deck 2

Question 1

A patient in a spica cast after hip surgery develops vomiting and a serum calcium of 15.3 mg/dL (equals 3.8 mmol/L). What should be the level of concern?

Answer 1

calcium >15 mg/dL or with significant symptoms need to treat immediately to lower the level
treatment: isotonic saline at 2-4x maintenance and furosemide to lower the Ca
need to monitor u/o and lutes (including Mg)
ECG monitoring - can get PVCs, Vtach, prolonged PR, prolonged QRS ad AV block
Additional treatment: glucocorticoids and antihypercalcemic agents

Question 2

What is Chvostek and Trousseau signs of ?

Answer 2

HYPOcalcemia (think of twitchy hippos)
Chvostek - tapping on facial nerve in front of ear results in upper lip movement
Trousseau - inflate BP cuff, leasd to carpopedal spasm

Question 3

What is hypoparathyroidism?

Answer 3

PTH increases reabsorption of Ca:
from bone
increases gastrointestinal and urinary absorption through the increasing synthesis of calcitriol

Question 4

Causes of hypoparathyroidism

Answer 4

1. gland anomalies
2. destruction by surgery or autoimmune processes
3. biosynthetic abnormalities
4. decreased distal cellular responsiveness to the hormone

can lead to acute and chronic hypocalcemia

Question 5

When to think of hypoparathyroidism

Answer 5

1. hypocalcemia
2. lenticular cataracts
3. behaviural changes - depression to psychosis
4. mucocutaneous candidiasis (familial form)
5. dry/scaly skin, psoriasis, patchy alopecia
6. brittle hair and fingernails
7. enamel hypoplasia - if hypocalcemia present during dental development

Question 6

syndrome with hypoparathyroidism

Answer 6

DiGeorge

Question 7

syndrome with hypercalcemia

Answer 7

williams syndrome

Question 8

What are the main causes of hypocalcemia in children (secrets)

Answer 8

1. nutritional (vitamin D intake, rarely inadequate calcium or excess phosphate )
2. Renal insufficiency (increased PO4 from decreased GFR or decreased alpha hydroxylase)
3. nephrotic syndrome (lowered albumin leads to lower calcium levels, decreased Ca absorption)
4. hypoparathyroidism (DiGeorge, autoimmune polyglandular disease, mitochondrial myopathy)
5. pseudohypoparathyroidism (resistance to PTH)
6. disorders of calcium sensor genes

Question 9

A patient is hypocalcemic and has a short fourth metacarpal. What disorder do you think of?

Answer 9

Albright herediatry osteodystrophy

short stature, obesity, DDelay, brachydactyly

Question 10

A patient with a brain injury has hyponatremia, what two diagnosis should you consider?

Answer 10

1. SIADH - will have evidence of intravascular volume overload , fluid restriction will lead to increased Na
2. cerebral salt wasting - pee out Na , usually in the first week after brain injury , resolves with time, will have signs of volume DEPLETION, fluid restriction will not increase serum sodium, can lead to hemodynamic instability (since you will continue to pee everything out)

Question 11

Criteria for SIADH

Answer 11

1. hyponatremia with reduced serum osmolality
2. urine osmolality elevated compared with serum osmolality : urine osmolality 20 meq/L)
3. normal renal adrenal and thyroid function
4. absence of volume depletion

**remember that ADH regulates the extracellular water volume

Question 12

Diabetes Insipidus - how to diagnose

Answer 12

excessive fluid loss

test: water deprivation and close monitoring
1. inappropriately dilute urine in the face of a rising or elevated serum osmolality
2. urine output stays high despite lack of oral input
3. changes in physical parameters consistent with dehydration

**a child who with water deprivation appropriately concentrates urine (>800 mOsm/L) and whose serum osmolality remains constant (<290) unlikely to have DI

at the end of the test, give them ADH - if they concentrate urine it is likely central, if not then peripheral

Question 13

A patient has DI, what could it be the first clinical sign of ?

Answer 13

tumor of hypothalamus or base of the skull (i.e. Wegener)

MRI is needed if considering DI diagnosis

Question 14

A patient with DKA is in shock, fluid management? severely volume depleted but not in shock?

Answer 14

shock - 20 cc/kg
volume depleted - 10 cc/kg
then rehydration should be given over 48 hours
severity of dehydration is often difficult to assess - usually rate is not in excess of 1.5-2x the usual maintenance fluid for weight
start with isotonic fluid (some places suggest 0.45 to reduce the chance of hyperchloremic metabolic acidosis)
don’t add K while anuric or K >5.0
don’t want to correct to quickly for the Na - (and also need to remember following corrected Na)

Question 15

Risk factors for cerebral edema

Answer 15

usually in the first 5-15 hours after treatment starts
RFs:
1. younger age
2. newly diagnosed
3 attenuated rise in serum sodium during therapy
4. greater hypocapnia
5. increased BUN
6. bicarb for acidosis
7. insulin in the first hour of treatment (BAD)
8. higher volumes of fluid during first 4 hours

Question 16

more risk of diabetes type 1 if father or mother affected?

Answer 16

more if father affected (6%) vs 2% for mother

Question 17

a patient with type 1 diabetes wakes up with high blood sugar in the morning, what t do?

Answer 17

check at 2-3 am - check for somogyi phenomenon - rebound hyperglycaemia after hypoglycaemia
more likely to happen with tighter glucose control

Question 18

what is the dawn phenomenon

Answer 18

rise in blood glucose in early Am hours , from increase in morning cortisol level, increased GH effect, insulinopenia since been longer since last insulin

Question 19

how long for microalbuminuria to develop with DM1

Answer 19

10-15 years

microscopic changes in glomerulous after 2 years

Question 20

what is the target HbA1C for different age groups

Answer 20

19 <7.0

Question 21

How to distinguish Type 1 and 2 diabetes

Answer 21

clinical characteristics
fasting insulin and C peptide - low in type 1, nomal or elevated in type 2
islet cell autoantibodies - present in type 1 , absent in type 2
can be useful

Question 22

which paediatric patients to screen for type 2 diabetes

Answer 22

start at age 10
BMI >85th percentile PLUS
any two of:
1. positive fhx
2. associated conditions - acanthuses nigricans, hypertension, dyslipidemia, PCOS

Question 23

Septic Optic dysplasia features

Answer 23

incomplete development of the septum pellucid with optic nerve hypoplasia and other midline abnormalities
nystagmus and visual impairment can lead o discover of optic nerve and brain abnormalities
associated with anterior and/or posterior pituitary hormone deficiencies in 25% of cases
f

Question 24

solitary maxillary incisor, what should you think of?

Answer 24

increase the chance of GH or other pituitary hormone deficiency
also think of this with mid facial anomalies (cleft lip/palate)

Question 25

What is Hall-Pallister syndrome

Answer 25

absence of pituitary with hypothalamic hamartoblastoma, post axial polydactyly, nail dysplasia, bifid epiglottis, imperforate anus, anomalies of heart/lung and kidneys

Question 26

Syndromes with short 4th metacarpals

Answer 26

turner pseudohypoparathyroidism albright osteodystrophy

Question 27

Acquired cause of pituitary hormone deficiency

Answer 27

usually multiplee hormones most common: craniopharyngioma other : CNS geminoma, histiocytosis, TB, sarcoidosis, toxo, meningitis, aneurists, trauma (including birth trauma, CYPT trauma et)

Question 28

Growth hormone deficiency causes

Answer 28

Genetic forms - abnormalities in receptor, GH genes, genes on X chromosome (different types, different inheritance for different causes Acquired cause - GH most likely to be disrupted: - malignancy needing radiotherapy, meningitis, histiocytosis, trauma

Question 29

Effects of cancer on growth

Answer 29

growth usually slows during radiation or chemo, improves for 1-2 years, then declines with development of GH deficiency, dosing and frequency of radiotherapy are important determinants of hypopituitarism GH deficiency almost universal after dose >35 Gy

Question 30

Which pituitary hormones most common affected by radiotherapy for cancer

Answer 30

GH most common | TSH and ACTH can also occur

Question 31

puberty in acquired GH deficiency (I don't know if they are specifically saying from cancer therapy or from any of the above causes)

Answer 31

puberty tends to be early rather than delay - likely to see kids in 8-10 year age range growing at rates normal for chronological age but subnormal for stage of puberty (since should be having their growth spurt!)

Question 32

Congenital hypopituitarism - manifestations

Answer 32

normal size and weight at birth if severe GH defects then >4SD below mean by 1 year of age can present with neonatal emergencies - apnea, cyanosis or severe hypoglycaemia with or without seizures boys can have microphallus can have GH deficiency, as well as hypoadernalism and hypothyroidism prolonged neonatal jaundice - elevation of conjugated and unconjugated bilirubin and may be mistaken for neonatal hepatitis head is round and face is short and broad, frontal bone is prominent, saddle shaped nose, eyes somewhat bulging underdeveloped mandible and chin, teeth are often crowded and arrive late pudgy looking small genitals length is mainly affected symptomatic hypoglycaemia after fasting usually have normal intelligence

Question 33

Acquired hypopituitarism manifestations

Answer 33

pituitary insufficiency signs atrophy of adrenal cortex, thyroid, gonads sexual maturation fails to take place or regresses if present tendency to hypoglycemia growth slows DI may present early but improves as anterior pituitary is progressively destroyed if timor then have timor symptoms

Question 34

craniopharyngioma - do you need to have neuro signs and symptoms

Answer 34

nope, can have growth slowing first neuro sx of craniopharyngiomas: visual field, optic atrophy, papilledema, CN palsy

Question 35

GH deficiency

Answer 35

moderate fo severe growth failure - height below the 1st percentile for age and sex of height >2D below sex adjusted mid-parent height

Question 36

True or false - should match IGF levels to chronological age in suspected acquired GH deficiency

Answer 36

false - should match to skeletal age | can have some overlap

Question 37

Diagnosis of GH deficiency

Answer 37

IGF1 can be helpful but not definitive diagnosis definitive diagnosis: stimulation of GH - by administering insulin, arginine, clonidine or glucagon in chronic GH deficiency need: 1. poor linear growth 2. delayed skeletal age 3. peak GH levels <10) in 2 tests

Question 38

GH deficiency diagnosed, what else do you need to test for ?

Answer 38

other pituitary functions | aka TSH, T4, ACTH, cortisol, gondotropins and gonadal steroids

Question 39

imaging for suspected hypo pit

Answer 39

CT will show suprasellar calcification of craniopharyngioma and bony changes of histiocytosis MRI more details of hypothalamus and pituitary (small pituitary/small stalk/

Question 40

kid with hypo pit, which is more common, craniopharyngioma or pituitary adenoma

Answer 40

craniopharyngioma are common and pituitary adenoma are rare

Question 41

Ddx of growth disorders

Answer 41

1. systemic disorders - greater loss of weight than length 2. genetic short stature 3. constitutional delay of growth 4. growth hormone deficiency 5. primary hypothyroidism (more common than GH deficiency) 6. psychosocial causes

Question 42

Constitutional growth delay:

Answer 42

normal length and weight at birth growth is normal for first 4-12 months of life height is then at lower percentile during childhood delayed pubertal growth spurt other family members with short stature in childhood, delayed puberty and eventual nomal stature IGF1 are low for chronological age but within nomal for bone age GH response to provocative testing - lower than in kids with more typical puberty Height predictions: guarded prognosis for normal adult height, based on height and bone age overestimate height in boys>girls can treat boys who have > 2year pubertal delay with shot course of testosterone to hasten puberty after 14 years of age

Question 43

Features of primary hypoT

Answer 43

more common than GH deficiency low T4 and elevated TSH levels may have subnormal response to GH provocation and enlarged sella need t have thyroid for GH synthesis, therefore need to check it before GH evaluation

Question 44

Psychosocial causes of poor growth

Answer 44

similar to hypopituitarism can have low IGF 1 and inadequate GH provocation puberty may be nomal or premature disturbed relationships

Question 45

symptoms that emotionally deprived children:

Answer 45

perverted/voracius appetites, enuresis, encopresis, insomnia, crying spasms and tantrums hyperphagia and normal BMI - show catch up growth in less stressful environments

Question 46

GH treatment: Indications for

Answer 46

``` approved in USA for 1. GH deficiency 2. Turner syndrome 3. end-stage renal failure before kidney transplant 4. Prader-Willi syndrome 5. IUGR 6. idiopathic short stature - height below the 1.2 percentile (-2.25 SD), predicted height <5th percentile and open epiphyses usually gain 2-3 inches of adult height ``` **remember that the doses of GH used for GH deficiency will help kids without GH deficiency too - still trying to see if other indications also

Question 47

Side effects of GH treatment

Answer 47

1. some kids with GH have developed leukaemia - however associated with associated RFs - i.e. radiation to brain; does not increase recurrence of brain tumours or leukaemia 2. pseudotumor cerebri 3. SCFE 4. gynecomastia 5. worsening of scoliosis 6. increased in body water in 1st 2 weeks 7. low insulin before treatment then normalize during GH replacement ->may increase risk of type 2 (NOT type 1) 8. former risk of Cretzfeld Jakob and antibodies to GH - hewer now that we use recombinant GH, no longer have risk of CJ and antibodies to GH 9. can develop primary or central hypothyroidism with GH treatment - need to check 10. risk of adrenal insufficiency on GH treatment - need to check

Question 48

How GH treatment works:

Answer 48

start ASAP SC administer most response in first year - growth velocity usually >95th percentile for age sometimes use GnRH agonist at the same time - to interrupt puberty and delay epiphyseal fusion in boys sometimes also do aromatase inhibitor to delay bone fusion

Question 49

When to stop GH treatment

Answer 49

1. patient happy with height | 2. growth rate 14 in girls and >16 in boys

Question 50

where is ADH made?

Answer 50

made in hypothalamus, secreted by posterior pituitary

Question 51

what decides secretion of vasopressin?

Answer 51

osmotic in hypothalamus | volume and pressure changes - baroreceptors in carotid sinus

Question 52

where is theist regulated

Answer 52

cortical and hypothalamic neurone | vasopressin before thirst is initiated - allows ingested water to be retained

Question 53

Types of DI

Answer 53

central - no vasopressin | peripheral 9aka nephrogenic) - kidney doesn't respond

Question 54

patient with polyuria and polydipsia, what tests to do

Answer 54

Na/K BUN/Cr glucose calcium urine osmolality, urine specific gravity, urine glucose

Question 55

Diagnosis of DI

Answer 55

serum osmolality is >300 mOsm/kg and urine osmolality

Question 56

urine osmolality >600 mOsm/kg in polydipsic/polyuric patient, is DI likely?

Answer 56

nope unlikely if the urine osmolality is >600mOsm/kg or if serum osmole <270 mOsm/kg **if serum osmole between 270-300 and have symptoms of DI, need to do water deprivation test

Question 57

Ddx of polyuria and polydipsia

Answer 57

1. Central DI - genetic (autosomal dominant) - acquired (from trauma, congenital malformations, neoplasms, infiltrative/autoimmune and infectious diseases, drugs) 2. Nephrogenic DI - genetic (X linked, AR, AD) - acquired (from hypercalcemia, hypokalemia, from drugs, from kidney disease) 3. primary polydipsia 4. diabetes mellitis

Question 58

Post op high urine output and dilute urine, 2 Ddx to consider?

Answer 58

DDx is post op diuresis vs. DI - both will have large volume of DILUTE urine 9volume is >200 ml/m2/hr) DIFFERENCE is serum osmoles (>300 mOsm in DI)

Question 59

Patient has neurosurgery and develops DI, what are the phases of DI?

Answer 59

Triphasic response 1. transient DI - lasts 12-48 hours - edema interferes with normal vasopressin secretion 2. SIADH - lasts up to 10 days - unregulated vasopressin release from dying neurons 3. can develop permanent DI if more than 90% of the neurons have been destroyed this is central DI

Question 60

Most common brain tumours associated with DI?

Answer 60

1. germinomas and pinealomas - because their location will be near the base of the hypothalamus where there are the most vasopressin axons large tumours can also cause DI through infiltration (i.e. 2. craniopharyngioma or optic glioma, although more likely to be post op complication for these Tests to diagnosis: beta HCG (secreted by these tumours) and should also do serial MRI (since don't always see germinoma initially) 3. heme malignancy - ie AML - can cause DI by infiltrating the pituitary stalk and sella

Question 61

Ddx of central DI

Answer 61

1. genetic mutations in vasopresin gene - AD form in first 6 years of life 2. trauma 3. congenital malformation - ie septio optic dysplasia, holoprosencephaly, family pituitary hypoplasia, empty sella, etc 4. neoplasms 5. infiltrative - ie langerhans cell histiocytosis and lymphocytic hypophysitis (hypophysitis is 50% of idiopathic central DI) 6. autoimmune 7. infectious diseases - (including meningitis, CMV< inflammatory disease of the brain) - can be transient 8. increased metabolism of vasopressin

Question 62

kid with DI, DM, optic atrophy and deafness

Answer 62

Wolfram syndrome - have vasopressin deficiency

Question 63

Drugs which can cause CENTRAL DI (inhibit vasopressin release)

Answer 63

``` ethanol phenytoin opiate antagonists halothane alpha adrenergic ```

Question 64

Nephrogenic DI - causes

Answer 64

1. genetic (less common but more severe than acquired causes) - usually in first several weeks, sometimes get polyuria/polydipsia only apparent after weaning or with more sleep) - can get fever, vomiting, dehydration as well as failure to thrive also - congenital Forms include: X linked, autosomal recessive, and autosomal dominant form

Question 65

3 forms of congenital nephrogenic DI and the mutation match them up X linked, autosomal recessive and autosomal dominant vasopresin receptor V2, aquaporin

Answer 65

x linked is the vasopressin receptor | the others are aquaporin 2

Question 66

Cause of acquired NEPHROGENIC DI

Answer 66

``` hypercalcemia hypokalemia lithium clozapine amphotericine methicillin rifampin others (demeclocycline, foscarnet) ``` diseases: ureteral obstruction, chronic renal failure, PCKD, medullary cystic disease, Sjogren, and sickle cel nutritional: decreased protein or sodium intake or excessive intake - diminished tonicity of the renal medullary interstitial

Question 67

How to treat central DI

Answer 67

1. neonates/young infants - fluid therapy is the best (can maintain plasma osmolality and sodium int eh high nomal range) hard to use vasopressin analogues in patients who need lots of fluids - always risk of significant hyponatremia diluted DDAVP has been used without severe hyponatremia but is not FDA approved 2. older kids - best choice is DDAVP - intranasal

Question 68

kid after neurosurgery high u/o also as high serum osmole and dilute urine. how to treat

Answer 68

likely central DI after neurosurgery treat with synthetic aqueous vasopressin (aka pitressin) limit fluid intake - 1L/m2/hour don't use doses >1000pg/ml can cause cutaneous necrosis, rhabdo, cardiac rhythm problems, hypertension switch from IV to PO ASAP so they can use their thirst mechanism to regulate osmolality

Question 69

Treatment of nephrogenic DI

Answer 69

non pharm: fix the underlying disorder; for congenital NDI - ensure adequate calories, avoid dehydration - can still get growth problems and MR sometimes though pharm treatment: thiaxides indomethacin/amiloride high doses DDAVP in some cases

Question 70

Causes of hyponatremia in children

Answer 70

``` Common 1. volume depletion 2. excessive salt loss 3. hypotonic fluid overload Uncomon SIADH ```

Question 71

What causes of hyponatremia have low IV (intravascular) volume and low urine Na

Answer 71

systemic dehydration decreased effective plasma volume (i.e. CHF, nephrotic, cirrhosis, mechanical ventiltion, burns, BPD, CF, asthma severe) primary salt loss- non renal Runner's hyponatremia

Question 72

What causes of hypontremia have low Intravascular volume and high urine sodium

Answer 72

(i. e. the kidney is peeing out Na even though it should't cause it's already low) 1. primary renal salt loss 2. cerebral salt wasting

Question 73

What causes of hyponatremia have high intravascular volume and high urine sodium

Answer 73

SIADH nephrogenic SIADH - which is essentially where the vasopressin receptor has a gain of function mutation decreased free water clearance can have normal or high IV volume and normal or high urine Na

Question 74

What are causes of hyponatremia with normal IV volume and normal urine Na

Answer 74

decreased free water clearance, primary polydipsia, pseudohyponatremia and factitious hyponatremia causes of pseudohyponatremia - from hyperTG, can also have it from hyperglycaemia - which causes increased water into the intravascular space

Question 75

Characteristics of SIADH

Answer 75

1. hyponatremia 2. inappropriately concentrated urine >100 mOsm/kg 3. normal or increased plasma volume 4. normal to high urine sodium 5. low serum uric acid Causes of SIADH in children:

Question 76

Ddx of SIADH in children

Answer 76

``` rare overall most common- too much vasopressin to treat central DI other causes: encephalitis brain tumours head trauma psych disease prolonged nausea pneumonia TB meningitis AIDS postictal phase after seizures can be the 2nd phase of the triphasic response after hypothalamic pituitary surgery (can happen in 35% of patient 1 week after surgery) drugs that increase vasopressin secretion and cause SIADH like hyponatremia oxcarbazepine/carbamazepine chlorpropamid vinblastine vincristine TCAS ```

Question 77

How does dehydration lead to hyponatremia

Answer 77

1. initial stages - hypernatremia and hyperosmolality 2. activation of vasopressin secretion and decrease in water excretion 3. hypovolemia and/or hypotension happens next, leads to more vasopressin release, leads o even less free water clearance and more hyponatremia (since you have more water intake and ongoing salt loss) urinary Na excretion is low - low GFR and renin angiotensin aldo (unless primary renal disease or diuretic) i.e. the body should be trying to hold on to the Na

Question 78

Treatment of dehydration and hypovolemia

Answer 78

rehydrate with Na containing fluids - i.e. normal saline/lactated Ringer leads to activation of RAS - then have diuresis, so need to be careful not too correct too quickly

Question 79

What are the consequences of too rapid correction of hyponatremia?

Answer 79

central pontine myelinolysis

Question 80

hyponatremia from CHF? (i.e. from decrease in effective plasma volume)?

Answer 80

1. treat underlying disorder | 2. AVP V2 receptor antagonists

Question 81

treatment of hyponatremia from primary salt loss

Answer 81

supplement with NaCl and fluids initially IV replace the urine volume with fluid containing 150-450 meq/L of sodium (DIFFERENT from SIADH - treat that with water restriction without sodium supplementation)

Question 82

Emergency treatment of hyponatremia

Answer 82

acute hyponatremia is if t correct too quickly - only enough to fix the mental status no faster than 12 mq/L/24 hour

Question 83

Chronic SIADH

Answer 83

oral fluid restriction | in young kids may also need to create a nephrogenic diabetes so they can have enough fluid for growth

Question 84

Treatment of cerebral salt wasting

Answer 84

restore IV volume with NaCl and water treatment of other causes of systemic dehydration replace ongoing urine Na losses