Transcript Fluid and Electrolyte Emergencies in Critically Ill Children

Fluid and Electrolyte
Emergencies in Critically Ill
Children
Ahmed Khamis Bamaga
MBBS
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
Case Study #1
• HPI:
• 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.
Case Study #1
What is your differential diagnosis?
What diagnostic studies would you order?
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, ...
Case Study #1
Laboratory studies
Serum studies
Sodium 126 mEq/L
Chloride 98 mEq/L
Potassium 3.7 mEq/L
Bicarbonate 25 mEq/L
BUN 4 mg/dL
Creatinine 0.4 mg/dL
Glucose 129 mg/dL
Osmolality 260 mosmol/kg
Urine studies
Specific gravity 1.025
Osmolality 645 mosmol/kg
Sodium 58 mEq/L
FeNa 2.4%
What are the primary abnormalities?
Case Study #1
Laboratory studies
Major abnormalities
1) Hyponatremia
2) Oliguria (inappropriately concentrated urine)
What is the most likely explanation for these findings?
Case Study #1
Syndrome of Inappropriate Antidiuretic Hormone
(SIADH)
• Variable etiology
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Trauma
Infection
Psychosis
Malignancy
Medications
Diabetic ketoacidosis
CNS disorders
Positive pressure ventilation
“Stress”
Case Study #1
SIADH
• Manifestations
• 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
Case Study #1
SIADH
• Diagnosis
• 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 !!

Case Study #1
SIADH
• Treatment
• Fluid restriction.
• 50-75% of maintenance requirements, be certain to include
oral intake.
• Daily weights.
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?
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?
Case Study #1
The saga continues
Stat labs:
Sodium 117 mEq/L
What would you do now?
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)(125-117)
= 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
Case Study #2
HPI:
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
Case Study #2
No one can obtain IV access after 15 minutes,
what would you do now?
Case Study #2
Place intraosseous line
Bolus 40 ml/kg of isotonic saline
Reassessment (HR 170, RR 40, BP 75/40)
Serum studies
Sodium 164 mEq/L
Chloride 139 mEq/L
Potassium 5.5 mEq/L
Bicarbonate 12 mEq/L
pH 7.07
pCO2 11
pO2 121
HCO3 8
BUN 75 mg/dL
Creatinine 3.1 mg/dL
Glucose 101 mg/dL
Case Study #2
What is the most likely explanation of this
patients acidosis?
Case Study #2
Metabolic acidosis and the anion gap
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 - (139 + 12) = 13
Case Study #2
Metabolic acidosis and the anion gap
1. Normal gap
1.
Renal “HCO3”
losses
Proximal RTA
Distal RTA
2. GI “HCO3”
losses
Diarrhea
2. Increased gap
1.  Acid prod
Lactate
DKA
Ketosis
Toxins
Alcohols
Salicylates
Iron
2.  Acid elimination
Renal disease
Case Study #3
• HPI:
• 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 130-150
ml/hour (~8ml/kg/hr).
What is your differential diagnosis?
What test would you order?
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, ….
Case Study #3
Laboratory studies
Serum studies
Sodium 155 mEq/L
Chloride 114 mEq/L
Potassium 4.2 mEq/L
Bicarbonate 22 mEq/L
BUN 13 mg/dL
Creatinine 0.6 mg/dL
Glucose 86 mg/dL
Serum osmolality: 320 mosmol/kg
Other
Urine specific gravity 1.005, no glucose.
Urine osmolality: 160 mosmol/kg
What are the main abnormalities?
Case Study #3
Laboratory studies
Major abnormalities
1) Hypernatremia
2) Polyuria (inappropriately dilute urine)
What is the most likely explanation?
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?
Case Study #3
Diabetes Insipidus
• Treatment
• Acute: Vasopressin infusion - begin with 0.5
milliunits/kg/hour, double every 15-30 minutes until urine
flow controlled
• Chronic: DDAVP (desmopressin)
• Warning
• Closely monitor for development of hyponatremia
Case Study #4
HPI:
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.
Case Study #4
What is your differential diagnosis?
What diagnostic studies would you order?
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
Case Study #4
Laboratory studies
Serum studies
Sodium 130 mEq/L
Chloride 99 mEq/L
Potassium 5.7 mEq/L
Bicarbonate 12 mEq/L
BUN 43 mg/dL
Creatinine 0.6 mg/dL
Glucose 48 mg/dL
Other
WBC: 13k (60% P, 30% L), HCT 35%, PLT 223k
Chest radiograph: no abnormalities
What are the electrolyte abnormalities?
Case Study #4
Diagnosis
Major abnormalities
1) Hyponatremic dehydration
2)
3)
4)
5)
Hypoglycemia
Hyperkalemia, mild
Acidosis
Azotemia
What is the most likely explanation for these findings?
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)
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
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
Case Study #4
Adrenal Insufficiency
• What should you do to treat this child?
Case Study #4
Adrenal Insufficiency
• Treatment
• Do not wait for confirmatory labs
• Fluid resuscitation - isotonic crystalloid
• Treat hypoglycemia
• Glucocorticoid replacement - hydrocortisone in stress
doses - 25-50 mg/m2 (1-2 mg/kg) IV
• Consider mineralocorticoid (Florinef®)
Case Study #5
• HPI:
• 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?
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
Cardiac Monitor
• What is this rhythm?
• What is your immediate treatment?
Case Study #5
Hyperkalemia
• Treatment (cont)
• Control effects
• Antagonism of membrane actions of potassium
 Calcium chloride 10-20 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
Case Study #6
• HPI:
• 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?
Case Study #6
Laboratory studies
Serum studies
Sodium 134 mEq/L
Chloride 98 mEq/L
Potassium 2.4 mEq/L
Bicarbonate 27 mEq/L
BUN 11 mg/dL
Creatinine 0.4 mg/dL
Calcium 9.2 mg/dL
Phosphorus 3.2 mg/dL
Other
EKG: Unifocal PVC’s
What is the main abnormality?
Case Study #6
Laboratory studies
Major abnormality
1) Hypokalemia
What would you do now?
Case Study #6
Hypokalemia
• Treatment
• Oral
• Safest, although solutions may cause diarrhea
• IV
• Peripheral: do not exceed 40-50 mEq/L potassium - Avoid
temptation to rapidly bolus
• Central: 0.5 -1 mEq/kg over 1-3 hours, depending on severity
• Replace magnesium also if low
• (25-50 mg/kg MgSO4)
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