Paroxysmal extreme pain disorder (previously familial rectal pain syndrome).
OBJECTIVE
To describe the clinical phenotype of paroxysmal extreme pain disorder (previously called familial rectal pain syndrome), an autosomal dominant condition recently shown to be a sodium channelopathy involving SCN9A.


METHODS
An international consortium of clinicians, scientists, and affected families was formed. Clinical details of all accessible families worldwide were collected, including age at onset, features of attacks, problems between attacks, investigational results, treatments tried, and evolution over time. A validated pain questionnaire was completed by 14 affected individuals.


RESULTS
Seventy-seven individuals from 15 families were identified. The onset of the disorder is in the neonatal period or infancy and persists throughout life. Autonomic manifestations predominate initially, with skin flushing in all and harlequin color change and tonic attacks in most. Dramatic syncopes with bradycardia and sometimes asystole are common. Later, the disorder is characterized by attacks of excruciating deep burning pain often in the rectal, ocular, or jaw areas, but also diffuse. Attacks are triggered by factors such as defecation, cold wind, eating, and emotion. Carbamazepine is effective in almost all who try it, but the response is often incomplete.


CONCLUSIONS
Paroxysmal extreme pain disorder is a highly distinctive sodium channelopathy with incompletely carbamazepine-sensitive bouts of pain and sympathetic nervous system dysfunction. It is most likely to be misdiagnosed as epilepsy and, particularly in infancy, as hyperekplexia and reflex anoxic seizures.
Royal Free and University College Medical School, London, UK.
C R
CR
Fertleman
C D
CD
Ferrie
J
J
Aicardi
N A F
NA
Bednarek
O
O
Eeg-Olofsson
F V
FV
Elmslie
D A
DA
Griesemer
F
F
Goutières
M
M
Kirkpatrick
I N O
IN
Malmros
M
M
Pollitzer
M
M
Rossiter
E
E
Roulet-Perez
R
R
Schubert
V V
VV
Smith
H
H
Testard
V
V
Wong
J B P
JB
Stephenson
D017668:Age of Onset; D000700:Analgesics / Q000627:therapeutic use; D000927:Anticonvulsants / Q000627:therapeutic use; D001919:Bradycardia / Q000209:etiology; D003937:Diagnosis, Differential; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis; D005123:Eye; D005260:Female; D005315:Fetal Diseases / Q000235:genetics / Q000503:physiopathology; D005483:Flushing / Q000209:etiology; D005727:Ganglia, Spinal / Q000503:physiopathology; D005799:Genes, Dominant; D006323:Heart Arrest / Q000209:etiology; D006801:Humans; D007231:Infant, Newborn; D015640:Ion Channel Gating / Q000235:genetics; D007568:Jaw; D008297:Male; D062556:NAV1.7 Voltage-Gated Sodium Channel; D009437:Neuralgia / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics / Q000503:physiopathology*; D009619:Nociceptors / Q000502:physiology; D010375:Pedigree; D010641:Phenotype; D010812:Physical Stimulation; D012007:Rectum; D012640:Seizures / Q000209:etiology; D020182:Sleep Apnea, Central / Q000209:etiology; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000172:deficiency / Q000235:genetics; D013577:Syndrome
D000700:Analgesics; D000927:Anticonvulsants; D062556:NAV1.7 Voltage-Gated Sodium Channel; C486866:SCN9A protein, human; D015222:Sodium Channels; D012964:Sodium