hypovolemia Flashcards
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Body Fluid Pathophysiology
- ECF > sodium, chloride, bicarb
- ICF > potassium and phosphate
- Body fluid osmolality 280-295 mOsm/kg
- Vasopressin is stimulated when osmolality is greater than 285 mOsm/kg or changes in blood volume or blood pressure,
Hypovolemia -renal causes
Mannitol • Diuretics • Tubulointerstitial injury • Hereditary defect • Some antibiotics • Diabetes Insipidus
low volume xtra renal
- Extrarenal causes
* Fluid loss from GI, skin and respiratory system • Fluid accumulation within tissue compartments
Treatment – replete the fluid and find the cause
normo
hypernatremic
metabolicacidosis
- Normo- or hyponatremia > NS
- Hypernatremic > ½ NS
- Metabolic acidosis > bicarb • Hemorrhage/anemia > red blood cell transfusion
Hyponatremia: Na < 135 mM
- Physical exam: generalized swelling, neuro symptoms (dizziness to seizures)
- Evaluation: labs and calculate water deficit and correct it over 48-72 hours
- Treatment: slow infusion of NS to avoid osmotic demyelination syndrome, increased risk of ODS with alcoholism, malnutrition, hypokalemia or liver transplants
- Euvolemic hyponatremia:
- Hypervolemic hyponatremia
- Acute symptomatic hyponatremia:
- Chronic hyponatremia:
- Euvolemic hyponatremia: treat underlying cause
- Hypervolemic hyponatremia: treat underlying cause and add an ACE
- Beer potomania: NS and eat a regular diet
- Acute symptomatic hyponatremia: hypertonic solution slowly, mechanical ventilation if necessary
- Chronic hyponatremia: fluid restrict
Hypovolemic and urine Na > 20
Hypovolemic and urine Na > 20 look for renal cause, urine Na < 20 look for extrarenal losses
Euvolemic and urine Na > 20
are they hypothyroid, medication causes or SIADH
Hypervolemic and urine Na >20,
acute or chronic renal failure, urine NA <20 nephrotic syndrome, cirrhosis, cardiac
Hypernatremia
Plasma Na 145 mM • High mortality 40-60% • Combined water and electrolyte deficit causes
• Causes • Diabetes insipidus • Trauma • Hydrocephalus • Inflammation • Renal and nonrenal routes • Insensible losses • Diarrhea most common GI cause • Osmotic diuresis most common renal water loss
hyper NA ECF volume increased
hypertonic NaCl or NaHCO3
Hyper NA - is ECF volume decreased
Is ECF volume decreased > evaluate urine osmole excretion rate
• Is ECF volume decreased > evaluate urine osmole excretion rate
- > 750 mOsm/d treat with diuretic
- < 750 mOsm/d treat with desmopressin
- Central DI: urine osmo increases • Nephrogenic DI: urine osmo unchanged
Hypernatremia – Evaluation and Management
- Physical exam: neuro symptoms, confusion to coma leading to cerebral edema and seizures
- Diagnostics: history, ROS for thirst, polyuria, source of water loss • Labs: serum and urine osmo
- Give DDAVP to differentiate between central and nephrogenic DI
- Treatment
- Find underlying cause • Admin free water by mouth or NG tube • Replace slowly 10 mM/d
Hypokalemia
- K < 3.5 mM • Impacts cardiac rhythm, BP, and CV morbidity
- Causes
- Decreased intake • Redistribution into cells such as metabolic alkalosis or hypothermia
- Non-renal loss: GI, sweat, hyperaldosteronism, bicarbonaturea, diarrhea
- Renal loss: medications
Hypokalemia – Evaluation and Management
- Physical exam: arrhythmias, polyuria, phosphaturia, bicarb retention
- Diagnostics: basic labs, osmolality, urinary pH, thyroid function
- Treatment: • Replace K orally, IV only if cannot take PO
- Correct underlying cause
Hyperkalemia
- K > 5.5 mM
- Causes:
- Pseudohyperkalemia – occurs with improper venipuncture
- Intra-extracellular shift as in acidosis, thermal trauma, succinylcholine admin
- Inadequate excretion
Hyperkalemia – Evaluation and Management
Physical exam: cardiac arrhythmias, Brugadas sign on EKG
• Diagnostics: • EKG • Basic labs
• Treatment:
• Treat cardiac effects immediately
• Reduce K level
• Remove K by sodium polystyrene sulfonate exchange, diuretics or HD
Hypercalcemia
- Ca > 10.1 mg/dl
- Causes:
- Excessive PTH production • Malignancy • Vitamin D overproduction • Hyperthyroidism • Immobilization • Excessive calcium intake • Medications
Hypercalcemia – Evaluation and Management
- Physical exam: • Mild elevation – asymptomatic • Vague neuropsychiatric symptoms • Lethargy, stupor, coma • GI distress • EKG changes
- Diagnostics: • Basic labs • EKG • PTH level
- Treatment • IV fluids (4-6 liters) • Hydrocortisone if vitamin D overproduction
Hypocalcemia
Hypocalcemia
• Ca < 8.9 mg/dl
• Causes: • Hypoparathyroidism
• Parathyroid agenesis or destruction • Reduced parathyroid function
• Hyperparathyroidism
• Impaired Vit D production • Medications • Acute pancreatitis • Rhabdomyolysis • Cancer
Hypocalcemia – Evaluation and Management
- Physical Exam: paresthesias, Chvosteks sign, carpal spasm, seizures, bronchospasm, laryngospasm, prolonged QT
- Diagnostics: basic labs, PTH level
- Treatment – based on severity • Calcium gluconate for symptomatic and severe cases •
Metabolic Alkalosis
Determine the cause
• Causes: • Bicarb load • GI loss • Renal causes • Diuretics • HTN • K deficiency • Excess mineral corticosteroids • High/low renin • Cushing’s syndrome • CA
• Treatment • NS or KCl or surgery
Alcoholic Acidosis:
IV fluids (NS or 5% dextrose)
Salicylate Induced Acidosis:
Gastric lavage, activated charcoal, IV bicarb, HD for severe cases
Ethylene Glycol Induced Acidosis
saline, osmotic diuresis, HD, thiamine, pyridoxine supplement
Methanol Induced Acidosis:
similar to ethylene glycol treatment
Isopropanol alcohol toxicity:
watchful waiting and supportive treatment
Lactic Acidosis
Bicarb therapy, treat underlying cause
Calculate AG • High AG
ketoacidosis, lactic acidosis, renal failure and toxins • NG Acidosis : GI tract bicarb loss, renal tubular acidosis
Respiratory Acidosis
- Causes: • Pulmonary disease • Medications • Head trauma • Alcohol • Bronchospasm
- Diagnostics • ABG, PFTs, basic labs, non-pulm work up
- Treatment - oxygen
Respiratory Alkalosis
- Causes: • CNS stimulation such as pain, fever, tumor, trauma • Pneumonia • Aspiration • Anemia • Medications • PE • Sepsis • Heat exposure
- Treatment- breathe into a brown bag, ventilator, beta-adrenergic blocker
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