Paroxysmal extreme pain disorder

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Paroxysmal extreme pain disorder is a condition characterized by skin redness and warmth (flushing) and attacks of severe pain in various parts of the body. The area of flushing typically corresponds to the site of the pain. The pain attacks experienced by people with paroxysmal extreme pain disorder usually last seconds to minutes, but in some cases can last hours. These attacks can start as early as infancy. Early in life, the pain is typically concentrated in the lower part of the body, especially around the rectum, and is usually triggered by a bowel movement. Some children may develop constipation, which is thought to be due to fear of triggering a pain attack. Pain attacks in these young children may also be accompanied by seizures, slow heartbeat, or short pauses in breathing (apnea).

As a person with paroxysmal extreme pain disorder ages, the location of pain changes. Pain attacks switch from affecting the lower body to affecting the head and face, especially the eyes and jaw. Triggers of these pain attacks include changes in temperature (such as a cold wind) and emotional distress as well as eating spicy foods and drinking cold drinks.

Paroxysmal extreme pain disorder is considered a form of peripheral neuropathy because it affects the peripheral nervous system, which connects the brain and spinal cord to muscles and to cells that detect sensations such as touch, smell, and pain.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Mutations in the SCN9A gene cause paroxysmal extreme pain disorder. The SCN9A gene provides instructions for making one part (the alpha subunit) of a sodium channel called NaV1.7. Sodium channels transport positively charged sodium atoms (sodium ions) into cells and play a key role in a cell's ability to generate and transmit electrical signals. NaV1.7 sodium channels are found in nerve cells called nociceptors that transmit pain signals to the spinal cord and brain.

The SCN9A gene mutations that cause paroxysmal extreme pain disorder result in NaV1.7 sodium channels that do not close completely when it is turned off, allowing sodium ions to flow abnormally into nociceptors. This increase in sodium ions enhances transmission of pain signals, leading to the pain attacks experienced by people with paroxysmal extreme pain disorder. It is unknown why the pain attacks associated with this condition change location over time or what causes the other features of this condition such as seizures and changes in breathing.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Paroxysmal extreme pain disorder is a rare condition; approximately 80 affected individuals have been described in the scientific literature.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Seizure · Very frequent (99-80%)

A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

Constipation · Frequent (79-30%)

Infrequent or difficult evacuation of feces.

Which doctor should you see?

The suggested department for discussing Paroxysmal extreme pain disorder is Neurology, with a neurologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which nervous-system findings help explain the symptoms?
• Would an assessment of walking, communication or daily function be helpful?
• Are rehabilitation or other specialist services relevant?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Paroxysmal extreme pain disorder. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.