A Study on Incidence and Etiology of Hyponatremia in Hospitalised Patients

Krishna Shankar, G (2010) A Study on Incidence and Etiology of Hyponatremia in Hospitalised Patients. Masters thesis, Madras Medical College, Chennai.


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INTRODUCTION Hyponatremia is the most common electrolyte disorder among hospitalized patients and has been associated with increased mortality. Hyponatremia is defined as a serum sodium concentration (Na+) less than 135 mEq/L. Serum sodium levels and serum osmolality are normally maintained under precise control by homeostatic mechanisms involving thirst, anti-diuretic hormone and the renal handling of filtered sodium. Hyponatremia occurs in a broad spectrum of patients who are asymptomatic or critically ill. Patients in whom the serum sodium concentration is greater than 130 mEq/L are usually asymptomatic, whereas those in whom these values are lower may have symptoms. Clinical symptoms vary from individual to individual. Majority of patients with hyponatremia are asymptomatic. Most patients with hyponatremia have non-specific symptoms or symptoms due to an underlying disease or disorder. The clinical manifestations of hyponatremia are produced by brain swelling and are primarily a function of the rate of fall of serum sodium concentration and not the absolute level. Symptoms occurring early in hyponatremia is usually anorexia, nausea, vomiting. Some patients may have headache and irritability. As serum sodium levels falls further patients develop neuropsychiatry symptoms. These symptoms range from restlessness, altered consciousness, lethargy, seizures to coma. As the symptomatology vary markedly, the diagnosis of hyponatremia is difficult to establish. Prompt recognition and optimal management of hyponatremia in hospitalized patients may reduce in-hospital mortality and symptom severity, allow for less intensive hospital care, decrease the duration of hospitalization and associated costs and improve the treatment of underlying co morbid conditions and patients’ quality of life. So the treating clinician should have a high index of suspicion to diagnose hyponatremia. There are serious neurological sequelae associated with hyponatremia and its management. The possible causes of hyponatremia should always be sought in every case. The presence of symptoms and duration of hyponatremia guide the treatment strategy. Thorough evaluation for hyponatremia mandates accurate history taking and clinical examination along with various investigations. AIMS AND OBJECTIVES: 1. To study the incidence of hyponatremia in hospitalized adult patients in medical wards. 2. To determine the etiology of clinically significant hyponatremia in 100 patients in medical wards. 3. To determine the clinical presentation of hyponatremia in these patients. 4. To study whether the primary disease is a cause for hyponatremia and whether other features cause hyponatremia also. 5. To study whether hyponatremia adds to morbidity and mortality. 6. To study the various diseases associated with hyponatremia. MATERIALS AND METHODS: Study Area: Madras Medical College and Government General Hospital is one of the largest hospitals in South India located in Chennai Metropolis, Tamil Nadu catering the needs of over one crore people. The Laboratory: The Biochemistry lab is a standardized laboratory. The methods used for estimation are: Methods → 1. Serum Sodium – HILITE/Transaminase 2. Serum Potassium – I.S.ELECTRODE (Ion selective Electrophoresis), 3. UREA – Glutaraldehyde LDH, 4. Creatinine – Jaffe Kinetic, 5. SUGAR – (GOD/POD/Glucose oxidase peroxidase), 6. LFT – Enzymes – kinetic, 7. TFT – Automated ELISA reader, 8. Urine Na – I.S.ELECTRODE, 9. Urine K – I.S.ELECTRODE, 10. Lipids – ENZYMATIC METHOD, 11. Urine osmolality – FREEZING POINT METHOD. Study Population: Patients admitted in Government General Hospital medical wards with serum sodium less than 130 mmol/L. Type and Duration of study: Cross section study, period of one and a half year (January 2008 to June 2009). Inclusion Criteria: All inpatients >12 years of age with atleast two serum sodium values <130 mmol/L. Exclusion Criteria: Patients with age less than 12 years and patients who are treated with Mannitol and osmotic diuretics. Sample size and Technique: One hundred patients of Government General Hospital, Chennai. The lab values of serum sodium of all patients from January 2008 to June 2009 was studied from which incidence of hyponatremia was calculated. Out of this hyponatremic patients, a sample size of 100 patients were randomly selected by Simple Random Sampling, from the Table of Random Numbers satisfying the inclusion criteria. STATISTICAL ANALYSIS: The descriptive statistics – mean, median, standard deviation, minimum value, maximum value, range was used to describe the data. 1. Central tendency (Average): a. Arithmetic Mean (X), b. Median, c. Mode, 2. Measures of dispersion: a. Range, b. Standard deviation. The mean and standard deviation are calculated. The values between (a) 1 standard deviation on either side of mean will include 68% of values (b) values of twice the standard deviation from the mean will have 95% of values.These are “Confidence limits” of mean. The data was entered into excel work sheet and above calculated. RESULTS: The total number of hospital admission in medical wards was 25,326 and serum sodium estimates was done for 21,020 patients. The number of patients with hyponatremia less than 130 mmol/L was about 3980 patients (18.9%). The number of patients with severe hyponatremia with serum sodium less than 120 mmol/L was 620 patients (2.95%). CONCLUSIONS: 1. Symptomatic hyponatremia is common among the hospitalized patients. 2. Neurological symptoms are common in hyponatremia patients. 3. SIADH and euvolumic hyponatremia formed the largest subgroup in the study. 4. Drugs, especially diuretics, are a common cause of hyponatremia. 5. A relatively large number of patients had endocrine abnormalities (thyroid, adrenal and pituitary). 6. The mortality was about 10%. It was mainly due to underlying primary diseases. 7. Older age groups had more incidence of hyponatremia. 8. Symptoms of hyponatremia increased with severity of hyponatremia.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Incidence and Etiology ; Hyponatremia ; Hospitalised Patients.
Subjects: MEDICAL > General Medicine
Depositing User: Subramani R
Date Deposited: 29 Mar 2018 03:11
Last Modified: 29 Mar 2018 03:11
URI: http://repository-tnmgrmu.ac.in/id/eprint/6726

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