A study of Hyponatremia in Hospitalized Patients

A study of hyponatremia in adult hospital inpatients over 16 yrs old admitted to the Hospital from the 1st of June 2006 to 10th of November 2006, showed that (50) out of (720) patients studied had serum sodium concentration below 135 meq/L. Twenty diuretics and 16 patients

The aim of the study was to determine the incidence, clinical characteristics, and causes of hyponatremia in medical wards of the Al-Diwaniah teaching Hospital.

Introdcution
Disorders of sodium are both the most common and probably the least understood electrolyte disorders in clinical medicine [1] .
Hyponatremia reflect a change in the proportion of sodium and water in plasma rather than a change in sodium content [2] .
Hyponatremia is the number one electrolyte abnormality in hospitalized patients [3] .A plasma sodium (Na+) concentration less than 135 meq/L usually reflects ahypotonic state [4] .Aetiology of hyponatremia Healty adults can drink up to 20 liters/day and the kidneys will respond with a vigorous water diuresis.
However , patients with restricted renal function, including older persons, cannot respond in this way and may become hyponatremic with much smaller volumes.
Most patients regulate their intake of water through the thirst mechanism [2] The most common causes of hyponatremia are shown in Table no  primarily neurological, and hyponatremic disorders should be suspected in patient who has acute mental state disturbance [5] .
Patients may be asymptomatic, or complain of nausea and malaise.As the plasma Na+ concentration falls, the symptoms progress to include headache, lethargy, confusion, obtundation, seizure and coma [2] .
Hyponatremia was graded as Mild, Moderate, and severe [6] as shown in The underlying cause can often be ascertained from an accurate history and physical examination, including an assessment of ECF volume status.
The differential diagnosis of hyponatremia, with an expanded ECF volume, and decreased effective circulatory volume includes heart failure, hepatic cirrhosis and nephritic syndrome.All these diseases have characteristic signs and symptoms.Patients with SIADH are usually euvolemic [4] .

PANTIENTS AND METHODS
During the period, from the 1st of June to the 10th of November 2006, 1035 adult (over 16 yrs) patients were admitted to the wards of the medical department.For logistical reasons, serum sodium was done to (720) patients & not to all.Hyponatremia was considered to present when the serum sodium was less than (135) meq/L.
Patients with hyponatremia were assessed clinically using special form with particular reference to the state of hydration, possible symptoms attributable to hyponatremia and the probable cause of the condition.
Normovolemic huponatremia was defined as the absence of clinical evidence of (ECF) volume depletion, absence of oedma and ascites, normal blood pressure, and JVP not raised.
Hypovolemic hyponatremia was defined as the presence of clinical evidence of (ECF) volume depletion (dry tongue & dry inelastic skin) , with hypotension in the supine or erect position or both, absence of ascites and dependent oedema without raised JVP.
Serum sodium was measured by Flame analyzer.Blood sugar, T.S. protein, blood urea, serum creatinine are also measured.

RESULTS
Out of the (720) patients where serum sodium were measured, 50(6%) patients were hyponatremic.The patients were aged 16-90 yrs (mean 54) and the age group most affected was (46-60) yrs, as shown in table (3).The most common cause of Hyponatremia was diuretics treatment which comprise (50%) of cases, the second most common cause was heart failure (32%), the 3rd most common cause was C.V.A. (20%) Sixteen percent of cases had renal failure, and (14%) had chest infection Table (6) .Fifteen patients (60%) out of 25 case who received diuretic therapy were female, while male comprised 40% of such cases Table (7).
Table (8) shows distribution of diuretic-induced hyponatremia according to the sex (Fig4).Sex No. of Cases % Male 10 40 Female 15 60 Total 25 100 Symptoms attributable to hyponatremia, such as mental confusion, anorexia, nausea, vomiting, and headache, are nonspecific and it is difficult in practice to judge whether hyponatremia or the underlying condition is responsible .Nevertheless, the hyponatremia was considered by treating doctors to be the cause of symptoms in (41) patients (82%).In seven cases, the symptoms were severe and in two were the reason for admission, Table (

Conclusion
Hyponatremia was common electrolyte disturbance in the medical ward.
The commonest cause of Hyponatremia was diuretic therapy Hyponatremia was symptomatic in most of the cases(82%) .

Table ( 10
) -Distribution of hyponatremic pt.according to state of hydration and diuretic thereapy (see alsoFig 6)of Natkunam A. et al. who found that (70%) of his cases were euvolemic hyponatremia.