Sodium and Water Balance Problems

Question 1

what clinical features are seen with hypernatraemia or hyponatraemia caused by too little or too much water

Answer 1

usually no clinical features seen

Question 2

what clinical features can be seen with hypernatraemia with increased extracellular volume

Answer 2

peripheral and/or pulmonary oedema, pleural effusion, pericardial effusion, raised JVP, cardiomegaly, basal crackles, hypertension

Question 3

what symptoms may be seen with hyponatraemia with decreased extracellular volume)

Answer 3

thirst, muscle cramps, nausea/vomiting, postural dizziness, can lead to hypotension, impaired cerebral perfusion, confusion, coma

Question 4

what signs may be seen with hyponatraemia with decreased extracellular volume

Answer 4

postural hypotension, low JVP, peripheral venoconstriction, tachycardia

Question 5

what are some causes of hyponatraemia due to too little Na

Answer 5

increased Na loss; adrenal/kidney, skin, gut pathology(not very common can be fatal)
decreased Na intake(very rare)

Question 6

what are some causes of hyponatraemia due to too much H2O

Answer 6

decreased H2O excretion; SAIDH(very common)

increased H2O intake; compulsive water drinking(very rare)

Question 7

what are some causes of hypernatraemia due to too much Na

Answer 7

increased Na intake; IV meds, near drowning, malicious(very rare)
decreased Na loss

Question 8

what are some causes of hypernatraemia due to too little H2O

Answer 8

increased H2O loss; diabetes insipidus(not very common)

decreased H2O intake; very old/young(quite common)

Question 9

what treatment is used for hyponatraemia due to too little Na

Answer 9

give sodium, either IV saline or orally

Question 10

what treatment is used for hyponatraemia due to too much H2O

Answer 10

remove water, by fluid restriction and eventually water will decrease

Question 11

what treatment is used for hypernatraemia due to too much Na

Answer 11

remove sodium, using loop diuretics and replacing water lost with use of these diuretics

Question 12

what treatment is used for hypernatraemia due to too little H2O

Answer 12

give water, in form of dextrose

Question 13

in what scenarios is hyper or hyponatraemia serious

Answer 13

if very low or very high, if symptomatic, if [Na] rises or falls suddenly

Question 14

what does SIADH mean

Answer 14

Syndrome of Inappropriate Anti-Diuretic Hormone

SIADH

Question 15

what does ‘inappropriate’ in SIADH mean

Answer 15

means that the release of ADH is inappropriate for the osmolal state

Question 16

what are the 2 types of stimuli for ADH release

Answer 16

osmotic(in health)

non-osmotic(in disease)

Question 17

what are some common non-osmotic causes of ADH release

Answer 17

hypovolaemia, hypotension, nausea/vomiting, pain

Question 18

describe the water and sodium balance in a patient with oedema

Answer 18

too much water and too much sodium

Question 19

describe why oedema is a vicious cycle

Answer 19

because body reacts to it as if dehydration, so releases ADH and aldosterone to retain H2O, most of which retained in interstitial fluid(ECF) so makes oedema worse