1. Fluid and Electrolyte Emergencies in Critically Ill Children
Ahmed Khamis Bamaga
MBBS

2. Objectives At the end of this presentation learners will be able to:
1) Recognize common fluid and electrolyte disorders in critically ill children
2) List a diagnostic strategy for these disorders
3) Apply appropriate management principles

3. Case Study #1 HPI: Hospital course:
A 3 month-old is in the PICU for shock following a two day history of fever and irritability. Blood and CSF cultures are positive for Streptococcus pneumoniae.
Hospital course:
Decreasing urine output (< 0.5 ml/kg/hr) over the last 24 hours.

4. Case Study #1
What is your differential diagnosis? What diagnostic studies would you order?

5. Case Study #1 Differential diagnosis
Oliguria
1) Pre-Renal (decreased effective renal blood flow)
Diminished intravascular volume, cardiac dysfunction, vasodilitation
2) Post-Renal
Outlet obstruction (intrinsic vs. extrinsic), foley catheter occlusion
3) Renal
Acute tubular necrosis, acute renal failure, SIADH, ...

6. Case Study #1 Laboratory studies
Serum studies
Sodium 126 mEq/L BUN 4 mg/dL
Chloride 98 mEq/L Creatinine 0.4 mg/dL
Potassium 3.7 mEq/L Glucose 129 mg/dL
Bicarbonate 25 mEq/L Osmolality 260 mosmol/kg
Urine studies
Specific gravity Sodium 58 mEq/L
Osmolality 645 mosmol/kg FeNa 2.4%
What are the primary abnormalities?

7. Case Study #1 Laboratory studies
Major abnormalities
1) Hyponatremia
2) Oliguria (inappropriately concentrated urine)
What is the most likely explanation for these findings?

8. Case Study #1 Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
Variable etiology
Trauma
Infection
Psychosis
Malignancy
Medications
Diabetic ketoacidosis
CNS disorders
Positive pressure ventilation
“Stress”

9. Manifestations Case Study #1 SIADH
By definition, “inappropriate” implies having excluded normal physiologic reasons for release of ADH:
1) In response to hypertonicity.
2) In response to life threatening hypotension.
Hyponatremia
Oliguria
Concentrated urine
elevated urine specific gravity
“inappropriately” high urine osmolality in face of hyponatremia
Normal to high urine sodium excretion

10. Diagnosis Case Study #1 SIADH Critical level of suspicion.
Demonstration of inappropriately concentrated urine in face of hyponatremia
 urine osmolality,  SG,  urine sodium excretion ( FeNa)
Be certain to exclude normal physiologic release of ADH
Frequently secondary to decreased perfusion
 Serum sodium,  urine osmolality,  urine sodium excretion (low FeNa)  consistent with dehydration or diminished renal blood flow. Look at patient more closely !!

11. Treatment Case Study #1 SIADH Fluid restriction. Daily weights.
50-75% of maintenance requirements, be certain to include oral intake.
Daily weights.

12. Case Study #1 The saga continues….
Hospital course:
Four hours after beginning fluid restriction, you are called because the patient is having a generalized seizure. There is no response to two doses of IV lorazepam (Ativan®) and a loading dose of fosphenytoin (Cerebyx®)
What is the most likely explanation?

13. Case Study #1 The saga continues
Seizure
1) Worsening hyponatremia
2) Intracranial event
3) Meningitis
4) Other electrolyte disturbance
5) Medication
6) Hypertension
What diagnostic studies would you order?

14. Case Study #1 The saga continues
Stat labs:
Sodium 117 mEq/L
What would you do now?

15. Case Study #1 Hyponatremic seizure
Treatment
Hypertonic saline (3% NaCl) infusion
To correct sodium to 125 mEq/L, the deficit is equal to
(0.6)(weight[kg])(125- measured sodium)
(0.6)(8)( ) = 38.4 mEq
Because patient is symptomatic with seizures, immediately increase serum sodium by 5 mEq/L
mEq sodium = (0.6)(8 kg)(5) = 24 mEq
3% NaCl = 0.5 mEq/L, therefore 24 mEq bolus = 48 mls, followed by slow infusion of remaining 14.4 mEq (29 mls) over next several hours

16. Case Study #2 HPI: Home meds: PE:
A 5 month-old girl presents with a one day history of irritability and fever. Mother reports three days of “bad” vomiting and diarrhea.
Home meds:
Acetaminophen and ibuprofen for fever
PE:
BP 70/40, HR 200, R 60, T38.3 C. Irritable, sunken eyes and fontanelle, skin feels like Pillsbury Dough Boy

17. Case Study #2
No one can obtain IV access after 15 minutes, what would you do now?

18. Case Study #2 Place intraosseous line Serum studies
Bolus 40 ml/kg of isotonic saline
Reassessment (HR 170, RR 40, BP 75/40)
Serum studies
Sodium 164 mEq/L BUN 75 mg/dL
Chloride 139 mEq/L Creatinine 3.1 mg/dL
Potassium 5.5 mEq/L Glucose 101 mg/dL
Bicarbonate 12 mEq/L
pH pCO2 11
pO HCO3 8

19. Case Study #2
What is the most likely explanation of this patients acidosis?

20. Case Study #2 Metabolic acidosis and the anion gap
Sodium - (chloride + bicarbonate)
Normal 12 +/- 2 meq/L
Elevated anion gap consistent with excess acid
Normal anion gap consistent with excess loss of base
164 - ( ) = 13

21. Case Study #2 Metabolic acidosis and the anion gap
2. Increased gap
1. Normal gap
Renal “HCO3”
losses
2. GI “HCO3”
losses
1.  Acid prod
2.  Acid elimination
Lactate
DKA
Ketosis
Toxins
Alcohols
Salicylates
Iron
Renal disease
Proximal RTA
Distal RTA
Diarrhea

22. Case Study #3 HPI: What is your differential diagnosis?
A five year old (18 kg) boy was involved in a a motor vehicle accident two days ago. He sustained an isolated head injury with intraventricular hemorrhage and multiple large cerebral contusions. Three hours ago, he had an episode of severe intracranial hypertension (ICP 90mm Hg, MAP 50mm Hg, requiring volume plus epinephrine infusion for hypotension. Over the last two hours, his urine output has increased to ml/hour (~8ml/kg/hr).
What is your differential diagnosis?
What test would you order?

23. Case Study #3 Differential diagnosis
Polyuria
1) Central diabetes insipidus
Deficient ADH secretion (idiopathic, trauma, pituitary surgery, hypoxic ischemic encephalopathy)
2) Nephrogenic diabetes insipidus
Renal resistance to ADH (X-linked hereditary, chronic lithium, hypercalcemia, ...)
3) Primary polydipsia (psychogenic)
Primary increase in water intake (psychiatric), occasionally hypothalamic lesion affecting thirst center
4) Solute diuresis
Diuretics (lasix, mannitol,..), glucosuria, high protein diets, post-obstructive uropathy, resolving ATN, ….

24. Case Study #3 Laboratory studies
Serum studies
Sodium 155 mEq/L BUN 13 mg/dL
Chloride 114 mEq/L Creatinine 0.6 mg/dL
Potassium 4.2 mEq/L Glucose 86 mg/dL
Bicarbonate 22 mEq/L Serum osmolality: 320 mosmol/kg
Other
Urine specific gravity 1.005, no glucose.
Urine osmolality: 160 mosmol/kg
What are the main abnormalities?

25. Case Study #3 Laboratory studies
Major abnormalities
1) Hypernatremia
2) Polyuria (inappropriately dilute urine)
What is the most likely explanation?

26. Case Study #3 Diabetes Insipidus
Diagnosis
Central Diabetes insipidus
1) Polyuria
2) Inappropriately dilute urine (urine osmolality < serum osmolality)
May be see with midline defects
Frequently occurs in brain dead patients
What should you do to treat this child?

27. Case Study #3 Diabetes Insipidus
Treatment
Acute: Vasopressin infusion - begin with 0.5 milliunits/kg/hour, double every minutes until urine flow controlled
Chronic: DDAVP (desmopressin)
Warning
Closely monitor for development of hyponatremia

28. Case Study #4 HPI: Home meds: PE:
A six year old, 25 kg, boy with severe asthma (S/P ECMO for a previous exacerbation) presents with a two day history of severe vomiting and diarrhea to the Emergency Department.
Home meds:
Albuterol MDI two puffs QID, Salmeterol MDI two puffs BID, Prednisone 10mg daily, Fluticasone 220 mcg two puffs BID
PE:
BP 70/40, HR 168, R 40, T39.0 C. He is very lethargic (GCS 11). Poor perfusion with cool extremities, mottling, and delayed capillary refill, otherwise no specific system abnormalities.

29. Case Study #4
What is your differential diagnosis? What diagnostic studies would you order?

30. Case Study #4 Differential diagnosis
Shock
1) Cardiogenic
Myocarditis
Pericardial effusion
2) Hypovolemic
Hemorrhage, excessive GI losses, “3rd spacing” (burns, sepsis)
3) Distributive
Sepsis, anaphylaxis

31. Case Study #4 Laboratory studies
Serum studies
Sodium 130 mEq/L BUN 43 mg/dL
Chloride 99 mEq/L Creatinine 0.6 mg/dL
Potassium 5.7 mEq/L Glucose 48 mg/dL
Bicarbonate 12 mEq/L
Other
WBC: 13k (60% P, 30% L), HCT 35%, PLT 223k
Chest radiograph: no abnormalities
What are the electrolyte abnormalities?

32. 1) Hyponatremic dehydration
Case Study #4 Diagnosis
Major abnormalities
1) Hyponatremic dehydration
2) Hypoglycemia
3) Hyperkalemia, mild
4) Acidosis
5) Azotemia
What is the most likely explanation for these findings?

33. Case Study #4 Adrenal Insufficiency
1o adrenal insufficiency (Addison’s disease)
Adrenal gland destruction/dysfunction (ie. autoimmune, hemorrhagic)
most common in infants 5-15 days old
2nd adrenal insufficiency
ACTH deficiency (ie. panhypopituitarism or isolated ACTH)
“Tertiary” or “iatrogenic”
Suppression of hypothalamic-pituitary-adrenal axis (ie. chronic steroid use)

34. Case Study #4 Adrenal Insufficiency
Manifestations
Major hormonal factor precipitating crisis is mineralcorticoid deficiency, not glucocorticoid.
Dehydration, hypotension, shock out of proportion to severity of illness
Nausea, vomiting, abdominal pain, weakness, tiredness, fatigue, anorexia
Unexplained fever
Hypoglycemia (more common in children and tertiary)
Hyponatremia, hyperkalemia, azotemia

35. Case Study #4 Adrenal Insufficiency
Diagnosis
Critical level of suspicion in all patients with shock
1) Demonstration of inappropriately low cortisol secretion
Basal morning level vs. random “stress” level
2) Determine whether cortisol deficiency dependent or independent of ACTH secretion.
 ACTH,  cortisol  1o adrenal insufficiency
 ACTH,  cortisol  2nd or tertiary insufficiency
3) Seek a treatable cause

36. Case Study #4 Adrenal Insufficiency
What should you do to treat this child?

37. Case Study #4 Adrenal Insufficiency
Treatment
Do not wait for confirmatory labs
Fluid resuscitation - isotonic crystalloid
Treat hypoglycemia
Glucocorticoid replacement - hydrocortisone in stress doses mg/m2 (1-2 mg/kg) IV
Consider mineralocorticoid (Florinef®)

38. Case Study #5 HPI: What do you do now?
An eight month old infant with autosomal recessive polycystic kidney disease presents with irritability. She is on nightly peritoneal dialysis at home. The lab calls a panic potassium value of 7.1 meq/L. The tech says it is not hemolyzed.
What do you do now?

39. Case Study #5 Hyperkalemia
Treatment
Immediately repeat serum potassium.
Do not wait for confirmatory labs especially if EKG changes present.
Anticipatory
Stop potassium administration including feeds

40. Cardiac Monitor
What is this rhythm?
What is your immediate treatment?

41. Case Study #5 Hyperkalemia
Treatment (cont)
Control effects
Antagonism of membrane actions of potassium
Calcium chloride mg/kg over 5 minutes; may repeat x2
Shift potassium intracellularly
Glucose 1 gm/kg plus 0.1 unit/kg regular insulin
Alkalinize (increase ventilator rate; Sodium bicarbonate 1 mEq/kg IV)
Inhaled 2 adrenergic agonist (albuterol)
Removal of potassium from the body
Loop / thiazide diuretics
Cation exchange resin: sodium polstyrene sulfonate (Kayexelate®) 1 gm/kg PO or PR (or both)
Dialysis

42. Case Study #6 HPI: What is your differential diagnosis?
A three year old boy is recovering from septic shock. He received 150 ml/kg in fluid boluses in the first 24 hours and has anasarca. You begin him on a bumetanide infusion (Bumex®) for diuresis. He develops severe weakness and begins to hypoventilate. You notice unifocal premature ventricular beats on his cardiac monitor.
What is your differential diagnosis?
What tests would you order?

43. Case Study #6 Laboratory studies
Serum studies
Sodium 134 mEq/L BUN 11 mg/dL
Chloride 98 mEq/L Creatinine 0.4 mg/dL
Potassium 2.4 mEq/L Calcium 9.2 mg/dL
Bicarbonate 27 mEq/L Phosphorus 3.2 mg/dL
Other
EKG: Unifocal PVC’s
What is the main abnormality?

44. Case Study #6 Laboratory studies
Major abnormality
1) Hypokalemia
What would you do now?

45. Case Study #6 Hypokalemia
Treatment
Oral
Safest, although solutions may cause diarrhea IV
Peripheral: do not exceed mEq/L potassium - Avoid temptation to rapidly bolus
Central: mEq/kg over 1-3 hours, depending on severity
Replace magnesium also if low
(25-50 mg/kg MgSO4)

46. Summary
Disorders of sodium, water, and potassium regulation are common in critically ill children
Diagnostic approach must be considered carefully for each patient
Strict attention to detail is important in providing safe and effective therapy