Non-thyroidal (euthyroid-sick) syndrome

• T₃ falls late in primary disease and is unreliable for diagnosis.

Management

Long-term Replacement

• Levothyroxine (T₄): initial 1.6 µg kg⁻¹ day⁻¹ orally (lower in elderly or cardiac disease); adjust every 6–8 weeks to keep TSH 0.5–2.5 mU l⁻¹.
• Liothyronine (T₃) reserved for combination therapy trials or myxoedema coma.

Myxoedema Coma (medical emergency)

1. Airway & ventilation; passive re-warming.
2. IV levothyroxine 4 µg kg⁻¹ loading (200–400 µg), then 50–100 µg daily.
3. IV liothyronine 5–20 µg followed by 2.5–10 µg 8to 12-hourly (omit or use low dose in elderly/ischaemic heart disease).
4. Hydrocortisone 100 mg IV 8-hourly until adrenal insufficiency excluded
5. Treat precipitant (sepsis, MI, stroke, trauma, surgery).

Anaesthesia for the Hypothyroid Patient

General Principles

• Mild–moderate disease: usually safe for surgery; continue oral levothyroxine on day of operation.
• Severe disease: delay elective surgery; if unavoidable, give IV T₄/T₃ and steroids as above.

System-by-system Considerations

System	Implication	Management
Airway	Macroglossia, pharyngeal oedema, large goitre	Prepare for difficult mask & intubation; have smaller tubes & bougies ready
Cardiovascular	↓CO, blunted baroreflex, pericardial effusion	Avoid hypotension; consider invasive arterial line ± TOE; use ephedrine or low-dose adrenaline rather than phenylephrine
Respiratory	Hypoventilation, OSA, pleural effusion	Controlled ventilation preferred; monitor capnography closely
Gastro-intestinal	Delayed gastric emptying	Rapid-sequence induction, pro-kinetic/metoclopramide
Haematology	Anaemia, factor VIII deficiency, platelet dysfunction	Correct coagulopathy; cell-saver if major blood loss expected
Temperature & metabolism	Hypothermia, hyponatraemia, hypoglycaemia	Active warming, warmed fluids, hourly glucose & electrolytes
Pharmacodynamics	Prolonged action of sedatives, NMBs, opioids	Reduce doses; use short-acting agents (propofol, remifentanil, atracurium); monitor neuromuscular blockade

Induction & Maintenance

• Etomidate or ketamine maintain BP; avoid large thiopentone/propofol boluses.
• Volatile or TIVA acceptable; MAC unchanged.
• Titrate non-depolarising relaxants to twitch monitoring (delayed recovery likely).

Post-operative Care

• Extubate fully awake; observe in HDU if airway oedema, effusion or severe disease.
• Monitor temperature, electrolytes, glucose and TSH/FT₄.
• Continue usual levothyroxine early (enteral) or IV if NPO.

Complications

Early	Late
Myxoedema coma, severe hypotension, ventilatory failure	Persistent bradycardia, pericardial effusion, delayed drug clearance

Parathyroid

Key Points

• Parathyroid hormone (PTH) is the principal regulator of extracellular ionised calcium; even minor changes trigger large shifts in neuromuscular excitability and cardiovascular function.
• Primary hyperparathyroidism (PHPT) is the commonest indication for parathyroidectomy and the only curative treatment. Minimally-invasive surgery guided by intra-operative PTH (ioPTH) sampling now achieves > 95 % cure with < 2 % recurrent laryngeal nerve (RLN) injury.
• Severe hypercalcaemia (Ca²⁺ > 3.0 mmol l⁻¹) increases peri-operative arrhythmia, gastrointestinal bleed and acute kidney injury; correct with volume resuscitation ± bisphosphonate or calcitonin before theatre.
• Hungry-bone syndrome (HBS) is the key post-operative threat; early recognition and aggressive calcium/activated-vitamin-D replacement reduce ICU admission and prolonged stay

Calcium-regulating Hormones

Hormone	Bone	Kidney	Gastro-intestinal tract	Net effect on [Ca²⁺]ᵢ
PTH	↑ Osteoclastic resorption	↑ Ca²⁺ reabsorption, ↓ PO₄³⁻ & HCO₃⁻ reabsorption, ↑ 1α-hydroxylase ( → calcitriol)	↑ Ca²⁺ absorption via calcitriol	↑
Calcitriol [1,25(OH)₂D₃]	Synergistic with PTH for bone turnover	Minor ↑ Ca²⁺ reabsorption	↑↑ Ca²⁺ & PO₄³⁻ absorption	↑
Calcitonin	↓ Osteoclastic resorption	↓ Ca²⁺ & PO₄³⁻ reabsorption	Minimal	↓

Fibroblast-growth-factor-23 (FGF-23) from osteocytes also lowers PO₄³⁻ and vitamin-D levels but has little acute peri-operative impact.

Primary Hyperparathyroidism

Typical biochemistry	Common manifestations (remember “STONES, BONES, GROANS, MOANS”)
↑ Serum Ca²⁺ (> 2.6 mmol l⁻¹) with inappropriately high PTH	Nephrolithiasis/nephrocalcinosis, osteoporosis or fragility fractures, dyspepsia/peptic ulcer, depression, muscle weakness, shortened QT

• Indications for surgery (AAES 2023)–symptomatic disease; serum Ca²⁺ > 0.25 mmol l⁻¹ above ULN; T-score < −2.5 or vertebral fracture; eGFR < 60 ml min⁻¹ 1.73 m⁻²; age < 50 y.

Anaesthesia for Parathyroidectomy

Pre-operative

1. Optimise calcium–hydrate with 0.9 % saline (100–200 ml h⁻¹), add loop diuretic once euvolaemic; give IV bisphosphonate (zoledronic acid 4 mg) or calcitonin 4 IU kg⁻¹ if Ca²⁺ ≥ 3 mmol l⁻¹.
2. Evaluate end-organ impact–ECG (short QT, AV block, VT), renal USS, DEXA; correct hypokalaemia, hypomagnesaemia.
3. Drug review–discontinue thiazides, lithium, digoxin; continue cinacalcet until morning of surgery.

Intra-operative

Item	Recommendation
Anaesthesia	Balanced GA (± superficial cervical plexus block). Total IV anaesthesia facilitates ioPTH timing.
Airway	Standard ETT; video-laryngoscopy preferred for re-do surgery. Preserve RLN with intermittent or continuous IONM; avoid/antagonise NMB after first twitch mapping.
Fluids	Warmed crystalloids 2–3 ml kg⁻¹ h⁻¹; avoid lactate (spurious Ca²⁺ rise).
Neuromuscular blockade	Response unpredictable in chronic hyperCa²⁺; titrate to TOF.
Monitoring	Standard + arterial line if Ca²⁺ > 3 mmol l⁻¹, significant cardiac disease or revision surgery.

Post-operative

• Hypocalcaemia / HBS
  • Risk factors: pre-op Ca²⁺ > 2.85 mmol l⁻¹, PTH > 30 pmol l⁻¹, alkaline-phosphatase > 2× ULN, vitamin-D deficiency, renal failure.
  • Monitor ionised Ca²⁺ 4-hourly for 24 h.
  • Treat symptomatic or Ca²⁺ < 1.0 mmol l⁻¹ with 10 ml 10 % CaCl₂ IV over 10 min → continuous infusion 0.5 mg kg⁻¹ h⁻¹; add calcitriol 0.5–1 µg day⁻¹.
• Airway–RLN palsy (1 %) presents with stridor or hoarse voice; assess before extubation.
• Analgesia–paracetamol + NSAID (if renal function allows) + low-dose opioid; avoid oversedation in hyperCa²⁺-related CNS depression.

Secondary & Tertiary Hyperparathyroidism (renal failure)

• Often require subtotal (3½-gland) parathyroidectomy; keep dialysis Ca²⁺ bath ≤ 1.25 mmol l⁻¹ pre-op.
• Post-op HBS incidence up to 45 %; commence prophylactic oral calcium carbonate 1 g QID + calcitriol 0.5 µg immediately after surgery.

Complications of Parathyroidectomy

Early (hours–days)	Late
Hypocalcaemia / HBS, RLN palsy, cervical haematoma, neck seroma	Persistent/recurrent PHPT (2–5 %), chronic voice fatigue, keloid

Adrenal Gland

Summary

Key Points

• The adrenal cortex (zona Glomerulosa → aldosterone, Fasciculata → cortisol, Reticularis → androgens) and medulla (catecholamines) together coordinate cardiovascular stability, volume status and stress responses.
• Primary hyperaldosteronism is now recognised in up to 10 % of hypertensive patients and is cured by unilateral laparoscopic adrenalectomy; pre-operative optimisation of K⁺ and blood pressure is essential.
• Cushing’s syndrome carries a five-fold higher peri-operative thrombo-embolic risk and demands meticulous glucose, electrolyte and positioning precautions.
• Adrenal insufficiency is rare but lethal; 100 mg hydrocortisone IV at the first suspicion of crisis saves lives.

Physiology

Cortical Hormones

Zone	Hormone	Principal actions	Key regulators	Notes
Glomerulosa	Aldosterone	↑Na⁺ & H₂O reabsorption, ↑K⁺ & H⁺ excretion	Renin-angiotensin system, K⁺	Acts via mineralocorticoid receptor in distal nephron
Fasciculata	Cortisol	Gluconeogenesis, anti-inflammatory, potentiates catecholamines	ACTH, diurnal rhythm, stress	90 % protein-bound; peaks 08 h
Reticularis	DHEA, androstenedione	Pubic/axillary hair, libido	ACTH	Minor in adult males
Medulla	Epinephrine (80 %), norepinephrine (20 %)	Fight-or-flight response	Sympathetic pre-ganglionic Ach	Cortisol from cortex enhances PNMT activity

Disorders of Cortical Function

Disorder	Hormones	Typical biochemistry	Salient features
Primary hyperaldosteronism (Conn)	↑ Aldosterone, ↓ Renin	ARR > 20, PAC > 10 ng dl⁻¹	Resistant hypertension, hypokalaemia, metabolic alkalosis
Secondary hyperaldosteronism	↑ Aldosterone, ↑ Renin	Renovascular, CHF, cirrhosis	Volume overload signs
Cushing’s syndrome	↑ Cortisol ± ACTH	Loss of diurnal variation, failure to suppress with dexamethasone	Central obesity, diabetes, myopathy, skin fragility, OSA
Primary adrenal insufficiency (Addison)	↓ Cortisol & aldosterone, ↑ ACTH	Hyponatraemia, hyperkalaemia, eosinophilia	Hyperpigmentation, postural hypotension
Secondary adrenal insufficiency	↓ Cortisol, normal aldosterone	Low/normal ACTH	Pituitary disease, chronic steroid therapy

Primary hyperaldosteronism–anaesthetic Implications

Pre-operative

• Normalise K⁺ > 3.5 mmol l⁻¹ with oral/IV supplements and mineralocorticoid receptor antagonists (spironolactone 25–100 mg day⁻¹).
• Control BP with calcium-channel blockers or MR antagonists; avoid ACE-I/ARB withdrawal if well-tolerated.
• Screen for obstructive sleep apnoea (OSA) and metabolic alkalosis (ABG).

Intra-operative

Consideration	Strategy
Haemodynamics	Expect labile hypertension during adrenal manipulation; treat with short-acting vasodilator (phentolamine 1 mg IV or clevidipine).
Electrolytes	Check arterial K⁺ after induction and at closure; treat promptly.
Neuromuscular blockade	Chronic hypokalaemia may prolong non-depolarising block–titrate to TOF.
Acid–base	Avoid hyperventilation and large bicarbonate loads (worsen alkalosis).

Post-operative

• Monitor K⁺ 6-hourly for 24 h–rebound hyperkalaemia can occur once aldosterone falls
• Most patients are normotensive within weeks; review antihypertensives at discharge.

Cushing’s syndrome–anaesthetic Considerations

System	Issues	Management
Airway & respiratory	Truncal obesity, buffalo hump, proximal myopathy, OSA	Ramped position, videolaryngoscope, CPAP pre-/post-op
Cardiovascular	Hypertension, LVH, accelerated CAD, hypercoagulability	Invasive BP, vigilant thromboprophylaxis, avoid fluid overload
Metabolic	Hyperglycaemia, hypokalaemia	Hourly capillary glucose, insulin infusion; replace K⁺
Skin & MSK	Thin skin, osteoporosis	Careful positioning, generous padding, avoid excessive neck extension
Infection risk	Immunosuppression, poor wound healing	Strict asepsis, prophylactic antibiotics

• Steroid cover: After adrenalectomy give hydrocortisone 100 mg IV at skin incision, then 50 mg IV 6-hourly × 24 h, tapering to physiological replacement.

Adrenal Insufficiency

Addisonian (adrenal) Crisis

• Triggers: surgery, sepsis, trauma, etomidate infusion.
• Treat immediately (do not await labs): Hydrocortisone 100 mg IV, 1 l 0.9 % saline over 1 h, then 200 mg hydrocortisone / 24 h by infusion or 50 mg IV 6-hourly.
• Monitor Na⁺, K⁺, glucose; correct hypoglycaemia and hyperkalaemia.

Peri-operative Steroid Supplementation (UK 2020 guidance)

Surgical stress	Examples	Additional hydrocortisone (above baseline)
Minor (e.g. ingrown toenail, cataract)	Local / MAC, < 30 min	None
Moderate (lap chole, hip replacement)	GA or regional, 1–2 h	50 mg IV at induction then 25 mg 8-hourly × 24 h
Major (cardiac, bowel resection)	GA > 2 h, major blood loss	100 mg IV at induction, then 200 mg / 24 h (infusion or 50 mg 6-hourly) until eating

• Patients on > 5 mg prednisolone equivalent for > 2 weeks in the past year should be assessed for HPA suppression and receive cover per table above

Catecholamine Excess: Phaeochromocytoma & Paraganglioma (PPGL)

Key Points

• Catecholamine-secreting tumours of chromaffin tissue may arise in the adrenal medulla (phaeochromocytoma, PCC) or extra-adrenal paraganglia (paraganglioma, PGL).
• Classic triad: paroxysmal headache, sweating and palpitations against a background of sustained or episodic hypertension.
• Every patient with an adrenal incidentaloma or resistant hypertension must be screened–unsuspected cases carry a peri-operative mortality up to 50 %.
• Safe surgery hinges on meticulous α-blockade, volume expansion, and intra-operative haemodynamic control.
• Long-term cure rates exceed 90 %, but all patients require lifelong biochemical follow-up for recurrence or metastatic disease.

Pathogenesis & Genetics

• ~40 % of PPGLs are hereditary; common syndromes: MEN-2, Von Hippel-Lindau, Neurofibromatosis-1, SDHx mutations.
• Genetic testing is recommended for all patients (guideline expert consensus 2023).

Clinical Presentation

Catecholamine effect	Manifestations
α-adrenergic	Severe hypertension, pallor, peripheral vasoconstriction, cardiomyopathy, hyperglycaemia
β-adrenergic	Tachyarrhythmias, tremor, anxiety, heat intolerance
Metabolic	Weight loss, impaired glucose tolerance
Paroxysms	Triggered by stress, induction, positioning, tumour manipulation

Diagnosis

1. Biochemistry
   • Plasma free metanephrines (supine, cannulated)–highest sensitivity.
   • 24 h urinary fractionated metanephrines/catecholamines if plasma equivocal.
2. Localisation
   • CT/MRI adrenals → 98 % detection.
   • Functional imaging (⁶⁸Ga-DOTATATE PET/CT or ¹²³I-MIBG) for extra-adrenal, multifocal or metastatic disease.
3. Pre-operative tests
   • ECG ± echocardiography (LV hypertrophy, cardiomyopathy).
   • Full blood count, U&E, glucose

Pre-operative Optimisation

Target	Measure
α-blockade (10–14 d)	Phenoxybenzamine 10 mg BD (↑ every 2 d) or selective α₁ blocker (doxazosin 2 mg → 8–16 mg). Aim seated BP < 130/80 mmHg, standing SBP > 90 mmHg, HR 60–80 bpm with mild orthostatic hypotension.
Volume expansion	High-sodium diet (≥ 5 g Na⁺ day⁻¹) + 2–3 l day⁻¹ fluid from day 5 to restore plasma volume (haematocrit ↓ ≤ 5 %).
β-blockade	Add propranolol or bisoprolol only after adequate α-blockade for tachycardia/arrhythmia control.
Adjuncts	Nifedipine or diltiazem for persistent hypertension; metyrosine (α-methyl-p-tyrosine) for metastatic or refractory disease.

Anaesthesia for PPGL Resection

Monitoring & Access

• Arterial line before induction, ± large-bore venous sheath, urinary catheter.
• Consider central line and trans-oesophageal echocardiography (TOE) in large tumours or poor LV function.

Induction & Maintenance

Phase	Suggested agents	Rationale
Induction	Propofol / Etomidate + opioid (fentanyl/remifentanil) + rocuronium	Attenuate sympathetic response; avoid histamine release & tachycardia
Maintenance	TIVA or sevoflurane ± remifentanil; BIS 40–60	Permit rapid haemodynamic titration
Regional	Thoracic epidural (open cases) for analgesia; will not blunt catecholamine surges

Haemodynamic Control

Event	First-line drug (bolus or infusion)
Hypertension/tachycardia (manipulation)	Sodium nitroprusside 0.5–5 µg kg⁻¹ min⁻¹, phentolamine 30–100 µg kg⁻¹ bolus, nicardipine 2 mg bolus then 2 mg h⁻¹, magnesium sulphate 30 mg kg⁻¹ load → 1–2 g h⁻¹
Tachyarrhythmia	Esmolol 0.5 mg kg⁻¹ → 50–200 µg kg⁻¹ min⁻¹
Post-ligation hypotension	Volume 10–20 ml kg⁻¹ crystalloid, then norepinephrine 0.05–0.3 µg kg⁻¹ min⁻¹ ± vasopressin 0.4 U h⁻¹

• Avoid: ketamine, pancuronium, atropine, ephedrine, histamine-releasing opioids/muscle relaxants, metoclopramide.

Metabolic Watchpoints

• Hourly glucose (rapid fall after tumour removal).
• Temperature and lactate (catecholamine-driven thermogenesis).

Post-operative Care

• HDU/ICU for 24 h: invasive BP, glucose 4-hourly, serum electrolytes.
• Continue vasopressor support until vascular tone recovers.
• Resume oral α-blocker day 1 if persistent hypertension; wean over 5–7 days.
• Check plasma metanephrines at 4 weeks; lifelong annual surveillance thereafter.

Special Situations

• Pregnancy: If diagnosed ≤ 24 weeks → laparoscopic adrenalectomy after α-blockade; > 24 weeks or during labour → elective caesarean section then tumour excision. Phenoxybenzamine and metoprolol considered safe.
• Unexpected intra-operative PCC: Halt surgery, secure airway, deepen anaesthesia, start SNP / phentolamine and aggressive fluids; proceed only in experienced centre.
• Bilateral adrenalectomy: Give hydrocortisone 100 mg IV at vein ligation, then 50 mg 6-hourly; commence lifelong steroid and mineralocorticoid replacement.

Carcinoid Syndrome

[Carcinoid syndrome video

Summary

Key Points

• Vaso-active amines (mainly serotonin) released by well-differentiated neuro-endocrine tumours (NETs) cause the triad flushing ± diarrhoea ± bronchospasm; episodic hypotension or hypertension constitutes a carcinoid crisis.
• Crisis can be precipitated by anaesthesia, tumour manipulation, hypoxia, hypotension, hypercarbia, hypothermia or histamine-releasing drugs.
• Octreotide is first-line prophylaxis and treatment: start a short-acting infusion 50–100 µg h⁻¹ at least 12 h pre-operatively, give a further 100 µg IV bolus before induction, and continue through surgery; repeat 100–200 µg boluses for breakthrough symptoms
• Right-sided valvular fibrosis develops in > 50 % of patients with chronic hormone exposure; obtain an echocardiogram in all symptomatic or metastatic cases.
• Phenylephrine or vasopressin restore pressure during post-resection vasoplegia; avoid epinephrine, norepinephrine and ephedrine (may provoke paradoxical release).

Pathophysiology

Mediator	Source	Principal effects
Serotonin (5-HT)	Enterochromaffin cells	Diarrhoea, abdominal cramping, coronary/mesenteric vasospasm, valvular fibrosis
Kallikrein → bradykinin	Tumour & peripheral conversion	Flushing, bronchospasm, hypotension
Histamine	Fore-gut tumours	Flushing, tachy-arrhythmia, bronchospasm

Clinical Spectrum

• Cutaneous: episodic pink-red flushing of face, neck and upper chest; fore-gut tumours may cause prolonged violaceous flush.
• Gastro-intestinal: watery diarrhoea, abdominal pain, pellagra (niacin depletion).
• Cardiac: tricuspid and pulmonary regurgitation, right-sided heart failure, supraventricular tachycardia.
• Respiratory: wheeze due to bronchoconstriction

Diagnosis

1. Biochemistry–plasma free metanephrines/chromogranin A, or 24 h urinary 5-HIAA > 50 µmol.
2. Imaging–CT/MRI for localisation; ⁶⁸Ga-DOTATATE PET for occult disease.
3. Cardiac–transthoracic echo for all with chronic syndrome or raised NT-proBNP (screen for carcinoid heart disease).

Peri-operative Management

View or edit this diagram in Whimsical.

Pre-operative

Task	Rationale
Continue long-acting somatostatin analogue (SSA)	Avoid hormone rebound
Start octreotide 50–100 µg h⁻¹ IV ≥ 12 h before GA	Reduces crisis incidence
Bolus 100 µg octreotide IV immediately pre-induction	Blunts intubation trigger
Correct electrolytes, niacin and iron deficiency	Optimise fluid status & nutrition
Echocardiography & ECG	Assess RV function, arrhythmia
Avoid drugs that provoke histamine (morphine, atracurium) or sympathetic surge (ketamine, desflurane induction)

Intra-operative

• Monitoring: A-line, ± CVP; TOE if severe RH dysfunction.
• Induction: Propofol / etomidate + remifentanil; rocuronium.
• Maintenance: Sevoflurane or TIVA; BIS 40–60; keep normothermia & normocapnia.
• Crisis treatment
  • Bolus octreotide 100 µg IV (repeat q 2 min).
  • Persistent hypotension → phenylephrine 50–100 µg IV or vasopressin 0.5–1 U; give fluid bolus.
  • Bronchospasm → octreotide bolus + H₁/H₂ blockade (diphenhydramine 25 mg, ranitidine 50 mg) + inhaled ipratropium; avoid β-agonists.

Octreotide

• Octreotide reduces vasoactive peptide release in carcinoid syndrome because it is a somatostatin analogue—a synthetic version of the naturally occurring hormone somatostatin, which broadly inhibits hormone secretion.

Mechanism of Action

• Somatostatin Receptors: Most neuroendocrine tumors, including carcinoid tumors, express somatostatin receptors, especially subtype 2 (SSTR2).
• Octreotide binds to SSTR2, mimicking somatostatin’s inhibitory effects.
• This binding inhibits the release of multiple vasoactive substances, including:
  • Serotonin
  • Bradykinin
  • Histamine
  • Prostaglandins
  • Tachykinins

Result

• Reduction in hormone secretion → Improvement of symptoms
• Stabilization of tumor activity in some case

Post-operative

• HDU/ICU for at least 24 h; continue octreotide 50 µg h⁻¹ for 12–24 h then wean.
• Monitor glucose (octreotide inhibits insulin), electrolytes and lactate.
• Resume long-acting SSA on schedule; arrange NET MDT review for oncological plan.

Carcinoid Crisis: Summary Algorithm

1. Recognise–abrupt flushing ± hypotension/ hypertension, tachycardia, bronchospasm.
2. Stop surgical stimulus where possible.
3. Octreotide–100 µg IV bolus → repeat; commence/ increase infusion 50–200 µg h⁻¹.
4. Supportive measures–100 % O₂, balanced crystalloid bolus, phenylephrine or vasopressin.
5. Bronchospasm Adjuncts–H₁/H₂ antagonists; hydrocortisone 100 mg IV (reduce kallikrein/ bradykinin).

Avoid in Carcinoid NET Surgery

• Succinylcholine (histamine release)
• Ephedrine, epinephrine, norepinephrine, B agonists (salbutamol)
• Morphine, meperidine, atracurium
• Ketamine bolus, desflurane during rapid changes
• Hypotension, hypoxia, hypercarbia, hypothermia–all increase mediator release

Multiple Endocrine Neoplasia (MEN)

Syndrome	Gene (inheritance)	Core tumours	Anaesthetic red flags
MEN 1 (“Wermer”)	MEN1 (AD)	Parathyroid → hyperCa²⁺, pancreatic NETs (gastrinoma, insulinoma), pituitary	Treat hypercalcaemia; screen for hypoglycaemic spells & raised ICP from pituitary macro-adenoma
MEN 2A	RET (AD)	Medullary thyroid carcinoma (MTC), phaeochromocytoma, parathyroid	Exclude phaeochromocytoma before any surgery; evaluate vocal cords after thyroid surgery
MEN 2B	RET (AD)	MTC, phaeochromocytoma, mucosal neuromas, marfanoid habitus	Anticipate difficult airway (tongue/lip neuromas), autonomic instability
MEN 4	CDKN1B (rare)	Similar to MEN 1 but no MEN1 mutation	Same as MEN 1

Always document calcium, metanephrines and pituitary hormones in MEN patients scheduled for anaesthesia.

Acromegaly

Summary of Acromegaly

Key Peri-operative Issues

System	Manifestations	Anaesthetic impact
Airway	Macroglossia, prognathism, sub-/supraglottic narrowing, large goitre (25 %)	Anticipate difficult mask & intubation; ramp, VL, smaller ETT; consider awake fibre-optic if stridor/voice change
CVS	HTN, LV hypertrophy, arrhythmias, cardiomyopathy	Pre-op echo if symptoms; invasive BP for trans-sphenoidal surgery
Respiratory	OSA (60 %), restrictive chest wall, PHT	Post-op CPAP/NIV, opioid-sparing
Metabolic	Insulin resistance/DM	Hourly glucose
MSK/soft tissue	Arthropathy, carpal tunnel, thickened skin	Positioning, arterial line collateral flow may be poor

• Technique tips
  • Avoid deep neck flexion/extension (cervical arthropathy).
  • Secure IV lines; oily skin may loosen ECG electrodes.
  • Neuromuscular monitoring—up to 30 % have myopathy with delayed recovery.

Anorexia Nervosa

Problem	Anaesthetic consequence	Management
Severe malnutrition, BMI < 17 kg m⁻²	Hypotension, hypothermia, impaired wound healing	Warm environment, gentle positioning, early antibiotics
Electrolyte depletion (↓K⁺, ↓Mg²⁺, ↓PO₄³⁻)	Arrhythmia, muscle weakness, re-feeding syndrome	Correct before elective surgery; replace PO₄³⁻ & thiamine with feeds
Cardiac atrophy, prolonged QT	Brady-/tachy-arrhythmia, arrest on induction	Baseline ECG ± echo; avoid QT-prolonging drugs
Delayed gastric emptying	Aspiration	RSI with head-up; pro-kinetic
Psychiatric co-morbidity	Poor cooperation, medication interactions	Pre-op psych review; clear consent

Elective surgery should be deferred if weight < 13 kg m⁻² or severe biochemistry derangements.

Diabetes Insipidus (DI)

Type	Aetiology	Key features	Peri-op strategy
Central	↓ ADH (pituitary / hypothalamus)	Polyuria, Uosm < 150 mOsm kg⁻¹	Desmopressin 1 µg IV q8-12 h; monitor Na⁺ 2-hourly
Nephrogenic	Renal resistance to ADH	Same biochemistry + high ADH	Continue thiazide ± amiloride; match urine with 0.45 % NaCl

• Treat hypernatraemia slowly (< 10 mmol L⁻¹ day⁻¹) to avoid cerebral oedema.
• Anticipate ↑ MAC requirement if Na⁺ > 155 mmol L⁻¹.

SIADH

Key Anaesthetic Concerns

• Chronic hyponatraemia (< 130 mmol L⁻¹) increases risk of postoperative delirium, seizures and delayed emergence.
• Over-rapid correction (> 8 mmol L⁻¹ in any 24 h) risks osmotic demyelination syndrome (ODS).

Diagnostic Criteria (euvolaemic hyponatraemia)

• Serum osmolality < 275 mOsm kg⁻¹.
• Urine osmolality > 100 mOsm kg⁻¹ with urine Na⁺ > 40 mmol L⁻¹.
• Normal thyroid, adrenal and renal function.

Peri-operative Management

Situation	Treatment
Elective surgery, Na⁺ < 125 mmol L⁻¹	Defer; fluid restrict (800–1000 mL day⁻¹) ± loop diuretic; treat cause.
Moderate symptoms (confusion, nausea)	3 % saline bolus 150 mL over 15 min; aim ΔNa⁺ + 4–6 mmol L⁻¹. Re-bolus if symptoms persist.
Severe symptoms (seizure, coma)	Two 150 mL 3 % saline boluses; monitor Na⁺ hourly. Add furosemide 20 mg IV if volume overloaded.
Chronic phase	Restrict water, consider oral urea, demeclocycline or vasopressin V₂ antagonist (tolvaptan) under specialist advice.

• Correction targets–maximum 10 mmol L⁻¹ first 24 h and 8 mmol L⁻¹ each subsequent 24 h; high-risk groups (malnutrition, alcohol use, hypokalaemia, liver disease) max 8 mmol L⁻¹ day⁻¹ from outset.

In Theatre

• Check plasma Na⁺ on arrival and 2-hourly intra-operatively.
• Avoid hypotonic fluids; use isotonic balanced crystalloids.
• Treat convulsions with benzodiazepine; give small hypertonic saline bolus rather than large continuous infusion.

Panhypopituitarism

• Hormone cover essentials
  1. Glucocorticoid–hydrocortisone 25 mg PO morning dose; give stress dose for surgery (see table below).
  2. Thyroxine–continue usual dose; never start before hydrocortisone in new diagnoses.
  3. Consider vasopressin deficiency (monitor urine output & Na⁺), sex-steroid replacement and GH in long-term care. Sudden hypotension or hypoglycaemia warrants immediate hydrocortisone 100 mg IV.

Porphyria

Porphyria

Key Points

• Acute hepatic porphyrias (AIP, variegate, hereditary coproporphyria, ALAD‐deficiency) may be triggered by porphyrinogenic drugs, fasting, infection, alcohol and stress
• A safe anaesthetic hinges on (1) avoiding unsafe drugs, (2) preventing physiological triggers and (3) being able to recognise and treat an acute attack swiftly.

Clinical Spectrum

Phase	Features
Acute attack	Severe abdominal pain, vomiting, autonomic instability (tachycardia ± hypertension), hyponatraemia/SIADH, motor neuropathy → respiratory failure, seizures
Chronic sequelae	Recurrent pain, neuropathic pain, chronic kidney disease, hypertension, anxiety & depression

Peri-operative Management

Pre-operative

• Haematology consultation; ensure intravenous haem arginate (hemin) 3 mg kg⁻¹ is immediately available.
• Continue high-carbohydrate diet; if NPO infuse 10 % dextrose-saline 1.5 mL kg⁻¹ h⁻¹.
• Correct hyponatraemia, anaemia and treat infection.
• Avoid prolonged fasting, dehydration and oestrogen-containing drugs.

Drug Safety (2024 Welsh National Acute Porphyria Service list)

wmic.wales.nhs.uk

frontiersin.org

Category	SAFE / PREFERRED	UNSAFE–AVOID
Induction	Propofol, Ketamine (single dose), Midazolam	Thiopentone, Etomidate†
Inhalational	Sevoflurane, Desflurane, Isoflurane, N₂O	Enflurane, Methoxyflurane
Analgesia	Fentanyl, Remifentanil, Morphine, Paracetamol, Ketamine	Diclofenac, Ketorolac
Muscle relaxants	Suxamethonium, Rocuronium, Cis-/Atracurium	Pancuronium (limited data)
Local anaesthetics	Lidocaine, Bupivacaine, Levobupivacaine, Ropivacaine‡	Prilocaine (limited data)
Antiemetic	Ondansetron, Dexamethasone	Metoclopramide*
Vasopressors	Phenylephrine, Vasopressin	Ephedrine
Others	Antibiotics: all β-lactams, clindamycin, ciprofloxacin safe	Rifampicin, Sulphonamides

† Etomidate probably safe in single dose but lacks robust data—prefer alternatives.
‡ Safe in large contemporary series; classify as “probably safe”.

Intra-operative Checklist

• Standard monitors + arterial line if autonomic instability anticipated.
• Maintain normoglycaemia and normothermia.
• Minimise surgical stress: adequate depth (BIS 40–60), analgesia and anti-emesis.
• Avoid hyperventilation-induced alkalosis (may precipitate attack).

Treating an Acute Porphyric Crisis

1. Stop precipitating drug / stimulus.
2. Haem arginate (hemin) 3 mg kg⁻¹ IV over 20 min daily × 4 days.
3. Glucose 10 % infusion 200 g day⁻¹.
4. Symptom control: opiate analgesia, midazolam / propofol for seizures (avoid phenytoin)
5. Correct hyponatraemia slowly; treat hypertension/tachycardia with short-acting β-blocker

Summary of a Safe Anesthetic

View or edit this diagram in Whimsical.

Summary of Drugs

• Avoid: Thiopentone, Sevoflurane, Ketamine, Diclofenac, Oxycodone, Rifampicin, Erythromycin, Ephedrine (TORE DESK).
• Caution: Etomidate, Levobupivicaine, Ropivacaine, Pentazocine, Mefenamic Acid, Vasopressin, Metaraminol, Dexamethasone, Hydrocortisone, Clopidogrel (HELD M CRAMP).

View or edit this diagram in Whimsical.

Links

• Electrolytes
• Anaesthesia emergencies
• Post op complications
• Pre-op assessment and investigation

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Past Exam Questions

Airway Obstruction After Thyroidectomy

Briefly discuss the potential causes of airway obstruction after a thyroidectomy and how they typically present. (10)

Anaesthesia for Acute Porphyria

a) The acute types of porphyria can complicate into an acute neurovisceral crisis.

• i) List 4 triggers for acute neurovisceral crisis in the perioperative period. (2)
• ii) List 2 cardiovascular symptoms that manifest during an acute crisis. (1)
  b) List the 3 mechanisms of drug porphyrinogenicity. (3)
  c) How will you manage an acute porphyria crisis? (4)

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References:

1. Crowley K, Scanaill PÓ, Hermanides J, Buggy DJ. Current practice in the perioperative management of patients with diabetes mellitus: a narrative review. British Journal of Anaesthesia. 2023 Aug;131(2):242-252. DOI: 10.1016/j.bja.2023.02.039. PMID: 37061429.
2. Chan S Y et al. High-flow nasal oxygen for shared airway procedures: systematic review and meta-analysis. Anaesth Intensive Care. 2024;52:123-33. pmc.ncbi.nlm.nih.gov
3. Fugazzola L et al. 2022 European Thyroid Association guideline for management of Graves’ hyperthyroidism. Eur Thyroid J. 2022;11:e210046. pmc.ncbi.nlm.nih.gov
4. Wong R, See T. Airway management in retrosternal goitre: review of 22 cases. Tech Respir Care Med. 2022;26:55-63. pmc.ncbi.nlm.nih.gov
5. Johnson P J P et al. Awake versus asleep intubation for mediastinal goitres: systematic review. Anesth Analg. 2025;140:889-900. pmc.ncbi.nlm.nih.gov
6. Meng L et al. High-flow nasal oxygen during suspension laryngoscopy: randomised controlled trial. J Int Med Res. 2023;51:300605052. journals.sagepub.com
7. Schneider R et al. Intra-operative neuromonitoring and recurrent laryngeal nerve injury: meta-analysis of 60 studies. Diagnostics. 2023;13:860. mdpi.com
8. Lin Y C et al. Endoscopic evidence of RLN outcomes with and without IONM: systematic review. Front Endocrinol. 2023;14:11507766. pmc.ncbi.nlm.nih.gov
9. Kim H G et al. Effects of different cisatracurium doses on RLN monitoring during thyroid surgery: RCT. Br J Anaesth. 2021;126:120-8. bjanaesthesia.org
10. van der Pas N et al. Risk of peri-operative thyroid storm in hyperthyroid patients: systematic review. Br J Anaesth. 2021;127:423-33. bjanaesthesia.org
11. Oettlé M et al. Anaesthesia for retrosternal thyroidectomy: South African cohort review. S Afr J Anaesth Analg. 2023;29:256-62. sajaa.co.za
12. StatPearls Publishing. Thyroid storm. Updated 2024 Jan. ncbi.nlm.nih.gov
13. Malhotra B, Bhadada SK. Perioperative management for non-thyroidal surgery in thyroid dysfunction. Indian J Endocrinol Metab. 2022;26:428-434. pmc.ncbi.nlm.nih.gov
14. Elshimy G, Chippa V, Correa R. Myxedema. StatPearls. 2023 Aug 14. ncbi.nlm.nih.gov
15. Ha J et al. 2023 Korean Endocrine Society consensus guidelines for the diagnosis and management of primary aldosteronism. Endocrinol Metab (Seoul). 2023;38:597-618. pubmed.ncbi.nlm.nih.gov
16. Society for Endocrinology. Adrenal Crisis–Clinical Guidance. Updated 2024. endocrinology.org
17. Lenders J WM, Duh Q-Y, Eisenhofer G, et al. Phaeochromocytoma and paraganglioma: Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2014;99:1915-42. pubmed.ncbi.nlm.nih.gov
18. StatPearls Publishing. Pheochromocytoma. Updated 2024 Oct. ncbi.nlm.nih.gov
19. StatPearls Publishing. Peri-operative management of pheochromocytoma. Updated 2023 Sep. statpearls.com
20. Casey RT, Hendriks E, Deal C, et al. International consensus on phaeochromocytoma & paraganglioma in children and adolescents. Nat Rev Endocrinol. 2024;20:729-48. nature.com
21. Gombert AJ et al. Peri-operative biochemical and clinical considerations in pheochromocytoma. Int J Mol Sci. 2023;26:6080. mdpi.com
22. Association of Anaesthetists & Royal College of Physicians. Guidelines for the management of glucocorticoids during the peri-operative period for patients with adrenal insufficiency. Anaesthesia. 2020. pubmed.ncbi.nlm.nih.gov
23. Villaseñor M et al. Peri-operative management of Cushing disease. J Endocr Soc. 2022;6(4):bvac185. pmc.ncbi.nlm.nih.gov
24. Eledrisi MS. Myxedema coma or crisis: treatment & management. Medscape. Updated 12 Jan 2024. emedicine.medscape.com
25. OpenAnesthesia. Hypothyroidism. Updated 23 May 2025. openanesthesia.org
26. Pavel M, et al. European Neuroendocrine Tumour Society guidance for carcinoid syndrome and carcinoid heart disease. J Neuroendocrinol. 2022;34:e13146. onlinelibrary.wiley.com
27. UKINETS & BSG. Peri-operative management of patients with NETs. 2023. ukinets.org
28. StatPearls Publishing. Carcinoid Syndrome. Updated 2024 Jan. ncbi.nlm.nih.gov
29. OpenAnesthesia. Carcinoid Syndrome–Anaesthetic considerations. Updated 2023 Sep. openanesthesia.org
30. Hallett J, et al. Peri-operative management of carcinoid crisis: expert consensus protocol. Eur J Surg Oncol. 2023;49:2285-92. magonlinelibrary.com
31. Society for Obesity & Bariatric Anaesthesia. SOBA-UK Adult Peri-operative Obesity Guideline. 2022. sobauk.co.uk
32. Society for Obesity & Bariatric Anaesthesia. SOBA-UK Paediatric Obesity Guideline. 2024. sobauk.co.uk
33. Ushakumari DS, Sladen RN. ASA consensus guidance on peri-operative management of GLP-1 receptor agonists. Anesthesiology. 2024;140:346-8. pubmed.ncbi.nlm.nih.gov
34. Schutzer-Weissmann J, et al. Apnoeic oxygenation in morbid obesity: HFNO vs facemask. Br J Anaesth. 2023;130:103-110. pubmed.ncbi.nlm.nih.gov
35. Lee J H, et al. High-flow nasal cannula for apnoeic oxygenation in obese adults: systematic review & meta-analysis. Anesth Analg. 2023;136:483-493. journals.lww.com
36. Samantray A, et al. Propofol induction dosing based on lean body weight vs fat-free mass in morbid obesity: randomised trial. Anaesthesia. 2023;78:1052-1060. pmc.ncbi.nlm.nih.gov
37. Lyons PG, et al. Peri-operative management of obstructive sleep apnoea: narrative review. Br J Anaesth. 2023;131:887-901. bjanaesthesia.org.uk
38. Butterworth J, Mackey D, Wasnick J. Morgan and Mikhail’s Clinical Anesthesiology, 7th Edition. 7th edition. New York: McGraw Hill Medical; 2022.
39. Allman K, Wilson I, O’Donnell A. Oxford Handbook of Anaesthesia. Vol. 4. Great Clarendon Street, Oxford, OX2 6DP, United Kingdom: Oxford University Press; 2016. 1295 p.
40. Children’s Hospital of Philadelphia. MEN2 peri-operative screening guidance. 2023. chop.edu
41. Fleseriu M, et al. Consensus on acromegaly diagnosis & management. Endocrine 2024;20:29–45. karger.com
42. BJA Education. Anaesthetic implications of acromegaly. 2023;23:210–17. academic.oup.com
43. McGuire E, et al. Anaesthesia for patients with anorexia nervosa. BJA Educ. 2023;23:18–25. bjaed.orgpmc.ncbi.nlm.nih.gov
44. Refardt J, Christ-Crain M. Diagnosis & management of central diabetes insipidus. J Clin Endocrinol Metab. 2023;107:2701-15. academic.oup.com
45. Association of Anaesthetists & RCP. Management of glucocorticoids during the peri-operative period. Anaesthesia. 2020;75:654-63. anaesthetists.org
46. PREdS collaborative. High vs low-dose peri-operative steroids: RCT protocol. Anaesthesia. 2024;79:1050-8. associationofanaesthetists-publications.onlinelibrary.wiley.com
47. Isberner N, Nydegger M. 2024 Safe list of drugs in acute porphyria. Welsh Medicines Advice Service; 2024. wmic.wales.nhs.uk
48. Floderer T, Klohr S. Anaesthesia in acute hepatic porphyria—a practical approach. Br J Anaesth Educ. 2025;25:182-9. pmc.ncbi.nlm.nih.gov
49. Stewart TG, et al. Safe use of sevoflurane in patients with acute intermittent porphyria: systematic review. Front Anaesth. 2023;2:10002. frontiersin.org
50. Spasovski G, et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia—2024 update. Nephrol Dial Transplant. 2024;39:1583-99. academic.oup.com
51. Aijaz N, Sterns RH. Rapid correction of hyponatraemia and risk of ODS: 2024 perspective. Kidney Med. 2024;6:100953.
52. The Calgary Guide to Understanding Disease. (2024). Retrieved June 5, 2024, from https://calgaryguide.ucalgary.ca/
53. FRCA Mind Maps. (2024). Retrieved June 5, 2024, from https://www.frcamindmaps.org/
54. Anesthesia Considerations. (2024). Retrieved June 5, 2024, from https://www.anesthesiaconsiderations.com/
55. ICU One Pager. (2024). Retrieved June 5, 2024, from https://onepagericu.com/

Summaries
Endocrine
Endocrine physiology
Obesity
Bariatric surgery
Anorexia
Ketoacidosis_ICU OP

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Copyright
© 2025 Francois Uys. All Rights Reserved

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