Pharngeal (branchial) embryopathies

Question 1

parathyroid & thymus anomalies

Answer 1

• ectopic tissue:
• ->insufficient migration
• ->excessive migration of inferior parathyroid (drawn inferiorly by co-migrationg thymus)
• absence of parathyroid and/or thymus

Question 2

abnormal persistence of pharyngeal groove or cervical sinus

Answer 2

• branchial cyst
• branchial sinus
• branchial fistula

often not detected until puberty when epithelium inc secretions

Question 3

branchial cyst

Answer 3

-completely enclosed epithelial-lined cavity

Question 4

branchial sinus

Answer 4

-opens to either externally or internally (into pharynx)

Question 5

branchial fistula

Answer 5

-open at both ends

Question 6

first arch syndromes

Answer 6

• Pierre Robin syndrome

- Treacher Collins syndrome

Question 7

PP3&4 syndrome

Answer 7

-DiGeorge syndrome

Question 8

Pierre Robin Syndrome

Answer 8

• micrognatia (mandibular hypoplasia)
• cleft palate
• glossoptosis (posterior-placed tongue)
• otitis media (CHL)
• 50% with CNS defects
• genetic and/or environmental factors
• 1/8500 births
• tracheostomy often required

Question 9

Treacher Collins syndrome (mandibulofacial dysostosis

Answer 9

• mid- and lower face malformations
• ->micrognatia
• ->malar (zygoma) hypoplasia
• ->faulty dentition
• ->possible cleft palate
• ->upper airway narrowing (apnea or SIDS)
• ear malformations (CHL)
• ->external ear: malformed auricles and microtia and microtia, external acoustic meatus stenosis/absence
• ->middle: malformed ossicles
• ->inner: possible abnormalities
• normal intelligence delays secondary to hearing loss
• 1/25000-1/50000
• autosomal dominant condition; teratogenic

Question 10

DiGeorge Syndrome

Answer 10

Primary:

• CV defects- heart and aorta
• Abnormal facies (like 1st arch: micrognathy, low set ears, auricular abnormalities)

Secondary:

• Thymic hypoplasia (immunological defects, T-cell deficient)
• Cleft palate (1st arch syndrome)
• Hypocalcemia (hypoparathyroidism) deletion of long arm of chrom 22

Question 11

causes of DiGeorge

Answer 11

• genetic
• alcoholic mother
• teratogens at w 4-6 (retinoic acid)
• maternal diabetes
• ~1/2500
• Poor prognosis: primary: CHD sec: severe immune deficiencies

Question 12

Ectopic Thyroid

Answer 12

• insufficient migration along path of thyroglossal duct:
• -> lingual (90%)
• ->anterior to hyoid
• excessive migration
• ->substernal

Question 13

Thyroglossal duct cyst

Answer 13

• midline structures

- midline cyst, elevated upon swallowing (fibrous connection with tongue)

Question 14

Pyramidal lobe

Answer 14

• excess lobe thyroid

- 50% of population

Question 15

why is it more common to find an ectopic inferior parathyroid gland than an ectopic superior parathyroid parathyroid gland

Answer 15

-both inferior and superior parathyroid glands can migrate insufficiently, but the inferior parathyroid is much more likely to migrate too far inferiorly bc it co-migrates with the thymus from the PG3

Question 16

developmental disorders of which parts of the PA apparatus may result in CHL?

Answer 16

• PA1&2: middle ear ossicles, tensor veli palatani & stapedius
• PMI: tympanic mem
• PP1: Eustachian tube, tympanic cavity, mastoid air cells
• PG1: external acoustic meatus