updated hyponatremia

Question 1

what is the normal range of sodium ?

Answer 1

135-145
hyponatremic is beellow 135

Question 2

what is the main ion iin intracellular fluids and extracellular fluid ?

Answer 2

intracellular - potassium
extracellular - sodium

Question 3

what is hyponatremia primarily a disorder of ?

Answer 3

disorder of water balance
water more than sodiumm in the extracellular space

Question 4

what is the presentation of hyponatremia ?

Answer 4

moderately severe : nausea without vomiting , confusion , headache

severe : vomiting , cardiorespiratory distress , abnormal and deep sleep, seizures, coma

all related to central nervous system affection

Question 5

what does the presence and severity off the symptoms of hyponatremia depend on ?

Answer 5

magnitude of the hyponatremia
rate at which it happened
( how much and how quickly )

Question 6

what is the pathogenesis inn hyponatremia ?

Answer 6

ICF osmolarity > ECF osmolarity

causing swelling of the cells including brain swelling and oedema

Question 7

how does the brain adapt to hyponatremia ?

Answer 7

1- increase in CSF flow so more drainage occurs
2- through transports found in brain cells, some osmolytes are excreted from these cells and take the water with them

Question 8

what is the clinical significance of the brain adaptation process ?

Answer 8

brain takes 48 hours to correct itself
so its important to avoid rapid correction of hyponatremia to avoid osmotic demyelination

Question 9

what are the 5 steps involved in the diagnosis of hyponatremia ?

Answer 9

1- repeated serum Na should be done ( directly from vein )
2- exclude drugs
3- exclude pseudo and translocation hyponatremia by measuring plasma osmolality
4- does thee patient have severe

Question 10

what are the hormones that act on the kidney ?

Answer 10

aldosterone and ADH ( vasopressin )
aldosterone on the proximal part of the collecting tubule and ADH on the distal part of the collecting tubule

Question 11

where are aldosterone and ADH secreted from ?

Answer 11

aldosterone from the medulla of the adrenal gland
vasopressin from the posterior pituitary

Question 12

what cotransporter do loop diuretics work on ?

Answer 12

sodium potassium chloride transporter in the ascending limb of the loop of henle

Question 13

what is the function of thiazide diuretics ?

Answer 13

blocks the reabsorption of Na-Cl in the DCT , which increases the amount of urine produced

Question 14

what is the function of loop diuretics ?

Answer 14

blocks NA-K-Cl co-transport inn loop of Henle

Question 15

what are the different types of hyponatremia ?

Answer 15

hypovolemic hyponatremia
euvolemic hyponatremia
hypovolemic hyponatremia

Question 16

what are the causes of hypovolemic hyponatremia ?

Answer 16

renal causes : tubulointerstitial disease , recovery phase of ATN , diuretics , addison’s disease , osmotic diuresis

extrarenal causes : diarrhea, vomiting, burns and haemorrhage

Question 17

what aree the tthre main causes of euvolemic hyponatremia ?

Answer 17

hypothyroidism - decreased cardiac output and so an increase in ADH
SIADH - abnormal ADH release so more water is retained in the kidney
psychogenic polydipsia - polyuria

Question 18

what are the causes of hypervolemic hyponatremia ?

Answer 18

renal failure
heart failure
liver failure
nephrotic syndrome

Question 19

what is the algorithm associated with the treatment of hyponatremia ?

Answer 19

is the patient symptomatic
if yes - 3% hypertonic saline
f not - perform a fluid status test

if the fluid status test is :
hypovolemic - 0.9 saline and treat the cause
euvolemic or hypeervollemic - water restriction, diuretics and treat the cause

Question 20

what are the causes of SIADH ?

Answer 20

caused by CNS disease
pullmonary disease
cancers
SSRIs, TCA

Question 21

what is the pathology in addison’s disease ?

Answer 21

1ry adrenal cortex insufficiency
decrease in aldosterone ( which normally reabsorbs sodium )
loss of sodium
hyperkaleemia
results in hyperkalemia , hyponatremia andd metabolic acidosis
mucocutaneous hyperpigmentation
postural hypotension