In the paper, we describe an adult case presented with refractory cephalalgia whose CSF suggested leukocytosis and inflammatory changes dominated by monocytes, the patient was first diagnosed as central nervous system infection and was treated with intravenous anti-infectious agents. Afterwards, existing headache and the lesions features in brain MRI reminded us to test anti-MOG antibodies both in serum and CSF. Finally, the patient was diagnosed with anti-MOG-antibody associated UCCE. When administrated with intravenous glucocorticoid, her symptom had a completely relief. At six months follow-up, her MOG antibodies in serum were quickly negative and her brain MR has the similar changes, and she has the better functional outcome.
MOGAD patients present great differences in brain MR[4–5], and no highly specific radiological features has been identified to differentiate MOGAD from non-MOG antibody cases. Study found more than half of the patients had no evident lesions in brain routine MR. However, compared with the elderly, younger patients tended to have a higher proportion of abnormal brain MR. The abnormal features in brain MR are as follows: larger size lesions which commonly located in the cerebellum、pons、midbrain、gray matter and juxtacortical areas. AEDM is commonly found in child cases, while MOGAD with unilateral cortical lesions is relatively seldom. When searching literatures, we found 10 reported cases of MOG antibody-positive UCCE, the majority was adult onset except for one case of childhood onset. In these cases[3,10−13],
the most common clinical presentations were epileptic seizures (9/10), headache (7/10), fever (3/10), optic neuritis (3/10), however, headache as the single feature of MOG antibody-associated UCCE was reported in only one case with chronic pulsatile headache, whose MRA showed vasodilatation of the left middle cerebral artery branches, and the authors assumed that meningeal irritation or vasodilatation of vessels along the cortical sulcus were the possible causes of migraine. Unlike this case, patient of our case had a non-pulsatile headache, and MRA did not find vascular dilatation, we speculate that it may be caused by increased intracranial pressure and focal inflammatory irritation. CSF results indentified that 8 of 10 cases showed leucocytosis and elevated protein was common in 4 of 10 cases, therefore, it is often easily misdiagnosed as infectious diseases in central nervous system, in the 10 cases mentioned above, 5 were initially misdiagnosed and were treated with antiviral drugs, until patients had recurrences, visual disturbance or typical features of brain MR, MOG antibodies with a cell-based assay were tested, and patients were eventually diagnosed as MOGAD. In therapeutic aspects, almost all cases(9/10) were administrated with immunotherapy, 7 cases were treated with high-dose IV methylprednisolone(HIMP),1 with dexamethasone (33mg everyday), 1 with methylprednisolone (40mg/day), and all the patients had good response to immunotherapy, six cases had no recurrence after corticosteroid therapy. Only one patient who manifested recurrent convulsive seizures followed by fever and headache was treated only with intravenous acyclovir, but she did not suffer from relapse for 2 years, hence, MOG antibody-positive UCCE may represent corticosteroid-responsive encephalitis and benign phenotype, but there is no agreement on the dose of the hormone. In addition, study indicated that MOG-Ab dynamics and their faster negativity would be an implication for good prognosis, besides a research from childhood encephalitis showed that cases with brain hypoperfusion had poor neurological outcome and those with local hypertransfusion were more likely to have seizure, which imply that cerebral perfusion may be associated with prognosis.
Our case of young adult female patient has two features. Firstly, as far as we know, this is the second case who presented headache as the single clinical symptom. Secondly, her symptom was completely relieved although the case was not treated with HIMP, and six months after discharge, she had no relapse, and her serum MOG antibodies and brain MR, including structural MR and ASL, turned to normal results, that may imply the better outcome and lower rate of relapse[14, 16].
In conclusion, headache can be the single symptom of MOG antibody-related UCCE and it had a good response to glucocorticoid. The main differential diseases include central nervous system infections and autoimmune encephalitis. When brain MR shows FLAIR hyperintense lesions in unilateral cerebral cortical, we should be reminded of MOG-antibody-positive UCCE. Moreover, further analysis is needed to develop a reasonable immunotherapy and methods for assessing recurrence.