Sunday, June 24, 2007

Diseases mimicking MS -- pearls

Five not to miss
1. Clinically isolated syndrome-- CIS-- Repeat MRI in one month to make MS diagnosis
2. Devic's disease(neuromyelitis optica or NMO)-- consider in patients with the combination of ON and transverse myelitis, repeated transverse myelitis, long segment lesions on spinal cord, Asians, patients without bands in CSF, and patients nonresponsive to medication among others. Serum IgG antibody for NMO (new test) segregates fairly reliably from MS. Pearl-- check hepatitis C antibodies. See www.Devicsnotes.blogspot.com for Wingerchuk criteria and more information.
3. Progressive multifocal leukoencephalopathy (PML)-- MRI lesions can mimic MS but they do not enhance. Check PCR to JC virus (papovavirus) in blood and CSF (latter is diagnostic, former is screening, urine is of no value as it is almost always positive). Pearl-- Patients may not have known HIV at time of presentation.
4. Spinal cord tumor-- astrocytoma or ependymoma most common. No brain lesion seen, CSF is negative. Cord may be enlarged. Lesion not necessarily in posterior columns as usual.

MS variants
5.tumefactive MS-- may resemble GBM. May be able to suspect MS with VEP's CSF but may require brain biopsy.
6. Marburg variant-- severe necrotizing rapidly fatal form of MS
7. Balo's concentric sclerosis-- a variant. Concentric rings may be mixed with other MS like MRI lesions.
8. ADEM-- no infallible wayof diagnosing, but ADEM is more common in kids, after vaccinations and infections, may have more gray matter lesions, or LOC or other unusual symptoms.

Ocular presentations/developing countries
9. Subacute myelo-optic neuritis (SMON) common in developing countries. MRI may be abnormal, CSF is not abnormal. May be caused by toxins (cooking oil) or vitamin deficiencies.
10. Eale's disease-- small vessel occlusive disease causing vitreous hemorrhages esp. in India and the Middle East. Opth'y exam and fluorescein angiographyis diagnostic.
11. Behcet's disease-- more common in Asia and Mediterranean. uveitis, MRI changes, CSF pleocytosis without bands, biopsy mucocutaneous ulcers to diagnose.
12. HERNS= hereditary endotheliopathy, retinopathy, nephropathy, and stroke-- aut dom, in Chinese leukoencephalopathy-renal syndrome, prominent dementia.

Systemic disease often cited in differential diagnosis
13. Sarcoid-- 90 % have pulmonary lesions, for biopsy. Meninges may be abnormal. Rarely, oligoclonal bands are positive.
14. Lupus-- Sjogren's-- may affect CNS and mimic MS. If long segment spine lesions are present and if bands are absent, send NMO antibody. For lupus check ANA, ds DNA autoab's and look for kidney/skin involvement. In Sjogren's check SS-A (Ro) and SS-B (La) antibodies.

Retinitis pigmentosa syndromes
15. NARP-- Neuropathy, ataxia, retinitis pigmentosa-- mitchondrial mutation in ATP'ase 6 gene causing visual and motor symptoms in a young person with MRI abnormalities, and sensory PN. Athena has a commercial test.
16. Usher syndrome-- congenital RP, hearing loss, ataxia, sometimes bands.

Other inherited diseases
17. CADASIL-


Infectious


Other ocular syndromes
Inflammatory uveitis/retinitis
AION
Cogan syndrome keratitis and episodes of estibular dysfunction, + hearing loss
Susac syndrome-- relapsing vertigo, vision loss, encephalopathy, abnormal fluorescein angiography and audiograms
Central serous chorioretinopathy-- mimics ON but due to detached retina
Neuroretinitis (stellate retinitis)-- unilateral visual loss, mimics ON due to capillary leak, with macular star formation.


Sneddon syndrome-- usually recurrent strokes, apl ab's, livedo reticularis

Eosinophilia-myalgia syndrome-- hypercoag state can make MRIi abnormal

Differential diagnosis of multiple sclerosis, approach

Rolak LA, Fleming JO. The Differential diagnosis oo multiple sclerosis. The Neurologist 2007;13:57-72.

Below is a brief synopsis of the diseases that can be confused with multiple sclerosis.

Rolak states that 2 factors most reliably identify patients without MS. The first is absence of typical symptoms such as ON, L'Hermitte's sign, sensory level, NGB, etc. The other is normal brain MRI and/or CSF.

Rolak identifies 20 MRI patterns that mimic MS, 15 diseases disseminated in space but not time, 15 disseminated in time but not space, and 20 disseminated in both, all in tables. He suggests against extensive screening for these diseases, arguing that is rarely cost and time productive use of resources and may generate false positives.

Most helpfully, Rolak outlines the seven most common diagnoses for patients without MS. By far, the commonest is psychiatric disease in several large series, including somatization, malingering, hypochondriasis, depression, anxiety. The second most common is everyday sensations that are misconstrued as abnormal, including vision changes, loss of power, and poor balance. Psych symptoms tend to be generalized, such as "weak all over" or "numb everywhere" whereas MS has a clear anatomic localization. The time course of MS symptoms-- onset with regression over days to weeks-- also differs from psychiatric disease. Third most common is migraine. Unilateral numbness and rarely, weakness can mimic MS and MRI shows whitish lesions which can be confused. Other less common causes include peripheral neuropathy, cervical stensosis, and vertigo.