Anti-NMDA receptor encephalitis Flashcards
Describe the pathophysiology of anti-NMDA receptor encephalitis [3]
Production of antibodies against the N-methyl-D-aspartate (NMDA) receptors
- These receptors are found predominantly in the central nervous system (CNS)
Pathophysiological process begins with the aberrant production of anti-NMDA receptor antibodies.
- Instigated by various triggers such as neoplasms, particularly ovarian teratomas which express NMDA receptors on their surface, or viral infections that induce molecular mimicry.
Describe the clinical course of Anti-NMDA receptor encephalitis [3]
Stereotypical presentation of Anti-NMDA receptor encephalitis often begins with a prodromal phase characterised by headache, fever, nausea or vomiting
This is followed by the development of psychiatric symptoms, which can range from mood changes and anxiety to psychosis
As the condition progresses, patients may develop neurological features such as seizures, movement disorders, autonomic instability and decreased levels of consciousness
Describe the psychiatric [3] and neurological [4] features of Anti-NMDA receptor encephalitis
Psychiatric Features
* Mood changes: Patients may present with rapid mood swings that are out of character. These can range from depression to mania.
* Anxiety: Severe anxiety is common and can be accompanied by agitation or even panic attacks.
* Psychosis: Hallucinations (both auditory and visual) and delusions may occur. Thought disorder, characterised by disorganised thinking or incoherence, can also be a feature.
Neurological Features
* Seizures: These can be focal or generalised. Status epilepticus may occur in severe cases.
* Movement disorders: Dyskinesias (especially orofacial), dystonia, choreoathetosis and rigidity may be observed. Catatonia is also a possibility.
* Autonomic instability: This includes hyperthermia, tachycardia, hypersalivation, hypertension or hypotension and urinary incontinence.
* Sleep disturbances: Insomnia or hypersomnia may occur. Some patients may exhibit irregular sleep-wake cycles or other circadian rhythm abnormalities.
Cognitive impairment is frequently seen in Anti-NMDA receptor encephalitis. Patients may exhibit memory deficits, attentional problems and executive dysfunction. In severe cases, a state of confusion or delirium can occur.
Which antibodies are seen in anti-NMDA receptor encephalitis? [2]
Anti-MuSK is an autoantibody specific to muscle kinase in myasthenia gravis with no evidence of a thymoma and without antibodies to acetylcholine receptors.
Anti-GM1 is an autoantibody specific to acute inflammatory demyelinating polyneuropathy (AIDP) variant of Guillain-Barre syndrome.
What is the first [4] and second line [2] immunotherapies for anti-NMDA receptor enceph. ? [2+]
First-line Immunotherapies:
Corticosteroids:
* Prednisolone or methylprednisolone are commonly used.
* High-dose intravenous corticosteroid therapy can be initiated for acute management.
* Intravenous Immunoglobulin (IVIg): IVIg can be administered concurrently with corticosteroids to enhance the immune response.
Plasma Exchange (PLEX): PLEX is another viable option, especially in severe presentations or if there is no response to corticosteroids and IVIg.
Second-line Immunotherapies:
* Rituximab: A monoclonal antibody that targets CD20 on B cells, leading to their depletion.
* Cyclophosphamide: An alkylating agent that suppresses the immune system. It can be used alone or in combination with rituximab.
Tumour search and removal is essential as Anti-NMDA receptor encephalitis is often paraneoplastic, most commonly associated with [] tumours
Tumour search and removal is essential as Anti-NMDA receptor encephalitis is often paraneoplastic, most commonly associated with ovarian teratomas
- Laparoscopic ovarian teratoma removal should be considered once the diagnosis is confirmed
Describe the stereotypical presentation of Japenese encephalitis and clinical course [+]
Non-specific, flu-like symptoms
The patient may present with fever, headache, and malaise, which are typically preceded by a prodromal period of 1-2 weeks post exposure to the Flavivirus
The clinical course of Japanese encephalitis can be divided into five stages: febrile stage (3-8 days), a critical stage (few hours - several days), a convalescent stage (1-2 weeks), a stationary stage (up to several months), and a recovery stage.
- However, the disease course can vary significantly among patients, and not all stages are clearly identifiable in every patient.
Dx of Japenese encephalitis? [1]
Diagnosis is by serology or PCR
- detection of JEV-specific IgM in serum or cerebrospinal fluid.
