Opisthotonus

Opisthotonus is a medical symptom characterised by severe muscle tension and spasms of the back and neck, in which the dog is in an abnormal body posture. In this position, the head is strongly hyperextended backwards, the back is arched, and the limbs are extended. This unnatural body posture indicates a severe neurological disorder, often affecting the brain or spinal cord.

What is opisthotonus?

The term opisthotonus describes a pathological muscle contraction that leads to extreme hyperextension of the neck and back. It is not an independent disease, but rather a symptom indicating severe neurological damage, often associated with disorders of the central nervous system (CNS). In this position, the muscles of the back and neck are highly tense, leading to a characteristic posture.

Causes of opisthotonus in dogs

Opisthotonus can be caused by various neurological disorders or injuries affecting the brain or spinal cord. The most common causes include:

1. Traumatic brain injury: A severe head trauma, such as from an accident or fall, can damage the brain and lead to opisthotonus. Brain injuries can affect areas responsible for muscle control and body posture.
2. Tetanus: Tetanus, caused by the bacterium Clostridium tetani, can lead to severe muscle spasms and opisthotonus. Tetanus often affects the nerve pathways that control muscle contractions, leading to persistent and painful muscle tension.
3. Meningitis or encephalitis: Inflammation of the meninges (meningitis) or the brain (encephalitis) can cause neurological symptoms such as opisthotonus. These conditions are frequently triggered by infections (bacterial, viral, or parasitic).
4. Brain tumours: Tumours in the brain or on the brainstem can impair the nerve centres that control musculature. This can lead to uncontrollable muscle contraction and the development of opisthotonus.
5. Hydrocephalus: In hydrocephalus (accumulation of fluid in the brain), pressure in the brain increases, which can impair normal nervous system function and lead to symptoms such as opisthotonus.
6. Poisoning: Toxic substances, such as strychnine or metaldehyde (an ingredient in slug pellets), can severely damage the nervous system and lead to opisthotonus.
7. Spinal cord injuries: Injuries to the spinal cord, for example from accidents or herniated discs, can also lead to abnormal body postures such as opisthotonus, as the nerve pathways controlling the muscles are impaired.

Symptoms of opisthotonus in dogs

Dogs with opisthotonus typically show very noticeable physical symptoms due to extreme muscle tension:

• Hyperextension of the neck and back: The dog’s head is strongly hyperextended backwards, and the back is arched.
• Stiffness of the limbs: The dog’s legs are often extended and stiff.
• Muscle spasms: Severe and persistent spasms of the back muscles, leading to a permanent abnormal posture.
• Altered consciousness: In more severe cases, the dog may be unconscious or in a coma-like state.
• Breathing difficulties: Due to muscle spasms in the chest area, breathing and oxygen exchange may also be impaired.

Depending on the cause, additional neurological symptoms may also occur, such as seizures, coordination disorders or paralysis.

Diagnosis of opisthotonus

Diagnosing opisthotonus requires a thorough examination by a vet, often a specialist in neurology. Diagnostic procedures include:

1. Clinical examination: A comprehensive physical and neurological examination is carried out to assess the severity of muscle spasms and other neurological signs.
2. Imaging techniques: X-rays, CT scans, or MRIs may be required to diagnose skull injuries, spinal cord damage, or brain tumours.
3. Blood tests: Blood tests help identify infections, inflammation, or toxic substances in the body that could be responsible for the symptoms.
4. Cerebrospinal fluid analysis: A lumbar puncture (withdrawal of fluid from the spinal canal) can be performed to detect signs of meningitis or encephalitis.
5. Tetanus test: If tetanus is suspected, a specific test can be carried out to detect the bacterium Clostridium tetani.

Treatment of opisthotonus in dogs

Treatment of opisthotonus depends on the underlying cause. The aim of treatment is to address the cause and alleviate symptoms:

1. Treatment of trauma and injuries: In cases of head or spinal cord injuries, surgical intervention may be necessary to relieve pressure on the brain or spinal cord.
2. Tetanus treatment: In cases of tetanus, the dog is treated with antitoxin, antibiotics and muscle relaxants to control muscle spasms and combat the infection.
3. Medication for spasms: Muscle relaxants and anticonvulsants (spasmolytic drugs) can be used to reduce muskletension and alleviate symptoms.
4. Treatment of meningitis or encephalitis: If there is an infection or inflammation of the brain, antibiotics, antiviral medications or corticosteroids are used depending on the cause.
5. Treatment of poisoning: In cases of toxic poisoning, the dog is treated accordingly with antidotes, detoxification therapies and symptomatic support.
6. Care and support: Dogs with opisthotonus often require intensive care, including fluid therapy, oxygen supply and in some cases artificial nutrition, to support recovery.

Prognosis

The prognosis for dogs with opisthotonus depends heavily on the cause of the condition. With tetanus or infections that are detected and treated early, there is a good chance of improvement. However, with severe head injuries, brain tumours or hydrocephalus, the prognosis may be more cautious, and recovery is often prolonged or uncertain.