Cerebral palsy

==Causes==
[[File:Fetal thrombotic vasculopathy - intermed mag.jpg|thumb |alt=refer to caption |[[Micrograph]] showing a fetal ([[placenta]]l) vein thrombosis, in a case of [[fetal thrombotic vasculopathy]]. This is associated with cerebral palsy and is suggestive of a [[hypercoagulable state]] as the underlying cause.]]
Cerebral palsy is due to abnormal development or damage occurring to the developing brain.<ref name="Yar2013" /> This damage can occur during pregnancy, delivery, the first month of life, or less commonly in early childhood.<ref name="Yar2013" /> Structural problems in the brain are seen in 80% of cases, most commonly within the [[white matter]].<ref name="Yar2013" />
More than three-quarters of cases are believed to result from issues that occur during pregnancy.<ref name="Yar2013" /> Most children who are born with cerebral palsy have more than one risk factor associated with CP.<ref>{{cite journal| vauthors = Eunson P |title=Aetiology and epidemiology of cerebral palsy|journal=[[Paediatrics and Child Health]]|date=September 2016|volume=26|issue=9|pages=367–372|doi=10.1016/j.paed.2016.04.011}}</ref> Cerebral palsy is not contagious and cannot be contracted in adulthood. CP is almost always developed en utero, or prior to birth.<ref>{{Cite web |title=Medical Errors During Pregnancy can Result in Cerebral Palsy |url=https://birthinjurylawyer.com/cerebral-palsy-lawyer |access-date=2024-03-16 |website=birthinjury.com |language=en}}</ref>

While in certain cases there is no identifiable cause, typical causes include problems in intrauterine development (e.g. exposure to radiation, infection, [[Intrauterine growth restriction|fetal growth restriction]]), [[hypoxia (medical)|hypoxia]] of the brain (thrombotic events, [[placental insufficiency]], [[umbilical cord prolapse]]), birth trauma during labor and delivery, and complications around birth or during childhood.<ref name="CPBeuk" /><ref>{{cite journal | vauthors = Sayed Ahmed WA, Hamdy MA | title = Optimal management of umbilical cord prolapse | journal = International Journal of Women's Health | volume = 10 | pages = 459–465 | date = 2018-08-21 | pmid = 30174462 | pmc = 6109652 | doi = 10.2147/IJWH.S130879 | doi-access = free }}</ref><ref name="nejm915" />

In Africa [[birth asphyxia]], [[kernicterus|high bilirubin levels]], and infections in newborns of the central nervous system are main cause. Many cases of CP in Africa could be prevented with better resources available.<ref>{{cite journal | vauthors = Burton A | title = Fighting cerebral palsy in Africa | journal = The Lancet. Neurology | volume = 14 | issue = 9 | pages = 876–877 | date = September 2015 | pmid = 26293560 | doi = 10.1016/S1474-4422(15)00189-1 | doi-access = free }}</ref>

===Preterm birth===
Between 40% and 50% of all children who develop cerebral palsy were born prematurely.<ref name="dev_beh_peds_2009" /> Most of these cases (75–90%) are believed to be due to issues that occur around the time of birth, often just after birth.<ref name="Yar2013" /> Multiple-birth infants are also more likely than single-birth infants to have CP.<ref name="saunders_2011" /> They are also more likely to be born with a [[low birth weight]].<ref>{{Cite journal |last1=Demeši Drljan |first1=Čila |last2=Mikov |first2=Aleksandra |last3=Filipović |first3=Karmela |last4=Tomašević-Todorović |first4=Snežana |last5=Knežević |first5=Aleksandar |last6=Krasnik |first6=Rastislava |date=April 12, 2016 |title=Cerebral palsy in preterm infants |url=https://pubmed.ncbi.nlm.nih.gov/29308865/ |journal=National Library of Medicine |volume=73 |issue=4 |pages=343–348 |doi=10.2298/VSP140321019D |issn=0042-8450 |pmid=29308865}}</ref>

In those who are born with a weight between 1&nbsp;kg (2.2 lbs) and 1.5&nbsp;kg (3.3 lbs) CP occurs in 6%.<ref name="Osk2013" /> Among those born before 28&nbsp;weeks of [[gestation]] it occurs in 8%.<ref name="Osk2016">{{cite journal | vauthors =  | title = Erratum | journal = Developmental Medicine and Child Neurology | volume = 58 | issue = 3 | pages = 316 | date = March 2016 | pmid = 26890023 | doi = 10.1111/dmcn.12662 | s2cid = 221682193 | doi-access = free }}</ref>{{efn|Incorrectly stated as 11% in 2013 <ref name="Osk2013" />}} Genetic factors are believed to play an important role in prematurity and cerebral palsy generally.<ref name="hallman_2012" /> In those who are born between 34 and 37&nbsp;weeks the risk is 0.4% (three times normal).<ref name="poets_2012" />

===Term infants===
In babies who are born at term risk factors include problems with the placenta, [[birth defect]]s, low birth weight, [[meconium aspiration|breathing meconium into the lungs]], a delivery requiring either the use of instruments or an emergency [[Caesarean section]], birth asphyxia, [[seizure]]s just after birth, [[Infant respiratory distress syndrome|respiratory distress syndrome]], [[hypoglycaemia|low blood sugar]], and infections in the baby.<ref name="mcintyre_2013" />

{{as of |2013}}, it was unclear how much of a role birth asphyxia plays as a cause.<ref name="ellenberg_2013" /> It is unclear if the size of the placenta plays a role.<ref name="teng_2012" /> {{as of|2015}} it is evident that in advanced countries, most cases of cerebral palsy in term or near-term neonates have explanations other than asphyxia.<ref name="nejm915" />

===Genetics===
[[File:Autosomal recessive - en.svg|right|thumb|Autosomal recessive inheritance pattern]]
Cerebral palsy is not commonly considered a genetic disease. About 2% of all CP cases are expected to be inherited, with [[GAD1|glutamate decarboxylase-1]] being one of the possible enzymes involved.<ref name="omim" /> Most inherited cases are [[autosomal recessive]].<ref name="omim" /> However, the vast majority of CP cases are connected to brain damage during birth and in infancy. There is a small percentage of CP cases caused by brain damage that stemmed from the prenatal period, which is estimated to be less than 5% of CP cases overall.<ref name="cdc.gov">{{Cite web|url=https://www.cdc.gov/ncbddd/cp/causes.html|title = Causes and Risk Factors of Cerebral Palsy &#124; CDC|date = 15 December 2020}}</ref> Moreover, there is no one reason why some CP cases come from prenatal brain damage, and it is not known if those cases have a genetic basis.<ref name="cdc.gov"/>

[[Cerebellar hypoplasia]] is sometimes genetic<ref>{{cite journal | vauthors = Parolin Schnekenberg R, Perkins EM, Miller JW, Davies WI, D'Adamo MC, Pessia M, Fawcett KA, Sims D, Gillard E, Hudspith K, Skehel P, Williams J, O'Regan M, Jayawant S, Jefferson R, Hughes S, Lustenberger A, Ragoussis J, Jackson M, Tucker SJ, Németh AH | title = De novo point mutations in patients diagnosed with ataxic cerebral palsy | journal = Brain | volume = 138 | issue = Pt 7 | pages = 1817–1832 | date = July 2015 | pmid = 25981959 | pmc = 4572487 | doi = 10.1093/brain/awv117 | quote = [...]a putative new gene had been found in Case 7, which is currently under investigation and will be presented elsewhere. }}</ref> and can cause [[ataxic cerebral palsy]].<ref>{{cite journal | vauthors = Parolin Schnekenberg R, Perkins EM, Miller JW, Davies WI, D'Adamo MC, Pessia M, Fawcett KA, Sims D, Gillard E, Hudspith K, Skehel P, Williams J, O'Regan M, Jayawant S, Jefferson R, Hughes S, Lustenberger A, Ragoussis J, Jackson M, Tucker SJ, Németh AH | title = De novo point mutations in patients diagnosed with ataxic cerebral palsy | journal = Brain | volume = 138 | issue = Pt 7 | pages = 1817–1832 | date = July 2015 | pmid = 25981959 | pmc = 4572487 | doi = 10.1093/brain/awv117 | quote = Case 6 had cerebellar vermis hypoplasia and Case 7 had global cerebellar hypoplasia (vermis and cerebellar hemispheres), both these cases were clinically stable. }}</ref>

===Early childhood===
After birth, other causes include toxins, severe [[jaundice]],<ref name="cdccauses" /> [[lead poisoning]], physical brain injury, [[stroke]],<ref>{{cite web|title = Cerebral Palsy | work = Johns Hopkins Pediatric Neurosurgery|url = http://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/pediatric_neurosurgery/conditions/cerebral_palsy.html|access-date = 18 September 2015| vauthors = Kieffer S |url-status = dead|archive-url = https://web.archive.org/web/20150930032633/http://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/pediatric_neurosurgery/conditions/cerebral_palsy.html|archive-date = 30 September 2015}}</ref> [[abusive head trauma]], incidents involving hypoxia to the brain (such as [[near drowning]]), and [[encephalitis]] or [[meningitis]].<ref name="cdccauses" />

===Others===
Infections in the mother, even those not easily detected, can triple the risk of the child developing cerebral palsy.<ref name="ucpref_2004" /> Infection of the fetal membranes known as [[chorioamnionitis]] increases the risk.<ref name="bersani_2012" />

Intrauterine and neonatal insults (many of which are infectious) increase the risk.<ref name="mwaniki_2012" />

[[Rh disease|Rh blood type incompatibility]] can cause the mother's immune system to attack the baby's red blood cells.<ref name="NINDS2013" />

It has been hypothesised that some cases of cerebral palsy are caused by the death in very early pregnancy of an identical twin.<ref name="pmid16354495" />