Antibody:  A substance produced by special cells of the body that counteracts the effects of a disease germ or its poisons.

Antigen:  a toxin or other foreign invader that can cause disease.  That triggers an immune response in the body, especially the production of antibodies. One of the main immune responses is the production of proteins that help to fight off the antigens. These proteins are called antibodies. 

Antineuronal antibodies: serve as markers that aid in discriminating between a true paraneoplastic neurological disorder (PND) and other inflammatory disorders of the nervous system.

Apoptosis: A form of cell death in which a programmed sequence of events leads to the elimination of cells without releasing harmful substances into the surrounding area. Destroyed.

Ataxia: Many symptoms of ataxia mimic those of being drunk, such as slurred speech, stumbling, falling, and incoordination. These symptoms are caused by damage to the cerebellum, the part of the brain that is responsible for coordinating movement.

Atrophy: shrinking, wasting away, deterioration, no longer function properly.

Autoimmune Encephalitis: is an entity that is caused by the autoantibodies themselves.  The auto-antibodies are made by plasma cells.  These are cells of your immune system.  The plasma cells secrete these antibodies and they target healthy brain cells causing them to malfunction or die. The Body is attacking itself.

Axon: nerve fiber, a long nerve cell that conducts electrical impulses in the brain.

B cell: a type of lymphocyte that produces antibodies, which bind to free-floating microbes circulating in the blood so that they cannot infect other cells.

blood-brain barrier:  a tight layer of cells and tissue that separates the brain from the rest of the body; a physical roadblock that normally keeps immune cells outside the brain.

Bradycardia: is a slower than normal heart rate. The heart usually beats between 60 and 100 times a minute in an adult at rest. If you have bradycardia your heart beats fewer than 60 times a minute. is a slower than normal heart rate. Bradycardia is caused by something that disrupts the normal electrical impulses controlling the rate of your heart’s pumping action. There are many things that can cause or contribute to problems with your heart’s electrical system.

CASPR2: (contactin-associated protein 2), an antibody in autoimmune encephalitis. This type of AE is often termed ‘limbic encephalitis’ (LE).

central line: a catheter placed into a larger vein for infusions, may be placed in the neck, chest, groin, or arm to give fluids, blood, or medications. It can stay in place longer than an iv and allows fluids to be given at a more rapid pace.

Central Nervous System: the brain and spinal cord, to which sensory impulses are transmitted and from which motor impulses emanate. The central nervous system supervises and coordinates the activity of the entire nervous system and interacts with the immune system.

Chorea: jerky involuntary movements affecting especially the shoulders, hips, and face.

CT scan:  computed tomography also known as CAT scan computed axial tomography- this test gives narrow beams through the body it builds a 3-D cross-section picture of the part of the body and displays it on the screen, sometimes a contrast dye is used because it can help show certain body structures more clearly.

Cytoxic:  Cell killing, toxic to cells.

Differential diagnosis: The process of weighing the probability of one disease versus that of other diseases possibly accounting for a patient’s illness.  Example:  The differential diagnosis of rhinitis (a runny nose) would be hayfever, the abuse of nasal decongestants, and, of course, the common cold.

 Dysphagia:       Is the medical term for the symptom of difficulty in swallowing.  It may be a sensation that suggests difficulty in the passage of solids or liquids from the mouth to the stomach.

Dyskinesia:  refers to a category of movement disorders that are characterized by involuntary muscle movements, including movements similar to tics or chorea and diminished voluntary movements. Dyskinesia can be anything from a slight tremor of the hands to an uncontrollable movement of the upper body or lower extremities. Discoordination can also occur internally especially with the respiratory muscles and it often goes unrecognized.  Dyskinesia is a symptom of several medical disorders that are distinguished by their underlying cause.

Dystonia: is a movement disorder in which your muscles contract involuntarily, causing repetitive or twisting movements (abnormal muscle tone or muscle spasms). The condition can affect one part of your body (focal dystonia), two or more adjacent parts (segmental dystonia) or all parts of your body (general dystonia).

Epitopes: extracellular antibodies binding within the cells that the antigen has entered.

Fulminant: sudden onset.

GAD65: Glutamic acid decarbonxyase-autoantibody, the pancreases needs GAD to function normally, so it is in the body but may accidentally change to attack brain cells, 70 % of people with diabetes have GAD  antibodies in their blood.

Glial cells: a cell in the nervous system that provides support and protection of neurons (nerve cells that conduct electrical impulses).

Glutamate binding NR2 subunit: is a receptor in the brain, these receptors play an important part in memory and learning.

Hemodynamic instability:  is a term used to indicate abnormal or unstable blood pressure and can suggest inadequate arterial blood flow to organs. It can also refer to a state in which pharmacological or mechanical support is necessary to maintain adequate cardiac output or blood pressure.

Hemophagocytic: when the immune system produces too many activated immune cells.

Hypertension: is high blood pressure.  Blood pressure is the force of blood pushing against the walls of arteries as it flows through them.  Arteries are the blood vessels that carry oxygenated blood from the heart to the body’s tissues.

Hyperthermia:  is elevated body temperature due to failed thermoregulation that occurs when a body produces or absorbs more heat than it dissipates. Extreme temperature elevation then becomes a medical emergency requiring immediate treatment to prevent disability or death.

Hypotension:  Low blood pressure occurs when blood pressure is much lower than normal. This means the heart, brain, and other parts of the body do not get enough blood. Normal blood pressure is usually between 90/60 mmHg and 120/80 mm.

Hypothermia:  is a medical emergency that occurs when your body loses heat faster than it can produce heat, causing a dangerously low body temperature. Normal body temperature is around 98.6 F (37 C). Hypothermia occurs as your body temperature passes below 95 F (35 C).

Hypoventilation:   is a condition that arises when air entering the alveoli, small air sacs in the lungs that are the site of respiratory gas exchange, is reduced. This causes levels of oxygen to decrease and the levels of carbon dioxide to increase. Hypoventilation may occur when breathing is too slow or shallow and is usually secondary to or a consequence of other medical conditions.

Immunoprecipitation: (IP) is the technique of precipitating a protein antigen out of solution using an antibody that specifically binds to that particular protein. This process can be used to isolate and concentrate a particular protein from a sample containing many thousands of different proteins.  

Immunosuppressive: describes a treatment that suppresses natural immune responses

Innate Immune System: provides immediate defense against infection.

IVIG: intravenous(given by an IV, in a vein) immunoglobulin (proteins and cells in the blood that function as antibodies)

Lymphocyte: a type of white blood cell involved in the human body’s immune system, of which there are two broad categories, T cells and B cells. Lymphocytes are an integral part of the body’s defenses because they are highly specific for antigens associated with microbes, tumor cells, transplants, allergies, and tissues attacked in autoimmune diseases. The immune system comprises clones of lymphocytes, each with a single specificity, and exposure to antigens leads to clonal expansion, the acquisition of helper and killer functions, and the formation of immune memory.

Lymphohistocytosis: increased immune cells known as histocytes and lymphocytes.

Metagenomic deep sequencing:  inventories nucleic acids present in laboratory stocks, providing an unbiased assessment of pathogen identity, the extent of genomic variation, and the presence of contaminants.

Monogenic: a single gene, or as a result of a single gene.

Myalgia:  the prefix my(o)-, which means ‘muscle’, and the suffix -algia, which refers to pain or a painful condition. Muscular pain or ache in a muscle which may be the result of injury, inflammation, overuse or inappropriate activity.

Myelin: a fatty rich system that surrounds nerve cells, insulates them, and increases the rate of electrical impulses along the axon ( nerve fiber).

Neopterin: belongs to a chemical group known as pteridines, they are a marker of inflammation or reflect autoimmunity.

Neurotransmitter:  chemical substance released by brain cells that help transfer an electrical impulse from one brain cell to another.

NMDAr:  N-methyl D aspartate receptor- a glutamate receptor(a primary excitatory neurotransmitter in the brain) it is a neurotransmitter found in the synapses of the central nervous system.

Onconeuronal antibodies: Antibodies against intracellular neuronal antigens ) usually occur as paraneoplastic syndromes in the context of cancer

Pathogenic:  Capability of an agent to cause disease to its host.

PICC line: peripherally inserted central line- a small thin tube inserted into a vein in your arm and passed into larger veins near the heart. It is often placed because it lasts longer than an intravenous line can last and can be used to give nutrition and medications that may irritate tissues in the smaller veins of the arm.

Pleocytosis: the presence of a greater number of cells than normal.

Propromal: stage of early signs or symptoms of an illness, but not yet clinically specific or severe.

Psychomotor agitation: is a set of signs and symptoms that stem from mental tension and anxiety. The signs are unintentional and purposeless motions; the symptoms are emotional distress and restlessness. Typical Symptoms may take the form of restlessness, tapping fingers or feet, abruptly starting and stopping tasks, rapid talking, racing thoughts and ideas, meaninglessly moving objects around, include pacing around a room, wringing the hands, uncontrolled tongue movement, pulling off clothing and putting it back on, and other similar actions. In more severe cases, the motions may become harmful to the individual, such as ripping, tearing, or chewing at the skin around one’s fingernails, lips, or other body parts to the point of bleeding. Psychomotor agitation is typically found in major depressive disorder or obsessive, and sometimes the manic phase in bipolar disorder.

Synapses: specialized junctions at which cells of the nervous system signal to one another and to nonneuronal cells, such as those of muscles and glands.

T cell: a type of lymphocyte that possesses highly specific cell-surface antigen receptors; types include CD4+ helper T cells, regulatory T cells, and killer T cells

Tachycardia:  abnormally rapid heart rate, usually taken to be over 100 beats per minute.

Voltage-gated potassium channels (VGKCs):  are transmembrane channels specific for potassium and sensitive to voltage changes in the cell’s membrane potential. During action potentials, they play a crucial role in returning the depolarized cell to a resting state.

White blood cells: any of the blood cells that are colorless, lack hemoglobin and contain a nucleus. They include the lymphocytes, dendritic cells, monocytes, neutrophils, eosinophils, and basophils; also called leukocytes.