Cervical dystonia (CD), sometimes called spasmodic torticollis, is a neurological movement disorder that causes involuntary muscle contractions in the neck. These contractions can lead to abnormal head positions, neck pain, and occasionally tremors¹.

While many cases develop without a clear cause (known as primary or idiopathic cervical dystonia), some occur because of an identifiable medical condition or external factor. These are called **secondary cervical dystonia (SCD).**²

Understanding what causes SCD, how it differs from primary cervical dystonia (PCD), and how it can be diagnosed accurately helps ensure more targeted and effective treatment.

What is secondary cervical dystonia?

Secondary cervical dystonia occurs when neck muscle spasms are caused by an identifiable factor — such as brain injury, medication effects, or metabolic disease. This is different from primary dystonia, which is usually genetic or idiopathic, meaning no clear cause can be found.

Recognising SCD is crucial, as treating the underlying problem — for example, stopping a triggering medication, treating an infection, or managing an injury — can significantly improve or even resolve symptoms.³

Cervical dystonia is the most common form of focal dystonia, meaning it affects a single body region. In secondary cases, it may also appear alongside other neurological symptoms such as tremor, rigidity, or slowed movement (bradykinesia).²

What causes SCD?

SCD can develop due to a wide range of conditions or exposures that affect the brain’s movement control systems, particularly a region called the basal ganglia, which helps regulate muscle tone and coordination.

Neurological injuries

Damage to the brain, spinal cord, or cervical nerves is one of the most recognised causes of SCD. Such injuries interrupt normal nerve signalling, resulting in involuntary contractions and abnormal posture.

• Brain injuries, especially to the basal ganglia, can disrupt movement control. These may result from stroke or traumatic brain injury, and symptoms sometimes appear weeks or months after the initial event.⁵
• Spinal cord or cervical nerve damage can also mimic dystonia, producing pain, spasms, or postural abnormalities. Clinical examination and imaging are often required to distinguish true dystonia from structural or nerve-related causes.⁶

Infections and inflammation

Infections such as meningitis or encephalitis can damage motor control centres, triggering SCD. These infections may cause direct neuronal injury or trigger an autoimmune response that alters brain function.⁸

Similarly, autoimmune conditions like lupus or multiple sclerosis (MS) may cause focal inflammation or demyelination, interfering with muscle control⁷.

Tumours and lesions

Brain or spinal tumours, vascular malformations, and other lesions can disturb normal movement control. Depending on their size and location, patients may also experience symptoms such as speech difficulty or vision changes.⁹ ¹⁰

Neurodegenerative diseases

SCD can develop as part of progressive neurological conditions where specific brain areas degenerate over time:

• Parkinson’s disease – the loss of dopamine-producing cells disrupts movement regulation¹²
• Huntington’s disease – an inherited condition causing involuntary jerky movements and dystonic postures¹¹
• Wilson’s disease – a rare genetic disorder where copper builds up in the brain and liver, affecting motor control. Early diagnosis and treatment can prevent progression¹³

Drug-induced dystonia

Certain medications, particularly those affecting dopamine pathways, can cause SCD. These include:

• Antipsychotics (used for psychiatric conditions)
• Anti-nausea medications

This form, known as tardive dystonia, can develop after prolonged use and sometimes persists even after the medication is stopped². Ironically, Parkinson’s disease drugs such as levodopa can also trigger dystonia in later stages because of dopamine level fluctuations.¹⁴

Toxins and metabolic disorders

Exposure to heavy metals (like lead or manganese), carbon monoxide poisoning, or metabolic or mitochondrial disorders can also lead to dystonia. These causes are uncommon but should be considered, particularly in children or when symptoms appear alongside developmental delays or organ dysfunction.

What can trigger or worsen symptoms?

Even with an underlying cause identified, certain triggers can worsen symptoms:

• Medication changes – starting, stopping, or changing the dose of dopamine-blocking drugs can set off dystonia
• Infections – may worsen brain inflammation or immune activity
• Stress and fatigue – while not direct causes, both can exacerbate existing dystonia and may act as triggers for flare-ups²,¹⁵

How is SCD diagnosed?

Diagnosis involves identifying both the dystonic symptoms and their underlying cause through clinical assessment and investigations.²,⁴,¹⁶

Physical examination

The clinician observes the pattern of neck muscle contractions and abnormal postures, looking for other neurological signs such as numbness, weakness, or visual and balance changes.

Medical and family history

A detailed history can reveal critical clues — for example, a past stroke, neck injury, infection, or medication change. SCD often develops suddenly, whereas primary dystonia tends to progress gradually.

Diagnostic tests

There is no single test for cervical dystonia; diagnosis relies on combining findings from multiple sources:

• Imaging (MRI or CT) – identifies structural abnormalities, tumours, strokes, or spinal compression
• Electromyography (EMG) – measures muscle activity to determine whether the problem arises in muscles or the nerves that control them
• Blood tests – screen for infection, autoimmune diseases, or toxins; liver and kidney tests help identify metabolic causes.
• Genetic testing – sometimes used to rule out inherited disorders that mimic dystonia

How is SCD treated?

Treatment focuses on managing both the cause and the symptoms. No single therapy suits everyone — care plans are tailored to individual needs.²,³,⁴

Botulinum toxin injections

This is the first-line treatment for most cases. Small doses are injected into overactive neck muscles, blocking acetylcholine, the chemical responsible for muscle contraction.

Effects usually appear within a few days, peak after 2–4 weeks, and last 2–6 months. Repeat injections are often required. Possible side effects include neck weakness, pain, or difficulty swallowing.

Oral medications

These may be used alongside botulinum toxin, especially when symptoms are widespread. Options include:

• Dopaminergic agents
• Anticholinergics
• Clonazepam
• Baclofen, a muscle relaxant

They can be effective but may cause side effects such as drowsiness or confusion, especially in older adults.

Surgical options

For severe or treatment-resistant cases, surgery may be considered:

• Deep brain stimulation (DBS) – electrodes placed in the globus pallidus deliver electrical impulses to normalise motor signalling
• Selective peripheral denervation – specific neck nerves responsible for dystonic contractions are surgically interrupted

Supportive therapies and self-care

• Physiotherapy helps improve flexibility and correct posture
• Aquatic therapy reduces strain and muscle stiffness through gentle resistance in water
• Psychological support helps individuals manage the emotional impact of living with a visible movement disorder
• Relaxation practices like mindfulness, yoga, or meditation can reduce stress and muscle tension

Summary

Secondary cervical dystonia (SCD) is a movement disorder caused by an identifiable factor that disrupts the brain’s motor control. Unlike primary dystonia, it often improves — or even resolves — once the underlying cause is identified and treated.

A thorough clinical evaluation, combined with medical history and investigations, is essential for accurate diagnosis. Treatment usually involves a combination of medication, botulinum toxin, therapy, and sometimes surgery, focusing on both cause and symptom management.

With the right care, many people experience significant symptom relief — and in some cases, a complete return to normal neck movement.

FAQs

What is the difference between primary and secondary cervical dystonia?

Primary cervical dystonia develops without a known cause, while secondary cervical dystonia results from another medical issue, medication, or injury.

Can secondary cervical dystonia go away on its own?

Sometimes. If the underlying cause is treated — for example, stopping a medication or treating an infection — symptoms can improve or resolve completely.

Is cervical dystonia hereditary?

Primary dystonia can have a genetic component, but secondary dystonia usually arises from an external or acquired factor rather than inheritance.

How long do botulinum toxin injections last?

They typically last between 2 and 6 months, after which repeat treatment is needed to maintain symptom relief.

Does stress make cervical dystonia worse?

Yes. Stress and fatigue are known to exacerbate muscle spasms and pain, even if they are not the root cause of dystonia.

Can exercise help with cervical dystonia?

Yes. Gentle stretching, posture correction, and physiotherapy can reduce stiffness and improve muscle control. Exercise should always be guided by a healthcare professional.