|Year : 2019 | Volume
| Issue : 2 | Page : 166-173
The prevalence of hypocalcemia in children with dengue infection: A 1-year cross-sectional study
Anshika Rajendra Singh, DK Dnyanesh
Department of Paediatrics, Jawaharlal Nehru Medical College, KLE Academy of Higher Education and Research, Belagavi, Karnataka, India
|Date of Web Publication||4-Jun-2019|
Dr. D K Dnyanesh
“ANUGRAH,” #89 Kalmeshwar Nagar, Kangralli BK Extension, Belagavi - 590 010, Karnataka
Source of Support: None, Conflict of Interest: None
INTRODUCTION: According to WHO, Dengue is fast emerging pandemic-prone viral disease affecting mainly urban poor areas in tropical and subtropical countries. One of the important electrolyte disturbance documented in critical phase of severe dengue is hypocalcaemia. Hypocalcaemia is seen in cases with severe dengue and has been claimed to be linked with the immune response and severity of infection.
OBJECTIVES: To study the prevalence of hypocalcaemia in children suffering from dengue infection. To study the association between the degree of hypocalcaemia and the severity of the illness.
SETTINGS AND DESIGN: This study was a one year cross sectional study, conducted in a tertiary care hospital.
METHODS AND MATERIAL: 100 subjects aged 1 month to 18 years suffering from dengue fever were included in the study. iCa and other biochemical parameters were done for all the subjects within 24 hour of admission. The collected data was coded and analyzed using ANOVA and chi-square tests.
RESULTS: The mean age was 9.65 yr. The subjects were classified as per 2009 WHO criteria. The prevalence of iCa was found to be 59.0%. 11.7% subjects with dengue without warning signs, 83.7% subjects of dengue with warning signs and 100% of the subjects of severe dengue had hypocalcaemia.
CONCLUSIONS: This study proves the association of the hypocalcaemia with the severity of dengue infection in the paediatric population and potentiates the use of ionic calcium as a biochemical marker to detect severe dengue infection early.
Keywords: Biochemical markers, dengue, hypocalcemia, ionic calcium, severe dengue
|How to cite this article:|
Singh AR, Dnyanesh D K. The prevalence of hypocalcemia in children with dengue infection: A 1-year cross-sectional study. Indian J Health Sci Biomed Res 2019;12:166-73
|How to cite this URL:|
Singh AR, Dnyanesh D K. The prevalence of hypocalcemia in children with dengue infection: A 1-year cross-sectional study. Indian J Health Sci Biomed Res [serial online] 2019 [cited 2019 Aug 24];12:166-73. Available from: http://www.ijournalhs.org/text.asp?2019/12/2/166/259639
| Introduction|| |
According to the World Health Organization (WHO), dengue is a fast emerging, pandemic-prone viral disease affecting tropical and subtropical countries. The incidence of the infection has risen to 30 folds in the past 50 years. In 2005, the World Health Assembly revised the International Health Regulations, which included dengue as one of the diseases of Public Health Emergency of International Concern as it needs health security due to its rapid epidemic spread beyond national borders.
Dengue is both a systemic and dynamic disease, and it has a wide spectrum of presentation. Its spectrum ranges from asymptomatic viral illness to severe dengue (SD) infection. In order to limit the morbidity and mortality due to dengue infection, there is an urgent need for early recognition of the illness and prompt and appropriate treatment. Early detection and access to proper medical care lowers fatality rates below 1%. Metabolic derangements including lactic acidosis, elevated transaminases, and rising serum creatinine and blood urea occur at the onset of the plasma leak phase. These changes are not to be seen in non-SD infections.
One of the important electrolyte disturbances documented in the critical phase of SD is hypocalcemia. Studies have linked calcium with the immune response and severity of infection of dengue virus. Cardiovascular manifestations of hypocalcemia include hypotension and reduced myocardial function. Nonetheless, evidence with regard to the role of calcium homeostasis in pediatric cases affected with dengue virus is limited, and current recommendations do not mention the need to monitor or correct blood calcium levels in dengue. Earlier done studies have proven the efficacy of ionized calcium over total calcium in serum for calcium status. The changes in the levels of serum calcium, especially ionized form, lead to symptoms of hypocalcemia. Ionized hypocalcemia most commonly presents as cardiovascular or neuromuscular insufficiency.
Various causes of hypocalcemia in dengue postulated are as follows:,
- Reduced Na+-K ATPase activity
- Reduced Ca+-ATPase activity
- Acquired parathyroid hormone deficiency
- Reduced 1-alpha-hydroxylase activity
- Reduced dietary Vitamin D
- Reduced calcium intake.
In another study, hypocalcemia was also found to be a marker of organ failure along with the severity of dengue. Myocarditis and dengue-related cardiac dysfunction have been linked to intracellular calcium derangements. Several studies suggest that the WHO criteria of severity alone may not be sufficient to categorize and treat dengue patients as they do not include biochemical changes.,
Thus, this study has focused on the prevalence of hypocalcemia in dengue infection by measuring ionized calcium and associating it with the severity of dengue according to the present WHO classification (2009).
- To study the prevalence of hypocalcemia in children suffering from dengue infection
- To study the association between the degree of hypocalcemia and the severity of the illness.
| Subjects and Methods|| |
- Study design – Cross-sectional observational study
- Study period – 1 year (January 2017–December 2017)
- Study place – Pediatric intensive care unit (PICU) and pediatric wards and pediatric emergency of KLE Hospital and Medical Research Centre, Belgaum.
- Sample size calculation and sampling method – Sample size was calculated as per the following formula:
n = 4pq/d2
p = Prevalence
q = 100-p
d = allowable error (10% of p)
Considering the above formula, the sample size required for this study was calculated as 100.
- Sampling method – We had selected every alternate patient admitted to the pediatric wards or ICU for the study.
- Children admitted to the PICU, pediatric emergency, and pediatric wards with serologically positive dengue infection (NS1 or immunoglobulin [Ig] IgM/IgG)
- Children aged between 1 month and 18 years.
- Children with mixed infections, for example, typhoid
- Children with clinically diagnosed rickets
- Children with known endocrinal, renal, hepatic, or cardiac disorders
- Children with known congenital bony anomalies – suspected rickets.
Prior to the commencement of the study, ethical clearance was obtained for the study from the Institutional Ethics and Research Committee, Jawaharlal Nehru Medical College, Belagavi. Parents of the children with probable dengue infection admitted in pediatric wards, pediatric emergency, and PICU under the Department of Paediatrics who fulfilled the selection criteria were explained about the nature of the study, and a written informed consent was obtained from the parents.
A probable case of dengue was diagnosed as per the WHO 2009 criteria. The sociodemographic data (age and gender), clinical presentation, and clinical diagnosis at admission were obtained, and a thorough clinical examination was performed. The serology of the patients was confirmed by dengue IgM and IgG enzyme-linked immunosorbent assay (ELISA) test and NS1 antigen. The findings were recorded in a predesigned and pretested pro forma. The demographical data of the patient and presenting complaints such as fever and its duration, presence of abdominal pain, vomiting, and any bleeding manifestations such as petechiae, epistaxis and melena, and organomegaly were collected and entered in the pro forma. The clinical parameters recorded were pertaining to the evidence of hemodynamic instability (pulse volume, blood pressure, and pulse pressure) and the evidence of fluid leakage (pleural effusion and ascites).
The following blood investigations were performed in the first 24 h of admission: hemoglobin (Hb); total leukocyte count (TLC); platelet count; packed cell volume (PCV); liver function tests namely serum bilirubin, serum albumin, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvate transaminase; prothrombin time (PT); international normalized ratio (INR); activated partial thromboplastin time (aPTT); and serum ionic calcium (iCa) levels. Serum ionized calcium was measured instead of serum total calcium.
Other investigations such as chest X-ray (CXR), ultrasonography (USG), and echocardiography (ECHO) were done based on clinical presentation as and when required. These investigations were done in case any complication was suspected. Pleural effusion was diagnosed by chest radiograph, and abdominal sonography was done to rule out ascites and to note the gall bladder wall thickness. Myocarditis was diagnosed by two-dimensional ECHO.
Blood was collected in an EDTA tube for Hb, TLC, platelet count, and PCV and was analyzed by an automated analyzer. For other investigations, blood was collected in plain tubes. Blood sample was collected in citrate bulb for PT/INR and aPTT. Cobas b121, based on the principle of ion selective electrode method, was used to measure serum ionized calcium in all the recruited patients.
The collected data were coded and entered in excel sheet and were analyzed using SPSS statistical software package version 10 (IBM corporation, Newyork, America). Continuous variables were represented by mean and standard deviation and were analyzed using independent sample t-test and ANOVA. The level of statistical significance (P value) was set to be <0.05.
| Results|| |
The present cross-sectional study was conducted in KLEs Dr. Prabhakar Kore Hospital and Medical Research Centre, in the wards, emergency, and PICUs. A total of 100 patients who fulfilled the inclusion criteria were analyzed. The sociodemographical data of the study population are shown in [Graph 1],[Graph 2],[Graph 3]. The mean age of presentation of the study population was 9.35 years.
Among the study population, it was observed that the most common presenting complaint was fever (97%) as shown in [Graph 4].
The study population was classified as per the 2009 WHO dengue classification as follows:
- Dengue fever (DF) without warning sign – 38%
- DF with warning signs (DWS) – 43%
- SD – 19%.
The association of the severity of dengue with the demographical data was determined by using ANOVA and Chi-square test. The mean age of the dengue patients without warning signs was 9.26 ± 4.37 years, DWS was 10.63 ± 4.08 years, and SD was 8.21 ± 3.27 years. There was no association between the severity of dengue and the age group (P = 0.078). Similarly, the gender of the participant had no association with the severity of the disease (P = 0.485). The socioeconomic status does not have any significant association with the severity of dengue infection (P = 0.364).
The clinical signs of the study children and their association with the severity of dengue as noted in the study are shown in [Table 1].
As shown in [Table 2], the level of Hb, TLC, and PCV did not affect the severity of dengue.
This showed that, in SD, the platelet counts were much lower as compared to that of DF without warning signs (P = 0.002). It was noticed from the investigations that, although aPTT was significantly different with P = 0.014, among different classes of dengue infection, the PT test was not statistically different among the children (P = 0.919).
In this study, the mean iCa noted was 1.05 mmol/L. On comparing the iCa between dengue without warning signs and DWS, P < 0.001 was obtained, denoting that even the iCa was significantly different even among those with DF without warning signs and those with DWS [Table 3].
Imaging modalities were utilized whenever there was a clinical suspicion of third-space loss such as pleural effusion, ascites, or myocarditis [Graph 5],[Graph 6],[Graph 7].
ECHO was done only in SD patients who were clinically suspected of having myocarditis. Out of which, only five underwent ECHO on the basis of clinical suspicion, in which three were abnormal and two were normal, that is, 15.7% of the SD patients had dengue myocarditis.
Prevalence of hypocalcemia
Hypocalcemia is defined as the serum ionized calcium levels below 1.1 mmol/L. The prevalence of hypocalcemia in the study population was 59%. Among that, 11.7% of the children with dengue without warning signs, 83.7% of children with DWS, and 100% of the children with SD had hypocalcemia. Hence, it was seen that hypocalcemia is associated with SD (P < 0.001) [Graph 8].
Hypocalcemia was seen to be more common in the age group of 5–10 years and least in infants (3.2%). There was no significant association between the presence of hypocalcemia with respect to age (P = 0.489) and with respect to the socioeconomic status of the participant (P = 0.318).
Hypocalcemia was seen to be more common in children with Hb of >12 g/dl (73%), but there was no significant association between the presence of hypocalcemia and Hb (P = 0.095). Nearly 81% of the children with hypocalcemia had low hematocrit and 87.3% had thrombocytopenia, but no significant association was observed (P = 0.073 and P = 0.625, respectively). Almost 33.3% of the hypocalcemic children had high INR. Hence, the presence of high INR was not associated with low iCa. There was no effect of low albumin on the calcium status of the children (P = 0.043) [Table 4].
CXR was done in 42% of the children, 64.2% of the CXR were abnormal; 42.9% of the children with abnormal findings on CXR were hypocalcemic. Hence, the presence of hypocalcemia has an association with abnormality on the CXR (P = 0.000).
USG was not done in most of the patients (87%); it was found that, among the children for whom USG was done, 19% had hypocalcemia associated with abnormal findings on the USG
(P = 0.012).
ECHO was done in only 5% of the children, with clinical features of myocarditis and hypocalcemia seen in 4.8% of them (P = 0.213), Hence, no significant association was observed between ECHO and hypocalcemia.
Thus, it is seen that CXR and USG findings are significant among patients with hypocalcemia.
| Discussion|| |
Dengue is one of the most important emerging viral diseases globally. It has a wide clinical spectrum of presentation. Early detection and correct prognostication may avoid severe complications leading to death. SD is associated with biochemical abnormalities such as elevation of liver enzymes, hypoproteinemia, and electrolyte imbalances.
The present study was conducted on 100 children, with the youngest child being 6 months old and the eldest being 17 years old. The mean age of the study population was 9.659 ± 4.13 years. Other Indian studies done in the pediatric population had comparable results. In another study by Faridi et al. in Delhi, the majority of patients with dengue infection (52.9%) were in the age group of 10–12 years. Another study done in South India by Sahana and Sujatha had the similar age predominance, i.e. 5 years and 15 years, respectively, with mean age at presentation of 8 years. In a study by Kumar et al., of 306 cases, majority (175 [57%]) were in the age group of 6–12 years. The mean age of the study population was estimated to be 7.8 ± 3.2 years.
Males were higher in number (58%) than females (42%) in the present study, with the male: female ratio being 1.3:1. A similar observation was found in a study done in Kerala and Delhi. This was probably due to more importance being given to the male children in the Indian society. Covered dress used by females may be another cause for fewer incidences. It was seen in the study that 34% of the children were from upper middle class followed by 27% from middle-class families. Whereas, in a study done at Mangalore in adult dengue patients, it was observed that majority (60%) of the population were unskilled laborers.
This comparison along with the other studies shows that fever and abdominal pain were the most common presenting features with which the children are brought to pediatricians. In this study, 97% of the children had fever, 55% had abdominal pain, 50% had vomiting, and 35% had petechiae. Similar clinical features were observed in different studies done by Sahana and Sujatha,, and Kumar et al.
In this study, 43% of the children were diagnosed to be having DWS, followed by 38% as DF without warning signs, and only 19% of patients were diagnosed as SD. Our hospital is a tertiary care center, so the maximum number of cases was referred from the peripheries. Hence, the higher proportion of serious cases was that of DWS. This was also in line with the observation seen in the study done by Kumar et al., where 131 (42.8%) were classified as DF without warning signs, 119 (38.8%) as DWS, and 56 (18.4%) as SD, according to the WHO guidelines. Similar results were seen in another study which showed that 48.1% of the children had dengue without warning signs.
In this study, dengue NS1 antigen was present in 62% of cases. It was noticed that, among the SD cases, 89% of the patients were positive for NS1. In a study done by Sahana and Sujatha, dengue NS1 antigen test was positive in 66.7% of cases. The presence of NS1 antigen was slightly higher in another study where 76% of the cases were positive for NS1 antigen. In a study done by Mishra et al., 47.2% of the 97 patients were positive for NS1 antigen, 11.3% for IgM/IgG ELISA, and only 5.14% of patients showed positivity for both tests.
In this study, the prevalence of anemia (<12 g/dl) was 33.0%, with the mean Hb count of the study population being 12.64 g/dl. In previously done comparable studies, it was observed that anemia was present in 14.8% of cases of dengue infection. Similarly, statistically significant values of mean Hb in severe (13 + 2.5) and non-SD (12 + 1.5) were found in a study done by Kumar et al.
Although leukopenia is a common marker in DF, in our study, the leukocyte counts were within normal range with a mean of 4332.66/mm3. In another comparable study, the prevalence of leukopenia was 25.77%. The study by Mishra et al. showed that only 5.8% of the study children had leukopenia.
Thrombocytopenia is another marker of dengue infection. Thrombocytopenia was taken as platelet count <1.5 lac/mm3. In our study, the prevalence of thrombocytopenia was 86%. There was statistical significance between classifications of dengue with respect to platelet counts. Many studies were done in different geographical locations which also confirmed the association of SD and thrombocytopenia. Studies done by Sahana and Sujatha and Kumar et al. showed the significance of platelet count in the detection of SD as a prognostic factor. In their study, Faridi et al. noticed that 100% of the children had thrombocytopenia.
The overall prevalence of hypocalcemia in our study was 59%. In the study population, 11.7% of children with dengue without warning signs, 83.7% children of DWS, and all the children of SD had hypocalcemia. There was an association between the severity of dengue infection and iCa. The mean iCa was found to be lowest among SD patients as compared to patients of dengue without warning signs. There was statistical significance between classification of dengue and iCa (F = 27.487, P < 0.001).
In an observational study done by Habbu and Shaikh on seventy individuals to determine biochemical parameters of DF in Solapur, Maharashtra, it was found that calcium level decreased in DF ranging from 5.5 to 10 mg/dl and 8 to 11 mg/dl among patients and controls, respectively, with P < 0.001.
A cross-sectional study conducted by Jayachandra et al. in Bengaluru showed that the mean serum-free calcium in their study was 3.82 ± 0.52 mg/dl. It was observed that the mean serum calcium (mg/dl) in SD was 3.07 ± 0.19, DWS was 3.70 ± 0.52, and dengue fever (DF) was 4.07 ± 0.40. It was concluded that the presence of hypocalcemia significantly correlated with the severity of dengue.
A study done by Azin et al. found that the levels of calcium in the serum of dengue patients decreased significantly (P = 0.000) as compared to that of healthy individuals (control group).
Similar low levels of calcium with statistically significant values (P < 0.001) were found in the study done by Kumar et al., with 7.3 ± 1.8 mg/dl in severe cases and 8.8 ± 0.8 in nonsevere cases. Contrast to the above evidence, no significant difference was found with respect to serum calcium according to age or sex of the children (<9 mg/dl in 14 cases, i.e., 41.1% and 9–11 mg/dl in 20 cases, i.e., 58.8%).
In a study done by Uddin et al., serum calcium level was low in a significant number of patients. The mean serum calcium was 8.7 ± 0.7 mg/dl in case of DF and lower, i.e., 7.8 ± 0.7 mg/dl in dengue hemorrhagic fever Grade III. Hence, it was concluded that degree of hypocalcemia is associated with the severity of Dengue infection.
In a pilot study done in Universidad del Noreste, Tampico (UNE), Tampico, there was a significant increase (P < 0.05) in the number of blood platelets of patients with clinical signs and symptoms of DF following oral administration of calcium carbonate (calcium carbonate CAL, 1.2–1.8 g/day; n = 10) when compared with a control group (CAL, 89 [46–132] vs. 206 [155–257; n = 10). Calcium also improved the overall clinical condition and reduced the duration of signs and symptoms of DF by 36%.
This study was conducted on a relatively small sample size, and hence cannot be used to prove the importance of iCa as a predictor of SD. This was an observational study, wherein serum iCa levels were done at the time of admission or within 24 h of admission; there was no uniformity in the day of investigating serum iCa. The serum iCa levels may vary depending on the day of illness. The other factors influencing the calcium metabolism such as phosphate, magnesium, and parathormone were not studied among these patients. These play a vital role in the regulation of calcium homeostasis in our body.
Studies are needed to understand the effects of calcium on the immune response in dengue infection and to analyze the effect of supplementation of calcium in DF for reduction of severity. In addition, adequately planned randomized controlled trials are also required to evaluate the efficacy of administration of calcium therapy in the prevention of complications.
The authors would like to thank the Department of Pediatrics, Jawaharlal Nehru Medical College, KAHER, Belagavi, Karnataka, India.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]