Module 02: Inborn Errors of Metabolism Flashcards
This pertains to the inherited diseased caused by interruptions in the various pathways involved in the metabolism of proteins, carbohydrates and or lipids.
Inborn errors of metabolism
What are the modes of transmission for IEM?
Autosomal recessive or X-linked.
Why is early diagnosis and treatment important for IEM?
Early diagnosis and prompt treatment are essential to prevent relentless course of physical and mental deterioration
Do IEMs usually produce symptoms immediately after birth?
No, most show no symptoms in the first 24 hours of life (EPISODIC).
These refer to the sequence of enzyme catalyzed reactions that lead to the conversion of a substance into a final product or excretable form.
Metabolic Pathways
Why are IEM symptoms often confused with other conditions?
They are episodic in nature of metabolic illness. The wide range of clinical symptoms that are associated with more common conditions like infection or sepsis).
Why is diagnosing IEMs challenging?
(A) Low incidence of these disorders.
(B) Lack of experience among pediatric subspecialties.
(C) Need for specialized testing.
What is required for substrate A to become substrate B?
An enzyme or pathway must act on substrate A.
What happens in IEMs regarding metabolic pathways?
There is a problem with the enzyme or hormone needed for metabolism, transformation, or catabolism.
What causes the interruption in the conversion of substrate A to B in IEMs?
A defect somewhere in the enzymatic chain or pathway.
Why is early detection of IEM important?
To identify affected babies before symptoms appear and prevent irreversible outcomes.
What are the goals of early detection in IEM?
(A) Quickly identify affected babies.
(B) Avoid missing cases.
(C) Minimize false-positive results.
(D) Early treatment can begin that prevents the negative and irreversible health outcomes for affected newborns.
What treatments are used for IEM?
These treatments are often inexpensive.
(A) Vitamin supplementation.
(B) Hormone supplementation.
(C) Avoidance of certain foods and chemicals.
(D) Dietary changes.
What technology is used for expanded newborn screening?
Tandem Mass Spectrometry (MS/MS).
How does Tandem Mass Spectrometry (MS/MS) work?
It separates and measures substances by their weight using a few drops of blood (MOLECULAR WEIGHT).
This type of congenital hypothyroidism pertains to the complete or partial absence of functional thyroid tissue or abnormal thyroid gland location.
Primary CH
This type of congenital hypothyroidism pertains to the defect in the brain areas responsible for stimulating thyroid hormone production, not the thyroid gland itself.
Secondary TH or Tertiary CH
What are the thyroid hormones?
(A) Tri-iodothyronine (T3).
(B) Thyroxine (T4).
Why is thyroxine or T4 important for newborns?
(A) Crucial for normal growth and development of the body and brain among newborns
(B) Excreted directly in the bloodstream
(C) Regulates temperature
This is a condition in which an individual does not produce enough thyroid hormone.
Congenital Hypothyroidism
What is the gland involved in congenital hypothyroidism?
Thyroid gland of the endocrine system
What causes Permanent Congenital Hypothyroidism (CH)?
(A) Defective thyroid gland development.
(B) Enzymatic defect in thyroxine synthesis.
(C) Pituitary dysfunction (rare).
What causes Transient Congenital Hypothyroidism (CH)?
Maternal intake of anti-thyroid medication or excess iodine.
What are the different clinical manifestations of congenital hypothyroidism?
(A) Hypotonia – Poor muscle tone.
(B) Prolonged jaundice – Due to immature liver conjugation of bilirubin, ↓ T4.
(C) Inactive defecation.
(D) Umbilical hernia.
(E) Pallor, coldness, and hypothermia – Due to ↓ T4.
(F) Edema and “rough” facial features.
(G) Enlarged tongue.
(H) Rough, dry skin.
(I) Open posterior fontanelles.
(J) Delayed overall development.
What is the appearance of a child with CH before treatment?
Puffed up, dull-looking face, and protruded tongue.
What is the appearance after treatment?
Alert-looking, less swelling, and tongue inside.
What are the late manifestations of CH?
(A) Mental retardation.
(B) Growth retardation.
(C) Delayed skeletal maturation.
(D) Delayed dental development and tooth eruption.
(E) Delayed puberty.
How is CH diagnosed?
- Newborn screening.
- Initial filter-paper blood-spot T4 measurement.
- TSH measurement (if low T4).
Additional tests:
(A) Decreased T4, T3, resin uptake.
(B) Decreased free T4.
(C) Thyroid hormone globulin.
(D) Thyroid scan to check thyroid structure.
What is the treatment for CH?
(A) Thyroid hormone replacement (Sodium L-thyroxine, synthroid, levothroid).
(B) Must be started before the child turns 2 weeks old.
(C) Oral administration of synthetic thyroid hormone indefinitely.
(D) Tablets should be crushed and added to food or a small amount of formula or breast milk.
What should NOT be given when administering thyroid hormone replacement?
Soy-based formulas and iron supplements (avoid during medication administration).
How is Congenital Hypothyroidism (CH) managed?
(A) Monitor T3, T4, and TSH levels to maintain optimum levels (TSH <4 IU/ml).
(B) Ensure early identification of the disorder.
(C) Ensure screening is performed.
(D) Explain to parents that lifelong treatment is required.
(E) Stress the importance of compliance with the drug regimen for normal growth and development
What should be taught to clients or parents with children who have CH in terms of signs and symptoms of drug overdose:
(A) Rapid pulse (heart compensates, BP increases = rapid pulse)
(B) Dyspnea
(C) Irritability (alteration in brain perfusion)
(D) Insomnia (hyper)
(E) Fever (increased thermoregulation)
(F) Sweating
(G) Weight loss (increase metabolic process)
This is a condition where the adrenal glands are enlarged due to abnormal increase in cells.
Congenital Adrenal Hyperplasia (CAH)
This gland is located above the kidneys.
Adrenal Gland
This pertains to the abnormal increase in cells that leads to enlargement.
Hyperplasia
What hormones are secreted by the Adrenal Gland?
(A) Mineralocorticoids (aldosterone, corticosterone).
(B) Glucocorticoids (cortisol, cortisone).
(C) Androgens (estrogen, testosterone).
(D) Catecholamines (epinephrine, norepinephrine).
(E) Peptides (somatostatin, substance P).
What are the parts of the Adrenal Gland and their functions?
(A) Adrenal Medulla
(B) Adrenal Cortex
This part of the adrenal gland has the roles of:
(1) Secretes norepinephrine and epinephrine.
(2) Prepares the body for fight or flight (adrenaline rush).
Adrenal Medulla
This part of the adrenal gland is responsible for the production of glucocorticoids, mineralcorticoids, and androgens.
Adrenal Cotex
Functions of Glucocorticoids.
(1) Stress hormone that responds to stress.
(2) Needed for glucose and protein metabolism.
(3) Protects the body from illness and surgery by increasing gluconeogenesis or decreasing the use of glucose.
(4) Decreases inflammatory response by reducing eosinophils and lymphocytes.
Functions of Mineralcorticoids.
(1) Maintains normal serum sodium levels.
Functions of Androgens.
(1) Responsible for male sexual differentiation.
What are the main functions of the Adrenal Cortex hormones?
(A) Glucocorticoids (Cortisol): Maintenance of normal blood sugar.
(B) Mineralocorticoids (Aldosterone): Maintenance of normal serum sodium.
(C) Androgens (Testosterone): Male sexual differentiation.
What enzyme is needed for the secretion of cortisol, aldosterone, and testosterone to be normal?
21-OH-Enzyme (Hydroxylase)
The 21-OH-Enzyme is crucial for normal adrenal gland function.
What is the result of having a normal amount of cortisol and androgen hormones?
Normal health and sexual development
Adequate levels of these hormones are essential for overall well-being.
What condition is characterized by the absence of 21-OH-Enzyme?
Congenital Adrenal Hyperplasia (CAH)
CAH leads to significant hormonal imbalances.
What are the health effects of decreased cortisol and aldosterone due to the absence of 21-OH-Enzyme?
Multiple health problems
Low levels of these hormones can affect various bodily functions.
What happens to androgen levels in CAH?
Increased androgen levels
Elevated androgen can lead to abnormal physical changes.
What are the consequences of increased androgen levels in CAH?
Genital changes and early puberty
These changes can impact sexual development and reproductive health.
What is the function of 21-hydroxylase (21-OH)?
it tells cortisol and aldosterone in the adrenal gland tp produce if the body needs it. (So congenital hyperplasia also pertains to a decreased production of cortisol)
Congenital Adrenal Hyperplasia is an endocrine problem related to what:
(A) Severe salt loss
(B) Dehydration
(C) Abnormally high levels of male sex hormones in both girls and boys
What inheritance pattern does Congenital Adrenal Hyperplasia (CAH) follow?
Autosomal Recessive Trait
Which enzyme is deficient in CAH (21-hydroxylase deficiency)?
21-hydroxylase (21-OH).
What effect does a deficiency in glucocorticoids (cortisol) have in CAH?
It causes low blood sugar (hypoglycemia).
What is the effect of a deficiency in mineralocorticoids (aldosterone) in CAH?
Low serum sodium and high serum potassium levels.
What effect does excess androgens (testosterone) have in CAH?
Masculinization of females.
What is the salt-losing (salt-wasting) form of CAH characterized by?
A deficiency in cortisol leads to a deficiency in aldosterone, resulting in no salt retention and fluid retention.