ACUTE DISSEMINATED ENCEPHALOMYELITIS

1. ACUTE DISSEMINATED ENCEPHALOMYELITIS

2. PATIENT DETAILS • 9 month old male visiting Jhb with his parents and brother, living in Durban • Three day history of mild gastroenteritis with a low grade fever and a cough. • One day history of not moving his left arm. • Birth history- NVD at a hospital in Natal, no birth complications and well after birth.

3. DETAILS CONTINUED • PMH- nil • PSH- nil • Allergies- nil known • Medications- Augmentin and Panado from a private GP. • Feeding- Nan, cereal, purity and some vegetables

4. DETAILS CONTINUED • Development- appropriate for his age i.e. pulling to stand, sitting on his own and saying a few words. • Social- lives in Durban with his parents and an older brother, all of whom are well. • Immunizations up to date according to mother.

5. ON EXAMINATION • Growth parameters all on 50th centiles • Vitals: essentially normal with a mild pyrexia • No lymphadenopathy • Not pale/jaundiced, not dehydrated • Chest: harsh breath sounds bilaterally • CVS: normal heart sounds no murmurs or gallop

6. EXAMINATION CONTINUED • Abdomen: soft, non tender, no organomegaly • CNS: lethargic and irritable but consolable, tone, power and reflexes decreased in left upper limb other limbs NAD mild terminal neck stiffness • ENT: mild pharyngitis

7. INVESTIGATIONS • Blood results FBC- 9,2/13,4/301 DIFF-27/10/62 U&E- 136/5/103/22/4,2/30 Glucose- 5 CRP- 2,3 • CXR- features suggestive of mild pneumonia • In view of the apparent localising signs, we requested a CT brain prior to doing the LP- essentially normal.

8. INVESTIGATIONS CONTINUED • LP results CSF-clear and colourless protein- 0,33 glucose- 4,1 chloride-123 polys- 0 lymphs- 40 erythrocytes- 0 no bacteria grown

9. ASSESSMENT AND MANAGEMENT • 9/12 old male infant with acute mild bronchopneumonia and viral meningoencephalitis. • Treatment: cefotaxime physiotherapy neurological consult

10. NEUROLOGICAL REVIEW • On review it was noted that there was mild weakness in the left upper limb and that the condition seemed to be progressing to involve the left lower limb. • A suggestion was made to order an MRI scan which was done a few days later at Donald Gordon Centre with a finding of Acute Disseminated Encephalomyelitis (ADEM).

11. ADEM • This is an inflammatory demyelinating disorder of the subcortical white matter. • Most frequently seen in children, m=f ; often evolving from antecedent infection or immunization. • Typical presentation: encephalitic signs with non specific CSF changes and minimal or no changes on CT brain.

12. ADEM CONTINUED • Thought to be an autoimmune disease via cross reactivity of the antiviral antibodies with the myelin autoantigens. • Viruses associated include HSV,HIV, HSV6, measles, hepatitis, influenza, EBV etc. • There has also been an association post immunisation for MMR,Influenza, BCG.

13. APPROPRIATE INVESTIGATIONS • Lymphocytosis, raised CRP and ESR • CSF- can have a raised protein but can be normal. • CT Brain - may be normal • MRI- gold standard for diagnosis T2 weighted images show areas of prolonged T2 in subcortical white matter, usually assymetrical.

14. TREATMENT • Empirically treated as a meningitis with cefotaxime +/- acyclovir. • Once diagnosis is made then steroids become the mainstay of management. • Physiotherapy can also be helpful.

15. DIFFERENTIAL DIAGNOSIS • At first presentation, it is difficult to differentiate between ADEM and MS. • New lesions and relapses, esp after 6/12 should alert to the possibility of MS. • MS - no prodromal viral illness and no fever or meninigism at presentation. It presents as a monosymptomatic syndrome eg optic neuritis or myelopathy and develops a relapsing remitting course.

16. PROGNOSIS OF ADEM • Most make excellent progress over the following days, weeks and months with no subsequent neurological impairment. • A minority have neurological impairment eg motor disability, visual/ cognitive or behavioural impairment.