QuestionSBA
QuestionChoice
This patient has pancytopenia on their blood film and is displaying signs and symptoms of bone marrow depression. Bone marrow depression occurs in roughly 1 in 1000 patients who take carbimazole. The suppression is usually temporary and should improve within weeks if the carbimazole is stopped. More common side effects include headache, nausea and rashes
32873
a
Carbimazole
QuestionChoice
Beta-blockers can lead to thrombocytopenia; however, pancytopenia is less common. Other side effects include fatigue, cold extremities and bronchospasm
32876
d
Metoprolol
QuestionChoice
Beta-blockers can lead to thrombocytopenia; however, pancytopenia is less common. Other side effects include fatigue, cold extremities and bronchospasm
32877
e
Nadolol
QuestionChoice
Beta-blockers can lead to thrombocytopenia; however, pancytopenia is less common. Other side effects include fatigue, cold extremities and bronchospasm
32874
b
Propranolol
QuestionChoice
Propylthiouracil is usually only prescribed by a specialist for hyperthyroidism. Propylthiouracil can lead to pancytopenia as well as hepatic disorders and hypersensitivity reactions. It is not first line because of the slightly increased likelihood of severe liver damage. Therefore, it is unlikely to have been prescribed to this patient
32875
c
Propylthiouracil
QuestionComment
It was really a 50/50 chance of getting this one right lol
7921
QuestionComment
Umm actually this should be a 100% chance of getting this right. You just need to spend more time on wards
23117
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subscriber
Big mo
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+1

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Obsessive Compulsive Diabetes
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Acute Myotonia
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Chapter
# Summary
 

Hyperthyroidism is a condition resulting from an overactivity of the thyroid gland leading to an excess of thyroid hormones in the body. The syndrome caused by this excess is termed thyrotoxicosis. The common primary causes include Grave's disease, toxic adenoma, toxic multinodular goitre, certain medications, and thyroiditis. Key signs of hyperthyroidism encompass increased basal metabolic rate, heat intolerance, tachycardia, weight loss, and sleep disturbances. Management strategies comprise medications, radio-iodine therapy, surgery, and symptomatic relief with beta-blockers.
 

# Definition
 - **Hyperthyroidism**: A condition in which the thyroid gland is overactive, leading to the production of excess thyroid hormones.
  
 - **Thyrotoxicosis**: The syndrome resulting from the presence of excessive thyroid hormones in the body, not always due to thyroid gland overactivity.
 

# Epidemiology
Hyperthyroidism predominantly affects women and the elderly, with an estimated prevalence of 1-2% in the general population. Grave's disease is the predominant cause.
 

# Aetiology
Primary causes of hyperthyroidism originate from the thyroid gland itself and include:
 - **Grave's disease**: Resulting from autoimmune stimulation of the thyroid gland by TSH receptor auto-antibodies.
 - **Toxic adenoma**: Adenoma that produces thyroid hormones.
 - **Toxic multinodular goitre**: Multiple thyroid nodules that produce thyroid hormones, leading to goitre.
 - **Medications**: Such as amiodarone.
 - **Thyroiditis**: Inflammation of the thyroid gland, e.g., de Quervain's thyroiditis.
 - Radiation exposure
 

Secondary causes of hyperthyroidism, or those not caused by thyroid dysfunction, include:
 

 - Amiodarone
 - Lithium
 - TSH producing pituitary adenoma
 - Choriocarcinoma (beta-hCG can activate TSH receptors)
 - Gestational hyperthyroidism
 - Pituitary resistance to thyroxine (i.e., failure of negative feedback)
 - Struma ovarii (ectopic thyroid tissue in ovarian tumours)
 

# Signs and Symptoms
General manifestations of hyperthyroidism include:
 

 - ↑ Basal metabolic rate
 - Heat intolerance
 - Tachycardia and arrhythmias
 - Weight loss
 - Diarrhoea
 - Sweaty skin
 - Insomnia and sleep disturbances
 - Restlessness and tremors
 - Goitre (depending on cause)
 

 [lightgallery1]
 

Both hyper- and hypothyroidism may result in:
 - Mood changes, depression, and anxiety
 - Menstrual disturbances
 

Specific features of **Grave's disease** are:
 

 - Exophthalmos/proptosis: Bulging eyes
 - Thyroid acropachy: Soft tissue swelling in extremities, nail clubbing, and periosteal new bone growth.
 - Pretibial myxoedema: Mucopolysaccharide deposition in the dermis leading to oedema and skin thickening, predominantly in the shins.
 

 [lightgallery]
 

# Differential Diagnosis
 - **Anxiety Disorder**: While hyperthyroidism can cause anxiety-like symptoms, it's essential to consider anxiety disorders as a separate diagnosis.
 - **Pheochromocytoma**: This rare adrenal gland tumor can produce excessive catecholamines, leading to symptoms such as palpitations, sweating, and high blood pressure. Careful evaluation, including urine and blood tests, is necessary to differentiate it from hyperthyroidism.
 - **Other Thyroid Disorders**: Hypothyroidism or other thyroid conditions can sometimes present with symptoms that overlap with hyperthyroidism. Thyroid function tests (TFTs) help distinguish between these thyroid disorders.
 

# Investigations
 

When evaluating a patient suspected of having hyperthyroidism, the following investigations are commonly performed:
 

 1. **Thyroid Function Tests (TFTs)**:
  - Elevated levels of free thyroxine (FT4) and free triiodothyronine (FT3) with suppressed thyroid-stimulating hormone (TSH) are indicative of hyperthyroidism.
 

 2. **Blood Tests for Thyroid Antibodies**:
  - Detecting thyroid antibodies, such as thyroid-stimulating immunoglobulins (TSIAb) or thyrotropin receptor antibodies (TRAb), can help diagnose the underlying cause, particularly in Grave's disease.
 

 3. **Ultrasound of the Thyroid**:
  - Ultrasonography is used to visualise the thyroid gland and assess its size, structure, and any nodules.
 

 4. **Radioiodine Uptake Test**:
  - This test measures the thyroid's ability to take up radioactive iodine. It helps determine the cause of hyperthyroidism (e.g., diffuse uptake in Grave's disease or focal uptake in a toxic nodule).
 

# Management
 

 1. **Antithyroid drugs (ATDs)**:
  - First-line treatment for most patients.
  - Carbimazole or propylthiouracil (PTU) is used, with carbimazole being preferred due to fewer side effects.
   - Carbimazole can cause agranulocytosis, a severe and potentially life-threatening condition characterized by a significant decrease in white blood cells (neutrophils). Patients should be advised to seek immediate medical attention if they experience symptoms like fever, sore throat, mouth ulcers, or other signs of infection while taking Carbimazole.
  - In pregnant women or those planning pregnancy, PTU is preferred in the first trimester.
 

 2. **Beta-blockers**:
  - Propranolol can be used for symptomatic relief, especially for symptoms associated with increased sympathetic activity.
 

 3. **Radio-iodine**:
  - Considered for definitive treatment, especially for relapsed disease or when ATDs are not suitable.
  - Not typically used in patients under age 40 due to potential increased cancer risk.
  - Radioiodine is a radioactive form of iodine that selectively concentrates in the thyroid gland. It damages the thyroid tissue, reducing its hormone-producing ability. 
  - Post-radioiodine therapy, patients often become hypothyroid, and they may require lifelong thyroid hormone replacement therapy.
 

 4. **Surgery (Thyroidectomy)**:
  - An option for those with large goiters causing compression, suspicion of malignancy, or when other treatments are contraindicated or refused.
  - Requires preparation with ATDs to achieve euthyroid state before surgery to minimize risks.
 

 **Regular monitoring** is crucial, including thyroid function tests, to ensure appropriate dosing of medications and to detect early signs of remission or relapse.
 

 

 

# Thyroid Storm
 

Thyroid storm is a rare but life-threatening medical emergency caused by untreated or inadequately managed hyperthyroidism. It is often precipitated by stressors like surgery, trauma, or infection. Key features of thyroid storm include:
 

 - Restlessness and agitation
 - High-output heart failure
 - Profound tachycardia
 - Fever
 - Delirium and altered mental status
 

Management of thyroid storm involves several principles:
 

 1. **Counteract Peripheral Action of Thyroid Hormone**:
  - Intravenous propranolol and digoxin help control heart rate and manage cardiac symptoms.
 

 2. **Inhibit Thyroid Synthesis**:
  - Propylthiouracil (PTU) through a nasogastric tube and Lugol's iodine are administered to reduce thyroid hormone production.
 

 3. **Corticosteroids**:
  - Steroids like prednisolone or hydrocortisone are given to inhibit peripheral conversion of T4 to the more active T3 form.
 

 4. **Supportive Care**:
  - Supportive measures include intravenous fluids, cooling measures for fever, and addressing any precipitating factors (e.g. infection).
 

# Complications of Hyperthyroidism
 

Hyperthyroidism can lead to various complications, including:
 

 - **Thyroid Eye Disease (TED)**:(see separate page in Ophthalmology section for more detail)
  - Smoking is the most important risk factor for development and increased severity of TED in patients with Grave's disease, so it is important to counsel patients on the importance of smoking cessation
  - Sight-threatening complications include: exposure keratopathy, compressive optic neuropathy and diplopia. 
  - Early medical management of TED has the potential to stabilise, slow or even reverse the disease process. Good control of thyrotoxicosis is essential and other medical therapies, such as steroids or other immunosuppressants, may be used
  - In sight-threatening TED, urgent surgical orbital decompression may be required, followed by intravenous corticosteroids
 - **Atrial Fibrillation**: Due to the increased strain on the heart, hyperthyroidism can lead to atrial fibrillation, a type of irregular heartbeat.
 - **High-Output Heart Failure**: The heart may become overworked, resulting in high-output heart failure.
 - **Osteopenia/Osteoporosis**: Hyperthyroidism can lead to bone loss and increase the risk of fractures.
 - **Upper Airway Obstruction**: Large goitres may cause upper airway obstruction, requiring intervention.
 - **Thyroid Cancer**: In some cases, hyperthyroidism may be associated with thyroid cancer, although it's not a common complication.
 - **Thyroid storm** - see above
 

# NICE Guidelines
 [NICE CKS on Hyperthyroidism](https://cks.nice.org.uk/hyperthyroidism)
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An example of a very large goitre.
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Proptosis and lid retraction seen in Grave's disease.
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Pancytopenia, a condition characterized by the reduction of all blood cell types, can be a rare side effect of carbimazole, a medication used to treat hyperthyroidism, due to its impact on bone marrow function.
A 56-year-old woman visits her GP due to the development of new mouth ulcers. She also complains about a sore throat. On examination, she is warm to the touch. She has started a new medication due to a recent diagnosis of hyperthyroidism.


Her bloods are as follows:


||||
|--------------|:-------:|---------------|
|Haemoglobin|101      g/L|(M) 130 - 170, (F) 115 - 155|
|White Cell Count|2.2x10<sup>9</sup>/L|3.0 - 10.0|
|Platelets|90x10<sup>9</sup>/L|150 - 400|


Which of these medications is most likely to be the cause?
a