1、Fluid and Electrolyte Emergencies in Critically Ill ChildrenRichard T. Blaszak, M.D. Stephen M. Schexnayder, M.D.ObjectivesAt 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
2、disorders 3) Apply appropriate management principlesCase 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 las
3、t 24 hours.Case Study #1What is your differential diagnosis?What diagnostic studies would you order?Case Study #1Differential diagnosisOliguria1) Pre-Renal (decreased effective renal blood flow)Diminished intravascular volume, cardiac dysfunction, vasodilitation2) Post-RenalOutlet obstruction (intri
4、nsic vs. extrinsic), foley catheter occlusion3) RenalAcute tubular necrosis, acute renal failure, SIADH, .Case Study #1Laboratory studiesSerum studiesSodium 126 mEq/LBUN 4 mg/dLChloride 98 mEq/LCreatinine 0.4 mg/dLPotassium 3.7 mEq/LGlucose 129 mg/dLBicarbonate 25 mEq/LOsmolality 260 mosmol/kgUrine
5、studiesSpecific gravity 1.025Sodium 58 mEq/LOsmolality 645 mosmol/kgFeNa 2.4%What are the primary abnormalities?Case Study #1Laboratory studiesMajor abnormalities1) Hyponatremia2) Oliguria (inappropriately concentrated urine)What is the most likely explanation for these findings?Case Study #1 Syndro
6、me of Inappropriate Antidiuretic Hormone (SIADH) Variable etiology 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
7、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 excretionCase Study #1 SIA
8、DH 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 osmolalit
9、y, 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 #1The saga continues.Hospita
10、l 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 #1The saga continuesSeizur
11、e1) Worsening hyponatremia2) Intracranial event3) Meningitis4) Other electrolyte disturbance5) Medication6) HypertensionWhat diagnostic studies would you order?Case Study #1The saga continuesStat labs:Sodium 117 mEq/LWhat would you do now?Case Study #1 Hyponatremic seizure Treatment Hypertonic salin
12、e (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/LmEq sodium = (0.6)(8 kg)(5) = 24 mEq 3% NaCl = 0.5 mEq/L, therefore
13、 24 mEq bolus = 48 mls, followed by slow infusion of remaining 14.4 mEq (29 mls) over next several hoursCase Study #2HPI: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 fe
14、verPE: BP 70/40, HR 200, R 60, T38.3 C. Irritable, sunken eyes and fontanelle, skin feels like Pillsbury Dough BoyCase Study #2No one can obtain IV access after 15 minutes, what would you do now?Case Study #2Place intraosseous lineBolus 40 ml/kg of isotonic salineReassessment (HR 170, RR 40, BP 75/4
15、0)Serum studiesSodium 164 mEq/LBUN 75 mg/dLChloride 139 mEq/LCreatinine 3.1 mg/dLPotassium 5.5 mEq/LGlucose 101 mg/dLBicarbonate 12 mEq/LpH 7.07 pCO2 11 pO2 121 HCO3 8 Case Study #2What is the most likely explanation of this patients acidosis?Case Study #2Metabolic acidosis and the anion gapAnion Ga
16、pSodium - (chloride + bicarbonate)Normal 12 +/- 2 meq/LElevated anion gap consistent with excess acidNormal anion gap consistent with excess loss of base 164 - (139 + 12) = 131. Normal gap2. Increased gap1.Renal “HCO3” losses2. GI “HCO3” losses Proximal RTA Distal RTADiarrhea1. Acid prod2. Acid elim
17、inationLactateDKAKetosisToxins Alcohols Salicylates Iron Renal diseaseCase Study #2Metabolic acidosis and the anion gapCase 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 mul
18、tiple 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 different
19、ial diagnosis?What test would you order?Case Study #3Differential diagnosisPolyuria1) Central diabetes insipidusDeficient ADH secretion (idiopathic, trauma, pituitary surgery, hypoxic ischemic encephalopathy)2) Nephrogenic diabetes insipidusRenal resistance to ADH (X-linked hereditary, chronic lithi
20、um, hypercalcemia, .)3) Primary polydipsia (psychogenic)Primary increase in water intake (psychiatric), occasionally hypothalamic lesion affecting thirst center4) Solute diuresisDiuretics (lasix, mannitol,.), glucosuria, high protein diets, post-obstructive uropathy, resolving ATN, .Case Study #3Lab
21、oratory studiesSerum studiesSodium 155 mEq/LBUN 13 mg/dLChloride 114 mEq/LCreatinine 0.6 mg/dLPotassium 4.2 mEq/LGlucose 86 mg/dLBicarbonate 22 mEq/LSerum osmolality: 320 mosmol/kgOtherUrine specific gravity 1.005, no glucose.Urine osmolality: 160 mosmol/kgWhat are the main abnormalities? Case Study
22、 #3Laboratory studiesMajor abnormalities1) Hypernatremia2) Polyuria (inappropriately dilute urine)What is the most likely explanation? Case Study #3Diabetes InsipidusDiagnosisCentral Diabetes insipidus1) Polyuria2) Inappropriately dilute urine (urine osmolality serum osmolality) May be see with midl
23、ine defectsFrequently occurs in brain dead patientsWhat should you do to treat this child?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 mo
24、nitor for development of hyponatremiaCase Study #4HPI: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,
25、 Prednisone 10mg daily, Fluticasone 220 mcg two puffs BIDPE: 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 #4What is your differential diagnosis?What
26、diagnostic studies would you order?Case Study #4Differential diagnosisShock1) CardiogenicMyocarditisPericardial effusion2) HypovolemicHemorrhage, excessive GI losses, “3rd spacing” (burns, sepsis)3) DistributiveSepsis, anaphylaxisCase Study #4Laboratory studiesSerum studiesSodium 130 mEq/LBUN 43 mg/
27、dLChloride 99 mEq/LCreatinine 0.6 mg/dLPotassium 5.7 mEq/LGlucose 48 mg/dLBicarbonate 12 mEq/LOtherWBC: 13k (60% P, 30% L), HCT 35%, PLT 223kChest radiograph: no abnormalitiesWhat are the electrolyte abnormalities? Case Study #4DiagnosisMajor abnormalities1) Hyponatremic dehydration2) Hypoglycemia3)
28、 Hyperkalemia, mild4) Acidosis5) AzotemiaWhat is the most likely explanation for these findings?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 insuffi
29、ciency 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 gl
30、ucocorticoid. 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, azotemiaCase Study #4 Adrenal Insufficienc
31、y 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 ACT
32、H, cortisol 2nd or tertiary insufficiency 3) Seek a treatable causeCase 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 r
33、eplacement - 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 pan
34、ic potassium value of 7.1 meq/L. The tech says it is not hemolyzed.What do you do now?Case Study #5Hyperkalemia Treatment Immediately repeat serum potassium. Do not wait for confirmatory labs especially if EKG changes present. Anticipatory Stop potassium administration including feedsCardiac Monitor
35、What is this rhythm?What is your immediate treatment?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 intracellularlyGlucose 1 gm/kg plus 0.1 unit/kg regular insulinAlkali
36、nize (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) DialysisCase Study #6 HPI: A three year old
37、 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 mo
38、nitor.What is your differential diagnosis?What tests would you order?Case Study #6Laboratory studiesSerum studiesSodium 134 mEq/LBUN 11 mg/dLChloride 98 mEq/LCreatinine 0.4 mg/dLPotassium 2.4 mEq/LCalcium 9.2 mg/dLBicarbonate 27 mEq/LPhosphorus 3.2 mg/dLOtherEKG: Unifocal PVCsWhat is the main abnorm
39、ality? Case Study #6Laboratory studiesMajor abnormality1) HypokalemiaWhat would you do now? Case Study #6Hypokalemia Treatment Oral Safest, although solutions may cause diarrhea IV Peripheral: do not exceed 40-50 mEq/L potassium - 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
