Fluid and Electrolyte Emergencies in Critically Ill Children

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Fluid and Electrolyte Emergencies in Critically
Ill Children

Ahmed Khamis Bamaga MBBS
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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

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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 (lt 0.5 ml/kg/hr) over the
  last 24 hours.

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Case Study 1
What is your differential diagnosis?What
diagnostic studies would you order?
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Case Study 1Differential 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, ...

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Case Study 1Laboratory 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 1.025 Sodium 58 mEq/L
• Osmolality 645 mosmol/kg FeNa 2.4
• What are the primary abnormalities?

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Case Study 1Laboratory studies

• Major abnormalities
• 1) Hyponatremia
• 2) Oliguria (inappropriately concentrated urine)
• What is the most likely explanation for these
  findings?

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Case Study 1 Syndrome of Inappropriate
Antidiuretic Hormone (SIADH)

• Variable etiology
• Trauma
• Infection
• Psychosis
• Malignancy
• Medications
• Diabetic ketoacidosis
• CNS disorders
• Positive pressure ventilation
• Stress

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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

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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 !!

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Case Study 1 SIADH

• Treatment
• Fluid restriction.
• 50-75 of maintenance requirements, be certain to
  include oral intake.
• Daily weights.

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Case Study 1The 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?

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Case Study 1The 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?

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Case Study 1The saga continues

• Stat labs
• Sodium 117 mEq/L
• What would you do now?

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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)(weightkg)(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

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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

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Case Study 2
No one can obtain IV access after 15 minutes,
what would you do now?
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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 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 7.07 pCO2 11
• pO2 121 HCO3 8

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Case Study 2
What is the most likely explanation of this
patients acidosis?
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Case Study 2Metabolic 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

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Case Study 2Metabolic acidosis and the anion gap
2. Increased gap
1. Normal gap
1. ? Acid prod
2. ? Acid elimination

• Renal HCO3
• losses

2. GI HCO3 losses
Renal disease
Lactate DKA Ketosis Toxins Alcohols
Salicylates Iron
Proximal RTA Distal RTA
Diarrhea
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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?

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Case Study 3Differential 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, .

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Case Study 3Laboratory 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?

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Case Study 3Laboratory studies

• Major abnormalities
• 1) Hypernatremia
• 2) Polyuria (inappropriately dilute urine)
• What is the most likely explanation?

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Case Study 3Diabetes Insipidus

• Diagnosis
• Central Diabetes insipidus
• 1) Polyuria
• 2) Inappropriately dilute urine (urine
  osmolality lt serum osmolality)
• May be see with midline defects
• Frequently occurs in brain dead patients
• What should you do to treat this child?

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Case Study 3Diabetes 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

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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.

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Case Study 4
What is your differential diagnosis?What
diagnostic studies would you order?
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Case Study 4Differential diagnosis

• Shock
• 1) Cardiogenic
• Myocarditis
• Pericardial effusion
• 2) Hypovolemic
• Hemorrhage, excessive GI losses, 3rd spacing
  (burns, sepsis)
• 3) Distributive
• Sepsis, anaphylaxis

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Case Study 4Laboratory 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?

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Case Study 4Diagnosis

• Major abnormalities
• 1) Hyponatremic dehydration
• 2) Hypoglycemia
• 3) Hyperkalemia, mild
• 4) Acidosis
• 5) Azotemia
• What is the most likely explanation for these
  findings?

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Case Study 4 Adrenal Insufficiency

• 1o adrenal insufficiency (Addisons 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)

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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

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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

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Case Study 4 Adrenal Insufficiency

• What should you do to treat this child?

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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)

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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?

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Case Study 5Hyperkalemia

• Treatment
• Immediately repeat serum potassium.
• Do not wait for confirmatory labs especially if
  EKG changes present.
• Anticipatory
• Stop potassium administration including feeds

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Cardiac Monitor

• What is this rhythm?
• What is your immediate treatment?

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Case Study 5Hyperkalemia

• 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

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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?

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Case Study 6Laboratory 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 PVCs
• What is the main abnormality?

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Case Study 6Laboratory studies

• Major abnormality
• 1) Hypokalemia
• What would you do now?

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Case Study 6Hypokalemia

• 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)

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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