Paroxysmal sympathetic hyperactivity

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Paroxysmal sympathetic hyperactivity ( PSH ) is a syndrome that causes episodes of increased activity of the sympathetic nervous system. Hyperactivity of the sympathetic nervous system may manifest as increased heart rate, increased respiration, increased blood pressure, diaphoresis, and hyperthermia. Previously, this syndrome has been identified as a common dysautonomia but is now considered a specific form of it. It has also been referred to as paroxysmal sympathetic instability with dystonia, or PAID, and sympathetic storms. More recently, however, studies have adopted the name of paroxysmal sympathetic hyperactivity to ensure specificity. PSH was observed more in patients younger than older. It also looks more common in men than women. There is no reason to know why this happens, although suspected pathophysiologic linkages exist. In patients who survived traumatic brain injury, the incidence of this episode was one out of every three episodes. PSH can also be associated with severe anoxia, subarachnoids and intracerebral hemorrhage, and hydrocephalus.

Video Paroxysmal sympathetic hyperactivity

Symptoms

Characteristics of sympathetic paroxysmal hyperactivity include:

• fever
• tachycardia
• hypertension
• tachypnea
• hyperhidrosis or diaphoresis
• dystonic posture
• pupil dilation
• watered

In cases where PSH episodes suffer from post-injury brain injury, especially traumatic brain injury, symptoms usually develop rapidly, usually within a week. Symptoms of onset have seen an average of 5.9 days post-injury. Episodes vary in duration and occurrence. Episodes can last as little as a few minutes or as long as ten hours, and they can occur several times a day. The duration of the episode has seen an average of 30.8 minutes and occurs five to six times a day. Episodes may occur naturally or arise from external triggers. Common triggers include pain or stimulation, movement or movement of the body, and bladder distention. Bladder distention has been observed in patients treated in intensive care units with simultaneous catheter use. The symptoms of PSH may last from week to year after the onset of onset. Because episodes continue over time, they have been found to be less common in events but lasting for prolonged periods.

Maps Paroxysmal sympathetic hyperactivity

Cause

The number of events that can lead to the development of many PSH symptoms. The exact path or cause of the development of the syndrome is unknown. Traumatic brain injury, hypoxia, stroke, anti-NMDA receptor encephalitis (although further associations are being explored), spinal cord injury, and many other forms of brain injury can lead to PSH onset. Even more vague diseases such as intracranial tuberculoma have been seen to result in paroxysmal sympathetic hyperactivity. It has been observed that this injury leads to the development of PSH or is seen in association with PSH, but the pathophysiology behind this disease and the syndrome is not well understood.

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Pathophysiology

A large number of theories exist for pathophysiology:

• The epileptiform discharge in the diencephalon, or interbrain, is a potential theory for PSH. This disposal can be identified using electroencephalography.
• Increased intracranial pressure is another theory. Currently, this theory seems less likely than others. Intracranial pressure has been seen to have no correlation with PSH episodes.
• Termination through the efferent inhibitory lining lesion of the cortical and subcortical regions of the brain is a potential theory. This theory deals with ablated inhibitory pathways or post-injury malfunctions. This causes the sympathetic pathways of the cortical and subcortical areas to become less controlled, resulting in a 'sympathetic storm'.
• The excitatory inhibition model shows that lesions in the mesencephalic region reduce the pathway of inhibition of the brain. This is thought to lead to a normally non-nociceptive pathway being nociceptive, resulting in a more activated peripheral sympathetic nervous system.
• Another theory deals with damage to brainstem function, particularly the brainstem stimuli center. In this case, rather than the damaged inhibition pathways and allowing the sympathetic pathways to propagate unhindered, the center of stimulation up-regulated, increases the sympathetic activity.

There are many theories related to the pathophysiology of sympathetic paroxysmal hyperactivity. It is possible that none or some of these theories are true. The ongoing research on PSH is focused on figuring out this pathway.

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Diagnosis

Diagnosing PSH can be very difficult because of the lack of general terminology in the circulation and the lack of diagnostic criteria. Different systems for diagnosis have been proposed, but the universal system has not yet been embraced. One example of the proposed diagnostic system requires confirmation of observation for four of the following six symptoms: fever greater than 38.3 degrees Celsius, tachycardia classified as 120 bpm or higher heart rate, hypertension is classified as a systolic pressure higher than 160 mmHg or pulse pressure is higher than 80 mmHg, tachypnea is classified as a respiratory rate higher than 30 breaths per minute, excessive sweating, and severe dystonia. Putting aside disease or other syndromes that show similar symptoms is very important for diagnosis as well. Sepsis, encephalitis, malignant neuroleptic syndrome, malignant hyperthermia, lethal katatonia, spinal cord injury (unrelated to PSH), seizures, and hydrocephalus (this can be attributed to PSH) are examples of diagnoses that should be considered due to similar manifestations of symptoms prior to confirming the diagnosis of PSH. PSH does not have a simple radiological feature that can be observed or detected on scanning.

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Prognosis

Patients who develop PSH after traumatic injury have longer hospitalization and longer duration in intensive care in cases where ICU care is required. Patients are often more susceptible to infection and spend more time on the ventilator, which can lead to an increased risk of various lung diseases. PSH does not affect mortality, but increases the amount of time it takes for patients to recover from injury, compared to patients with similar injuries who do not have PSH episodes. Often it takes patients who develop PSH longer to achieve the same level of brain activity seen in patients who do not develop PSH, even though PSH patients eventually reach the same level.

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Treatment

Various methods are used to treat PSH. Medications are used to terminate episodes or prevent them from occurring. Hyperbaric oxygen therapy has been explored as well. Other treatments have been used, but their success is measured on a case-by-case basis. Successful treatment with qualitative results or efficacy for a wider range of patients has not been developed.

Medication

The two most common drugs used in the treatment of paroxysmal sympathetic hyperactivity are morphine sulfate and beta-blockers. Morphine is useful in helping to stop episodes that are already beginning to happen. Beta-blockers are helpful in preventing the occurrence of a 'sympathetic storm'. Other drugs that have been used and in some cases have been helpful are dopamine agonists, various other opiates, benzodiazepines, clonidine, and baclofen. Chlorpromazine and haloperidol, both dopamine antagonists, in some cases exacerbate the symptoms of PSH. These medicines are used today for treatment; the exact path is unknown and the broad assistance is speculative.

Morphine

Morphine has been found to be effective in aborting episodes; sometimes it is the only drug that can combat the sympathetic response. Morphine helps lower respiratory rates and hypertension. This is given in doses of two milligrams to eight milligrams but can be given up to twenty milligrams. Nausea and vomiting are common side effects. Withdrawal is sometimes seen in patients.

Beta-blocker

Non-selective beta-blockers are the most effective in reducing the frequency and severity of PSH episodes. They help reduce the effects of circulating catecholamines and lower the metabolic rate, which is high in patients during PSH episodes. Beta-blockers also help reduce fever, diaphoresis, and in some cases dystonia. Propanolol is a common beta blocker given because of the fact it penetrates the blood-brain barrier relatively well. Usually given in doses of twenty milligrams to sixty milligrams every four to six hours in the treatment of PSH.

More

Clonidine is an alpha-receptor agonist that helps decrease sympathetic activity leaving the hypothalamus and reduce circulating catecholamines. It helps in lowering blood pressure and heart rate, but it does not show many effects on other symptoms. It can also increase sympathetic inhibition in the brain stem. Bromocriptine is a dopamine agonist that helps lower blood pressure. The effect is simple, but they are not well understood. Baclofen is a GABA agonist that helps control muscle spasms, proven to be very helpful in treating dystonia. Benzodiazepines bind to GABA receptors and work as muscle relaxants. Benzodiazepines also combat high blood pressure and respiratory rate; However, they are associated with glaucoma, which is a rather serious side effect. Gabapentin inhibits the release of neurotransmitters in the dorsal horn of the spinal cord and various areas of the central nervous system. It helps treat mild symptoms and can be tolerated for a longer period of time compared to other drug treatments. Dantrolene helps fight dystonia and fever by affecting muscle contraction and relaxation cycle. This inhibits the release of calcium from the sarcoplasmic reticulum, inhibiting muscle contraction. This causes less respiration, but can be very harmful to the liver. Again, these treatments look case-by-case and treat symptoms well. They do not treat the syndrome as a whole or preventatively. Efficacy varies patients to patients, such as symptoms.

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History

The first published case of paroxysmal sympathetic hyperactivity is the Wilder Penfield case report of a 41-year-old woman, JH, published in 1929. She had third ventricular cholesteatoma. He showed increased respiration, increased heart rate, diaphoresis, and increased blood pressure. He also showed minor symptoms: pupil dilation, hiccups, and lacrimation. At that time, the episode was called 'autencephalic epilepsy diencephalic'. It is believed that the sympathetic and parasympathetic nervous system exhibits excess activity. The future may hold non-pharmacological solutions such as renal sympathetic denervation.

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References

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External links

• International Dysautonomia
• Dysautonomia Information Network
• The Dysautonomia Foundation

Source of the article : Wikipedia