Craniofacial exam 1 Flashcards
(164 cards)
0
Q
proteins can be turned on and off
aka?
A
on- phosphorylated
off- dephosphorylated
1
Q
proteins
A
complex, 3D molecules
essential for normal human structure and function.
composed of chains of amino acid.
partially or completely folded to determine shape.
(20 amino acids and each protein had unique amino acid chain and unique shape)
humans produce ~30k proteins
2
Q
the blueprint for making a human?
A
DNA
3
Q
DNA - coiled ladder shape
- rungs..
A
composed of nucleotides
two nucleotides pair to form each rung.
4
Q
Types of nucleotides
A
- adenine
- guanine
- thymine
- cytosine
5
Q
which nucleotides pair together?
A
cytosine-guanine
adenine-thymine
6
Q
where is most of our DNA found?
A
in the nuclei of all our cells
- but also found in mitochondria
7
Q
components of a gene
A
- promoter (starting point for gene’s activity)
- coding region - exon (codes for specific amino acid. sequence of 3 nucleotides)
- Introns (non-coding DNA between exons
8
Q
98% of DNA is what?
A
- Non-coding DNA
9
Q
How many human genes?
A
20k to 25k
10
Q
Non-coding DNA
A
- intons (sections within genes)
- also sequences between genes
- function isn’t completely understood
- some play role in gene expression
11
Q
What are variations of a gene?
A
alleles
12
Q
RNA
A
- copies the protein recipe from the gene.
- RNA -> single strand of nucleotide
- Uracil replaces thymine
13
Q
RNA protein copying process
A
- DNA unwound
- 2 pairs separate
- one side as template
- enzyme matches new nucleotides to appropriate partner on DNA (This is called transcription)
- splices out interon.
- binds nucleotides into a strand (mRNA)
- mRNA exits nucleus and travels to ribosome
- ribosome makes the protein.
14
Q
What is transcription?
A
- This is started in the nucleus
- making of mRNA
15
Q
What is translation?
A
This is the baking.
- the making of the protein
- in the ribosome
16
Q
Making of the protein
A
- made by the ribosome
- tRNA supplies amino acid to the ribosome
- ribosome assembles them according to recipe
- this is called translation ***
17
Q
what are chromosomes?
A
strands of DNA and associated proteins.
- compact way to protect, organize and package DNA into the cell.
- 46 total chromosomes in each cell.
- 23 pairs (22 autosomes and 1 sex chromosome)
- x-shaped
18
Q
Chromosome shape
A
x shaped central narrowing -> centromere p - short arms q - long arms Bands along the arms. These bands are numbered
19
Q
Gene location specified by…
A
chromosome number, arm, and band number or range
ex. FOXP2 gene - 7q31
20
Q
Mitochondrial DNA
A
located in each cell’s mitochondria
contains 37 genes
genes code for enzymes essential for mitochondrial function
21
Q
Gene mutations
A
- affect a single gene
- changes nucleotide sequence
- occur in two ways
- results in incorrect or non-functional protein.
22
Q
two ways gene mutations occur
A
hereditary - present throughout lifetime and in every cell.
acquired - caused by environmental factors or error in DNA copying during cell division
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Q
Types of mutations
A
- substitutions - one nucleotide replaced by another.
- insertion of nucleotide
- deletion of nucleotide
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Patterns of inheritance of mutations
- autosomal dominant - only one gene mutation on an autosome.
- autosomal recessive - requires 2 mutations (one on each autosome).
- x-linked - mutation on X chromosome. Typically affects males more than females.
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categorization of anomalies
1. syndromes
2. sequences
3. associations
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mutations are...
when something goes wrong with genes or chromosomes
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Syndromes
1. multiple anomalies having a single cause.
| 2. may be chromosomal or gene-based.
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Chromosomal syndromes may result from...
1. deletion of whole chromosome.
2. addition of whole chromosome.
3. addition of part of chromosome.
4. restructured chromosome.
5. rearrangement of chromosomes.
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syndromes caused by chromosomes
| - problems present
typically present with severe problems that may include:
- intellectual disability.
- short stature
- heart anomalies
- brain anomalies
- limb anomalies
as well as most have craniofacial malformations and communication problems.
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whole chromosome deletion
Rare
| example: Turner Syndrome
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Turner Syndrome
- affects females only
- all or part of one X chromosome missing
- problems may include:
1. short stature
2. webbed short neck with low posterior hair line.
3. infertility
4. variable cognitive and cardiac anomalies
5. variable physical anomalies.
32
Whole Chromosome Addition
- additional chromosome results in a trisomy
- rare with exception of Down Sydrome
- problems may include: 1. cognitive impairment, 2. midface deficiencies, 3. cardiac anomalies, 4. upslanting eyes
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Chromosome deletions
- most common chromosomal abnormality.
| - example: cri du chat
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Cri Du Chat
caused by deletion of short arm of chromosome 5
| - problems may include: 1. cognitive impairments, 2. cardiac problems, 3. facial asymmetry, 4. hypertelorism
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most congenital anomalies are ..?
genetic-based disorders caused by single gene disorder
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Gene disorders can often be predicted by ..?
mode of inheritence:
1. autosomal dominant
2. autosomal recessive
3. X-linked recessive
4. X-linked dominant
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Sequences
- multiple anomalies triggered by a single structural anomaly or error in development.
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some common sequences
1. Robin sequence
| 2. DiGeorge sequence
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Robin sequence
- developing child presents with micrognathia
- > micrognathia leads to abnormal placement of tongue.
- > displaced tongue leads to cleft palate.
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Associations
- multiple anomalies that occur together more often than would be predicted by chance.
- limited number of associations have been identified.
- examples: VACTERL and CHARGE
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Teratogens
- can cause morphological and/or functional anomalies when the fetus is exposed to them.
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Teratogenicity
depends on the ability of the teratogen to cross the placenta.
- effects depend on: potency of the teratogen, duration of exposure, and when the fetus is exposed.
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examples of teratogens
1. therapeutic drugs
2. alcohol
3. infectious agents
4. radiation
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Genetic testing
- examination of genes
- examination of chromosomes
- biochemical testing (proteins and enzymes)
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Newborn Genetic screenings
- required in all states
- number of screened disorders varies by state
- MI screens for 50+ disorders
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Karyotyping
- used to examine chromosomes (number and structure)
- almost any tissue can be used
- takes about a week to get results
- type of genetic testing
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Fluorescence in situ hybridization (FISH)
- maps genetic material in a person's cells
- used to visualize specific genes or portions of genes.
- results available much faster than karyotyping
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genetic counseling
- after testing, family is seen for genetic counseling.
- results are presented
- questions are answered
- planning for medical interventions, if necessary
- determine risk of recurrance
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SLP role in syndrome ID
- understanding the effects on communication and other developmental issues.
- interaction with other professionals for patient management.
- making referrals for further study.
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Normal development of the palate
- primary palate begins at 7 weeks
- secondary palate begins at 9 weeks
- develop independent of one another.
- closure begins at the incisive foramen and proceeds forward to form the alveolar ridge and then lip. Then backward to form the hard palate and velum.
51
Primary palate
- wedge-shaped
- consists of 1. median portion of the upper lip, 2. alveolus, 3. anterior portion of maxilla to the incisive foramen
- incisive foramen
- Alveolus and anterior part of maxilla also known as the premaxilla
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Secondary Palate
- Palatal shelves or palatine processes that fuse to form the hard palate and soft palate.
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cleft lip/palate
- lack of fusion of the lip, alveolus, hard palate, and/or soft palate.
- each child is different and presents with different degree of cleft.
- many children with clefts also present with other associated anomalies.
- vary in severity.
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when does cleft lip/palate occur
- during the early embryonic period and is present at birth.
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classification of clefts
1. primary palate (cleft lip)
a. complete, b. incomplete, c. unilateral or bilateral
2. secondary palate (cleft palate)
a. complete, b. incomplete
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submucous cleft
- oral mucosa is intact
| - underlying muscle and/or bone is clefted
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Cleft lip/palate statistics
- frequency between 1:500 and 1:750 births
- complete clefts of the lip and palate are more frequent than isolated clefts of the lip or palate.
- more males show clefts of the lip and palate than females.
- more females exhibit clefts of the palate only.
- high rate in Asians than Caucasians and higher in caucasians than african americans
- associated anomalies more likely to occur in cleft palate only.
- associated anomalies more likely to occur in bilateral cleft lip and palate than unilateral clefts.
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theories of isolated cleft lip/palate
- two major theories:
1. multifactorial threshold model
2. major gene hypothesis model
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multifactorial model
- theory for isolated cleft lip/palate
- posits a threshold for expression of a cleft
- combination of genetic and environmental factors must exceed a threshold for a child to be born with a cleft
* * used frequently in genetic counseling for isolated clefts.
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major gene hypothesis
- theory for isolated cleft lip/palate
| - isolated clefting is caused by some single mutant gene
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multiple anomalies and clefting statistics
- more than 350 different syndromes include clefting as one of the presenting conditions.
- ~60% of patients present with isolated cleft lip with or w/o cleft palate.
- ~40% of the population have a syndrome.
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craniofacial anomalies
- at birth, cranial bones are bonded together by loose connections called sutures.
- sutures allow skull to grow as the child's brain grows.
- sutures eventually close and become solidified
- if a suture(s) close too early skull growth is restricted (craniosynostosis)
- occurs at rate of ~1:2000-3000 births
63
4 types of synostosis
1. sagittal synostosis- most common- skull becomes long and narrow.
2. coronal synostosis- 2nd most common
3. metopic synostosis- pointed or triangular forehead from top- sides of forehead appear pinched causing eyes to look like they are too close together.
4. Lamboid synostosis- one of most infrequent- flattening of the head on the affected side.
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Identify Anomalies
- ~70% of congenital anomalies are present in the head, face, and limbs.
- observations of these areas noninvasive and can be easily carried out by an SLP.
- SLP makes referral to a geneticist for confirmation and/or further testing.
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SLP roles include
| - craniofacial anomalies -
1. instruction on feeding and swallowing skills.
2. discussion of feeding problems and demonstrating feeding techniques.
3. discussion of the course of overall treatment.
4. discussion regarding how speech and language may be affected by clefts.
5. discussion of concomitant disorders the child may be at high risk for. eg., conductive hearing loss.
6. providing parents with an approximate time table for the provision of overall services to the child.
7. answering any other questions that caregivers might have.
8. allowing parents to voice their concerns and feelings.
9. making referrals, if necessary.
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main concerns for newborns
| - craniofacial anomalies -
- feeding
| - maintaining an adequate airway
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Types of airway obstruction
| - craniofacial anomalies -
1. tongue dorsum to posterior pharyngeal wall.
2. tongue compression of the soft palate to the pharyngeal wall
3. lateral pharyngeal wall movement that obstructs the airway.
4. pharyngeal circular constriction of the airway.
68
Treatment of upper airway problems
| - craniofacial anomalies -
1. positioning in prone (helps get the tongue out of the way)
2. nasopharyngeal intubation (breathing tube)
3. oral orthopedic appliances
4. glossopexy (tongue stitched to mandible to keep out of way)
5. mandibular distraction treatment (lengthening the mandible)
6. tracheostomy
69
Obstructive Sleep Apnea
A. usually silent, especially in very small neonates
B. no loud snoring
C. inspiratory stridor either not present or intermittent.
D. high incidence in children with craniofacial anomalies.
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treatments for obstructive sleep apnea
1. CPAP
| 2. surgery
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anomalies of the ear
| - external -
1. atresia - closure of a normal opening.
2. aural atresia - closure of the auditory canal.
3. microtia - small auricle/pinna
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treatments for anomalies of the ear
| - external -
a. surgery and/or
| b. bone conduction hearing aids.
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anomalies of the ear
| - middle -
1. ossicles may be absent , hypoplastic (small in size), or ankylosed (fused).
2. tympanic membrane may be absent or hypoplastic.
3. middle ear malformations cause conductive hearing loss.
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treatments for anomalies of the ear
| - middle -
a. surgery and/or
| b. bone conduction hearing aids.
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Eustachian tube function
1. at rest, Eustachian tube is closed.
| 2. during swallowing, yawning tensor veli palatini muscle contracts to open the tube.
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purpose of opening of the eustachian tubes
a. ventilates middle ear
b. equalize middle ear pressure with environment.
c. allows fluids to drain.
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eustachian tube malfunction
children with cleft palate or submucous cleft at greater risk due to abnormality of tensor muscles.
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anomalies of the ear
| - inner -
1. malformations can occur in the cochlea, vestibular system, auditory nerve.
2. cause sensorineural hearing loss.
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treatments for anomalies of the ear
| - inner -
a. hearing aid(s)
| b. cochlear implant(s)
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Anomalies of the nose
1. nasal cavity compromised by midline cleft deformities
2. deviated septum
3. stenotic nares secondary to lip repair.
4. anterior obstruction of the nasal cavity
5. posterior obstruction of the nasal cavity
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deviated septum
| - anomalies of the nose -
1. common with unilateral cleft lip/palate
| 2. deflects to the cleft side of the nose.
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Anterior obstruction of the nasal cavity
| - anomalies of the nose -
1. due to deviated septum or stenotic nares.
| 2. causes nasal cul-de-sac resonance.
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Posterior obstruction of the nasal cavity
| - anomalies of the nose -
1. due to choanal stenosis/atresia or enlarged adenoids.
| 2. causes hyponasality
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Anomalies of the maxilla
A. mid-face deficiency aka hypoplasia
B. anterior crossbite with Class III malocclusion
C. pharyngeal and nasal airway restriction.
D. Hyponasality
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anomalies of the upper lip
Short upper lip after cleft repair
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short upper lip after cleft repair is due to..
1. basic dysmorphology from the cleft lip
2. contractile effects of the scar from the lip repair.
3. lip shortening due to protruding premaxilla.
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Short upper lip can cause..
1. cause difficulty with bilabial competence at rest
2. affect production of bilabial sounds.
3. result in labiodental placement as a substitute.
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Anomalies of the tongue
A. Macroglossia
B. microglossia, lobulated tongue - rarely cause speech problems.
C. ankyloglossia (tongue-tie)
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Macroglossia
1. tongue is very large relative to the oral cavity size.
| 2. associated with Down's Syndrome and Beckwith-Wiedeman syndrome
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Macroglossia results in..
a. lingual protrusion
b. drooling
c. airway obstruction
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Macroglossia
| - effects on speech -
a. interferes with lingual-alveolars
b. palatal-dorsal production is common
c. frontal (and occasionally lateral) distortion
d. oral cul-de-sac resonance often noted.
92
Ankyloglossia (tongue-tied)
1. congenital anomaly
2. very common
3. rarely causes speech problems.
4. on protrusion, tongue indented in midline and looks heat-shaped.
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ankyloglossia
| - clipping only necessary when.. -
a. feeding/eating is affected.
| b. gingiva separates between lower incisors.
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Tonsils and adenoids
- play a role in the immune system
95
Waldeyer's Ring
1. complex of lymphoid tissue that encircles the pharynx.
2. tonsils (palatine tonsils)
3. adenoids (pharyngeal tonsils)
4. lingual tonsils
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hypertrophic tonsils and adenoids
- common in young children
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hypertrophic tonsils can cause..
a. pharyngeal cul-de-sac resonance
b. nasal emission if tonsil limits lateral wall motion or interfere with VP closure.
c. velar fronting if it displaces the tongue down and forward.
d. difficulty swallowing a bolus.
98
hypertrophic adenoids can cause...
a. hyponasality
b. airway obstruction
c. skeletal malocclusion, if jaw is always open for oral breathing.
99
infant Oral/Pharyngeal Anatomy
A. infant oral anatomy smaller and different from adult.
| B. Pharyngeal anatomy also smaller and different from adult.
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Infant oral anatomy
| - smaller and different from adult
1. oral cavity is small relative to tongue size.
2. buccal pads are large.
3. there are no teeth.
4. tongue rests anterior to alveolar ridge and contacts lower lip.
5. Temporomandibular joint does not allow much jaw movement.
6. oral anatomy is well suited for suckling (extension-retraction movements of the tongue).
101
Infant pharyngeal anatomy
| - smaller and different from adult.
1. pharynx is short.
2. tongue base, soft palate, and pharyngeal walls in close approximation.
3. larynx is 1/3 the sie of adult and high in the hypopharynx.
4. high laryngeal position causes the epiglottis to pass superiorly to the free margin of the soft palate and project into the nasopharynx.
5. pharyngeal anatomy well suited for the suck-swallow-breathe synchrony.
6. head, chin, neck relationship are ideal for the suck-swallow-breathe synchrony
102
Purpose of feeding
1. provides oral-sensory and oral-motor stimulation.
2. facilitates state regulation and maintains homeostasis.
3. provides calming and sense of well-being.
4. enhances bonding and interactions with caregiver.
5. serves as a foundation for other functions, including speech.
103
normal infant feeding and early development
Oral Phase
Pharyngeal Phase
Esophageal Phase
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Oral Phase
Nipple compression and generation of negative pressure occur for sucking
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Pharyngeal Phase
Tongue base, velum, and posterior pharynx provide driving force for bolus transfer to esophagus
106
Esophageal Phase
- UES opens for bolus transfer to esophagus
| - LES opens to allow bolus entrance into stomach
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suck-swallow-breath ratio
1:1:1 or 2:1:1
108
Changes in Anatomy with Growth and Maturation
- significant oral, pharyngeal, and laryngeal growth takes place in the first 2 to 3 years of life
- neuromuscular function matures, particularly oral-motor function
- growth and maturation lead to changes in feeding and swallowing patterns
109
signifiant oral, pharyngeal, and laryngeal growth
- oral cavity becomes larger with mandibular growth
- tongue tip descends and moves posteriorly
- teeth erupt
- pharynx elongates
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Children with significant feeding problems may need
- a nasogastric tube (NG tube).
| - a gastrostomy tube (G tube) might also be used.
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NG tube
Nasogastric tube
- tube passed through one naris into the stomach
- syringe is used to deliver food through the tube
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G tube
Gastronomy tube
- tube is inserted directly into the stomach
- bolus or continuous feeding
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feeding problems warranting NG/G tube include
- oral sucking problems
- extended feeding
- nasal reflux
- choking
- gagging
- excessive air intake
114
Feeding problems for children with cleft lip and alveolus only
- infant may have initial problems achieving an adequate lip seal on the nipple.
- inadequate seal may cause difficulty generating negative pressure for sucking.
115
Feeding problems for children with cleft palate only
- depends on the extent of the cleft
- infant may be unable to generate negative pressure for suction.
- infant may be unable to find a hard palatal surface for compression of the nipple
- infant may experience nasal regurgitation.
116
Feeding problems for children with both cleft lip and palate
- infant will have significant difficulty with all aspects of feeding
- significant nasopharyngeal reflux
- breastfeeding is usually not possible
117
Feeding after cleft lip and palate repair
- post op recommendations vary
- some discourage sucking and may recommend cup or spoon instead
- some recommend supplemental tube feeding for a short time
- some allow unrestricted feeding
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Craniofacial anomalies likely to cause feeding problems
- micrognathia
- macroglossia
- pharyngeal stenosis
- laryngeal cleft
- tracheoesophageal fistula
- glossoptosis
- midface retrusion
- choanal atresia
119
Conditions that often affect feeding and swallowing
- Pierre Robin sequence
- Moebius syndrome
- hemifacial microsomia
120
Most infants with clefts can feed with _________ __________.
simple modifications
121
Considerations for modified nipples
- pliability - helps reduce suction and compression required
- shape - traditional vs elongated (NUK style often works better)
- length - should provide adequate contact between palate and tongue
- hole type - affects flow rate, round or x shaped.
- hole size - affects flow rate
122
Bottle modifications
- angled neck bottle
- helpful when positioning has to be very upright
- allows for downward flow of milk without forcing baby to adapt an extended head-neck position.
123
Positioning the infant
- semi-upright (at least 60 degrees) is best
- facilitates control of jaw, cheek, lip, and tongue movements
- allows gravity to assist with swallow
- helps prevent nasal regurgitation
124
positioning of the nipple
- place nipple under palatal bone to aid nipple compression.
| - place nipple on opposite side of cleft lip.
125
Pacing intake
- fluid must be provided in rhythm with the infant's sucking compressions
- feeding should modify pace when there are signs of stress
126
ways to regulate flow
- tilt nipple slightly upwards
| - partially remove the nipple from the oral cavity
127
signs of stress when feeding
- eye widening or changes in facial expression
- decrease in level of alertness
- avoidance of feeding
- coughing or choking
- signs of excessive air intake
- signs of fatigue
128
additional strategies to help with feeding
- provide jaw and cheek support
- preventing excessive air intake (increase frequency of burping, once every ounce)
- manage nasal regurgitation
- feeding should be consistent (same nipple, bottle and position)
129
Feeding Obturators
- prosthetic appliance to assist with feeding
- there are pros and cons
- most cleft palate centers do not recommend their use
130
Oral Hygiene
- infants with clefts have fluids in cleft area and nose -> can cause infection
- caregiver should cleanse cleft and surrounding areas after feedings with a washcloth, gauze, or toothette
131
transitioning to cup
- consider when developmentally appropriate.
- Medela SoftCup feeder can help with transition
- most surgeons recommend transitioning prior to surgery
- Nipple in the mouth and sucking can cause breakdown of cleft repair.
132
Introducing solid foods
- usually around 4-6 months
- rice cereals and strained food
- use appropriate positioning, small boluses, slow pace, alternate with liquid to assist with clearance
133
Assessment instruments for complex feeding problems
- VFSS
| - FEES
134
Assessing complex feeding problems
- assess infant's ability to safely feed
| - determine effect of compensatory strategies on feeding performance.
135
Feeding specialist team members
- gastroenterologist
- nutritionist
- nurse
- SLP
- OT
- behavioral psychologist
- otolaryngologist
- pulminologist
- consulting radiologist
136
Clefts and breastfeeding
- trials should be supported
- not usually a problem with cleft lip
- very challenging with cleft palate due to difficulties with compression and suction
- upright position is recommended
- pumping breast milk should be recommended when breastfeeding is not possible.
137
supplemental systems for breastfeeding
- uses a reservoir and a tube system
| - system supplements the breast milk.
138
Dentition - definition
position of the teeth
139
Occlusion - definition
position of the jaws relative to one another
140
Dental/Occlusal anomalies
- common in children with cleft or craniofacial anomalies
- dental anomalies have greatest effect on speech if present before or during speech development
- dental anomalies have least effect on speech when occur after development of speech
- can cause articulation errors
- SLP must correct these artic errors
141
Normal dentition
- Deciduous (baby) teeth - 20 total; 10 in each arch.
- succedaneous (permanent) teeth - 32 total; 16 in each arch.
- central and lateral incisors in premaxilla
- canine and lateral incisors border incisive sutures
142
Normal occlusion
- Class one occlusion
- important for: aesthetics, biting & chewing, and speech.
- overjet
- overbite
143
Normal dentition and speech
- upper and lower lips must be able to approximate for bilabial and labiodental sounds
- tongue rests in mandible, just under alveolar ridge
- tongue must be able to move up and down
- alveolars -> closing teeth is done to elevate mandible, positioning the tongue tip under alveolar ridge.
- alveolars require contact between tongue tip and alveolar ridge
144
abnormal structures and occlusion can cause
- obligatory distortion
| - compensatory error
145
Obligatory Distortion
- placement is normal, but structural abnormalities interfere with articulation.
- causes speech sound distortion
146
Compensatory error
- articulation altered to compensate for structural abnormalities.
- causes sound substitution error
147
Dental anomalies
- abnormal overjet (buck teeth)
- abnormal overbite
- underjet (anterior crossbite)
- underbite
- rotated/malformed teeth
- supranumerary (too many) teeth
- ectopic (erupting in wrong place) teeth
- missing teeth
- open bite
- crossbite
- protruding premaxilla
148
effects of abnormal over jet
- horizontal relationship between incisors exceeds 2mm
- can affect production of bilabials
- labiodental placement may be used as a substitute
149
effects of underjet
- reversal of the normal upper to lower incisor relationships.
- upper incisors are inside lower incisors
- may cause maxillary teeth to interfere with tongue tip placement for lingual alveolar sounds
150
Abnormal overbite
- too much overlap of upper incisors over lower incisors
151
underbite
aka deep bite
| vertical overlap of lower incisors over upper incisors
152
Effects of underbite or overbite
- can shorten vertical dimension of oral cavity during occlusion
- > can cause crowding of tongue tip movement
- > can affect lingual-alveolar sounds
153
rotated teeth
- common in craniofacial anomalies
| - central incisors and lateral incisors (if present) often rotated toward cleft
154
effects of rotated teeth
- if tooth is in area of tongue tip movement, the airstream could be diverted laterally, causing a lateral lisp
- lateral distortion can also occur if there is an attempt to compensate for the position and interference of the tooth
155
Supernumerary teeth
- May interfere with tongue tip movement during speech
| - effect on speech depends on the size and position of the teeth
156
effect of supernumerary (too many) teeth/ectopic (normal teeth that erupt in abnormal positions) teeth
- can cause lateral distortion
157
missing teeth
- lateral incisors and/or canines often missing because they border the line of the cleft.
- effect on teeth depends on size of oral cavity and the extent of crowding
158
open bite
- one or more maxillary teeth fail to occlude with the opposing mandibular teeth
159
open bite
| - causes -
- missing teeth
- poor occlusion due to digit or pacifier sucking habits.
- skeletal discrepancies
160
crossbite
- maxillary teeth are inside the lower teeth
| - common with history of cleft
161
crossbite types
- single tooth
- anterior crossbite
- lateral crossbite
- posterior crossbite
- complete crossbite
162
effects of crossbite
- can cause maxillary teeth to articulate against tongue during occlusion causing:
+ fronting of alveolars
+ lateral distortion alveolar fricatives
+ interference with labio-dental placement resulting in a reverse labio-dental placement.
163
posterior crossbite
- involves posterior teeth (molars)
- unilateral or bilateral (often bilateral with history of cleft palate
- results in a narrow maxillary arch and intra-oral crowding.
