Guillain-Barré Syndrome (GBS)

Guillain-Barré Syndrome (GBS)

Introduction & Epidemiology

• GBS is an autoimmune disorder (a postinfectious polyneuropathy) Involving motor, sensory and autonomic nerves.
• GBS is a heterogeneous condition With several variant forms that is the most common cause of Acute flaccid paralysis.
• The peak incidences Occur at late adolescence.

Etiology And Pathogenesis

• More than 60% Of patients with GBS have been diagnosed with an infection in the 3 weeks prior to the onset of weakness.
• The most common antecedent symptoms is: Fever, cough, sore throat, and nasal discharge.

Antecedent events in GBS:

• Rabies and swine influenza vaccines.
• Cytomegalovirus, Epstein-Barr, Varicella Zoster, Zika virus infection.
• Hepatitis A, B, C, E and HIV.
• Campylobacter Jejuni, Mycoplasma Pneumonia bacterial infections.
• Chlamydia Pneumoniae, acute Toxoplasmosis protozoan infection.
• Mandible surgery, operation of the spine, cardiac surgery.
• Blood transfusion and transplantation.
• Antibiotics, allopurinol, thiabendazole, danazol, corticosteroids, D-penicillamine, gold salt, vincristine, zimelidine, stavudine, organophosphate poisoning, arsenic poisoning.
• Genetic predisposition: HLA, immunoglobulin KM genes.

Clinical Presentation

Symptoms:

• Initial symptoms include numbness and paresthesia, Followed by weakness.

• The paresthesias spread proximally, But rarely pass the wrists and ankles.

• Tenderness on palpation and pain in muscles (Neck, back, buttock, and leg pain) are common in the initial stages. Affected children are irritable.

• Weakness usually begins in the lower extremities And progressively involves the trunk, the upper limbs, and, finally, the bulbar muscles.

• Proximal and distal muscles Are involved relatively symmetrically, but asymmetry is found in 9% of patients.

• Onset is gradual And progresses over days or weeks; the process plateaus in 1-28 days.

• Weakness can progress To inability or refusal to walk and later to “Flaccid tetraplegia”. Maximal severity of weakness is usually reached by 4 wk after onset.

• The weakness is more prominent in proximal muscles, With the lower limbs being more affected than the upper limbs.

Phases of GBS:

1. The progressive phase, Which lasts a few days to 4 weeks.
2. The plateau phase, Which consists of persistent symptoms and lasts for a few days or weeks.
3. The improvement phase, When recovery takesplace.

Complications:

• Cranial nerve involvement: Facial droop (may mimic Bell palsy), diplopias, dysarthria, dysphagia, ophthalmoplegia, pupillary disturbances.
• Respiratory complaints: Dyspnea on exertion, shortness of breath, difficulty swallowing, slurred speech.
• Cardiovascular complications: Heart rhythm abnormalities, blood pressure variability (both hypo- and hypertension), myocardial involvement, acute coronary syndromes, and electrocardiographic changes.
• Other complications: Bowel and bladder function problems, facial flushing, anhidrosis and/or diaphoresis, Deep venous thrombosis (DVT) And consequent pulmonary embolism, residual numbness or other sensations.
• Relapse: 7%.
• Congenital Guillain-Barré syndrome.

Neurological Examination

Characteristic features:

• Reduced strength of muscles.
• Lower extremity weakness, Symmetrically and progressively.
• Upper extremity, trunk, facial, and oropharyngeal weakness.
• Facial weakness (cranial nerve VII), cranial nerves VI, III, XII, V, IX, and X.
  • (Involvement of facial, oropharyngeal, and ocular muscles results in facial droop, dysphagia, dysarthria).
• Ophthalmoparesis, ptosis.
• Reduced or absent tendon reflexes (Hypo- or areflexia, respectively).
• Hypotonia.
• Sensory changes.

Specific signs to look for:

• Tachycardias and bradycardias.
• Tachypnea.
• BP lability (Alterations between hypertension & hypotension).
• Respiratory: Poor inspiratory effort or diminished breath sounds.
• Abdomin: Paucity or absence of bowel sounds (Paralytic ileus).
• Suprapubic tenderness or fullness (Suggestive of Urinary retention).

Diagnosis And Differentials

Diagnosis:

• The typical clinical features.
• Progressive weakness In both arms and both legs. The progression of the typical symptoms over days to 4 weeks, the relative symmetry of the symptoms, the presence of mild sensory symptoms, and symptoms indicative of cranial nerve involvement and/or autonomic dysfunction.
• Cerebrospinal fluid (CSF): Protein level (>400 mg/l), with normal CSF cell counts.
• Electromyography (EMG) and nerve conduction studies (NCS).
• Pulmonary function.
• A basic peripheral neuropathy workup Is recommended if the diagnosis is uncertain.
• Magnetic resonance imaging (MRI) and computed tomography (CT) Scanning of the spine.
• Labs: Electrolyte levels, calcium and glucose, LFTS, kidney function tests, CPK level, CBC and ESR.

Differential diagnosis:

• Spinal cord lesions: Acute transverse myelitis, epidural abscess, tumors/vascular malformations, poliomyelitis (natural or live virus)/enteroviruses, cord compression from vertebral subluxation related to congenital abnormalities or trauma.
• Peripheral neuropathies:
  • Toxic: Vincristine / glue sniffing / heavy metal: Gold, arsenic, lead / organophosphate pesticides.
  • Infections: HIV / diphtheria / lyme disease.
  • Inborn errors of metabolism: Porphyria.
  • Critical illness: Polyneuropathy.
• Neuromuscular junction disorders: Tick paralysis, myasthenia gravis, botulism.
• Myopathies: Periodic paralyses, dermatomyositis, critical illness myopathy.
• Other: Hypercalcemia.

Normal nerve vs. Nerve affected by guillain-barre (damaged myelin / exposed fiber).

Treatment

• Optimal care In a hospital setting with Intensive care Facilities.
• Plasma exchange (Plasmapheresis).
• Intravenous immunoglobulin g.
• Mechanical ventilation.
• Pain management (NSAIDS, Gabapentin, opioids).
• Monitoring for infectious complications (Eg, Pneumonia, urinary tract infections, septicemia).
• Physical, occupational, and speech therapy.