Thyroiditis in Children
Introduction to Thyroiditis in Children
Thyroiditis refers to inflammation of the thyroid gland, which can occur in various forms in pediatric populations. It is a significant endocrine disorder that can affect growth, development, and overall health in children. The condition can be acute, subacute, or chronic, and may lead to either hyperthyroidism or hypothyroidism, depending on the specific type and stage of the disease.
In children, the most common forms of thyroiditis include:
- Hashimoto's thyroiditis (chronic lymphocytic thyroiditis)
- Subacute thyroiditis
- Acute suppurative thyroiditis
- Silent thyroiditis
- Drug-induced thyroiditis
Understanding the various forms of thyroiditis, their presentation, and management is crucial for pediatricians and endocrinologists to provide optimal care for affected children.
Etiology of Thyroiditis in Children
The causes of thyroiditis in children vary depending on the specific type:
1. Hashimoto's Thyroiditis
- Autoimmune disorder
- Genetic predisposition (HLA-DR3, HLA-DR5)
- Environmental factors (iodine excess, radiation exposure)
- Associated with other autoimmune conditions (Type 1 diabetes, celiac disease)
2. Subacute Thyroiditis
- Viral infections (mumps, influenza, coxsackievirus)
- Post-viral inflammatory response
3. Acute Suppurative Thyroiditis
- Bacterial infections (Staphylococcus aureus, Streptococcus species)
- Immunocompromised states
- Congenital pyriform sinus fistula
4. Silent Thyroiditis
- Autoimmune etiology
- Postpartum thyroiditis in adolescents
5. Drug-Induced Thyroiditis
- Amiodarone
- Interferon-α
- Tyrosine kinase inhibitors
- Immune checkpoint inhibitors
Clinical Presentation of Thyroiditis in Children
The clinical presentation of thyroiditis in children can vary widely depending on the type and stage of the disease. Common symptoms and signs include:
General Symptoms
- Goiter (thyroid enlargement)
- Neck pain or tenderness (in subacute and acute thyroiditis)
- Fatigue
- Weight changes
- Growth disturbances
Hyperthyroid Phase Symptoms
- Tachycardia
- Nervousness and irritability
- Heat intolerance
- Tremors
- Weight loss despite increased appetite
Hypothyroid Phase Symptoms
- Fatigue and weakness
- Cold intolerance
- Constipation
- Dry skin
- Weight gain
- Delayed growth and puberty
It's important to note that the presentation can be subtle in children, and symptoms may develop gradually, especially in chronic forms like Hashimoto's thyroiditis.
Diagnosis of Thyroiditis in Children
Diagnosing thyroiditis in children involves a combination of clinical assessment, laboratory tests, and imaging studies:
1. Clinical Examination
- Thorough history taking
- Physical examination, including thyroid palpation
- Assessment of growth and development
2. Laboratory Tests
- Thyroid Function Tests:
- TSH (Thyroid Stimulating Hormone)
- Free T4 (Thyroxine)
- Free T3 (Triiodothyronine) in selected cases
- Thyroid Antibodies:
- Anti-thyroid peroxidase (anti-TPO) antibodies
- Anti-thyroglobulin (anti-Tg) antibodies
- Inflammatory Markers:
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP)
3. Imaging Studies
- Thyroid Ultrasound:
- Assess gland size and echotexture
- Identify nodules or cysts
- Radioactive Iodine Uptake (RAIU) and Scan:
- Differentiate between various forms of thyroiditis
- Assess thyroid function and structure
4. Fine Needle Aspiration (FNA)
In cases of suspicious nodules or to confirm Hashimoto's thyroiditis
5. Additional Tests
- Complete blood count (in case of acute suppurative thyroiditis)
- Blood cultures (if infectious etiology is suspected)
- Thyroid stimulating immunoglobulin (TSI) to rule out Graves' disease
Treatment of Thyroiditis in Children
Treatment approaches for thyroiditis in children depend on the specific type, severity, and phase of the disease:
1. Hashimoto's Thyroiditis
- Levothyroxine replacement therapy for hypothyroidism
- Regular monitoring of thyroid function and adjustment of medication
- Management of associated autoimmune conditions
2. Subacute Thyroiditis
- Symptomatic treatment with NSAIDs for pain and inflammation
- Beta-blockers for symptomatic hyperthyroidism
- Corticosteroids in severe cases
- Temporary levothyroxine supplementation if hypothyroidism develops
3. Acute Suppurative Thyroiditis
- Antibiotic therapy based on culture and sensitivity
- Drainage of abscesses if present
- Surgical management of pyriform sinus fistula if identified
4. Silent Thyroiditis
- Observation and monitoring in mild cases
- Beta-blockers for symptomatic hyperthyroidism
- Levothyroxine supplementation if hypothyroidism persists
5. Drug-Induced Thyroiditis
- Discontinuation or modification of the offending drug when possible
- Management of thyroid dysfunction as per other forms of thyroiditis
General Management Principles
- Regular follow-up and monitoring of thyroid function
- Patient and family education about the condition
- Screening of family members for thyroid disorders
- Psychosocial support and counseling when needed
Prognosis of Thyroiditis in Children
The prognosis of thyroiditis in children varies depending on the specific type and management:
1. Hashimoto's Thyroiditis
- Generally good prognosis with appropriate levothyroxine replacement
- Lifelong therapy is often required
- Regular monitoring needed to adjust treatment and manage potential complications
2. Subacute Thyroiditis
- Usually self-limiting with complete recovery within 6-18 months
- Rare cases may progress to permanent hypothyroidism
- Recurrence is possible but uncommon
3. Acute Suppurative Thyroiditis
- Good prognosis with prompt antibiotic treatment
- Surgical intervention may be necessary for complicated cases or recurrent infections
- Thyroid function usually remains intact
4. Silent Thyroiditis
- Most cases resolve spontaneously within 3-6 months
- A small percentage may develop permanent hypothyroidism
- Recurrence is possible, especially in postpartum cases
5. Drug-Induced Thyroiditis
- Prognosis depends on the causative drug and duration of exposure
- Thyroid function often normalizes after drug discontinuation
- Some cases may require ongoing thyroid hormone replacement
Long-term Considerations
- Impact on growth and development if not adequately managed
- Potential for developing other autoimmune disorders
- Importance of long-term follow-up and monitoring
- Psychosocial aspects of chronic disease management in children
Hashimoto's Thyroiditis in Children
Hashimoto's thyroiditis, also known as chronic lymphocytic thyroiditis, is the most common cause of acquired hypothyroidism in children and adolescents.
Etiology
- Autoimmune disorder with genetic and environmental factors
- Associated with HLA-DR3 and HLA-DR5 genotypes
- Higher incidence in females
- Often coexists with other autoimmune disorders (e.g., Type 1 diabetes, celiac disease)
Pathophysiology
- T-cell mediated autoimmune response against thyroid antigens
- Production of anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) antibodies
- Gradual destruction of thyroid follicles leading to hypothyroidism
Clinical Presentation
- Often asymptomatic in early stages
- Gradual onset of hypothyroid symptoms:
- Fatigue, cold intolerance
- Weight gain, constipation
- Dry skin, brittle hair
- Delayed growth and puberty
- Goiter (painless thyroid enlargement)
- Rarely, transient hyperthyroidism ("Hashitoxicosis")
Diagnosis
- Thyroid function tests: Elevated TSH, low or normal free T4
- Thyroid antibodies: Positive anti-TPO and/or anti-Tg antibodies
- Thyroid ultrasound: Heterogeneous echogenicity, increased vascularity
- Fine-needle aspiration (rarely needed): Lymphocytic infiltration
Treatment
- Levothyroxine replacement therapy
- Initial dose based on age, weight, and TSH level
- Regular monitoring and dose adjustments
- Management of associated autoimmune conditions
- Regular follow-up for growth and development
Prognosis
- Generally good with appropriate treatment
- Lifelong therapy often required
- Potential for other autoimmune disorders
- Regular monitoring for thyroid nodules and rarely, thyroid lymphoma
Subacute Thyroiditis in Children
Subacute thyroiditis, also known as de Quervain's thyroiditis or granulomatous thyroiditis, is less common in children than in adults but can occur.
Etiology
- Believed to be triggered by viral infections
- Common culprits: mumps, influenza, coxsackievirus, adenovirus
- Possible genetic predisposition (HLA-Bw35)
Pathophysiology
- Post-viral inflammatory response in the thyroid gland
- Granulomatous inflammation with giant cells
- Disruption of thyroid follicles leading to hormone release
Clinical Presentation
- Acute onset of thyroid pain and tenderness
- Systemic symptoms: fever, fatigue, myalgia
- Thyroid dysfunction phases:
- Initial hyperthyroidism (2-6 weeks)
- Euthyroid phase (2-4 weeks)
- Hypothyroid phase (2-6 months)
- Recovery to euthyroid state
- Firm, tender goiter on examination
Diagnosis
- Clinical presentation and physical examination
- Thyroid function tests: Reflect the phase of illness
- Elevated ESR and CRP
- Low or absent radioactive iodine uptake
- Thyroid ultrasound: Hypoechoic areas, reduced vascularity
Treatment
- Symptomatic management
- NSAIDs for pain and inflammation
- Corticosteroids in severe cases
- Beta-blockers for symptomatic hyperthyroidism
- Temporary levothyroxine supplementation if hypothyroidism persists
Prognosis
- Self-limiting condition in most cases
- Complete recovery within 6-18 months
- Rare recurrence (<5% of cases)
- Small risk of permanent hypothyroidism (<5%)
Acute Suppurative Thyroiditis in Children
Acute suppurative thyroiditis, also known as acute infectious thyroiditis, is a rare but potentially serious form of thyroiditis in children.
Etiology
- Bacterial infections
- Common pathogens: Staphylococcus aureus, Streptococcus species
- Less common: Pneumococcus, Salmonella, anaerobes
- Predisposing factors:
- Congenital pyriform sinus fistula (left side more common)
- Immunocompromised states
- Recent upper respiratory tract infection
Pathophysiology
- Direct bacterial invasion of the thyroid gland
- Abscess formation within the thyroid tissue
- Acute inflammatory response
Clinical Presentation
- Rapid onset of neck pain and swelling
- Fever, chills, and systemic illness
- Dysphagia, odynophagia
- Erythema and warmth over the thyroid region
- Lymphadenopathy
- Thyroid function usually remains normal
Diagnosis
- Clinical presentation and physical examination
- Laboratory tests:
- Elevated white blood cell count with left shift
- Elevated ESR and CRP
- Blood cultures
- Imaging studies:
- Ultrasound: Hypoechoic or heterogeneous areas, abscess formation
- CT or MRI: To assess extent and identify pyriform sinus fistula
- Fine-needle aspiration: For culture and sensitivity
Treatment
- Prompt antibiotic therapy
- Initial broad-spectrum coverage
- Tailored based on culture and sensitivity results
- Drainage of abscesses if present
- Supportive care: hydration, pain management
- Surgical management of pyriform sinus fistula if identified
Prognosis
- Good prognosis with prompt and appropriate treatment
- Potential complications if untreated:
- Abscess rupture
- Septicemia
- Rare thyroid dysfunction
- Recurrence possible if underlying fistula not addressed
Silent Thyroiditis in Children
Silent thyroiditis, also known as painless thyroiditis or lymphocytic thyroiditis, is less common in children but can occur, especially in adolescents.
Etiology
- Autoimmune etiology, similar to Hashimoto's thyroiditis
- May be triggered by immune system changes
- Postpartum period in adolescents
- Recovery from hyperthyroidism treatment
Pathophysiology
- Lymphocytic infiltration of the thyroid gland
- Disruption of thyroid follicles leading to hormone release
- Transient thyrotoxicosis followed by hypothyroidism
Clinical Presentation
- Often asymptomatic or mild symptoms
- Triphasic course:
- Thyrotoxic phase (2-8 weeks): mild hyperthyroid symptoms
- Hypothyroid phase (2-8 weeks): fatigue, weight gain
- Recovery phase: return to euthyroid state
- No pain or tenderness in the thyroid gland
- Small, firm goiter may be present
Diagnosis
- Thyroid function tests: Reflect the phase of illness
- Low radioactive iodine uptake during thyrotoxic phase
- Thyroid antibodies may be positive (but lower than in Hashimoto's)
- Ultrasound: Normal or slightly heterogeneous thyroid
Treatment
- Often requires only observation and monitoring
- Beta-blockers for symptomatic thyrotoxicosis if needed
- Levothyroxine supplementation if hypothyroid phase is prolonged or symptomatic
- Patient and family education about the self-limiting nature
Prognosis
- Excellent prognosis with spontaneous resolution in most cases
- Complete recovery within 3-6 months
- Small risk of recurrence (especially in postpartum cases)
- A minority (<10%) may develop permanent hypothyroidism
Drug-Induced Thyroiditis in Children
Drug-induced thyroiditis is an inflammation of the thyroid gland caused by certain medications. While less common in children than adults, it can occur, especially in those receiving specific treatments.
Etiology
- Common causative drugs:
- Amiodarone
- Interferon-α
- Tyrosine kinase inhibitors
- Immune checkpoint inhibitors (e.g., pembrolizumab, nivolumab)
- Mechanisms vary depending on the drug
Pathophysiology
- Amiodarone: Direct toxicity and immune-mediated mechanisms
- Interferon-α: Immune stimulation leading to autoimmune thyroiditis
- Tyrosine kinase inhibitors: Disruption of thyroid hormone synthesis
- Immune checkpoint inhibitors: Enhanced T-cell response against thyroid antigens
Clinical Presentation
- Variable presentation depending on the drug and mechanism
- May manifest as:
- Thyrotoxicosis (often transient)
- Hypothyroidism
- Alternating hyperthyroidism and hypothyroidism
- Symptoms similar to other forms of thyroiditis
- Often occurs weeks to months after starting the medication
Diagnosis
- Thorough medication history
- Thyroid function tests: TSH, free T4, free T3
- Thyroid antibodies: May be positive in some cases
- Radioactive iodine uptake: Often low in thyrotoxic phase
- Ultrasound: May show heterogeneous echotexture
- Monitoring of thyroid function before and during treatment with high-risk medications
Treatment
- Management depends on the causative drug and thyroid status
- Amiodarone-induced thyroiditis:
- Type 1 (iodine-induced): Thionamides, potassium perchlorate
- Type 2 (destructive): Glucocorticoids
- Interferon-induced thyroiditis:
- Thyrotoxic phase: Beta-blockers for symptomatic relief
- Hypothyroid phase: Levothyroxine replacement
- Tyrosine kinase inhibitor-induced thyroiditis:
- Levothyroxine replacement for hypothyroidism
- Dose adjustment or alternative medication if severe
- Immune checkpoint inhibitor-induced thyroiditis:
- Often self-limiting, supportive care
- Levothyroxine for persistent hypothyroidism
- Consider discontinuation or modification of the offending drug when possible
Prognosis
- Variable, depending on the causative drug and individual factors
- Amiodarone-induced thyroiditis:
- Type 1: May require long-term management
- Type 2: Often self-limiting, but may lead to permanent hypothyroidism
- Interferon-induced thyroiditis: Usually resolves after drug discontinuation, but may lead to permanent thyroid dysfunction in some cases
- Tyrosine kinase inhibitor-induced thyroiditis: Often reversible upon drug discontinuation
- Immune checkpoint inhibitor-induced thyroiditis: May lead to permanent hypothyroidism requiring lifelong replacement therapy
Monitoring and Follow-up
- Regular thyroid function tests during and after treatment with high-risk medications
- Long-term follow-up to monitor for development of permanent thyroid dysfunction
- Patient and family education about the potential for thyroid dysfunction and symptoms to watch for
- Coordination between endocrinologists and other specialists managing the primary condition
Special Considerations in Children
- Impact on growth and development if thyroid dysfunction is prolonged
- Careful dose adjustments of thyroid medications based on age and weight
- Potential effects on other endocrine systems and overall metabolism
- Psychosocial support for children dealing with multiple medical issues
