Paediatrics Flashcards
Craniosynostosis
Premature fusion of one or several of the cranial sutures.
Issues:
increased intracranial pressure
visual impairment
deafness
Sequence of Closure of Sutures
Metopic (frontal) Frontal -mFront to
Back First (2-3 months)
Coronal: Frontal & Parietal
Lateral to Medial
Second
Lambdoid: Parietal & Occipital
Lateral to Medial
Third
Sagittal: Parietal Back to Front
Fourth
- Sutures normally have a serrated (saw tooth) contour
- With early closure the suture will lose the serrated appearance - becoming more dense
and sharp. Eventually the suture will disappear completely. - For the purpose of multiple choice, you should think about synostosis (early closure) as
likely syndromic - and focus your memorizing on this point. - Having said that, sagittal and unilateral coronal synostosis are typically idiopathic
Types of Craniosynthosis
Metopic
(frontal) Trigonocephaly
Coronal Brachycephaly
Lambdoid Turricephaly
(if bilateral)
Sagittal
Scaphocephaly
or
Dolichocephalic
Trigonocephaly
Metopic Synostosis
* Eyes are close together (hypotelorism)
* Ethmoid sinuses underdeveloped
* Medial part of the orbit slants up
* Single suture synostosis most frequently
associated with cognitive disorders (growth
restriction of the frontal lobes)
“Quizzical Eye” appearance
Brachycephaly
Coronal Synostosis
* Unilateral subtype is more common.
* Unilateral type causes the ipsilateral orbit to
elevate, and contralateral frontal bone to
protrude “frontal bossing”
* Bilateral form is Rare - should make you think
syndromes (Borat’s brother Bilo*).
“Harlequin
Eye”
* if unilateral.
Turricephaly
Lambdoid synostosis
(if bilateral)
* Tall Cranium (oxycephaly, acrocephaly)
* See Next Page for Unilateral Discussion
Least Common Form
Scaphocephaly
or
Dolichocephalic
Sagittal synostosis - most common form
* Long, Narrow Head.
* Looks like an upside-down boat.
* Usually the kids have a normal IQ
* Usually the kids do NOT have hydrocephalus
* Associated with Marfans
(both are tall and skinny).
POSITIONAL
PLAGIOCEPHALY
Infants that sleep on the same side every night develop a flat spot on the preferred dependent area of the head (occipital flattening).
Onset: Weeks After Birth
Ipsilateral Ear: Anterior
Frontal Bossing: Ipsilateral
Most common cause of an abnormal
skull shape in infant
Management is conservative
(sleep on the other side for a bit)
True Unilateral Lambdoid Synostosis
If this is bilateral think underlying
Rhombencephalosynapsis
Onset: Birth
Ipsilateral Ear: Posterior / Inferior
Frontal Bossing: Contralateral
Rare as Fuck
Management is Surgery
THIS vs THAT: Positional Plagiocephaly vs True Unilateral Lambdoid Synostosis
Next steps?
Outside of the jungle (or the year 1987), the
diagnosis of synostosis is going to be made with history and CT + 3D.
If asked what test to order I would say
CT with 3D recons. Having said that, they could show you a skull plain film (from 1987) and ask you to make the diagnosis on that.
If the test writer was feeling particularly cruel
and bitter he/she could show the diagnosis
with ultrasound. In that case, remember that
a normal open suture will appear as an
uninterrupted hypoechoic fibrous gap
between hyperechoic cranial bones (Bright -
Dark - Bright, Bone - Suture - Bone).
Although certain MR gradient sequences can
be used, MRI has traditionally been
considered unreliable in identifying sutures
individually.
Buzz words of skull X-ray/CT and NF1
For the purpose of multiple
choice, there are numerous
random bone buzzwords
that are supposed to elicit
the reflexive diagnosis
NF-1 in your brain when
you hear / read them.
The more common ones include:
* Absence / Dysplasia of the Greater
Sphenoid Wing,
* Tibial Pseudoarthrosis,
* Scoliosis, and
* Lateral Thoracic Meningocele.
I’d like to add “bone defect in the region
of the lambdoid suture ” or the “asterion
defect” to that list of reflex generators.
It’s rare and poorly described - therefore
potentially high yield.
Clover Leaf Skull Syndrome
- Also referred to as Kleeblattschadel for the purpose of
fucking with you - Contrary to what the name might imply - this complex
deformity is not associated with an increased ability to hit
green lights, reliably find good parking spots, or win the
lottery. I think that’s because the shape is more 3 leaf clover, and not
4 leaf One might assume, a head shaped like a 4 leaf clover would
probably be luckier. - Instead, this deformity is characterized by enlargement of the head
with a trilobed configuration, resembling a three-leaved clover. - Results from premature synostosis of coronal and lambdoid sutures
(most commonly), but often the sagittal closes as well. - Hydrocephalus is a common finding.
- Syndromic Associations: Thanatophoric dysplasia, Apert syndrome
(severe), Crouzon syndrome (severe)
Additional Craniosynostosis Syndromes:
Most of the time (85%) premature closure is a primary (isolated) event, although
it can occur as the result of a syndrome (15%). The two syndromes worth having
vague familiarity with are Apert’s and Crouzon’s.
Apert’s Syndrome
Brachycephaly (usually)
Fused Fingers (syndactyly) - “sock hand”
—typically symmetrically fused hands and feet
Crouzon’s Syndrome
Brachycephaly (usually)
1st Arch structures (maxilla and mandible hypoplasia).
Hydrocephalus (more than Apert’s)
Chiari I malformations 3: ~70% of cases
Associated with patent ductus arteriosus and aortic
coarctation.
Short central long bones (humerus, femur) - “rhizomelia’’
Crouzon’s ‘C’s: Coronal sutures fused, Can’t Chew (1st arch structures), Chiari I,
Coarctation, hydroCephalus, Central bones short (rhizomelia). Crazy eyes (exopthalmos).
What are the 3 different skull marking patterns?
Convolutional Markings
Copper Beaten
Luckenschadel - “Lacunarr”
Convolutional Markings
Normal gyral impressions on
the inner table of the skull.
You also see them along the
anterior portions of the skull not
just the posterior.
You see them primarily during
normal rapid brain growth (age
3-7).
Usually mild and favors the
posterior skull.
If you see them along the more
anterior skull then you should
think about a “copper beaten”
skull from the increased
intracranial pressure.
Copper Beaten skull markings
The same thing as convolutional
markings (the normal gyral
impressions), just a shit ton
more of them.
You also see them along the
anterior portions of the skull not
just the posterior.
Think about things that cause
increased intracranial
pressure.
Classic examples;
* Craniosynostosis
* Obstructive Hydrocephalus
Luckenschadel Markings
Oval, round, and finger shaped
defects (craters) within the
inner surface of the skull. Most
prominent in parietal bones.
Different than Copper Beaten
in that:
(A) They aren’t gyriform.
(B) They aren’t related to
increased ICP.
(C) They are usually present at
birth.
Instead they are the result of
defective bone matrix.
Classic Association:
* Cliiari II malformation /
Neural Tube Defects.
Lytic Skull Lesions
Lytic skull lesions in kids can come from a couple of different things
LCH
Infection
Tumour-Mets,
Cysts: Epidermoid Cysts; Leptomeningeal Cysts, etc…).
The two I want you to focus on are LCH and
the Leptomeningeal Cyst (which I will discuss later in the chapter).
LCH (Langerhans Cell Histiocytosis) - Too many fucking dendritic cells - with local invasion. It is a sorta pseudo mahgnancy thing. Nobody really understands it…. For the purpose of the exam
think about this as a beveled hole in the skull. The skull is the most common bone involved with LCH. It is a pure lytic lesion (no sclerotic border). The beveled look is because it favors the inner table. It can also produce a sequestrum of intact bone (“button sequestrum).
A Gamesmanship: If they tell you (or infer) the kid has neuroblastoma - think about a met
Parietal Foramina
These paired, mostly round, defects in the
parietal bones represent benign congenital
defects. The underlying cause is a delayed or
incomplete ossification in the underlying
parietal bones.
They can get big and confluent across the
midline. Supposedly, (at least for the big ones
> 5mm) they are associated with cortical and
venous anomalies.
Wormian bones Definition and what is normal
In technical terms, there are a bunch of extra squiggles around the lambdoid sutures.
“Intrasutural Bones” they call them.
These things are usually idiopathic - however, if
you see more than 10 you should start thinking
syndromes.
^ Gamesmanship:
< 10 = Idiopathic
> 10 = First think Osteogenesis Imperfecta
> 10 + Absent Clavicle = Cleidocranial
Differential for Excessive Wormian bones
Pyknodysostosis
Osteogenesis Imperfecta
Rickets
Kinky Hair Syndrome
(Menke s /Fucked Copper Metabolism)
Cleidocranial Dysostosis - absent clavicle
Hypothyroidism / Hypophosphatasia
One too many 21st chromosomes (Downs)
Primary Acro-osteolysis (Hajdu-Cheney)
Dermoid or Epidermoid of the skull
In the context of the skull, you can
think about these things as occurring
from the congenital misplacement of
cells from the scalp into the bony
calvarium.
The result is a growing lump of
tissue (keratin debris, skin glands,
etc…) creating a bone defect with
benign appearing sclerotic borders.
There are a few differences between
the two subtypes that could be
potentially testable (contrasted
masterfully in the chart).
Although, I suspect a “what is it ? ”
type question is more likely. As
such, look through some google
image examples to prepare yourself
for that contingency.
Epidermoid of the Skull
Histology: Only Skin
(Squamous
Epithelium)
Age of Onset: Present between
age 20-40
Location: Parietal Region is
Most Common
(“behind the ears ”)
CT: CSF Density
MRI: T1 Variable,
T2 Bright,
NO Enhancement
Dermoid of the Skull
Histology: Skin + Other Stuff
Like Hair Follicles,
Sweat Glands Etc..
Age of Onset: Typically have an earlier presentation
Location: Tend to midline. The skin ones tend to be around the orbits. Associated with encephalocoeles - especially when midline
CT: More heterogenous with calcifications (internal or peripheral may be present)
MRI: T1 intense, T2 intense +/- wall enhancement
Scalp Haematomas
There are 3 scalp hematoma subtypes. Because the subtypes are fairly similar, there is a high likelihood a sadistic multiple choice writer will attempt to confuse you on the subtle differences - so let’s do a quick review.
Subgaleal Haemorrhage
Cephalohaematoma
Caput Succedaneum
Subgaleal Haemorrhage
Location: Deep to the Aponeurosis
(between aponeurosis and
periosteum)
Suture Relationship: NOT limited by
suture lines
Trivia: Covers a much larger area
than a cephalohematoma
Complications: Potentiallv life-threatening
- rapid blood loss.
Often not seen undl 12-72
hours post delivery.
Cause: Vacuum Extraction
Cephalohaematoma
Location: Under the Periosteum
(skin of the bone)
Suture Relationship: Limited bv suture lines
(won’t cross sutures)
Trivia: Outer border may calcify as a rim
and leave a deformity - sorta like
a myositis ossificans.
Complications: Usually requires no intervention
(resolves within a few weeks)
Can get super infected (E.Coli).
Abscess would require drainage.
Can cause skull osteomvelitis.
Cause: Instrument or Vacuum Extraction
Caput Succedaneum
Location: Subcutaneous
Hemorrhage
(superficial to
the aponeurosis)
Suture Relationship: NOT limited by
suture lines
Trivia:
Complications: Requires no
intervention
(resolves within
a few days)
Cause: Prolonged Delivery
Skull Fractures
Accidental (and non-accidental) head trauma is supposedly (allegedly, allegedly) the most common
cause of morbidity and mortality in children. As you might imagine, the pediatric skull can fracture just like the adult skull - with linear and comminuted patterns. For the purpose of multiple choice, I think we should focus on the fracture patterns that are more unique to the pediatric population:
Diastatic, Depressed, and “Ping-Pong”
- Diastatic Fracture: This is a fracture along / involving the suture. When they intersect it is usually fairly obvious. It can get tricky when the fracture is confined to the suture itself The most common victim of this sneaky fracture is usually the Lambdoid, followed by the Resident reading the case on
night float .. .with Attending backup (asleep in bed). How does one know there is traumatic injury to a suture ? Classically, it will widen. This is most likely to be shown in the axial or coronal plane so you can appreciate the asymmetry ( > 1 mm asymmetry relative to the other side). - Depressed Fracture: This is a fracture with inward displacement of the bone. How much inward displacement do you need to call it “depressed” ? Most people will say “equal or greater to the thickness of the skull.” Some people will use the word “compound” to describe a depressed fracture that also has an associated scalp laceration. Those same people may (or may not) add the
word “penetrating ” to describe a compound fracture with an associated dural tear.
Will any of those people be writing the questions ? The dark side clouds everything. Impossible to see the future is. - Ping Pong Fracture: This is actually another subtype of depressed fracture but is unique in that it is a greenstick or “buckle” type of fracture. Other potentially testable differences include:
- Outcomes: Ping Pong fractures typically have a favorable / benign clinical outcome
(depressed fractures have high morbidity). - Etiology: Diastatic and depressed fracture types usually require a significant whack on
the head. Where as “ping pong” fractures often occur in the setting of birth trauma
(Mom’s pelvic bones +/- forceps). - Imaging Appearance: Ping Pong fractures are hard as fuck to see. To show this on a
test you’d have to have CT 3D recons demonstrating a smooth inward deformity. You could never see that shit on a plain film. I can’t imagine anyone being a big enough
asshole to ask you to do that. Hmmm…. probably.
Fracture vs normal suture
Fracture: >3 mm, wide centre, darker and straight line with angular turns
Normal suture: <2mm, equal width, lighter and squiggly line with curves.
Management of Fracture
CT
Unlike linear fractures (which usually heal without complication), depressed fractures often require surgery. Some general indications
for surgery would include:
- Depression of the fragments > 5mm (supposedly fragments more
than 5mm below the inner table are associated with dural tears), - Epidural bleed
- Superinfection (abscess, osteomyelitis)
- “Form” (cosmetic correction to avoid looking like a gargoyle),
- “Function” (if the frontal sinus is involved, sometimes they need
to obliterate the thing to avoid mucocele formation).
Leptomeningeal Cyst
A favorite of board examiners since the Cretaceous Period.
Typical Pathogenesis:
- Step 1; You fracture your noggin,
tear the underlying dura.
AND - Step 2: Leptomeninges herniate through the torn dura into the fracture site.
Step 3: Over time (a few months) CSF
pulsations progressively widen the
fracture site and prohibit normal healing.
Step 4: You know you shouldn’t, but you
just can’t resist the urge to poke your own
brain through the now cavernous cranial
defect.
Step 5: The poking triggers a powerfiil hallucinogenic experience. You have a telepathic
conversation with a room filled with self transforming elf machines.
You are overwhelmed with tremendous curiosity about exactly
what/who they are and what they might be trying to show you.
Step 6: You develop epilepsy from poking your brain too much.
Or was it not enough? - you can’t remember
Sinus Pericranii
A rare disorder that can be shown as a focal skull defect with an associated vascular malformation. The
underlying pathology is a low flow vascular malformation - which is a communication between a dural
venous sinus (usually the superior sagittal) and an extra cranial venous structure via the emissary veins.
It is not classically associated with discoloration of the overlying skin.
Most likely way to show this:
(1) MRI - with some type of vascular sequence
post contrast or MRA/TOF.
(2) CT showing the skull defect - wanting a next step
(ultrasound or MRI to demonstrate the vascular
component).
NAI - what characteristic findings
Inconsistent history
Subdural haematoma
Retinal haemorrhage
DAI/Parenchymal Contusion
Cerebral oedema, stroke
Depressed skull fracture or fracture crossing suture line
Chronic subdural (CSF Density) vs prominent CSF spaces
Chronic subdural: Medial displacement of bridging vein and usually unilateral. If bilateral, usually asymmetric in size.
Priminant CSF spaces - cortical veins are adjacent to the inner table. Usually symmetrical.
NAI and ICH
Subdurals have a stronger association with NAI relative to epidurals e.g. vigorous shaking tearing bridging cortical veins.
Look high: Thrombosed hyperdense cortical veins at the vertex.
Look low: Retroclival haematoma (thin hyper dense sliver in the pre-pontine region.
Look lower: oedema within the cervical soft tissues.
Periventricular Leukomalacia HIE
This is the result of an ischemic / hemorrhagic injury, typically from a hypoxic insult during
birthing.
The kids who are at the greatest risk are premature and little (less than 1500 g).
The testable stigmata is cerebral palsy - which supposedly develops in 50%.
The pathology favors the watershed areas (characteristically the white matter dorsal and lateral to the lateral ventricles).
The milder finding can be very subtle. Here are some tricks:
(1) Use PreTest Probability: The kid is described as premature or low birth weight.
(2) Brighter than the Choroid: The choroid plexus is an excellent internal control. The
normal white matter should always be less bright (less hyperechoic) when compared to the
choroid.
(3) “Blush ’’ and “Flaring” : These are two potential distractors that need to be differentiated
from legit grade 1 PVL.
“Blush ” describes the physiologic brightness of the posterosuperior periventricular white matter - this should be less bright than choroid, and have a more symmetric look. “Flaring” is similar to blush, but a more hedgy term. It’s the
word you use if you aren’t sure if it’s real PVL or just the normal brightness often seen in
premature infants white matter.
The distinction is that “flaring” should go away in a
week.
Grade 1 PVL persists > 7 days.
The later findings are more obvious with the development of cavitary periventricular cysts.
The degree of severity is described by the size and distribution of these cysts. These things take
a while to develop - some people say up to 4 weeks. So, if they show you a day 1 newborn
with cystic PVL they are leading you to conclude that the vascular insult occurred at least 2
weeks prior to birth (not during birth - which is often the case).
The most severe grade (4), which has subcortical cysts, is actually more common in
full term infants rather than preterms.
BESSI vs Subdural Hygroma
Positive cortical vein sign = BESSI or cortical atrophy
Negative cortical vein sign = subdural hygroma
Retroclival haematoma
Below the tectorial membrane = epidural
Above the tectorial membrane = subdural
Enlarged extra-axial
fluid spaces: BESSI
Extra-axial fluid spaces are
considered enlarged if they
are greater than 5 mm.
BESSI is the name people
throw around for “benign
enlargement of the
subarachnoid space in
infancy.” The etiology is supposed to
be immature villa (that’s why
you grow out of it).
It’s the most common cause of macrocephaly.
Typically presents around month 2 or 3, and has a strong male predominance.
Typically resolves after 2 years with no treatment,
There is an increased risk of subdural bleed - either spontaneous or with a minor trauma. This
subdural is usually isolated (all the same blood age), which helps differentiate it from nonaccidental
trauma, where the bleeds are often of different ages.
Trivia - Pre-mature kids getting tortured on ECMO often get enlarged extra-axial spaces. This isn’t really the same thing as
BESSI but rather more related to fluid changes / stress.
Enlarged
symmetric
subarachnoid
spaces favoring
the anterior aspect
of the brain
(spaces along the
posterior aspect of
the brain are
typically normal).
Brain parenchyma is normal and there is either
normal ventricle size or very mild communicating hydrocephalus. Communicating meaning that all 4 ventricles are big.
Germinal Matrix Hemorrhage [ GMH)
the
germinal matrix is highly vascular. It’s also very friably and susceptible to stress.
Additionally, premature brains suck at cerebral blood flow auto-regulation. Mechanism:
Fragile vessels + too much pressure/flow = bleeds
An important thing to understand is that the germinal matrix is an embryological entity. So it
only exists in premature infants. As the fetus matures the thing regresses and disappears.
By 32 weeks, germinal matrix is only present at the caudothalamic groove.
By 36 weeks, you basically can’t have it (if no GM, then no GM hemorrhage).
Take home point - No GM H em orrhage in a full term infant.
Gamesmanship: Similar looking bleed in a fiill term infant say “choroid plexus
hemorrhage” (not GMH).
The scenario will always call the kid a premature infant (probably earlier than 30 weeks). The
earlier they are bom the more common it is. Up to 40% occur in the first 5 hours, and most
have occurred by day 4 (90%). A good thing to remember is that 90% occur in the first week.
Screening for GMH: Who, Why and When?
Head US is used to screen for this pathology. Testable trivia includes:
- Who should be screened? Premature Infants (<32 weeks, < 1500 grams). Premature Infants
with Lethargy, Seizures, Decreased Hematocrit or a history of “he don’t look so good.” - When do you do the head US? First week of life (remember this is when 90% of them occur).
Some people will tell you - “first week and first month” (but that varies from institution).
Some people will also say - “every kid gets a head US prior to discharge from the NICU” - but
that is mainly done to detect PVL (not necessarily GMH).
