Clinical profile and etiology of thyroid disorders in children at a tertiary care hospital

 

 

Abstract               Background: Congenital hypothyroidism is the most common preventable cause in India and worldwide. Thyroid hormones deficiency in infancy leads to irreversible impairment of neuro-cognitive function and physical and mental retardation. The disorders of thyroid hormone can be due to diseases of the thyroid gland itself (primary), secondary to pituitary disorder (secondary) or due to hypothalamic diseases (tertiary). Aim: To determine clinical profile and etiology of thyroid diseases in children. Material and Methods: A hospital based prospective observational study performed in new-borns and children below 18 years if they had clinical suspicion of thyroid dysfunction. Thyroid profile were done if there was suspicion of hypothyroidism and Free T3 and TSH if there was suspicion of hyperthyroidism. Other investigations like USG thyroid, thyroid 99m technetium scan anti TPO and anti TG antibody levels were done to look for the etiological diagnosis. Results: The mean age of patients was 10.67±4.23 years with male to female ratio of 1:3.6. Out of 70 cases, 67 cases (95.7%) were hypothyroidism and 3 cases (4.3%) were hyperthyroidism. The most common clinical presentation in patients with hypothyroidism was constipation 37 cases (55.2%) and in patients with hyperthyroidism palpitations was most common in 3 cases (100%). Out of 57 cases having suspicion of autoimmune aetiology, 44 cases (77.19%) had elevated anti TPO antibodies and 49 (85.96%) cases had elevated anti TG antibodies. Conclusion: Congenital hypothyroidism is one of the major preventable thyroid disease if diagnosed early. Hence, screening of all newborns and children should be mandatory. Autoimmune thyroid diseases are now the major leading cause of thyroid disorders in childhood.

Key Word: Children, thyroid disorders, congenital hypothyroidism, autoimmune thyroiditis

               

 

 

 

 

INTRODUCTION

Disorders of thyroid gland are commonest endocrine disorder in India.¹In paediatric age group thyroid hormones are primarily concerned with maintenance of growth, metabolism and mental development.^2,3 Thyroid hormones deficiency in infancy leads to irreversible impairment of neuro-cognitive function and physical and mental retardation.³ It is a spectrum of disorders manifesting either as hypo or hyper functioning of the thyroid gland reflected in the circulating levels of Tri-iodothyronin (T3), Thyroxin (T4) and Thyroid stimulating hormone (TSH). The disorders of thyroid hormone can be due to diseases of the thyroid gland itself (primary), secondary to pituitary disorder (secondary) or due to hypothalamic diseases (tertiary).⁴ Congenital hypothyroidism is the most common preventable cause with worldwide incidence of 1:3000-4000. In India this ratio is 1:2500 -2800.^2,3 Autoimmune thyroid diseases are now major leading cause of thyroid disorders in childhood and now considered the most common cause of acquired hypothyroidism. They include Hashimoto’s thyroiditis and lymphocytic thyroiditis. Their clinical manifestations range from euthyroid goiter to hypo or hyperthyroid state.^5,6The present study was conducted to determine the clinical profile and etiology of thyroid disorders in children at a tertiary care centre.

MATERIAL AND METHODS

A hospital based observational study was performed in newborns and children below 18 years fulfilling the inclusion criteria visiting the outpatient and in-patient Department of Paediatric in a tertiary care teaching hospital having clinical suspicion of thyroid dysfunction.

Inclusion Criteria

• New-borns.
• Children below 18 years of age.
• Patients with clinical features suggestive of thyroid disorders like constipation, short stature, lethargy, goiter, mental retardation, obesity, prolonged neonatal jaundice, palpitations, etc.,

Exclusion Criteria         

• Patients having normal thyroid function tests.
• Patient on any medication altering the thyroid hormone status.
• Patient in whom informed consent could not be obtained.

Sample size

The prevalence of 13% was taken from a study done by Singh A et al.⁷ Sample size was calculated using the formula-n= 4PQ/ d². Where, P=Prevalence from previous study, Q=100-P, d=absolute or relative error. In our study, P=13%, Q= 100-13 = 87, d = absolute error taken as 3%. So, n = 4x13x87/3². Thus, n = 503.

Methodology

Thyroid profile consisting of TSH, free T4 and Total T4 was done if there was suspicion of hypothyroidism and in suspicion of hyperthyroidism thyroid profile consisting of TSH and free T3 was done. Patients having abnormal thyroid function, which is defined as per the standard cut offs of free T3, total T4, freeT4 and TSH according to different age groups⁸ were evaluated further in the study and taken as a positive case. Later detailed demographic data including family history of thyroid disorders, use of iodised salt, vital parameters, anthropometry, systemic examination, examination of the thyroid gland was performed. Further tests like complete blood count in cases was done. USG thyroid was done in all the positive case and looked for presence of goiter. In case of suspicion of congenital hypothyroidism the patient is subjected to 99^m technetium scan. In cases of suspected autoimmune aetiology tests like anti thyroid peroxidase antibodies (anti TPO) and anti-thyroglobulin antibodies (anti TG) were performed in the patients. Normal reference values of anti TPO levels is < 35 IU/ml and anti TG antibody levels is < 20 IU/ml.⁹

Statistical analysis

Data was entered into Microsoft Excel (Windows 7; Version 2007) and analysis were done using the Statistical Package for Social Sciences (SPSS) for windows software (version 22.0; SPSS Inc., Chicago). Descriptive statistics such as mean and standard deviation (SD) for continuous variables, frequencies and percentages were calculated for categorical variables were determined.

 

RESULTS

Out of 503 patients screened, 433 (86.1%) patients had normal TSH levels and 70 patients had abnormal TSH levels. These 70 patients with abnormal TSH are evaluated further in the study. Out of 70 cases, maximum number of cases belonged to age group of 10-12 years (32.9%), followed by 16 cases belonged to 13-15 years (22.9%), 11 cases were between to 7-9 years (15.7%), 9 cases between 16-18 years (12.9%),6 cases between 4-6 years (8.6%), 4 cases were between < 1year (5.7%),and 1 case between 1-3 years (1.4%).The mean age of 10.67±4.23 years. Out of 70 cases, 15 were male (21.4%),and 55 were female with (78.6%) with over all male to female ratio of 1:3.6. Out of 70 cases, 67 cases (95.7%) were hypothyroidism and 3 cases (4.3%) were hyperthyroidism.

 

Table 1: Signs and symptoms of patients with Hypothyroidism (N=67)

The most common clinical presentation in cases with hypothyroidism was constipation in 37 cases (52.9%) followed by 35 cases with short stature (52.2%),31 cases with dry skin (46.3%),30 cases with lethargy(44.8%),cold intolerance 25 cases(37.3%) (Table 1).

 

 

 

 

 

 

Table 2: Signs and symptoms of patients with Hyperthyroidism (N=3)

Chief Complaints	No. of patients	Percentage
Palpitations	3	100%
Increased frequency of stools	2	66.7%
Heat Intolerance	2	66.7%
Hyperactivity	1	33.3%
Pallor	1	33.3%
Short stature	1	33.3%
Tachycardia	1	33.3%
Swelling in the neck	1	33.3%
Not gaining weight	1	33.3%

Out of 3 cases, all three had palpitations (100%), 2 cases had increased frequency of stools (66.7%), 2 cases had heat intolerance (66.7%) (Table 2). Three out of 70 cases had family history of thyroid disorders (4.3%) and 67 cases had no family history of thyroid diseases (95.7%). All the 3 were hypothyroid cases. Out of 70 cases 13 cases had thyroid enlargement on examination (18.6%), 57 cases had no thyroid enlargement (81.4%). Out of 70 cases,14 cases had goiter (20%), 9 had hypoplastic features(12.9%) and 47 cases were having normal USG thyroid (67.1%). Out of 13 cases with congenital hypothyroidism, 10 cases (77%) were thyroid dysgenesis followed by dyshormonogenesis in 3 cases (23%). In 10 cases of thyroid dysgenesis 7 were hypoplastic (70%), 2 cases had aplasia (20%) and 1 had ectopic thyroid (10%).

 

Table 3: Diagnosis in study subjects (N=70)

Out of 70 cases, 54 (77.1%) were autoimmune hypothyroidism in which 40 (74.1%) cases had no goiter and 14 had goiter (25.9%), 13 (18.6%) were congenital hypothyroidism, 10 cases are thyroid dysgenesis (77%),3 cases are dyshormonogenesis(23%). Out of 70 cases, 3 cases (4.3%) were hyperthyroidism without goiter (100%) (Table 3). Out of 70 cases, 10 cases where having co-morbidities, out of which 5 cases were type 1 diabetes mellitus (7.1%), 4 cases had cerebral palsy (5.7%), 1 case had turner syndrome (1.4%).

 

 

DISCUSSION

Out of 503 patients tested having suspicion of thyroid dysfunction, 70 children had abnormal thyroid dysfunction, 67 were hypothyroid and 3 were hyper thyroid. Estimated prevalence in our study was 13.9%. Thyroid disorders are well known to be more in female than male of all age groups.⁴In our study, out of 70 cases, 15 were male (21.4%) and 55 were female (79.6%) with ratio of 1:3.6. In a study done by Hunter I et al¹⁰out of 140 cases 37 were male and 103 were female and the male to female ratio was 1:2.8. Kapil U et al¹¹noted that out of 1254 children between age group of 6-12 years for the prevalence of IDD in children, the male to female ratio was 1:2.9. In a study done by Desai M et al⁶out of 78 cases 58 were female and 20 males, the male to female ratio was 1:2.9. In our study, out of 70 cases, the most common age group presenting with thyroid dysfunction is between 10-12 (32.9%) years of age. In a study done by Desai M et al⁶maximum cases were in age group 9-12 years (44%) and (61%) in 6-12 years of age. Singh A et al⁷ noted that out of 65 cases having thyroid dysfunction, most of the patient belonged to age of 0-1years and 9-12 years of age. In our study, out of 67 cases of hypothyroidism, the most common clinical presentation in patients was constipation (55.2%) followed by short stature (52.2%). Desai M et al⁶ noted that most common clinical presentation was constipation(87%) followed by lethargy (55%).Singh A et al⁷ noted that out of 61 hypothyroid cases the most common clinical presentation was short stature (59%) followed by lethargy (49.2%). Virmani A et al¹² noted that the most common clinical presentation was short stature (44%). The most common clinical presentation in hyperthyroidism cases was palpitation (100%), followed by increased frequency of stools (66.7%). In a study by Singh A et al⁷ out of 4 cases of hyperthyroidism, the most common clinical presentation was tachycardia (100%), followed by palpitations (75%). In our study, 3 cases (4.4%) had family history of thyroid disorders. In a study done by Singh A et⁴³ al 4 cases (6.5%) had family history of thyroid disorders. In our study, 14 (20%) children with thyroid dysfunction had thyroid gland enlargement which was confirmed by ultrasound thyroid showing goiter. Desai M et al⁶ reported prevalence of goiter in 38% children with thyroid hormone abnormalities. Pradhan R et al¹³noted the prevalence of goiter was 25%. Similarly, Shah NA et al¹⁴noted that out of 16 cases, 3 cases had prevalence of goiter (5%). In our study out of 70 cases with thyroid dysfunction, 67 cases (97.7%) were hypothyroidism and 3 cases (4.3%) were hyperthyroidism. In a study done by Desai M et al⁶ out of 800 cases 79% were having hypothyroidism and 2% were having hyperthyroidism. Shah NA et al¹⁴noted that out of 16 cases 6 cases were having hypothyroidism (37.5%) and 1 case had hyperthyroidism(6.25%). Singh A et al⁴³ noted that out of 65 cases, 61 cases were having hypothyroidism(93.8%) and 4 cases were having hyperthyroidism(6.1%). In our study, out of 67 cases of hypothyroidism, 54 cases were autoimmune hypothyroidism (80.5%), and 13 cases were congenital hypothyroidism (19.5%). In a study done by Meena P et al⁶ noted that 40% cases were autoimmune hypothyroidism and 46% cases were congenital hypothyroidism. In our study out of 70 cases, 10 cases had co-morbidities, the commonest being type 1 diabetes mellitus 5 cases (7.1%), followed by cerebral palsy 4 cases (5.7%) and 1 case of Turner syndrome(1.4%).In a study done by Singh A et al⁴³ out 65 cases, 5 cases were having congenital heart disease (7.69%) followed by thalassemia and cerebral palsy 4 cases(6.15%).

 

CONCLUSION

Congenital hypothyroidism is one of the major preventable thyroid disease if diagnosed early. Hence, screening of all new born and children should be mandatory as early diagnosis and treatment helps in prevention of mental retardation and other complications of thyroid disorders. Other thyroid diseases commonly seen in paediatrics age group are autoimmune thyroiditis, goiter and rarely hyperthyroidism. Autoimmune thyroid disorders are now emerged as a leading cause of thyroid disorders in paediatric age group. Many cases have been encountered in our study where in patients with autoimmune thyroid disorders are having anti TPO antibodies negative but anti TG antibodies positive.

 

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