Efficacy of Physical Therapy Management for Guillain Barré Syndrome
Chapter 1
INTRODUCTION
Guillain-Barré syndrome is a disorder in which the body’s immune system attacks part of the peripheral nervous system. The first symptoms of this disorder include varying degrees of weakness or tingling sensations in the legs. In many instances, the weakness and abnormal sensations spread to the arms and upper body. These symptoms can increase in intensity until the muscles cannot be used at all and the patient is almost totally paralyzed. In these cases, the disorder is life-threatening and is considered a medical emergency. The patient is often put on a respirator to assist with breathing. Most patients, however, recover from even the most severe cases of Guillain-Barré syndrome, although some continue to have some degree of weakness. Guillain-Barré syndrome is rare.
Usually Guillain-Barré occurs a few days or weeks after the patient has had symptoms of a respiratory or gastrointestinal viral infection. Occasionally, surgery or vaccinations will trigger the syndrome. The disorder can develop over the course of hours or days, or it may take up to 3 to 4 weeks. No one yet knows why Guillain-Barré strikes some people and not others or what sets the disease in motion. What scientists do know is that the body’s immune system begins to attack the body itself, causing what is known as an autoimmune disease. Guillain-Barré is called a syndrome rather than a disease because it is not clear that a specific disease-causing agent is involved. Reflexes such as knee jerks are usually lost. Because the signals traveling along the nerve are slower, a nerve conduction velocity (NCV) test can give a doctor clue to aid the diagnosis. The cerebrospinal fluid that bathes the spinal cord and brain contains more protein than usual, so a physician may decide to perform a spinal tap.
Guillain-Barre syndrome is a serious disorder that occurs when the body’s defense (immune) system mistakenly attacks part of the nervous system. This leads to nerve inflammation that causes muscle weakness.Guillain-Barre syndrome is an autoimmune disorder (the body’s immune system attacks itself). Exactly what triggers Guillain-Barre syndrome is unknown. The syndrome may occur at any age, but is most common in people of both sexes between ages 30 and 50.It often follows a minor infection, such as a lung infection or gastrointestinal infection. Most of the time, signs of the original infection have disappeared before the symptoms of Guillain-Barre begin.
The swine flu vaccination in 1976 may have caused rare cases of Guillain-Barre syndrome. However, the swine flu and the regular flu vaccines used today have not resulted in more cases of the illness.
Chapter 2
ANATOMY
ANATOMY
The anatomy of the brain is complex due its intricate structure and function. This amazing organ acts as a control center by receiving, interpreting, and directing sensory information throughout the body. There are three major divisions of the brain. They are the forebrain, the midbrain, and the hindbrain.
Brain Divisions
The forebrain is responsible for a variety of functions including receiving and processing sensory information, thinking, perceiving, producing and understanding language, and controlling motor function. There are two major divisions of forebrain: the diencephalon and the telencephalon. The diencephalon contains structures such as the thalamus and hypothalamus which are responsible for such functions as motor control, relaying sensory information, and controlling autonomic functions. The telencephalon contains the largest part of the brain, the cerebral cortex. Most of the actual information processing in the brain takes place in the cerebral cortex.
The midbrain and the hindbrain together make up the brainstem. The midbrain is the portion of the brainstem that connects the hindbrain and the forebrain. This region of the brain is involved in auditory and visual responses as well as motor function. The hindbrain extends from the spinal cord and is composed of the metencephalon and myelencephalon. The metencephalon contains structures such as the pons and cerebellum. This region assists in maintaining balance and equilibrium, movement coordination, and the conduction of sensory information. The myelencephalon is composed of the medulla oblongata which is responsible for controlling such autonomic functions as breathing, heart rate, and digestion.
Fig.2.1 Cross section of Brain
- Prosencephalon – Forebrain
- Mesencephalon – Midbrain
- Diencephalon
- Telencephalon
- Rhombencephalon – Hindbrain
- Metencephalon
- Myelencephalon
Structures
The brain contains various structures that have a multitude of functions. Below is a list of major structures of the brain and some of their functions.
– Involved in cognition and voluntary movement
– Diseases related to damages of this area are Parkinson’s and Huntington’s.
– Relays information between the peripheral nerves and spinal cord to the upper parts of the brain
– Consists of the midbrain, medulla oblongata, and the pons
– Speech production
– Understanding language
Central Sulcus (Fissure of Rolando)
– Deep grove that separates the parietal and frontal lobes
– Controls movement coordination
– Maintains balance and equilibrium
– Outer portion (1.5mm to 5mm) of the cerebrum
– Receives and processes sensory information
– Divided into cerebral cortex lobes
– Frontal Lobes -involved with decision-making, problem solving, and planning.
– Occipital Lobes-involved with vision and color recognition
– Parietal Lobes – receives and processes sensory information
– Temporal Lobes – involved with emotional responses, memory, and speech
– Largest portion of the brain
– Consists of folded bulges called gyri that create deep furrows
– Thick band of fibers that connects the left and right brain hemispheres
– Twelve pairs of nerves that originate in the brain, exit the skull, and lead to the head, neck and torso
Fissure of Sylvius (Lateral Sulcus)
– Deep grove that separates the parietal and temporal lobes
– Amygdala – involved in emotional responses, hormonal secretions, and memory
– Cingulate Gyrus – a fold in the brain involved with sensory input concerning emotions and the regulation of aggressive behavior
– Fornix – an arching, fibrous band of nerve fibers that connect the hippocampus to the hypothalamus
– Hippocampus – sends memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrievs them when necessary
– Hypothalamus – directs a multitude of important functions such as body temperature, hunger, and homeostasis
– Olfactory Cortex – receives sensory information from the olfactory bulb and is involved in the identification of odors
– Thalamus – mass of grey matter cells that relay sensory signals to and from the spinal cord and the cerebrum
– Lower part of the brainstem that helps to control autonomic functions
– Membranes that cover and protect the brain and spinal cord
– Bulb-shaped end of the olfactory lobe
–
– Involved in the sense of smell
– Endocrine gland involved in biological rhythms
– Secretes the hormone melatonin
– Endocrine gland involved in homeostasis
– Regulates other endocrine glands
– Relays sensory information between the cerebrum and cerebellum
– Nerve fibers located inside the brainstem
– Regulates awareness and sleep
– Helps to control voluntary movement and regulates mood
– The dorsal region of the mesencephalon (mid brain)
– The ventral region of the mesencephalon (mid brain).
– connecting system of internal brain cavities filled with cerebrospinal fluid
– Aqueduct of Sylvius – canal that is located between the third ventricle and the fourth ventricle
– Choroid Plexus – produces cerebrospinal fluid
– Fourth Ventricle – canal that runs between the pons, medulla oblongata, and the cerebellum
– Lateral Ventricle – largest of the ventricles and located in both brain hemispheres
– Third Ventricle – provides a pathway for cerebrospinal fluid to flow
– Region of the brain where spoken language is understood
Chapter 3
PHYSIOLOGY
PHYSIOLOGY
Immune system
The immune system is a complex system that is responsible for protecting us against infections and foreign substances. There are three lines of defense: the first is to keep invaders out (through skin, mucus membranes, etc), the second line of defense consists of non-specific ways to defend against pathogens that have broken through the first line of defense (such as with inflammatory response and fever). The third line of defense is mounted against specific pathogens that are causing disease (B cells produce antibodies against bacteria or viruses in the extracellular fluid, while T cells kill cells that have become infected). The immune system is closely tied to the lymphatic system, with B and T lymphocytes being found primarily within lymph nodes. Tonsils and the thymus gland are also considered lymph organs and are involved in immunity.
The lymphatic system and the immune system are terms that are used interchangeably to refer to the body’s ability to defend against pathogens. The lymphatic system is comprised of three interrelated functions: (1) Removal of excess fluids, lymph, from body tissues, (2) Absorption of fatty acids and subsequent transport of fat, chyle, to the circulatory system and (3) Formation of white blood cells (WBCs), and initiation of immunity through the formation of antibodies, lending specific resistance to pathogens.
Lymphatic Pathways
The lymphatic system acts as a secondary circulatory system, except it collaborates with white blood cells in lymph nodes to protect the body from being infected by cancer cells, fungi, viruses or bacteria. Unlike the circulatory system, the lymphatic system is not closed and has no central pump; the lymph moves slowly and under low pressure due to peristalsis, the operation of semilunar valves in the lymph veins, and the milking action of skeletal muscles. Like veins, lymph vessels have one-way, semilunar valves and depend mainly on the movement of skeletal muscles to squeeze fluid through them. Rhythmic contraction of the vessel walls may also help draw fluid into the lymphatic capillaries. This fluid is then transported to progressively larger lymphatic vessels culminating in the right lymphatic duct (for lymph from the right upper body) and the thoracic duct (for the rest of the body); these ducts drain into the circulatory system at the right and left subclavian veins.
Figure 3.1: lymph node of cell
Lymph
Lymph originates as blood plasma that leaks from the capillaries of the circulatory system, becoming interstitial fluid, filling the space between individual cells of tissue. Plasma is forced out of the capillaries by hydrostatic pressure, and as it mixes with the interstitial fluid, the volume of fluid accumulates slowly. Most of the fluid is returned to the capillaries by osmosis. The proportion of interstitial fluid that is returned to the circulatory system by osmosis is about 90% of the former plasma, with about 10% accumulating as overfill. The excess interstitial fluid is collected by the lymphatic system by diffusion into lymph capillaries, and is processed by lymph nodes prior to being returned to the circulatory system. Once within the lymphatic system the fluid is called lymph, and has almost the same composition as the original interstitial fluid.
Oedema
Oedema is the swelling that forms when too much tissue fluid forms or not enough taken away. It can be caused by a variety of conditions such as allergic responses (too much vasodilation), starvation (lack of albumin in blood lowers osmotic pressure and decreases amount of fluid returning to capillaries), and lymphatic disorders (e.g. blockage due to parasite in elephantiasis, or removal of lymph nodes due to a radical mastectomy). Edema is common in the lower extremities when people spend a lot of time sitting, because the fluid return is based largely on the massaging action of skeletal muscles.
Lymphatic Vessels and Ducts
The lymphatic vessels are similar in structure to the cardiovascular veins, meaning they also have valves. They are dependent upon the contraction of skeletal muscle, respiratory movements and valves that do not allow backward flow. The vessels merge before entering one of two ducts.
- Thoracic Duct: This duct is much larger than the lymphatic duct. It serves the abdomen, lower extremities and the left side of the upper body (head, neck, and arm)
- Right Lymphatic Duct: This duct serves all of the right side of the upper body and thoracic area (head, neck).
Organs, Tissues and Cells of the Immune System
The immune system consists of a network of lymphatic organs, tissues, and cells. These structures are supported by the reticuloendothelial system: loose connective tissue with a network of reticular fibers. Phagocytic cells, including monocytes and macrophages, are located in the reticular connective tissue. When micro-organisms invade the body, or the body encounters antigens (such as pollen), antigens are transported to the lymph. Lymph is carried through the lymph vessels to regional lymph nodes. In the lymph nodes, the macrophages and dendritic cells phagocytose the antigens, process them, and present the antigens to lymphocytes, which can then start producing antibodies or serve as memory cells. The function of memory cells is to recognize specific antigens in the future.
Primary Lymphatic Organs – The primary lymphatic organs are the red bone marrow and the thymus. They and are the site of production and maturation of lymphocytes, the type of white blood cell that carries out the most important work of the immune system.
- Red Bone Marrow Red bone marrow, the soft, spongy, nutrient rich tissue in the cavities of certain long bones, is the organ that is the site of blood cell production.
Some of the white blood cells produced in the marrow are: neutrophils, basophils, eosinophils, monocytes, and lymphocytes. Lymphocytes differentiate into B lymphocytes and T lymphocytes. Red bone marrow is also the site of maturation of B lymphocytes. T lymphocytes mature in the thymus.
Figure 3.2: primary lymphatic organ
Side of thorax, showing surface markings for bones, lungs (purple), pleura (blue), and spleen (green)
Thymus Gland – The thymus gland is located in the upper thoracic cavity posterior to the sternum and anterior to the ascending aorta. The thymus is an organ that is more active in children, and shrinks as we get older. Connective tissue separates the thymus into lobules, which contain lymphocytes. Thymic hormones such as thymosin are produced in the thymus gland. Thymosin is thought to aid in the maturation of T lymphocytes.
The Thymus is critical to the immune system. Without a thymus, a person has no ability to reject foreign substances, blood lymphocyte level is very poor, and the body’s response to most antigens is either absent or very weak
- Immature T lymphocytes travel from the bone marrow through the bloodstream to reach the thymus. Here they mature and for the most part, stay in the thymus. Only 5% of T lymphocytes ever leave the thymus. They only leave if they are able to pass the test: if they react with “self” cells, they die. If they have the potential to attack a foreign cell, they leave the thymus.
Secondary Lymphatic Organs–The secondary lymphatic organs also play an important role in the immune system as they are places where lymphocytes find and bind with antigens This is followed by the proliferation and activation of lymphocytes. The secondary organs include the spleen, lymph nodes, tonsils, Preyer’s patches, and the appendix. holding a reservoir of blood.located in the upper left region of the abdominal, i
Figure 3.3: Brain cell structure
Fig3.4: Structure of the lymph node.
1. Efferent lymphatic vessel
2. Sinus
3. Nodule
4. Capsule
5. Medulla
6. Valve to prevent backflow
7. Afferent lymphatic vessel.
- Lymph Nodes – are small oval shaped structures located along the lymphatic vessels. They are about 1-25 mm in diameter. Lymph nodes act as filters, with an internal honeycomb of connective tissue filled with lymphocytes that collect and destroy bacteria and viruses. They are divided into compartments, each packed with B lymphocytes and a sinus. As lymph flows through the sinuses, it is filtered by macrophages whose function is to engulf pathogens and debris. Also present in the sinuses are T lymphocytes, whose functions are to fight infections and attack cancer cells. Lymph nodes are in each cavity of the body except the dorsal cavity. Physicians can often detect the body’s reaction to infection by feeling for swollen, tender lymph nodes under the arm pits and in the neck, because when the body is fighting an infection, these lymphocytes multiply rapidly and produce a characteristic swelling of the lymph nodes.
- Tonsils – are often the first organs to encounter pathogens and antigens that come into the body by mouth or nose. There are 3 pairs of tonsils in a ring about the pharynx.
- Peyer’s patches – located in the wall of the intestine and the appendix, attached to the cecum of the large intestine, intercept pathogens that come into the body through the intestinal tract.
The nervous system is divided into two main parts: The central nervous system (CNS) is made of the brain and the spinal cord. The brain is enclosed inside the skull and the spinal cord is enclosed inside the vertebral column for protection. The peripheral nervous system (PNS) is made of nerves that branch from the CNS. The cranial nerves branch from the brain and supply areas in the head such as the eyes, the facial muscles, the ears, and the nose. The CNS functions mostly in gathering sensory information from nerves of the PNS, processing this information, and then transmitting signals, again by the nerves of the PNS, to effectors, or target organs or tissues, to react to this sensory input All cells have membrance potential, but only certain kinds of cells-like neurons and muscle cells- have the ability to change their membrane potential. Collectively these cells are called excitable cells.
The membrance potential of an excitable cell in a resting (unexcited) state is called resting potential. Cells can change their membrane potential in response to stimuli that can be received via gated ion channels. Stimuli can cause an electrical gradient to be conducted across the membrane, called hyperpolarization. Depolarization is a reduction in the electricial gradient across the membrane. In an excitable cell, such as a neuron, the response to a depolarizing stimulus is graded with stimulus intensity only up to a particular level of depolarization, called the threshold position. If a depolarization reaches the threshold, a different type of response called an action potential is triggered. It is important to note, however, that hyperpolarizing stimuli do not produce action potentials, but make it even more likely that an action potential will be triggered by making it more difficult for a depolarizing stimulus to reach threshold. The action potential, then, is the actual nerve impulse the cell transmits. The magnitude of the action potential is independent of the strength of depolarizing stimuli that triggers it. This whole sequence of events occurs in mere milliseconds.
Figure 3.5: Structure of the neuron
Each muscle cell contains very thin fibers called myofibrils. Each myofibril is surrounded by a special type of endoplasmic reticulum called the sarcoplasmic reticulum. Each myofibril is divided alongside its length into units called sacromeres. These sacromeres contract and relax. They are made of alternating actin and myosin filaments. Actin is made of thin protein filaments and myosin of thick ones. Contraction of muscles results from the sliding of these two fibers past one another. Extending from the myosin to the actin filaments are tiny movable arms. When induced by ATP, these arms move forward slightly. When they do, they drag the actin fibers past the myosin fibers, thus causing muscle contraction.
Sensory system
A sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, somatic sensation (touch), taste and olfaction (smell). In short, senses are transducers from the physical world to the realm of the mind.
The receptive field is the specific part of the world to which a receptor organ and receptor cells respond. For instance, the part of the world an eye can see, is its receptive field; the light that each rod or cone can see, is its receptive field.<href=”#cite_note-0″>[1] Receptive fields have been identified for the visual system, auditory system and somatosensory system, so far.
Stimulus
Sensory systems code for four aspects of a stimulus; type (<href=”#Modality”>modality), intensity, location, and duration. Arrival time of a sound pulse and phase differences of continuous sound are used for localization of sound sources. Certain receptors are sensitive to certain types of stimuli (for example, different mechanoreceptors respond best to different kinds of touch stimuli, like sharp or blunt objects). Receptors send impulses in certain patterns to send information about the intensity of a stimulus (for example, how loud a sound is). The location of the receptor that is stimulated gives the brain information about the location of the stimulus (for example, stimulating a mechanoreceptor in a finger will send information to the brain about that finger). The duration of the stimulus (how long it lasts) is conveyed by firing patterns of receptors.
Figure 3.6: Sensory system of brain
Modality
A stimulus modality (sensory modality) is a type of physical phenomenon that can be sensed. Examples are temperature, taste, sound, and pressure. The type of sensory receptor activated by a stimulus plays the primary role in coding the stimulus modality.
In the memory-prediction framework, Jeff Hawkins mentions a correspondence between the six layers of the cerebral cortex and the six layers of the optic tract of the visual system. The visual cortex has areas labelled V1, V2, V3, V4, V5, MT, IT, etc. Thus Area V1 mentioned below, is meant to signify only one class of cells in the brain, for which there can be many other cells which are also engaged in vision.
Hawkins lays out a scheme for the analogous modalities of the sensory system. Note that there can be many types of senses, some not mentioned here. In particular, for humans, there will be cells which can be labelled as belonging to V1, V2 A1, A2, etc.:
V1 (vision)
The human eye is the first element of a sensory system: in this case, vision, for the visual system.
Visual Area 1, or V1, is used for vision, via the visual system to the primary visual cortex.
A1 (auditory – hearing)
Auditory Area 1, or A1, is for hearing, via the auditory system, the primary auditory cortex.
Somatosensory Area 1, or S1, is for touch and proprioception in the somatosensory system. The somatosensory system feeds the <href=”#Brodmann_areas_3.2C_1_and_2″ title=”Postcentral gyrus”>Brodmann Areas 3, 1 and 2 of the primary somatosensory cortex. But there are also pathways for proprioception (via the cerebellum), and motor control (via Brodmann area 4).
G1 (gustatory – taste)
Gustatory Area 1, or G1, is used for taste.
O1. (olfactory – smell)
Olfactory Area 1, or O1, is used for smell. In contrast to vision and hearing, the olfactory bulbs are not cross-hemispheric; the right bulb connects to the right hemisphere and the left bulb connects to the left hemisphere.
Figure 3.7: Cranial nerve of brain
Sensory and Motor Both Origin Nuclei Function
Cranial nerve zero (CN0 is not traditionally recognized.) Sensoryolfactory trigone, medial olfactory gyrus, and lamina terminalis
New research indicates CN0 may play a role in the detection of pheromones Linked to olfactory system in human embryos<href=”#cite_note-pmid15604533-3″>[4]
Purely SensoryTelencephalonAnterior olfactory nucleusTransmits the sense of smell; Located in olfactory foramina in the Cribriform plate of ethmoid
II Optic Nerve
Purely SensoryDiencephalonGanglion cells of retinaTransmits visual information to the brain; Located in optic canal
III Oculomotor nerve
Mainly MotorMidbrainOculomotor nucleus, Edinger-Westphal nucleusInnervates levator palpebrae superioris, superior rectus, medial rectus, inferior rectus, and inferior oblique, which collectively perform most eye movements; Also innervates m. sphincter pupillae, as well as the muscles of the ciliary body. Located in superior orbital fissure
Mainly MotorMidbrainTrochlear nucleusInnervates the superior oblique muscle, which depresses, rotates laterally (around the optic axis), and intorts the eyeball; Located in superior orbital fissureVTrigeminal nerveBoth Sensory and MotorPonsPrincipal sensory trigeminal nucleus, Spinal trigeminal nucleus, Mesencephalic trigeminal nucleus, Trigeminal motor nucleusReceives sensation from the face and innervates the muscles of mastication; Located in superior orbital fissure (ophthalmic nerve – V1), foramen rotundum (maxillary nerve – V2), and foramen ovale (mandibular nerve – V3)
Mainly MotorPosterior margin of PonsAbducens nucleusInnervates the lateral rectus, which abducts the eye; Located in superior orbital fissure
VII Facial nerve
Both Sensory and MotorPons (cerebellopontine angle) above oliveFacial nucleus, Solitary nucleus, Superior salivary nucleusProvides motor innervation to the muscles of facial expression, posterior belly of the digastric muscle, and stapedius muscle, receives the special sense of taste from the anterior 2/3 of the tongue, and provides secretomotor innervation to the salivary glands (except parotid) and the lacrimal gland; Located and runs through internal acoustic canal to facial canal and exits at stylomastoid foramen
VIII Vestibulocochlear nerve (or auditory-vestibular nerve or statoacoustic nerve)
Mostly sensoryLateral to CN VII (cerebellopontine angle)Vestibular nuclei, Cochlear nucleiSenses sound, rotation and gravity (essential for balance & movement). More specifically. the vestibular branch carries impulses for equilibrium and the cochlear branch carries impulses for hearing.; Located in internal acoustic canal
Both Sensory and MotorMedullaNucleus ambiguus, Inferior salivary nucleus, Solitary nucleusReceives taste from the posterior 1/3 of the tongue, provides secretomotor innervation to the parotid gland, and provides motor innervation to the stylopharyngeus. Some sensation is also relayed to the brain from the palatine tonsils. Sensation is relayed to opposite thalamus and some hypothalamic nuclei. Located in jugular foramen
Both Sensory and MotorPosterolateral sulcus of MedullaNucleus ambiguus, Dorsal motor vagal nucleus, Solitary nucleusSupplies branchiomotor innervation to most laryngeal and all pharyngeal muscles (except the stylopharyngeus, which is innervated by the glossopharyngeal); provides parasympathetic fibers to nearly all thoracic and abdominal viscera down to the splenic flexure; and receives the special sense of taste from the epiglottis. A major function: controls muscles for voice and resonance and the soft palate. Symptoms of damage: dysphagia (swallowing problems), velopharyngeal insufficiency. Located in jugular foramen
XI Accessory nerve (or cranial accessory nerve or spinal accessory nerve)
Mainly MotorCranial and Spinal RootsNucleus ambiguus, Spinal accessory nucleusControls sternocleidomastoid and trapezius muscles, overlaps with functions of the vagus. Examples of symptoms of damage: inability to shrug, weak head movement; Located in jugular foramen
Mainly MotorMedullaHypoglossal nucleusProvides motor innervation to the muscles of the tongue (except for the palatoglossus, which is innervated by the vagus) and other glossal muscles. Important for swallowing (bolus formation) and speech articulation. Located in hypoglossal canal
Chapter 4
DEFINITION
Definition
AIDP (acute idiopathic demyelinating polyneuropathy), AIP(acute infective polyneuropathy), LGBSS(Landry-Guillain-Barre-Strohl syndrome),AIP(acute idiopathic polyneuropathy).
Predisposing factor:
Although there is no definite aetiology of GBS there are certain factors which have been found to predispose to the occurance of GBS.
1. Age:
Common between 15 to 25 years of age.
2.Sex:
Common in females.
3.Infection:
Viral in the form of Epstein Barr Virus,bacterial in the form of mycoplasma pneumonia.
4.Drugs:
Prolonged use of antidepressant drugs like zimelidine gold therapy which are neurotoxins are found to cause GBS.
5.Autoimmune:
Due to the presence of an antigen CD(+ve) T cells.
6.Ideopathic
Whithout any known causes.
Chapter 5
CLASSIFICATION
Classification
Six different subtypes of Guillain–Barré syndrome exist:
Acute inflammatory demyelinating polyneuropathy (AIDP) is the most common form of GBS, and the term is often used synonymously with GBS. It is caused by an auto-immune response directed against Schwann cell membranes.
Miller Fisher syndrome (MFS) is a rare variant of GBS and manifests as a descending paralysis, proceeding in the reverse order of the more common form of GBS. It usually affects the eye muscles first and presents with the triad of ophthalmoplegia, ataxia, and areflexia. <href=”#Anti-GQ1b” title=”Anti-ganglioside antibodies”>Anti-GQ1b antibodies are present in 90% of cases.
Acute motor axonal neuropathy (AMAN),<href=”#cite_note-McKhann1991-0″>[1] also known as Chinese paralytic syndrome, attacks motor nodes of Ranvier and is prevalent in China and Mexico. It is probably due to an auto-immune response directed against the axoplasm of peripheral nerves. The disease may be seasonal and recovery can be rapid. Anti-GD1a antibodies<href=”#cite_note-Ho1995-1″>[2] are present. <href=”#Anti-GD3″ title=”Anti-ganglioside antibodies”>Anti-GD3 antibodies are found more frequently in AMAN.
Acute motor sensory axonal neuropathy (AMSAN) is similar to AMAN but also affects sensory nerves with severe axonal damage. Like AMAN, it is probably due to an auto-immune response directed against the axoplasm of peripheral nerves. Recovery is slow and often incomplete.<href=”#cite_note-Griffin1995-2″>[3]
Acute panautonomic neuropathy is the most rare variant of GBS, sometimes accompanied by encephalopathy. It is associated with a high mortality rate, owing to cardiovascular involvement, and associated dysrhythmias. Impaired sweating, lack of tear formation, photophobia, dryness of nasal and oral mucosa, itching and peeling of skin, nausea, dysphagia, constipation unrelieved by laxatives or alternating with diarrhea occur frequently in this patient group. Initial nonspecific symptoms of lethargy, fatigue, headache, and decreased initiative are followed by autonomic symptoms including orthostatic lightheadedness, blurring of vision, abdominal pain, diarrhea, dryness of eyes, and disturbed micturition. The most common symptoms at onset are related to orthostatic intolerance, as well as gastrointestinal and sudomotor dysfunction (Suarez et al. 1994). Parasympathetic impairment (abdominal pain, vomiting, obstipation, ileus, urinary retention, dilated unreactive pupils, loss of accommodation) may also be observed.
Bickerstaff’s brainstem encephalitis (BBE), is a further variant of Guillain–Barré syndrome. It is characterized by acute onset of ophthalmoplegia, ataxia, disturbance of consciousness, hyperreflexia or Babinski’s sign. The course of the disease can be monophasic or remitting-relapsing. Large, irregular hyperintense lesions located mainly in the brainstem, especially in the pons, midbrain and medulla are described in the literature. BBE despite severe initial presentation usually has a good prognosis. Magnetic resonance imaging (MRI) plays a critical role in the diagnosis of BBE. A considerable number of BBE patients have associated axonal Guillain–Barré syndrome, indicative that the two disorders are closely related and form a continuous spectrum.
Chapter 6
INCIDENCE
According to an epidemiologic survey, the average annual incidence of GBS in this subcontinent is 3.0 cases per 100,000 populations. In comparing age groups, the annual mean rate of hospitalizations in this subcontinent related to GBS increases with age, being 1.5 cases per 100,000 population in persons aged less than 15 years and peaking at 8.6 cases per 100,000 population in persons aged 70-79 years.
International
A widespread syndrome, GBS has been reported throughout the world. Most studies show annual incidence figures that are similar to those in the United States, without geographical clustering.
In epidemiologic surveys, the overall death rate related to GBS ranges from 2-12% of patients. GBS-associated mortality rates increase markedly with age. In the United States, the case-fatality ratio ranges from 0.7% among persons younger than 15 years to 8.6% among individuals older than 65 years. Survey data has shown that in patients aged 60 years or older, the risk of death is 6-fold that of persons aged 40-59 years and is 157-fold that of patients younger than 15 years. Although the death rate increases with age in males and females, after age 40 years males have a death rate that is 1.3 times greater than that of females.
GBS-related deaths usually occur in ventilator-dependent patients, resulting from such complications as pneumonia, sepsis, adult respiratory distress syndrome, and, less frequently, and autonomic dysfunction. Underlying pulmonary disease and the need for mechanical ventilation increase the risk of death, especially in elderly patients. Length of hospital stays also increases with advancing age, because of disease severity and associated medical complications.
GBS has been reported throughout the international community. In North America, Western Europe, and Australia, most patients with GBS meet electrophysiologic criteria for demyelinating polyneuropathy. In northern China, up to 65% of patients with GBS have axonal pathology.
A slight male preponderance is seen in most studies, especially in older patients.
GBS has been reported in all age groups, with the syndrome occurring at any time between infancy and old age. In the United States, the syndrome’s age distribution seems to be bimodal, with the incidence of GBS peaking in the elderly population and reaching its second-highest level in young adults. Infants appear to have the lowest risk of developing GBS.
Chapter 7
ETIOLOGY
GBS is considered to be a post infectious, immune-mediated disease targeting peripheral nerves. Up to two thirds of patients report an antecedent illness prior to the onset of neurologic symptoms.Respiratory infections are most frequently reported, followed by gastrointestinal infections.
In several studies, C jejuni was the most commonly isolated pathogen. Serology studies in a Dutch GBS trial identified 32% of patients as having had a recent C jejuni infection, while studies in northern China documented infection rates as high as 60%.Gastrointestinal and upper respiratory tract symptoms can be observed with C jejuni infections. C jejuni infections can also have a subclinical course, resulting in patients with no reported infectious symptoms prior to development of GBS. Patients who develop GBS following an antecedent C jejuni infection often have a more severe course, with rapid progression and a prolonged, incomplete recovery. A strong clinical association has been noted between C jejuni infections and the pure motor and axonal forms of GBS.
The virulence of C jejuni is thought to be based on the presence of specific antigens in its capsule that are shared with nerves. Immune responses directed against capsular lipopolysaccharides produce antibodies that cross-react with myelin to cause demyelination. C jejuni infections demonstrate significant association with antibodies against gangliosides GM1 and GD1b. Although GM1 antibodies can be found with demyelinating GBS, GM1 antibodies are more common in the axonal and inexcitable groups. Even in the subgroup of patients with GM1 antibodies, however, the clinical manifestations vary. Host susceptibility is probably one determinant in the development of GBS after infectious illness.
Cytomegalovirus (CMV) infections are the second most commonly found infections preceding GBS; they account for the most common viral triggers of GBS. The aforementioned Dutch GBS study found CMV to be present in 13% of patients.CMV infections present as upper respiratory tract infections, pneumonias, and nonspecific, flulike illnesses. GBS patients with preceding CMV infections often have prominent involvement of
the sensory and cranial nerves. CMV infections are significantly associated with antibodies against the ganglioside GM2.
Other significant, although less frequently identified, infectious agents in GBS patients include Epstein-Barr virus (EBV), Mycoplasma pneumoniae, and Varicella-Zoster virus. An association between GBS and human immunodeficiency virus (HIV) also is well recognized. Infections with Haemophilus influenzae, para-influenza virus type 1, influenza A virus, influenza B virus, adenovirus, and herpes simplex virus have been demonstrated in patients with GBS, although not more frequently than they have in controls.Various events, such as surgery, trauma, and pregnancy, have been reported as possible triggers of GBS, but these associations remain mostly anecdotal in the medical literature. Vaccinatio