Endocrine, H&N Flashcards
Ant triangle of neck boundaries
Superior: lower border of mandible
Anterior: midline
Posterior: anterior border of SCM
What does the ant triangle of the neck contain?
Carotid sheath
Post triangle of the neck boundaries + what does it contain
Anterior: posterior border of SCM
Posterior: anterior of trapezius
Inferior: clavicle
Contains spinal accessory nerve
Bony landmarks of C3-T3
C3: hyoid bone
C4: thyroid cartilage notch
C6: cricoid cartilage
C5-T1: thyroid gland
T2/3: suprasternal cartilage
Common carotid arteries split at the level of
C4
External carotid artery branches
Superior thyroid
Ascending pharyngeal
Lingual
Facial
Occipital
Posterior auricular
Maxillary
Superficial temporal
(Some Anatomists Like Freaking Out Poor Medical Students)
Internal carotid artery branch
enters carotid canal, gives off ophthalmic artery
Right IJV unites with the ___ vein behind ___ to give rise to ___. This vein joins the left ___ to form the ___.
subclavian
sternoclavicular joint
right brachiocephalic
brachiocephalic vein
superior vena cava
Most common cause of neck mass is
enlarged lymph node
Rule of 80s in neck masses (5 rules)
80% non-thyroid are neoplastic
80% neoplastic masses are malignant
80% malignant are SCC
80% of malignant are metastatic
80% of metastases are from primary sites above level of clavicle
DD of midline neck mass
submental lymph node
thyroglossal cyst
thyroid nodule in isthmus
sublingual dermoid cyst
plunging ranula
DD of ant triangle neck mass
lymph node along ant border of SCM
thyroid nodule
submandibular gland mass
branchial cyst
carotid body tumour
carotid aneurysm
DD of posterior triangle neck masses
lymph node
cystic hygroma
cervical rib
brachial plexus neuroma
Investigation of neck masses
triple assessment
- clinical exam
- histology: FNAC
- imaging: CT neck w contrast
biochemical tests for neck masses
fbc
thyroid function
+/- calcium panel
+/- calcitonin (medullary thyroid cancer)
Types of endoscopy for neck masses
Panendoscopy - triple endoscopy
- flexible nasopharyngoscopy
- bronchoscopy
- esophagogastroscopy
Nodules that move with swallowing
thyroglossal cyst, thyroid nodule
nodules that move w swallowing and tongue protrusion
thyroglossal cyst
*thyroid nodule moves with swallowing but NOT with protrusion
what is a thyroglossal cyst?
cystic expansion of remnant thyroglossal tract - failure of thyroglossal duct to obliterate after descent of thyroid gland from foramen cecum at base of tongue to anterior neck
where can thyroglossal cyst occur?
anywhere from base of tongue to behind sternum, most commonly adjacent to hyoid bone
Treatment for thyroglossal cyst
Sistrunk operation - removal of cyst + thyroglossal tract + central portion of hyoid bone
removing cyst alone can risk recurrence
What is a dermoid cyst & causes
small non-tender mobile subcutaneous lump - can be fluctuant, skin-coloured, bluish
congenital - inclusion of epidermis along lines of fusion of skin dermatomes (ends of eyebrows, midline of nose, midline of neck/trunk)
what is a plunging ranula & causes
pseudocyst of sublingual/submandibular ducts
congenital: due to imperforate salivary duct
acquire: trauma to sublingual glands causing mucus extravasation, formation of pseudocyst
Branchial cysts form ___ masses. Occurs due to ___
anterior triangle neck
failure of fusion of 2nd and /or 3rd branchial arches, causing failure of obliteration of 2nd branchial cleft (most common)
Branchial cysts form ____ (location)
1st cleft: near parotid gland
2nd cleft: anterior to upper/middle third of SCM
3rd/4th cleft: left side of neck - can present as suppurative thyroiditis
Branchial cysts may form fistulas that run ___
between tonsillar fossa and anterior neck, passes between internal and external carotid arteries
What is a chemodectoma and where is it located
carotid body tumour
tumour of the paraganglion cells - benign but locally invasive
located at the bifurcation of common carotid artery
Features of chemodectoma
solid, non-painful mass at level of hyoid bone
pulsatile but not expansile - transmitting pulses from carotid artery
mostly do not secrete catecholamines, but 5% do - rule out associated syndromes like pheochromocytoma
how to differentiate chemodectoma and carotid body aneurysm
aneurysm can occur at any level, tumour occurs only at level of hyoid bone
angiography to detect tumour - hypervascular mass that displaces bifurcation
Genetic associations of paragangliomas
MEN2, VHL, NF1, Carney-Stratakis dyad
What is a cystic hygroma, where is it found
congenital cystic lymphatic malformation
found posterior triangle of neck, can be multiple interconnecting/separate cysts
features of cystic hygroma
soft, fluctuant, compressible
can be found in other locations - axilla, groin
“brilliantly transilluminable”
What is a cervical rib, where is it found
hard mass in posterior triangle, at the root of neck
cervical rib causes ___
thoracic outlet syndrome - compression of brachial plexus trunks, subclavian artery and/or subclavian vein
Neuroma is a __, found in __
slow growing tumour arising from peripheral neural structures of neck (eg. brachial plexus)
posterior triangle of neck
Cervical lymph nodes are divided into ___ levels
seven
Drainage of H&N structures into what level of lymph nodes
Oral cavity: Level I, II, III
Thyroid, larynx: Level II - VI (thyroid first spreads to level VI - central nodes)
Nasopharynx: II - V
Differentials of enlarged lymph node (*categorise)
infectious
inflammatory
neoplastic
Infected lymph nodes causes
viral - EBV, CMV, HIV
bacterial - TB, strep/staph
fungal/parasitic - toxoplasma
neoplastic lymph node causes
primary - lymphoma
metastases - H&N (90%), other sites (breast, lung, renal, GIT)
inflammatory lymph nodes causes
Kikuchi, Kimura, SLE, sarcoidosis
Nerves easily injured in submandibular gland excision
marginal mandibular nerve (CN VII)
lingual nerve (CN V3)
hypoglossal nerve
Structures running in the parotid gland (lateral to medial)
facial nerve & branches
retromandibular vein
external carotid artery
Parotid duct runs 5cm across ____, below the ____, pierces the ___ and empties into ___
masseter
zygomatic arch
buccinator
opposite upper 2nd molar tooth
Histology of each salivary gland & their contribution to saliva
parotid - mostly serous (25% of saliva)
submandibular - mixed serous and mucinous (70% of saliva)
sublingual - mostly mucinous (5% of saliva)
What is sialolithiasis and which gland does it most commonly occur in
Stones in the salivary gland/duct
Submandibular gland
Presentation of sialolithiasis
Pain and swelling of gland a/w meal times
Can cause gland inflammation (sialadenitis) and infection/abscess, purulent discharge observed at duct opening
Most salivary gland tumours occur in the ___ gland, and are mostly __
parotid, benign
80% of the benign tumours are pleomorphic adenomas
Tumours that occur in smaller glands are more likely to be ___
malignant
Most common benign tumour of parotid gland
pleomorphic adenoma
clinical features of pleomorphic adenoma
slow-growing, painless
irregular surface
chance of malignant transformation if left unexcised
2nd most common tumour of salivary gland, only occurs in __. Related to ___, occurs in ___.
Warthin’s tumour, parotid
cigarette smoking, occurs in older patients
Unlike pleomorphic adenoma, Warthin’s tumour is ___ to become malignant
unlikely
can be left alone
embryonic origin of thyroid, parathyroid glands
thyroid: endoderm, from foramen caecum
inferior para: from 3rd pharyngeal pouch, migrate tgt with thymus
superior para: from 4th pharyngeal pouch
arterial supply of thyroid & parathyroid
superior TA - from external carotid
inferior TA - from thyrocervical trunk, branch of subclavian
Thyroid Ima Artery - 5% of pts
*inferior TA supplies parathyroid
Venous supply of thyroid
Superior TV: drains into IJV
middle TV: drains into IJV
inferior TV: drains into brachiocephalic
impt nerves and artery relationships in thyroid
1) external branch of superior laryngeal nerve & superior thyroid artery
2) recurrent laryngeal nerve & inferior thyroid artery
nerve damage in thyroid surgery and what is affected
1) external branch of superior laryngeal nerve supplies cricothyroid - tenses vocal cord. damage affects ability to produce high pitch
2) RLN - supplies all intrinsic muscles of larynx except cricothyroid. unilateral damage causes hoarseness. bilateral causes acute dyspnea
thyroid stimulation pathway
TRH (from hypothalamus) -> TSH (from pituitary) -> T3 , T4 (from thyroid)
Common causes of primary hyperthyroidism
Graves’ disease
toxic multinodular goitre
toxic adenoma
common causes of secondary hyperthyroidism
pituitary adenoma
gestational thyrotoxicosis
neoplasms - ovarian teratoma, choriocarcinoma, metastatic thyroid carcinoma
antithyroid drugs: ___ used for 1st trimester, switch to ___ for 2nd and 3rd trimester
Propylthiouracil (PTU) - less teratogenic
Carbimazole - less hepatotoxicity
Impt side effect of antithyroid drugs
agranulocytosis
Common causes of hypothyroidism
iodine deficiency (most common)
hashimoto’s
autoimmune
cretinism - maternal hypothyroidism leading to thyroid agenesis/dysgnesis
myxedema coma - severe hypothyroidism precipitated by infection/trauma/surgery
Risk factors for thyroid malignancy
Age, gender
Exposure to ionising radiation
Family history
Associated with familial adenomatous polyposis, Gardner syndrome, Cowden disease, MEN2
what is gestational hyperthyroidism?
Hyperemesis gravidarum: High HCG levels in 1st trimester -> stimulates TSH receptors
Thyroid cytopathology is graded by the ____
Bethesda system
used to grade chance of malignancy, guides management
follicular cell derived thyroid cancers
papillary, follicular, hurthle cell, anaplastic cancers
non-follicular cell derived thyroid cancers
medullary cancer, thyroid lymphoma
PTC spread by ___, FTC spread by ___
lymph, blood
Thyroid swellings move on ___, thyroglossal cyst moves on ___
swallowing only
swallowing & tongue protrusion
Suspicious features on ultrasound (6) a/w thyroid cancer
1) taller than wide
2) micro-calcifications
3) intranodular vascularity
4) margins - infiltrative, spiculated
5) hypoechoic
6) presence of lymphadenopathy
Radioisotope used for thyroid scan
Sodium pertechnetate
Iodine 123
Indications for thyroid surgery (6 Cs)
Cancer
Cosmesis
Cannot treat medically
Compressive symptoms
Compliance problems
Child-bearing
___ syndrome is associated with medullary carcinoma. Screen for ___
MEN2A/2B
Pheochromocytoma
Hashimoto’s thyroiditis increases risk of ___
lymphoma
Ionising radiation increases risk of ____ and ___
papillary and follicular cell carcinoma
Medullary cancer causes ____ due to production of ___
flushing, diarrhea
calcitonin
Most common sites of mets for thyroid cancers
lung, bone, brain
+ liver for medullary
T staging for thyroid based on
size of nodule
T3: invaded strap muscle
T4: invaded major neck structures
Molecular tests for each tumour
PTC: BRAF mutation
FTC: RAS mutation
Medullary: RET oncogene
Immediate post-surgical complications of thyroidectomy
Haematoma formation under/above strap muscles - tracheal compression
Injury to RLN and SLN
tracheomalacia - tracheal floppines due to chronic compression by large goiter
thyrotoxic storm - resection release t4 into blood
Intermediate post-thyroidectomy complication
Hypoparathyroidism causing hypocalcemia, leading to (CATS go Numb)
Convulsion
Arrhythmias
Tetany
Spasm
Numbness of extremities
MEN1 tumour suppressor gene mutation affects
3Ps
Parathyroid - hyperplasia
Pancreas - neuroendocrine tumours
Pituitary - anterior pit adenoma, growth hormone secreting tumours
MEN2A:
Activating proto-oncogene (RET) mutation causes/affects
Medullary thyroid CA
Pheochromocytoma
Parathyroid
Hirschsprung disease
MEN2B: Activating proto-oncogene (RET) mutation causes/affects
Medullary thyroid CA
Pheochromocytoma
*no parathyroid in men2b
Most common cause of painful thyroid gland
DeQuervain’s thyroiditis
preceded by URTI
viral infection causing damage to thyroid follicular cells
Drugs that cause thyroiditis
Amiodarone, lithium, IL-2, IFN-alpha
___ parathyroid migrates with the thymus, can sometimes be found within
Inferior
Superior parathyroid arises from ___ pharyngeal ___, inferior arises from ____
4th pharyngeal pouch
3rd pharyngeal pouch
PTH ___ calcium in blood, calcitonin ___ calcium in blood
increases, decreases
PTH effects on kidney
increases reabsorption of calcium & vitamin D
increases excretion of phosphate
Calcitonin effects
Inhibit reabsorption of calcium in kidney and intestines
Inhibit reabsorption of phosphate
Mnemonic for hyperparathyroidism
stones, bones, moans, groans
kidney stones
bone pain - osteoporosis
abdominal groans - PUD,
pancreatitis, cholelithiasis
psychiatric moans - depression, psychosis
parathyroid 4 gland hyperplasia associated with
MEN 1 and 2a
most common cause of primary hyperparathyroidism
parathyroid adenoma
What is hungry bone syndrome?
- occurs after parathyroid gland removal
- high calcium levels suppressed PTH production in normal glands
- sudden drop in PTH stops osteoclastic activity in bone
- osteoblastic activity continues. bone takes a lot of calcium, phosphate, magnesium
What causes secondary hyperparathyroidism?
Chronic hypocalcaemia
Happens most commonly in chronic renal failure. Lack of calcium/vit D reabsorption
What causes tertiary hyperPTH?
Long term secondary hyperPTH, parathyroid glands develop autonomous secretion of PTH without need for stimulation by calcium
Substances produced by adrenal glands
Cortex:
- zona glomerulosa: aldosterone
- zona fasciculata: cortisol
- zona reticularis: sex hormones
medulla:
- catecholamines (epinephrine, norepinephrine)
Adrenal incidentalomas can be classified into
Benign (non-secreting): adenoma, nodular hyperplasia
Benign (secreting): conn’s, cushing’s, pheochromocytoma
Malignant: adrenal cortical CA
Hyperaldosteronism commonly presents with
resistant HTN (>= 3 drugs)
hypokalaemia
HTN can be young onset
Most common cause of hypercortisolism
Iatrogenic (exogenous glucocorticoid use)
Cushing’s disease is ___
Cushing’s syndrome is ___
pituitary adenoma causing excessive ACTH secretion
adrenal hyperplasia/adenoma/carcinoma causing cortisol hypersecretion
Ectopic ACTH can cause cushing’s syndrome. Ectopic ACTH seen in
Small cell lung cancer
Thymic tumours
medullary thyroid cancer
carcinoid (neuroendocrine) tumours of pancreas/gut
Hypercalcaemia can result from ___ malignancies
squamous cell lung cancer
multiple myeloma
Clinical features of phaeochromocytoma (5 Ps)
pain - headache, chest pain
palpitation - tachycardia, tremor
pressure - HTN
perspiration
pallor
Rule of 20 for pheochromocytoma (6)
20% malignant
20% children
20% extra-adrenal
20% bilateral
20-25% familial (MEN2, VHL, NF1, tuberous sclerosis)
In managing pheochromocytoma, ___ given before ___ because
alpha blockers, beta blockers
Beta blockers block vasodilation in the peripheries -> alpha receptors are unopposed -> keep stimulating vasoconstriction -> high bp
Must use alpha blockers to block vasoconstrictive effects of alpha receptor first
