Seriously ill Child

Question 1

In the primary assessment of the sick child, what are the 3 aspects of breathing that should be assessed?

Answer 1

1. EFFORT
   - RR, recessions, insp or exp noises, grunting, accessory muscle use, nasal flaring, gasping
2. EFFICACY
   - degree of chest expansion, auscultation, sats measurement
3. EFFECT (on other organs)
   - HR, skin colour, mental status

Question 2

Name the 3 circumstances where an increased effort in breathing will not be present despite failure of the respiratory system?

Answer 2

1. If severe respiratory problems have been present for a prolonged time, fatigue develops
2. In presence of cerebral depression e.g. raised ICP, encephalopathy, poisoning. Depresses the respiratory drive
3. Concurrent neuromuscular disease

Question 3

T or F: central cyanosis is an early consequence of hypoxia

Answer 3

False.
Late sign, only occurs when SpO2 is < 70%
Note if child is anaemic may not be present at all

Question 4

Aspects used to assess cardiovascular status in the primary assessment of the sick child?

Answer 4

Heart rate
Pulse volume
Cap refill

Question 5

Pre-terminal cardiovascular signs?

Answer 5

Hypotension
Rapidly falling heart rate

Associated with poor systemic perfusion

Question 6

Effect of cardiac inadequacy on the respiratory system?

Answer 6

increased respiratory rate, but wont have recessions

incr in RR is caused by the metabolic acidosis from circulatory failure

Question 7

Systemic effects of cardiac inadequacy?

Answer 7

• mottled pale skin
• drop in urine output
• drop in mental status (poor cerebral perfusion)

Question 8

Decorticate posturing

Answer 8

flexed arms, extended legs

Question 9

Decerebrate posturing

Answer 9

extended arms, extended legs

Question 10

What is Cheyne-Stokes breathing pattern

Answer 10

an abnormal pattern of breathing characterized by progressively deeper, and sometimes faster, breathing followed by a gradual decrease that results in an apnoea. The pattern repeats, with each cycle usually taking 30 seconds to 2 minutes.

Question 11

What is Cushing’s response and what does it mean

Answer 11

Systemic hypertension with sinus bradycardia

Indicates compression of the medulla oblongata caused by herniation of of the cerebellar tonsils through the foramen magnum

Question 12

Fluid bolus in children if inadequate circulation

Answer 12

20mg/kg (crystalloid)

Question 13

Signs of raised ICP

Answer 13

decreasing conscious level
asymmetrical pupils
abnormal posturing
abnormal ocular motor reflexes

Question 14

Difference between acidaemia/alkalaemia and acidosis/alkalosis

Answer 14

acidaemia + alkalaemia represent the acidity of the blood outwith the normal range.
acidosis + alkalosis refer to the underlying processes that result in the acidaemia/alkalaemia

Question 15

What is the carbonic acid reaction

Answer 15

CO2 + H2O – H2CO3 – H + HCO3

Question 16

T or F: bicarbonate crosses the BBB.

What does this mean for CSF & serum levels of bicarbonate

Answer 16

False. Cannot cross. Secreted in the CSF as it is produced in the choroid plexus

CSF bicarbonate levels approximate serum levels some hours previously

Question 17

T or F: CO2 crosses the BBB

What does this mean for CSF & serum levels of CO2

Answer 17

True.

CSF CO2 and serum CO2 are essentially equivalent concurrently

Question 18

Rewrite the carbonic acid reaction, expressed as the concentration of hydrogen ions

Answer 18

[H+] = K x ( [CO2] / [HCO3] )

where K is the dissociation constant

Question 19

Henderson-Hasselbach equation

Answer 19

pH = pK + log ( [HCO3] / PCO2 )

where pK is approx 6.1

Question 20

How does the pH of CSF contribute to the respiratory drive

Answer 20

pH of CSF is a major contributor to the respiratory drive

If CSF becomes acidotic then there is increased respiratory drive to exhale CO2

Reverse also true

Question 21

What is the role of bicarbonate

Answer 21

To act as an electrical buffer to accommodate other electrolyte changes

Question 22

What cation has the greatest impact on the concentration of [HCO3] if it changes

Answer 22

Na

Question 23

What anion has the greatest impact on the concentration of [HCO3] if it changes

Answer 23

Cl-

Question 24

What is the anion gap

Answer 24

Incorporates all the other anions/cations for which measurements aren’t usually available in order to provide wider context for acid-base balance

Question 25

Anion gap calculation

Answer 25

AG = (Na + K) - (HCO3 + Cl)

Question 26

What cations/anions are incorporated into the anion gap

Answer 26

Alb (- ve) Phos (- ve) Xa (unmeasured weak acids) (- ve) Lactate (- ve) Ca (+ ve) Mg (+ ve)

Question 27

Why are Ca and Mg not routinely included in the anion gap calculation

Answer 27

The concentrations of these are small and vary minimally

Question 28

Which anion can be included into the anion gap to expand the calculation and why is this done

Answer 28

Albumin Forms a large component of the normal anion gap & can vary dramatically in acute injury or illness, so if not included it could mask the severity of the acidotic process

Question 29

What is the anion gap calculation with albumin included and why is it like this

Answer 29

AG = (Na + K) - (HCO3 + Cl) + 0.25x(42-Alb) 0.25 because albumin is only slightly charged so add a quarter of the albumin deficit to remain realistic

Question 30

What is base excess and what does it tell us in practice

Answer 30

The amount of acid or base that needs to be added to a blood sample in order to return the pH to 7.40 at a temp of 37C at a PCO2 of 5.3kPa It removes the respiratory component and allows us to quantify the metabolic components of. The acid-base abnormality

Question 31

Fluid requirement in a well, normal child

Answer 31

First 10kg - 100ml/kg (per day) or 4ml/kg (per hour) Second 10kg - 50ml/kg (per day) or 2ml/kg (per hour) Subsequent kg - 20ml/kg (per day) or 1ml/kg (per hour)

Question 32

Approximate urine & stool losses

Answer 32

Urine 30ml/kg/day or 1-2ml/kg/hr Stool 0-10ml/kg/day

Question 33

Consequence of hypernatraemia

Answer 33

Brain damage - the brain shrinks as a result of intracellular dehydration and blood vessels can tear or clot up

Question 34

Consequence of hypernatraemia that is too rapidly corrected

Answer 34

Cerebral oedema | Convulsions

Question 35

Consequence of hyponatraemia that is too rapidly corrected

Answer 35

Demyelination | Permanent brain injury

Question 36

Principles of Rx of hypernatraemia

Answer 36

1. Treat shock first 2. Calculate maintenance fluid and estimate fluid deficit 3. Lower serum Na at rate no higher than 0.5mmol/h 4. Check other electrolytes 5. Monitor electrolytes frequently 6. Clinical assess hydration and weigh frequently Use isotonic saline e.g. 0.9% NaCl or 0.9% NaCl with 5% glucose

Question 37

Causes of hypernatraemia

Answer 37

Excessive Na intake e.g. iatrogenic poisoning, NAI Excessive water loss e.g. diabetes insipidus, diarrhoea Or combo of both e.g. children with gastroenteritis given excessive sodium in rehydration fluid

Question 38

Causes of hyponatraemia

Answer 38

Excess water intake or retention Excessive Na loss Or combo of both

Question 39

Rx of hyponatraemia if child is fitting

Answer 39

Needs rapid partial correction of Na to stop the fitting 4ml/kg of 3% NaCl over 15 mins - will raise serum Na by approx 3 mmol and usually stops the seizures

Question 40

Rx of hyponatraemia if child asymptomatic

Answer 40

If due to excessive water intake or retention - fluid restrict to 50% of intake requirements

Question 41

Principles of Rx of hyponatraemia

Answer 41

1. If fitting use hypertonic (3%) NaCl at 4ml/kg 2. Calculate maintenance fluid and estimate fluid deficit 3. Raise serum Na at rate no higher than 0.5mmol/h 4. Check other electrolytes 5. Monitor electrolytes frequently 6. Clinical assess hydration and weigh frequently

Question 42

Is Na mainly extracellular or intracelluar ion

Answer 42

Extracellular

Question 43

Is K mainly extracellular or intracellular ion

Answer 43

Intracellular

Question 44

Causes of hypokalaemia

Answer 44

``` Diarrhoea Alkalosis Volume depletion Primary hyperaldosteronism Diuretic abuse ```

Question 45

Causes of hyperkalaemia

Answer 45

``` Renal failure Acidosis Adrenal insufficiency Cell lysis Excessive potassium intake ```

Question 46

What is the underlying mechanism of hypokalaemia in patients who are alkalotic or receiving insulin or salbutamol?

Answer 46

Total body potassium depletion hasn't occurred, there has been redistribution of potassium into cells Therefore management of underlying cause is indicated

Question 47

Drugs causing hyperkalaemia

Answer 47

ACEI ARBS B blockers

Question 48

Management of hyperkalaemia if > 6 or abnormal ECG

Answer 48

1. Stabilise cardiac membrane - calcium gluconate or calcium chloride 2. Shift K into cells - Glucose/insulin infusion AND neb salbutamol (Consider sodium bicarb if pH <7.2) 3. Remove K from the body - Furosemide or Ca resonium (Consider dialysis if appropriate)

Question 49

Before using sodium bicarb in a hyperkalaemic patient, what other electrolyte should be checked and why

Answer 49

Calcium Hyperkalaemia can be accompanied my marked hypocalcaemia, esp in prfound sepsis or renal failure Giving Na bicarb in hypocalcaemia can provoke hypocalcaemic crisis - tetany, convulsions, hypotension, arrhythmias

Question 50

Causes of hypocalcaemia

Answer 50

Can be part of any severe illness Specific conditions: - severe rickets - hypoparathyroidism - pancreatitis - rhabdomyolysis - acute and chronic renal failure

Question 51

Causes of hypercalcaemia

Answer 51

- hyperparathyroidism - hypervitaminosis A or D - idiopathic hypercalcaemia of infancy - malignancy - thiazide diuretic abuse - skeletal disorders

Question 52

Symptoms of hypercalcaemia

Answer 52

``` long standing anorexia malaise weight loss failure to thrive vomiting ```

Question 53

Pathophysiology of DKA

Answer 53

Relative or absolute lack of insulin Therefore inability to metabolise glucose Leads to hyperglycaemia and osmotic diuresis No insulin, so fat is used as source of energy, leading to production of large quantities of ketones and metabolic acidosis Initial compensation of the acidosis by hyperventilation & a respiratory alkalosis. As it progresses, there is a combo of acidosis, hyperosmolality and dehydration, leading to coma

Question 54

Rx of DKA

Answer 54

1. ABCDE Principles of DKA Mx: 1. Only give fluid bolus if signs of shock 2. Rehydrate with 48 hours of replacement fluid - use 'reduced volume' calculations (large volumes of fluid replacement can precipitate cerebral oedema) 3. Replace insulin - start IV insulin infusion 1-2 hours after beginning IV fluids 4. PICU involvement if considering use of inotropes if signs of hypotensive shock

Question 55

Major complications of DKA

Answer 55

Cerebral oedema - avoid by slow normalisation of osmolality and hydration - monitor for headache, recurrence of vomiting, irritability, reduced GCS, inappropriate bradycardia, high BP Cardiac dysrhythmias - usually 2y to electrolyte disturbances Pulm oedema - careful fluid replacement required Acute renal failure