ملخص

Creatinine

• Increased with a fall in GFR, in individuals with high musclemass, and with some drug

Urea

Increased with a fall in glomerular filtration rate (GFR),reduced renal perfusion or urine flow rate, and in high protein intake or catabolic states

HCO3

Abnormal in acid–base disorders
Cl
-changes in parallel with plasma Na
- Low in metabolic alkalosis
High in some form of metabolic acidosis
K
-reflect K shifts in and out of cells
-Low levels usually excessive losses
-High levels renal dysfunction
Na reflects reciprocal changes in body water content

Hyponatremia

sodium concentration < 135 mEq/L Defined as
Normal physiologic measures protects against hyponatremia
Thus, in most cases, some impairment of renal excretion of water is present

Deplesional Hyponatremia

Hypovolemic Hyponatremia
Diarrhea ,Vomiting
Adrenal insufficiency(Addison disease )
Thiazide overdose..
loss of Na.
Decrease intake of Na, Excessive sweating→ increased thirst → intake of excessive amounts of pure water only without Na

Delusional Hyponat

A-Euvolemic
SIADH
Primary Polydipsia
B-Hypervolemia
Cirrhosis and CHF, Nephrotic Synd

Neurological symptoms

Lethargy, headache, confusion seizures and coma
Muscle symptoms
Cramps, weakness
Gastrointestinal symptoms
Nausea, vomiting, abdominal cramps, and diarrhea


Psuedohyponatremia
High blood sugar or protein level can cause falsely depressed sodium levels .
Normal ADH response to low sodium is to be suppressed to allow water excretion thereby raising serum sodium conc.

Causes of Hyponatremia can be classified based on ADH level

Hyponatremia with ADH inappropriately elevated

1-Volume Depletion

True volume depletion (i.e. bleeding)
Effective circulating volume depletion (i.e. heart failure and cirrhosis)
2- Increase plasma Osmolality
3-SIADH
causes of SIADH :
CNS disease – tumor, ,
Pulmonary disease – TB, pneumonia,
Cancer
Drugs NSAIDs, SSRIs
Surgery - Postoperative
Idopathic – most common


Hyponatremia with appropriately suppressed eg. Primary polydypsia

Assessment

1-Hyponatremia can be asymptomatic
2-It may present with mild symptoms such as nausea and malaise
3- it may present with more severe symptoms such as seizures, coma or respiratory arrest

With no severe symptoms : fluid restriction started, next step is

to assess volume status to help determine cause
Hypovolemic dry mucous membranes, sunken eyes
Euvolemic normal appearing
Hypervolemic Edema, Jaundice
3 lab tests :
Serum Osmolality
Urine Osmolality
Urine Sodium
Symptoms tend to occur at serum sodium levels lower than 120 or when a rapid decline in sodium levels occur

Hyponat. Develops over hours or days have high.morbidity due to cerebral oedema relatively rapid correction with 3% hypertonic saline generally raise serum sodium

Delusional Hyponatremia

Oral fluid restriction is the first step
Removal of cause of SIADH,
Demeclocycline
Deplesional Hypovolemic hyponatremia
isotonic (0.9%) saline
Hypervolemic Hyponatremia
treat underlying cause ,Causious Duiretics with fluid restriction


The serious complication of replacing sodium too fast is Central Pontine Myelinolysis
elevation of sodium and the symptoms are either irreversible or only partially reversible
Symptoms include: dysarthria, dysphagia, paraparesis, quadriparesis, lethargy, coma or even death
Hypernatremia
Produced by either administration of hypertonic fluids or loss of thirst or failure of ADH mechanisms
Water moves from ICF → ECF &Cells dehydrate

Causes of Hypernatremia

loss of pure water.
Insufficient intake of water
GIT losses
Diabetes Insipidus
Osmotic Diuresis
Diabetic ketoacidosis
Hypothalamic lesions which affect thirst function
Sodium Overload

Initial symptoms include lethargy, weakness and irritability

Can progress to twitching, seizures , coma
Resulting decrease in brain volume can lead to rupture of cerebral veins leading to hemorrhage


Severe symptoms usually occur with rapid increase to sodium concentration
Sodium concentration greater than 180 mEq are associated with high mortality

DiagnosisSerum osmolality, urine osmolality and urine sodium conc.If urine osmolality is lower than serum osmolality then DI is suspected :Administration of Desmopressin- will differentiate it:
Urine osmolality will increase in central DI, no response in nephrogenic DI

Treatment of hypernatremia

Typical fluids given in form of Dextrose 5%

sodium should not be lowered by more than 12 mEq/L in 24 hours

Same as hyponatremia, sodium should not be rised by more than 12 mEq/L in 24 hours