The document discusses Phenylketonuria (PKU) and congenital hypothyroidism. PKU is an inherited disorder that prevents the breakdown of phenylalanine. It can cause intellectual disabilities if not treated through a phenylalanine-restricted diet. Congenital hypothyroidism is caused by thyroid gland issues present at birth and can lead to developmental delays without thyroid hormone treatment. Both conditions are screened for at birth through blood tests and require lifelong management through specialized diets or thyroid hormone supplementation.

1. Endocrine Disorders
Endocrine
disorders
1

2. Phenylketonuria
PKU
Endocrine
disorders
2

3. What is PKU?
 it is an Autosomal recessive inborn error of metabolism found on the
12th chromosome
 Causing an inherited metabolic disease that passes through families
 It is rare condition characterized by the deficiency in the enzyme
(Phenylalanine Hydroxylase).
 Normally: phenylalanine  tyrosine by liver enzyme phenylalanine hydroxylase
(PAH)
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4. PKU
Genogram
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5. How PKU is Inherited?
 In order for a child to inherit PKU, both parents must be PKU carriers.
 Boys and girls are equally at risk of inheriting this disorder.
 In this condition, an amino acid called phenylalanine builds up in the
bloodstream, causing brain damage.
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6. Incidence of PKU
 1 out of 50 people are carriers of this defective gene; causing
incidence of 1 in 10,000 to 1in 15,000 births.
 Mostly those of northern European background.
 Asians, and Africans are less commonly affected.
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7. Etiology of PKU
 Phenylalanine is one of the essential amino acids found in many foods.
 The baby is born lacking the ability to break down phenylalanine into
tyrosine.
 It is characterized by higher than normal levels of phenylalanine in the blood
 The brain suffers and damaged due to a tremendous buildup of
phenylalanine which causes mental retardation
 In which mental retardation can be prevented by a specific diet low in
Phenylalanine and higher in Tyrosine
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8. Diagnosis of PKU
 Nearly all cases of PKU in the
United States are found in
newborns screening tests
after birth
 A small sample of blood to
test if the trait is present on
the 12th chromosome.
 A “heel stick” is done and
then collected on special
blotter paper
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9. Diagnostic findings
 Normal: 120 – 360 umol/L or 1.6mg/dl
 PAH Deficient:
 Mild: 600 – 1200 umol/L
 Classical: > 1200 umol/L
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10. Physical Findings
 Because Phenylalanine is involved in the body’s
production of melanin which is the pigment for skin
and hair color – children with PKU generally have
lighter skin, hair and eyes (Albinism).
 Defficience inTyrosine, affect the formation of
Hormones like Epinephrine and Thyroxine
• Accumulation of Phynylalanine leads to decreasd
neurotransmitters; Dopamine and Tryptophan
which affect the normal development of the brain
and CNS leading to disturbance in the cortical
lamination that leads to mental retardation
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11. Symptoms of PKU
 Vomiting
 Skin Rashes
 Hyperactivity
 Small head size
 Mental Retardation
 Behavioral and social problems
 Seizures tremors or jerking movements
 A musty odor in the skin, breath or urine caused by too
much Phenylketonuria
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The inability to change Phenylalanine
Hydroxylase to Phenylalanine causes all of
these symptoms.

12. Treatment of PKU
 A life long restricted diet of a reduced
protein diet is recommended to reduce
build up of phenylalanine
 Association with attention-deficit
hyperactivity disorder (ADHD) most
common problem in those who don’t
follow a strict diet
 If diet is properly followed especially in
first few years of life where it is most
crucial an outcome of better physical and
mental health will follow
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13. Treatment of PKU
 Frequent monitoring of phenylalanine levels
 Once weekly during 1st year
 Twice monthly from 1 – 12 years
 Monthly after 12 years
 Possible supplementation of tyrosine to promote
normal growth and development
 Foods high in phenylalanine, such as breast milk, meat,
chicken, fish, nuts, cheese.
 Kuvan is the first FDA approved drug for treating PKU.
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14. Medical Nutrition Therapy
 Initial
 Treatment implemented 7 – 10 days old
 Phenylalanine-free formula
 Infants and Toddlers
 90% protein requirements
 80% energy requirements
 Reliable source of vitamins and minerals
 Supplemented with evaporated milk, regular infant formula, or
breast milk during infancy and early childhood
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15. Medical Nutrition Therapy
 Later
 Low-phe content foods introduced at the appropriate age
and used as a supplement to the formula mixture
 Vegetables
 Fruits
 Breads/cereals
 Fats
 Free foods
 5-6 months: Pureed foods
 7-8 months: Finger foods
 8 – 9 months: Use of cup
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16. Daily Phenylalanine
Requirement
 0 – 3 months = 40- 70 mg/kg
 4 - 6 months = 30 - 50 mg/kg
 7 – 12 months = 30 - 40 mg/kg
 1 – 3 years = 20 – 40 mg/kg
 4 – 6 years = 15 – 35 mg/kg
 7 – 15 years = 10 – 25 mg/kg
 15 – 18 years = 5 – 15 mg/kg
 Adult = 5 – 10 mg/kg
Daily Tyrosine Requirements
 0 – 5 months
60 – 80 mg/kg
 6 – 12 months
40 – 60 mg/kg
 1 – 10 years
25 – 85 mg/kg
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17. Prevention of PKU
 Patients are highly recommend to have strong relationship with physician
 An Enzyme Assay can determine if parents carry defective gene
 Chorionic villus Sampling - screen unborn baby for possibility of PKU
 It is very important that women with PKU closely follow a strict low-phenylalanine
diet both before becoming pregnant and throughout the pregnancy, since build-
up of this substance will damage the developing baby even if the child has not
inherited the defective gene.
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18. Nursing considerations
 Although PKU is a life-long disease, people who have PKU have
the same average life expectancy as those who do not have the
disease.
 Genetic counseling is important especially to newly married and
diagnosed couples
 Provide parental and professional support to promote normal
growth and development
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19. Research findings
 Several studies indicated that the
discontinuation of the restricted diet might
lead to deficits in:
 Neuropsychological functions
 Cognitive ability
 Also it showed:
 Severe mental and psychiatric disorders such as
anxiety, depression, phobias, social withdrawal and
tremors
 It is recommended to continue the restricted
diet to life-long, or at least till age 20 – with
some modifications.
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20. Hypothyroidism
and
Hyperthyroidism
Endocrine
disorders
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21. Congenital Hypothyroidism- CH
 Clinical condition associated with decreased function of the thyroid gland
and a decrease in the circulating level of thyroid hormones
 1:3500 to 1:4000 newborns
 One of most common preventable causes of mental retardation
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22. Causes of CH
 The most common cause of congenital
hypothyroidism is iodine deficiency.
 Most commonly due to defect of development
of the thyroid gland itself, resulting in an
absent (athyreosis) or underdeveloped
(hypoplastic) gland.
 A hypoplastic gland may develop higher in the
neck or even in the back of the tongue.
 A gland in the wrong place is referred to as
ectopic, and an ectopic gland at the base or back
of the tongue is a lingual thyroid.
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23. Causes of CH
 Some of these cases of developmentally abnormal glands result
from genetic defects, and some has no identifiable cause.
 Genetic defects of thyroxine or triiodothyronine synthesis within a
structurally normal gland.
 Among specific defects are:
1. thyrotropin (TSH) resistance
2. organification defect
3. iodine trapping defect
 The defect sometimes might be due to a deficiency of thyroid
stimulating hormone, either isolated or as part of congenital
hypopituitarism.
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24. Iodine Deficiency Disorders
(IDD)
 Endemic goiter
 Endemic cretinism
 Intellectual disability
 Growth retardation
 Neonatal hypothyroidism
 Increased early and late pregnancy loss
 Increased perinatal and infant mortality
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25. Iodine Deficiency Disorders
(IDD)
 Most common preventable cause of mental deficits in the world
 The WHO estimated that 20 million people in the world had
varying degrees of preventable brain damage due to effects of
iodine deficiency on fetal brain development
 Population at risk for IDD caused by low levels of iodine in the
soil was estimated to be 1 billion, approximately 20% of whom
have goiter
 Estimates of prevalence of neonatal hypothyroidism in various
regions where goiter is endemic range from 1 to 10%, as
compared with only 0.025% in iodine-sufficent regions
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26. Iodine Deficiency Disorder
 IDD severe to cause goiter in 30% or more of population
 Correction of iodine deficiency before pregnancy
 Severe hypothyroidism in infancy termed cretinism
 Maternal hypothyroidism is a factor contributing to cretinism
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27. CH – Signs and Symptoms
 Anemia is due to decreased oxygen carrying requirement
 Retardation of mental development and growth manifest in
later infancy and largely irreversible
 Feeding problems, failure to thrive, constipation, a hoarse cry
 Protuberance of abdomen, dry skin, poor growth of hair and
nails, delayed eruption of deciduous teeth, umbilical hernia
 Delay in holding up the head, sitting, walking and talking
 Limb disproportionately short in relation to the trunk
 Severe mental deficiency, and low IQ
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28. CH – Signs and Symptoms
 Delayed closure of fontanelles, head to be large in relation to the
body
 Naso-orbital configuration remains infantile
 Maldevelopment of femoral epiphyses  waddling gait
 The teeth are malformed and susceptible to caries
 A broad, flat nose, wide set eyes, periorbital puffiness, large
protruding tongue, sparse hair, rough skin, short neck, and
protuberant abdomen with umbilical hernia
 A small but significant number (3-7%) of infants with congenital
hypothyroidism have other birth defects, mainly atrial and
ventricular septal defects in their heart
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29. CH Screening
 Highly sensitive immunoassay methods
 Direct measurement of serum thyroxine and TSH
 Filter paper blood spots
 Gurantee detection and treatment from the first weeks
of life
 Majority of children who were treated early experienced
normal growth and neurologic development and
normal-range IQ values
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30. Diagnosis of CH
 Diagnosis of primary hypothyroidism is confirmed by decreased levels of
serum thyroid hormone (total or free T4) and elevated levels of TSH.
 Thyroxin-binding globulin (TBG) levels can be measured in infants with
suspected TBG deficiency.
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31. Treatment of CH
 The rule in the treatment of congenital hypothyroidism is early
diagnosis and thyroid hormone replacement.
 Most important treatment variables are the dose and timing of
thyroxine therapy (Levothyroxine).
 Initial thyroxine dose 10-15 ug/kg/day, Can be given as a single
weekly dose
 Endemic cretinism can be prevented by appropriate iodine
supplementation. Iodization of salt is the usual method.
 Calcium supplements may be useful, Vitamin D therapy is
necessary, and IV calcium gluconate is recommended.
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