Abstracted from authoritative source:
rapid onset weakness, sensory deficits, and bowel/bladder dysfunction
50% of patients are complete paraplegic with virtually all of the patients having a degree of bladder/bowel dysfunction
Infections leading to TM include, but are not limited to, enteroviruses, West Nile virus, herpes viruses, HIV, human T-cell leukemia virus type 1 (HTLV-1), Zika virus, neuroborreliosis (Lyme), Mycoplasma, and Treponema pallidum.
Urinary retention may be the first sign of myelitis
There is a bimodal peak between ages 10 to 19 and ages 30 to 39.
The incidence of transverse myelitis is approximately 1 to 8 new cases per 1 million people per year.
- The onset of transverse myelitis is acute to subacute.
- Neurologic symptoms are prominent. Symptoms include motor, sensory, and/or autonomic dysfunction.
To diagnose transverse myelitis, a compressive cord lesion must be excluded first. Exclusion is usually performed by magnetic resonance imaging (MRI). This is followed by a confirmation of inflammation either by a gadolinium-enhanced MRI or lumbar puncture (LP).
The standard of care and the first-line therapy for the treatment of transverse myelitis is intravenous glucocorticoids. High-dose intravenous glucocorticoids should be initiated as soon as possible. There should not be a delay in treatment while waiting for test results. There are few contraindications to glucocorticoid therapy. Potential regimens would include methylprednisolone or dexamethasone for 3 to 5 days.
Most patients with idiopathic transverse myelitis should at least have a partial recovery. This recovery should begin within 1 to 3 months and should continue to progress with exercise and rehabilitation therapy. Recovery may take years, and some degree of persistent debilitation may exist.
A differential diagnosis for Transverse myelitis should include any diseases causing myelopathy. Such examples would include compressive myelopathy from herniated discs, vertebral body compression fractures, epidural abscesses/masses, and spondylitis.
Logic description: events with a diagnosis of transverse myelitis indexed on diagnosis of transverse myelitis, related spinal disease or symptoms of transverse myelitis, followed by a diagnosis of transverse myelitis within 30 days. Events have a 365 days washout period. The events persist for 1 day. Symptoms of Transverse Myelitis included asthenia, muscle weakness, myelitis, paresthesia.
- This cohort definition has cohort id # 63 in OHDSI Phenotype library (pending peer review).
Insights from Cohort Diagnostics
- Was performed on 10 data sources, available on https://data.ohdsi.org/PhenotypeLibrary/ see cohort id C63: [P] Transverse myelitis (or symptoms with transverse myelitis) 365dWO (1Ps, 0Era), with the largest data sources having counts ~ 10,000 persons.
- Incidence rate: as expected incidence is higher in 20 to 50 years range. The rate was about 0.001 to 0.01 per 1,000 per year, but is still higher than expected range of 1 to 8 new cases per 1 million - suggesting specificity error. Another observation is an increase in 2015/2016 compared to previous years in most US data sources. This also suggests that the coding change in USA in 2015 (ICD9CM to ICD10CM had an impact on persons being identified with this condition).
- Index event breakdown: Some data sources appear to index on SNOMED ‘Transverse myelopathy syndrome’ while other data sources index on SNOMED acute transverse myelitis. The most common icd9cm vocabulary was 341.20 Acute (transverse) myelitis NOS, 341.22 Idiopathic transverse myelitis; and icd10cm was Acute transverse myelitis in demyelinating disease of central nervous system, G37.3. Note the change in semantic meaning from ICD9CM to ICD10CM, specifically the emphasis on ’ in demyelinating disease of central nervous system’ suggesting co-existence of demyelinating diseases like Multiple Sclerosis. e.g., Acute transverse myelitis (concept ID 139803) was the primary concept in the US and JMDC databases. In the US databases there were a significant number of index events with the concept Idiopathic transverse myelitis (concept ID 134330). In CPRD all subjects were included with an index event of Transverse myelopathy syndrome (concept ID 443904).
- Visit context: majority of persons (>80%) appear to be in outpatient setting. This suggests that there are large number of persons who have the code while being in an outpatient. This is surprising considering the seriousness of the presenting symptoms of rapid onset generalized weakness. I would have expected higher urgent, emergency room or inpatient stays.
- Characterization: About 10 to 20% persons have multiple sclerosis. About 10% have muscle weakness. More than 20% had a MRI and at least 10% had CT. The presence of relatively high multiple sclerosis in the 30-day time window post-index and in the 31-365D window post-index may suggest specificity error, but presence of multiple sclerosis is NOT considered a disqualifier for having acute transverse myelitis, infact acute transverse myelitis occurs in high frequency among persons with multiple sclerosis. Prednisone was started (drugEraStart) in about 10% of persons.
Limitation of this cohort definitions (source of errors): This cohort definition has many errors, and its use should be with caution.
- compared to the clinical description - this cohort definition appears to do a decent job with sensitivity but may suffer from specificity issues.
- Potential loss of sensitivity may be because of not using ICD10CM code of acute flaccid myelitis. But it is unclear if this code represent transverse myelitis.
- Potential loss of specificity are supported by the lower prevalence of concepts related to strengtheners (symptoms, signs, tests, treatments) in the temporal period around cohort start date. We did observe about 20% MRI utilization and 10% steroid utilization - however, considering the seriousness of this illness and its expected relatively rapid progression, we would expect higher utilization of emergency room and inpatient stay. Although most persons identified appear to have some form of neurological disorder - that may be related to but not be acute transverse myelitis. Further the incidence rate appears higher than anticipated.
- It is possible that the shift from ICD9CM and ICD10CM and the absence of equivalence code may explain the pattern seen in incidence rate plot. We did not evaluate if replacing G04.82 Acute flaccid myelitis would fix the specificity errors.
- Cohort end date is currently fixed at 1 day after cohort start date. This may be improved as persons who have Transverse Myelitis are expected to have transverse myelitis and its sequela for months if not years, it does not resolved.
PheValuator: not done
** Patient profile review** I performed a review of random sample of 20 individual cases on two data sources to understand the characteristics of persons, This was not conclusive