Not done Week 8: Metabolism/endocrine disorders

Anterior pituitary hormones (6)

• Thyroid stimulating hormone (TSH)

• Growth hormone (GH)

• Adrenocorticotropic hormone (ACTH)

• Lutenizing hormone

• Follicle stimulating hormone

• Prolactin

Endocrine disorders associated with the pituitary (4)

• Diabetes insipidus

• SIADH

• GH deficiency

• Precocious puberty

Endocrine disorders associated with the thyroid (2)

• Hypothyroidism (often Hashimoto’s)

• Hyperthyroidism (often Grave’s)

Endocrine disorders associated with the adrenal gland (2)

• Cushings

• Congenital Adrenal Hyperplasia (CAH)

Endocrine disorders associated with the pancreas (1)

diabetes mellitus

Table 28.2 to understand hormone function

Diabetes insipidus (DI)

Impaired posterior pituitary leads to deficiency in ADH, causing kidneys to fail to reabsorb water, so it diffused into the urine

• inability to respond to ADH?

DI signs and symptoms (3 major, 5 others)

• Polyuria

• Polydipsia

• Hypernatremia

• Sudden/abrupt onset

• Dehydration

• Weight loss

• Irritability

• Changes in the urine — colorless, dilute, no glucosuria

Risk factors for DI

• Trauma to vasopressin neurons

• Congenital pituitary defects

• Infections (meningitic/encephalitis)

• Vascular abnormalities (aneurysm)

• Tumors

Red flags that a kid had DI

• Older kids

• Younger kids

• Babies

• Older: always going to the bathroom

• Younger: can’t potty train

• Babies: rare, but they will be super irritable and only be soothed if they are given water (not satisfied by BM)

Central DI treatment (2)

• Low solute diet (low sodium and protein)

• Desmopressin (DDVAP)

Central DI teaching needs

• Low sodium and low protein

• DDVAP treatment will cause decreased u/o and dosages need to be titrated to achieve the desired effect

• Treatment is lifelong

• Medication adherence is essential — medical alert bracelet

Why should DI patients have a low sodium diet?

they already have very high sodium so we can’t have them eating a lot of processed foods

DI diagnostic methods

• Scans — CT and MRI to look at pituitary gland

• Labs and urinalysis

• Water deprivation test

DI lab and urinalysis results

• Labs — high Na+

• Urine — low specific gravity and osmolality

Water deprivation test

assess the ability of the kidney to concentrate urine under the influence of ADH

• normal results will show decreased urine specific gravity and no change in serum sodium

Water deprivation test method

1. withhold fluids for 8 hrs

2. measure urine and plasma osmolality

3. give DDVAP

4. recheck levels over the next several hours

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

hypersecretion of ADH

• transient but life-threatening endocrine emergency

• feedback mechanism malfunction — continues to secrete ADH regardless of serum osmolality

SIADH is the opposite of what disease?

Diabetes insipidus

SIADH risk factors

• Brain tumors

• Infection (meningitis)

• Head trauma

• Craniotomy

• Secondary to some medications (chemo)

• Vasopressive/DDVAP overdose (used to treat DI or enurisis)

Why is SIADH life threatening if no addressed? Who has the best chance of survival?

• Excess ADH causes flluid fro kidneys to be reabsorbed into central circulation and then leads to decreased serum sodium

• if not corrected quickly it can lead to cerebral edema and even brain death

  • infants have a better chance of surviving cerebral edema bc of their fontanelles being open and allowing for some stretch

SIADH signs and symptoms

• Fluid retention and low sodium

• Hypokalemia and hypocalcemia

• Increased ICP and cerebral edema d/t water moving into cells

• Lethargy/weakness

• Seizures

• Confusion

• Hallucinations

• If Na+ <120 — anorexia, N/V, stomach cramps, irritability

SIADH diagnostic criteria

• Weight gain from fluid retention

• Hypotonicity: low serum osmolality

• Elevated urine osmolality

• Hyponatremia

• High urine sodium concentrations

• Normal adrenal and thyroid function

SIADH treatment

• general

• mild

• severe

• Monitor weight

• Monitor I/Os

• Treat underlying cause

• Mild: fluid restrictions

• Severe: electrolyte (Na+ and K+) and fluid overload management; use diuretics to prevent overload to heart and lungs

SI vs DI memory trick

SIADH: Soaked Inside

DI: Dry Inside

Growth Hormone (GH) Deficiency

Hypopituitarism — failure of the anterior pituitary to secrete GH

• GH stimulates growth factor, which then promotes linear growth, bone mineral density, and growth in all body tissues

• **Lack of GH impairs the body’s ability to metabolize protein, fat, and carbs

GH deficiency: Idiopathic vs Primary

• Idiopathic: no known underlying cause — can be nutritional or psychosocial (reversible)

• Primary: destruction of the anterior pituitary gland or hypothalamus d/t a tumor, infection, or trauma

• can be congenital

GH deficiency signs and symptoms

• Thin hair

• Slow nail growth

• Increased periumbilical fat

• Micropenis and small testes if gonadotropin deficiency

• Frontal bossing

• Small jaws

• Delayed teeth

• Small hands/feet

• Delayed growth velocity (short statute — <3% for age)

• Hypoglycemia

• Delayed bone age (bone mineral density)

GH deficiency complications

• *Short statute

• Delay in puberty

• Emotional difficulties

  • body image

  • short child treated as younger bc of height

  • teasing

GH deficiency diagnostic methods

• CT/MRI to rule out tumors

• history of family and child’s growth patterns

• overnight studies of GH secretion

• bone age/skeletal age

  • compare x-rays with other kids their age and sex

  • growth plates will have less minerals and appear darker on images

GH deficiency treatment timing

MUST be treated BEFORE the growth plates close to attain maximal adult height

GH deficiency treatment

• Primary

• Secondary

• Primary: Subcutaneous synthetic GH

• Secondary: remove tumor or other cause

Synthetic GH injection side effects

• Hyperglycemia

• Risk of SCFE

• Scoliosis d/t quick growth

When do we stop synthetic GH injections?

when the epiphyseal growth plates fuse

Precocious Puberty

development of sexual characteristics before the usual age of puberty

• Girls before 8 y/o

• Boys before 9 y/o

Central vs peripheral precocious puberty

• Central: early puberty related to Gonadotropic Releasing Hormone (GnRH) that follows a normal puberty pattern

• Peripheral: early puberty in which estrogen or testosterone hormones are released, which is not related to GnRH — related to the ovaries, testicles, adrenal glands, or pituitary gland

Central precocious puberty common causes

• Tumor in brain or SC

• Hydrocephalus (abnormal CSF buildup in ventricles of brain)

• Head trauma/infection

• Congenital adrenal hyperplasia

• Hypothyroidism

Peripheral precocious puberty common causes

• A tumor in the adrenal glands or in the pituitary gland that releases estrogen or testosterone

• Ovarian cysts/tumors

• Genetic conditions: McCune-Albright Syndrome

• Exposure to external sources of estrogen or testosterone (e.g., creams, ointments, child eating mom’s birth control bc it looks like candy)

Central precocious puberty diagnosis

• History

• Plot growth velocity (will see accelerated linear growth)

• Tanner staging

• Bone age studies (L wrist will show advanced bone age)

• Head CT/MRI

• Pelvic US in girls (look for ovarian cysts)

• Endocrine labs (look at hormone levels)

• Response to GnRH stimulation confirms the diagnosis of CPP

Precocious puberty treatment

• Tumor removal if cause

• Halt sexual development and prevent short statute