Etiological Factors Responsible For Disability

INTRODUCTION

Disability is a worldwide phenomenon that has no boundaries and cuts across countries, sex, age, religion, race, social statuses, and economic and political positions. Its prevalence and incidence in the contemporary world are high and worrisome. It is estimated that there are more than 2 billion physically challenged people worldwide and the majority are from developing countries. EnoughInfo.com

The Nigerian National Assembly in 2013 estimated that there are over 20 million people living with disability in the country (www.nassnig.org/nass/). However, this number has increased by a wide margin because according to the Center for Disability and Development Innovations (CeDDI, 2016), the approximate number of disabled people in the country is 25 million. The United Nations (UN) projected that in every ten people in
In Nigeria, one person is suffering from one type of disability or the other.

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1. WHAT IS A DISABILITY

Defining Disability:

According to the Convention on the Rights of Persons with Disabilities, disability is used to describe the condition whereby physical and social barriers prevent a person with impairment from taking part in the normal life of the community on an equal footing with others (Article 1).

Therefore, disability is not just a mere health predicament. It is a multifarious experience that affects the person’s body and his or her ability to function equally in the society in which he or she lives According to many definitions, disability is an impairment that may be cognitive, developmental, intellectual, mental, physical, sensory or some combination of these.

Other definitions describe disability as the societal disadvantage arising from such impairments. Disability substantially affects a person’s life activities and may be present from birth or occur during a person’s lifetime

2. FACTORS RESPONSIBLE FOR DISABILITY

For a deep understanding of the topic at hand, I will like to break down the factors responsible for disability into two (2) categories. How to Handle a Bully in School

• Prenatal
• Perinatal

1. PRENATAL FACTORS

The prenatal stage is the time between conception and birth. This period is generally divided into three stages:

• Germinal stage: The two-week period after conception is called the Germinal Stage.
• Embryonic stage: The Embryonic Stage lasts from the end of the germinal stage to two months after conception.
• Fetal stage: The last stage of prenatal development is the Fetal Stage, which lasts from two months after conception until birth. Around twenty-two to twenty-six weeks after conception, the fetus reaches the age of viability, after which it has some chance of surviving outside the womb if it is born prematurely. The chances of a premature baby’s survival increase significantly with each additional week it remains
  in the mother’s uterus.

Prenatal factors include:

• Preconceptional factors
• Prenatal Infections
• Exposure to toxins
• Environmental toxins
• Maternal chronic illness
• Maternal nutritional deficiencies

a. PRECONCEPTIONAL FACTORS:

Preconceptional causes of developmental disability relate predominantly to genetic disorders or malformation syndromes. Genetic disorders are the most commonly identified causal factor for intellectual and other disabilities and include single-gene disorders, multifactorial and polygenic disorders, and chromosomal abnormalities. Genetic disorders
associated with developmental delay include aneuploidies and inborn errors of
metabolism. Steps to Apply for Belarus Student Visa in Nigeria

b. PRENATAL INFECTIONS:

i. HIV:

Maternal HIV increases the risks for prematurity and being small for
gestational age (SGA); both effects are associated with increased risk of
mortality and developmental delay. HIV enters the central nervous system
days to weeks after primary exposure. The virus causes neuronal damage
and cell death, leading to progressive encephalopathy with motor
disabilities, as well as microcephaly and brain atrophy, with cognitive
and language delays.

ii. Cytomegalovirus (CMV) :

Ten percent of affected infants show signs
of infection at birth, with a substantial risk of neurological sequelae such
as sensorineural hearing loss (SNHL), intellectual delay, microcephaly,
seizure disorders and cerebral palsy.

iii. Rubella:

There are an estimated 110,000 cases of congenital
rubella annually worldwide.  Maternal infection during pregnancy transmits
the rubella virus to the fetus, causing deafness, congenital cataracts,
microcephaly, seizures, and intellectual disability.

iv. Syphilis:

Like all the preventable STIs, syphilis has been linked to
preterm labor, low birth weight, and death. Congenital syphilis can cause
deafness, microcephaly, intellectual disability, and visual impairment
through interstitial keratitis.

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c. PRENATAL TOXINS:

i. Smoking:

Maternal smoking during pregnancy increases the risk of
placenta previa, placental abruption, and preterm labor. It also
has adverse effects on fetal growth.

ii. Alcohol:

Exposure to alcohol in utero is the most common teratogenic
cause of developmental disabilities, including microcephaly, cognitive
disability, learning disabilities, ADHD, and behavioral challenges.

iii. Other drugs:

Maternal exposure to other toxins, including recreational
drugs and certain medications (e.g., valproic acid, phenytoin sodium,
isotretinoin [Accutane]), can also cause developmental disabilities.

d. ENVIRONMENTAL TOXINS

Exposure to lead, mercury, and chemical compounds such as polychlorinated
biphenyls (PCB) and alcohol can be identified as contributing causes of
intellectual disability in 4% to 5% of cases.

i. Lead:

Lead can cross the placenta beginning at 12 weeks gestation and
accumulate in fetal tissue. Pregnant women and young children absorb
more lead when ingested; up to 70% compared with 20% for the general
population. Natural exposure occurs in soil pollution, leaded gasoline,
paint products, pesticides, and industrial activity can raise lead levels in the
air, soil, and water sources. International Scholarships( Where, When and Requirements)

ii. Mercury:

All forms of mercury can cross the placenta and be
transported into fetal blood. The most common cause of prenatal mercury
poisoning is eating fish and shellfish species known to contain higher
levels of mercury during pregnancy.

iii. Arsenic:

Arsenic is naturally present in high levels in groundwater,
which can contaminate water used for drinking, preparing food and
irrigating food crops. Arsenic is also present in the soil and prenatal exposure
is associated from both sources with intellectual disability and
developmental delay.

e. MATERNAL CHRONIC ILLNESSES

Illnesses such as diabetes, hypertension, renal disease, and autoimmune
disorders are associated with complications of pregnancy that can adversely
affect a fetus or newborn child.

Maternal diabetes increases the risk of fetal anomalies, macrosomia (a birth
weight >4000 grams), subsequent birth injury, and hypoglycemia, all of which
can negatively impact developmental outcomes in the infant. Hypertension, alone
or combined with a renal or autoimmune disorder, can cause placental
insufficiency and inadequate fetal growth.

Nutritional deficiencies

i. Folic acid deficiency:  is associated with neural tube defects.
ii. Iodine deficiency:  is considered by the WHO to be the leading and most preventable cause of brain damage worldwide.

A component of thyroid hormones, iodine is essential for brain development,
particularly from the second trimester of pregnancy through the third year of life.

2. PERINATAL FACTORS

The perinatal period commences at 22 completed weeks (154 days) of gestation
and ends seven completed days after birth. Perinatal and maternal health are
closely linked.

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Perinatal factors may include:

• Pregnancy-related complications
• Infections
• Rh isoimmunization
• Prematurity and low birth weight

A. PREGNANCY-RELATED COMPLICATIONS

In countries where prenatal and obstetrical care are difficult to access, chronic
maternal disease and pregnancy-related complications often go undetected.
Conditions that, left untreated, may contribute to premature birth and/or
the developmental delay includes:

• Gestational diabetes is associated with macrosomia, and risk of birth injury, hypoglycemia in the infant, and later gestational stillbirth.
• Hypertensive disorders (e.g., pre-eclampsia and eclampsia), which can cause
  serious, long-term disabilities, have a higher incidence in developing
  countries. Pre-eclampsia and eclampsia are associated with placental
  insufficiency and preterm delivery.
• Multigenerational pregnancies have a higher rate of obstetrical complications
  during the pregnancy and at the time of delivery.
• Birth trauma is associated with macrosomia, maternal obesity, breech
  presentation, operative vaginal delivery, small maternal size, and maternal
  pelvic anomalies. Serious birth trauma (e.g., intracranial hemorrhage) is
  uncommon but can cause developmental disabilities. Most, but not all,
  neurological injuries to peripheral nerves (e.g., brachial plexus injuries)
  resolve over time. How To Apply For Schengen Tourist Visa From Nigeria

A. PERINATAL INFECTIONS

• STIs: Congenital transmission of herpes viruses 1 and 2 is associated with a high
  risk of long-term neurological problems. Without treatment, 30% to 50% of
  infants born to mothers with untreated gonorrhea, and up to 30% with
  untreated chlamydia will develop ophthalmia neonatorum, which can lead to
  blindness if not treated early.
• Bacterial infections: can be transmitted from mother to child transplacentally,
  during pregnancy or during delivery, by passage through the birth canal.
  Congenital bacterial infections leading to neonatal sepsis and meningitis are an
  an important cause of neonatal morbidity in developing countries.
• Invasive Group B strep (GBS) occurs at an estimated rate of 0-3.06/1000 live
  births in developing countries compared to 0.24/1000 live births in developed
  countries. Invasive GBS disease is associated with long-term disabilities,
  including seizures, developmental disabilities, and vision and hearing impairment.
• Listeria Infection can occur following maternal ingestion of uncooked meats,
  prepared meat products and vegetables, and unpasteurized milk or foods made
  from unpasteurized milk. The pregnant mother may experience flu-like
  symptoms: fever, muscle aches, nausea, and diarrhea. Transmission to the fetus
  causes sepsis and meningitis with subsequent sequelae

C. Rh Isoimmunization

Undiagnosed or untreated Rh isoimmunization is associated with anemia and
severe hyperbilirubinemia, and may result in seizures, deafness, cognitive delays
and cerebral palsy in infants who survive.

D. PREMATURITY AND LOW BIRTH WEIGHT

Preterm birth (<37 weeks gestation) is a global problem. Risk factors for preterm
delivery includes multi-fetal pregnancy, uterine abnormalities, placental bleeding,
prenatal drug exposure, chronic maternal illness, hypertensive disorders,
chorioamnionitis, prolonged rupture of the membranes, and bacterial vaginosis.
Lack of prenatal care, underimmunization, and inadequate treatment for maternal
infections or other medical issues, including STIs, can all contribute to
developmental disabilities in a preterm infant.

CONCLUSIONS

Developmental disabilities can reflect a complex constellation of problems in any child,
but particularly for newcomer children, where etiology is often unclear. Sometimes a
number of pre-and perinatal risk factors are involved, coexisting and having multiple,
cumulative effects on developmental outcomes. Some signs of disability are evident at
birth, others present as late as school age.

Developmental disabilities occur worldwide. However, the lack of access to quality
prenatal, delivery, and postnatal care causes significant morbidity in developing regions.
Immigrants and refugees are at higher risk of developmental disabilities, with specific
risk factors depending on their country of origin. Healthcare providers need to be
mindful of general risks for all newcomers but also alert to specific patient risks,
recognizing the contribution of family, immigration, and ethnic history as well.

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REFERENCES

Rudolph C, Rudolph A, Lister GE, et al., eds.  Rudolph's Pediatrics, 22nd edn. New York,
NY: McGraw-Hill Professional, 2011.

American Academy of Pediatrics, Committee on Children with Disabilities, 2001. Role of
the pediatrician in family-centered early intervention services. Pediatrics
2011;107(5):1155-7.

WHO, 2012. Congenital anomalies: Fact sheet no. 370:
www.who.int/mediacentre/factsheets/fs370/en/
WHO, 2013. Rubella and congenital rubella syndrome

(CRS): www.who.int/immunization_monitoring/diseases/rubella/en/
Dagnew AF, Cunnington MC, Dube Q, et al. Variation in reported group B streptococcal
disease incidence in developing countries. Clin Infect Dis 2012; 55(1):91-102.
Centers for Disease Control and Prevention. ABCs Report: Group B Streptococcus,
2012: http://www.cdc.gov/abcs/reports-findings/survreports/gbs12.html