File Name: approach to fluid and electrolyte disorders and acid base problems .zip
As part of routine health screening or when your healthcare practitioner suspects that you have an imbalance of one of the electrolytes usually sodium or potassium or an acid-base imbalance. You may be able to find your test results on your laboratory's website or patient portal. However, you are currently at Lab Tests Online. You may have been directed here by your lab's website in order to provide you with background information about the test s you had performed. Lab Tests Online is an award-winning patient education website offering information on laboratory tests.
Rasha D. Peer Reviewer. Christopher J. Statement of Financial Disclosure. To reveal any potential bias in this publication, and in accordance with Accreditation Council for Continuing Medical Education guidelines, we disclose that Dr.
Dietrich editor , Dr. Skrainka CME question reviewer , Ms. Wurster nurse planner , Dr. Sawaya author , Dr.
Haines peer reviewer , Ms. Coplin executive editor and Ms. Mark executive editor report no relationships with companies related to the field of study covered by this CME activity. Normal potassium levels vary by age. See Table 1. Mild hypokalemia is a potassium level between Hypokalemia can be acute or chronic, depending on the etiology. Gastroenteritis is the most common cause of pediatric hypokalemia. Potassium is an intracellular ion whose concentration is regulated by multiple mechanisms:.
Specific illnesses will lower the serum potassium in different ways. Diarrhea results in the loss of potassium through the gastrointestinal tract. However, vomiting does not directly cause hypokalemia through gastrointestinal losses, but results in alkalosis secondary to the loss of gastric fluids and volume loss, and the alkalosis increases potassium excretion from the kidneys.
Hypovolemia releasing aldosterone , diuretics, genetic renal tubular disorders, and osmotic diuresis e. See Table 2. Intracellular Shift normal total body potassium. Hypokalemic periodic paralysis rare and familial. Hypokalemia affects many organs since it causes cellular dysfunction. The main organs affected are the muscles rhabdomyolysis , heart, nervous system, and kidneys. Clinical Features. Once hypokalemia is established, a detailed history to identify the potential cause is important.
A history of diarrhea or vomiting can easily establish the cause without having to do an extensive workup. Ask about medication use and changes in enteral or parenteral formulation, such as total parenteral nutrition TPN. Clinical effects may include muscle weakness, respiratory distress, palpitations or chest pain from arrhythmia, confusion, lethargy, polydipsia, and polyuria. Physical Exam. Evaluate the vital signs and complete a rapid assessment, identifying signs of shock, respiratory failure, or dysrhythmia.
Neurologic signs of hypokalemia may include confusion, lethargy, hyporeflexia, and flaccid paralysis. Hypoactive bowel sounds and a distended abdomen can be seen with ileus secondary to hypokalemia. Generalized muscle weakness and pain are seen in rhabdomyolysis. Diagnostic Studies.
Serum electrolytes will establish the hypokalemia. When the etiology of the hypokalemia can be determined by the history e. However, if there is a diagnostic dilemma, a full set of electrolytes, urine potassium to creatinine ratio, a blood gas to evaluate for acidosis or alkalosis, serum blood urea nitrogen BUN , creatinine, magnesium and glucose, and a urine chloride are indicated: 3.
Look for potential complications of hypokalemia if the child is symptomatic. An elevated creatine phosphokinase CPK and urinary myoglobin reflect an acute rhabdomyolysis secondary to the hypokalemia. The following ECG changes appear sequentially with worsening hypokalemia; however, they do not correlate with a specific potassium level: prolonged PR interval, flattened T waves, depressed ST segment, U waves, ventricular fibrillation, and torsade de pointes.
Aim for a KCl rate of 0. Stable patients with chronic hypokalemia, for example secondary to medications or chronic disease, preferably are treated with oral potassium.
A potassium-sparing diuretic also can be used to correct serum potassium slowly in conjunction with a nephrologist. Repeat potassium levels after the infusion. Potassium phosphate and potassium bicarbonate also can be used if the hypokalemia is associated with hypophosphatemia and alkalosis, respectively.
Note that potassium infusions may cause phlebitis. Therefore, use a maximal rate of 0. Additional Aspects. If present, always treat hypomagnesemia and hypochloremia concomitantly, as they may exacerbate the symptoms of hypokalemia. Treat hypomagnesemia with magnesium supplementation, and hypochloremia with normal saline. The following are recommendations, not strict guidelines. The most common cause of hyperkalemia is pseudohyperkalemia, followed by renal or adrenal diseases.
Pseudohyperkalemia is a falsely elevated serum potassium level. This is quite common in children secondary to hemolyzed blood. When suspected, always draw another sample, while ensuring that it is as free-flowing as possible.
Another cause of pseudohyperkalemia is leukocytosis. Increased Intake increased total body potassium. Decreased Excretion decreased total body potassium. Iatrogenic causes e. Medication use e. As described above, potassium is an intracellular ion whose concentration is regulated by multiple mechanisms:.
Specific illnesses will affect these mechanisms differently. See Table 3. Severe hypovolemia causes poor tissue perfusion and metabolic acidosis and decreased potassium excretion from the kidneys. One of the most emergent complications of hyperkalemia is cardiac instability resulting in dysrhythmias and potential death.
Identifying the cause of hyperkalemia is crucial to its management. Before further diagnostic workup is started, ask about chronic diseases e. A new diagnosis of leukemia or Burkitt lymphoma puts the patient at a very high risk for hyperkalemia secondary to tumor lysis, even before chemotherapy is started. Symptoms of hyperkalemia are uncommon, but if present include paresthesias, myalgias, weakness, and ascending flaccid paralysis sparing the respiratory muscles.
As with all potentially sick children, look for signs of shock, respiratory failure, or dysrhythmia. A thorough neurological exam will identify the specific findings of hyperkalemia described above.
For patients with a dysrhythmia or neuromuscular symptoms, check a serum potassium level. Once true hyperkalemia is established, check a full set of electrolytes. For rhabdomyolysis, check serum creatine phosphokinase and urine myoglobin.
For tumor lysis, add a complete blood count, uric acid, and lactate dehydrogenase. For possible renal disease, order a urinalysis, urine electrolytes, and serum and urine osmolality. Check an ECG on all patients with hyperkalemia, whether symptomatic or not. Specific ECG changes appear sequentially and depend on the serum potassium level.
See Table 4. Once initial stabilization is performed following the PALS algorithms, focus on managing the hyperkalemia, irrespective of the underlying cause. Step 1: Cardiac Protection: The increase in extracellular potassium changes the membrane potential of cardiac cells, putting the heart at risk for dysrhythmias.
Calcium chloride can also be used; however, it poses the risk of tissue necrosis during infusion. Repeat the dose if needed based on ECG changes. The effect is immediate but also transient; therefore, steps 2 and 3 should be started concomitantly. Step 2: Shifting Extracellular Potassium into the Cells: While cardiac protection is taking place, the fastest way to decrease serum potassium is via an intracellular shift.
This can be accomplished by several means. First, infuse insulin and glucose concomitantly. Insulin shifts potassium into cells, but puts the child at risk for hypoglycemia, hence the need for the glucose. Second, start inhaled albuterol via a nebulizer or a metered-dose inhaler. In addition, sodium bicarbonate also may be used.
However, its effect is unpredictable and should not be used as a first-line or sole therapy. Step 3: Increasing the Elimination of Potassium: Start with a loop diuretic e. The former promotes potassium excretion through the kidneys and the latter through the gastrointestinal tract by binding potassium. Hydrate if renal function allows. Finally, hemodialysis in consultation with a nephrologist may be required for recalcitrant hyperkalemia or renal failure.
Metrics details. In clinical practice, both the history and laboratory testing are paramount to making an accurate diagnosis. Situations in which laboratory findings and patient history are not congruent pose a diagnostic dilemma. We report a case of a young woman presenting with a myriad of electrolyte and acid-base disorders. Difficulty in reaching a unifying diagnosis persisted due to discordant patient history.
Employing a systematic approach to the interpretation of serum chemistries is the most effective way to ensure abnormalities are detected and correctly.
Written and peer-reviewed by physicians—but use at your own risk. Read our disclaimer. These conditions can be categorized as acidoses or alkaloses and have a respiratory or metabolic origin, depending on the cause of the imbalance. Diagnosis is made by arterial blood gas ABG interpretation.
Your blood needs the right balance of acidic and basic alkaline compounds to function properly. This is called the acid-base balance. Your kidneys and lungs work to maintain the acid-base balance. Even slight variations from the normal range can have significant effects on your vital organs. Acid and alkaline levels are measured on a pH scale.
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