ELECTROLYTES

Are particles that carry electrical charge and are present in blood, plasma and urine.

Substances whose molecules dissociate into

ions when placed into water cations- positively charged e.g Na+, K+, Mg++, Ca++

anions – negatively charged e.g Cl - ,

What is an electrolyte?

Essential minerals necessary for nerve and muscle function

Maintain body fluid balance Regulate acid base balance

Electrolytes

Positive cations : potassium K+, sodium Na +, magnesium Mg2+, calcium 2+

Negative cations :

phosphate PO4 3-, chloride Cl_

Buffer : bicarbonate HCO3-

Types of electrolytes

Intracellular fluid (ICF) :- prevalent cation – K+, Mg++ prevalent anion - PO4

- - -

Extracellular fluid ( ECF) :- prevalent cation – Na+

prevalent anion - Cl-

Distribution

Transmission and conduction of nerve and muscle impulse

Required for repolarization of cell membrane to a resting state after an action potential

Maintenance of cardiac rhythms Acid base balance Normal : 3.5 -4.5 mmol/l

POTASSIUM or K+

High serum K caused by :- massive intake impaired renal secretion shift from ICF to ECF : massive cell

destruction e.g brain injury, crush injury

Hyperkalaemia

Manifestation :Weak or paralysed skeletal musclesVF or cardiac standstillSmall P waves and high peaked T waves REMEMBER ALS GUIDELINES

Hyperkalaemia

CORRECTION increase elimination ( diuretics, dialysis)Force K+ from ECF to ICF by IV insulin with

dextrose or sodium bicarbonatereverse membrane effects of elevated ECF

K+ by administrating Calcium Gluconate IV

Hyperkalaemia

CAUSES : Kidney malfunction Diabetic ketoacidosis Gastrointestinal tract losses : vomiting,

diarrhoeaMg deficiency : alcohol abuse Metabolic alkalosis

HYPOKALAEMIA

Clinical signs / CorrectionCardiac arrthymias : gradual sagging ST

segment, flattening of T waves , appearance of U wave

Severe muscle weakness shallow respiration : threatening respiratory

functionCorrection : oral or IV

HYPOKALAEMIA

Most prevalent cation in ECF Plays a major role :-

ECF volume and concentration : retain body water Generation and transmission of nerve impulsepH balance Normal concentration : 135- 145 mmol/l

SODIUM or Na+

Elevated serum sodium: mostly water deficit causes hyper osmolality lead to cellular

dehydration Primary protection: thirst mechanism from

hypothalamus

Hypernatraemia

Clinical signs Seizures, coma leading to irreversible brain damage

Correction : not with WATER !!

Giving NaCl solution or with addition to dextrose: gradually reduced to avoid cerebral oedema

Hypernatraemia

Causes: Low Na in plasma caused by liver failure, kidney failure and

overhydration . Proportional to excess water :SIADH (syndrome of

inappropriate anti-diuretic hormone secretion)Manifestation : nausea, vomiting, headache, confusion, lethargy ,

restlessness, muscle weakness, spasms, cramps, seizures, coma .

Non cardiogenic pulmonary oedema .

Hyponatremia

Correction :- Find the cause Hypervolemia : both water and sodium level high liver cirrhosis, CHF, correction :- address liver and cardiac function Euvolaemic hyponatremia: excess water but body Na+ level is

same Hypothoridism , steroid (glucosteroid deficiency )

Correction : water restriction Hypovolaemic hyponatraemia : both water and sodium low prolonged vomiting, severe diarrhoea, decreased oral intake ,

diuretic use Correction : administration of NaCl.

Hyponatremia

2nd most abundant cation in ICF Energy metabolism : glucose utilisation ,

fatty acid synthesis, muscle contraction Na+ – K + pump Affects Ca ++ homeostasis Release and action of PTH

Magnesium

Malabsorption : inflammatory bowel diseaseAlcoholism Following parathyrodiectomyHypercalaemia

Correction : IV MgSO4

Hypomagnesaemia

Block synaptic transmission : deep tendon reflexes

Effect on smooth muscles : ileus and urinary retention

Bradycardia and hypotension : effects on Ca+

+ & K +

Correction:IV Ca++ Renal patient : dialysis

Hypermagnesaemia

Transmission of nerve impulse Muscle contraction :Myocardial Blood clotting Formation of bones and teethBalance controlled by : parathyroid hormone Calcitonin Vitamin D

CALCIUM

Eating disorderLack of parathyroid hormone

Hypocalcaemia

Hyper parathyroid hormoneVitamin D overdoseProlonged immobilisation

Hypercalcaemia

Decreased memory Confusion , fatigue Constipation

Correction :- excretion of excess Ca++ with loop diuretics

Hydration with isotonic saline

Clinical symptoms

Maintains acid-base status Kidney regulation Good indictors of acid-base balance

Bicarbonates HCO3

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