Prevalence
Causes
Clinical
features
Investigations
Therapy
Prognosis
|  | | | Causes |
Note:
Common causes of
hyponatraemia
are heart failure and iatrogenic.
|
Causes of
hyponatraemia (Na < 128 mmol/l)
|
%
(95% CI)
|
congestive heart failure
c
|
30%
(19% to 41%)
|
SIADH
|
24%
(14% to 35%)
|
post-surgical (overtransfusion with 5% dextrose)
|
18%
(8.9% to 28%)
|
hypertension (usually due to diuretic use)
|
15%
(6.5% to 24%)
|
fluid overload
|
17%
(7.7% to 26%)
|
chronic renal failure
|
12%
(4.2% to 20%)
|
acute renal failure
|
11%
(3.2% to 18%)
|
Common causes of severe
hyponatraemia
are diuretics and SIADH
|
Causes of severe
hyponatraemia (Na < 110 mol/l)
|
%
(95% CI)
|
Chronic causes
c
|
84%
(76% to 93%)
|
diuretic agents only
|
36%
(24% to 48%)
|
SIADH
|
28%
(17% to 39%)
|
oedematous disorders
|
14%
(5.5% to 23%)
|
Addison's disease
|
4.7%
(0.0% to 9.9%)
|
chronic renal failure
|
1.6%
(0.0% to 4.6%)
|
Acute causes
|
16%
(6.7% to 25%)
|
parenteral fluids and SIADH
|
7.8%
(1.2% to 14%)
|
psychotic polydipsia
|
6.3%
(0.3% to 12%)
|
Addison's disease
|
1.6%
(0.0% to 4.6%)
|
|
internal medicine