Prodromal Infection Trigger Acute Onset Anti-DPPX Encephalitis without CNS Hyperexcitability Symptoms: A Case Report

Dipeptidylpeptidase-like protein-6 (DPPX) antibody
associated encephalitis can present with protracted
encephalitis, symptoms of central nervous
system(CNS) hyperexcitability, and cerebellar signs.
Most of these patients onset subacutely and have
diarrhea in the initial phase. We report a 26-year-old
Chinese female, who had ten days history of upper
respiratory tract infection, followed by headache,
dizziness, gait instability suddenly. Neurological
examination demonstrated prominent vertical
nystagmus, astasia and cognitive impairment. CSF
testing for neuronal autoantibodies revealed DPPX
antibody IgG titerAfter treatment with IV
methylprednisolone combined with IV
immunoglobulin, her neurological symptoms improved
markedly. This case illustrated that anti-DPPX
autoimmune encephalitis could be triggered by
prodromal infection and onset acutely. Patients may
only show cerebellar signs and cognitive impairment
without CNS hyperexcitability. Performing an autoantibody
examination might aid differential diagnosis.
Dipeptidylpeptidase-like protein-6 antibody is a rare
neuronal surface antigen that might cause autoimmune
encephalitis Anti-DPPX encephalitis commonly
D ؤ ects elder people, and sympton onset is usually
insidious. Most of the patients may have
gastrointestinal signs before showing CNS
manifestation. Neurocognitive deficLts, sleep
disturbance, central hyperexcitability, cerebellar signs
are frequently observed Here, we describe a Chinese
anti-DPPX encephalitis young patient presenting with
acute onset, prominent vertical nystagmus and ataxia,
who was triggered by prodromal infection. Antibodyassociated
encephalitis characterized by specLfic
autoantibodies has been recognized in the last ten
years. It is a diverse group of syndromes that include
two groups: classic paraneoplastic disorders (PNDs)
and autoimmune encephalitis [2]. Нe latter is caused
by the direct interaction between antibodies and their
target antigens on neuronal surfaces and synapses [3].
Our case was a 26- year-old Chinese woman who
presented with acute onset ataxia, vertigo, and
cognitive impairment.
Нe patient showed obvious vertical and torsional
nystagmus and ataxia. Cognitive impairment of shortterm
memory was also observed, but she did not have
any gastrointestinal symptoms or progressive
encephalomyelitis with rigidity and myoclonus
(PERM)- like presentation. DPPX is a regulatory
subunit of the Kv4.2 potassium channel complex,
which is expressed in neuronal dendrites and soma. Its
function is to increase the surface expression and
channel conductance of Kv4.2 channels additional
treatment with plasma exchange and rituximab.
Patients with a long-term history of AE might have
lengthy hospitalizations and multiple relapses [4-6].
Нerefore, an early diagnosis and initiation of therapy is
very important for a good long Overall, our case
verLfied that prodromal infection may trigger acute
onset anti-DPPX encephalitis. Prominent vertical
nystagmus, ataxia, cognitive impairment without
PERM may occur in anti-DPPX encephalitis. Early
immunotherapy is important for the positive longterm
outcomes of patients. Her leukocyte count had
decreased to 39/mL (96% lymphocytes) and the
protein level was 31mg/dl (0–60 mg/dl). At her 6-
month follow-up she was able to walk unassisted
without any evidence of ataxia last three months.
Family history revealed no abnormalities.

Author(s): Juanjuan Chen,

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