INFLAMMATORY POLYNEUROPATHY (GUILLAIN-BARRÉ SYNDROME)
G61.0
*Notifiable condition,
DESCRIPTION
Guillain-Barré syndrome (GBS) is an acute autoimmune-mediated polyradiculoneuropathy which is precipitated by a preceding viral or other infection. It is the most common acquired polyneuropathy in children.
Different forms or variants of Guillain-Barré syndrome are described depending on the clinical and/or neurophysiological characteristics.
Acute Inflammatory Demyelinating Polyradiculoneuropathy (AIDP)
- This is the most common form, accounting for 80–90% of cases.
- Characterised mainly by:
- symmetrical, ascending motor weakness,
- areflexia, i.e. absence of tendon reflexes,
- distal sensory alteration,
- pain/paraesthesia.
Acute motor axonal neuropathy (AMAN)
- A purely motor form of GBS.
- It involves predominantly motor nerves and has an axonal pattern on electrophysiology (nerve conduction studies).
- Although there are similarities with AIDP, the clinical picture tends to be more severe with more patients suffering from respiratory failure.
Acute motor-sensory axonal neuropathy (AMSAN)
- Another axonal form of GBS but with sensory involvement.
- It is not frequently found in children.
Miller-Fisher Syndrome
- Patients have external ophthalmoplegia, sensory ataxia, weakness with areflexia.
- Electrophysiological and CSF studies are similar to AIDP.
Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP)
- May be considered a chronic variant of AIDP.
- Most often starts insidiously and progresses slowly, but can have onset like GBS.
- It is managed differently from GBS and should be referred.
DIAGNOSTIC CRITERIA
Clinical
- Preceding respiratory tract or gastrointestinal infection.
- Symmetrical, flaccid muscle weakness with early areflexia.
- The muscle weakness may ascend rapidly upwards to involve the trunk, arms, face and cranial nerves.
- Bulbar paralysis and respiratory failure may develop.
- Autonomic dysfunction.
- Relatively mild, or absence of, sensory signs.
- Exclude the following:
- Acute disseminated encephalomyelitis (ADEM)
- poliomyelitis, a rare cause of hypotonia with abrupt onset of weakness (usually asymmetrical) in association with a febrile illness,
- transverse myelitis:
- initial flaccid weakness and areflexia typically involving the lower limbs maximally,
- occasionally with pain at the onset, but rapidly progressing to spasticity and hyperreflexia,
- also, a sensory level on the trunk,
- bladder and rectal sphincter involvement.
- diphtheria,
- botulism.
Investigations
Screen for AFP
- Send two stool specimens taken 24–48 hours apart to the National Institute of Virology via the local laboratory.
- The stool sample needs to be sent within 14 days of onset of paralysis to exclude poliovirus infection.
CSF
- CSF findings after 1 week show elevated protein and no cells or only a few cells, i.e. albumino-cytological dissociation.
- CSF glucose is normal.
GENERAL AND SUPPORTIVE MEASURES
- Notify as Acute Flaccid Paralysis.
- Admit to a high or intensive care unit.
- Monitor respiratory and autonomic functions closely:
- peak expiratory flow rate,
- blood pressure,
- respiratory rate,
- heart rate,
- forced vital capacity (FVC),
- bulbar functions,
- arterial blood gases.
- Ventilation is recommended when:
- PCO₂ levels start rising,
- there is a progressive fall in the peak expiratory flow rate,
- tachycardia and sweating occur,
- inspiratory efforts are weak,
- inability to talk.
Note:
These changes precede hypoxaemia detected on blood gas analysis, and ventilation should begin before frank hypoxaemia occurs.
Respiratory care must be meticulous.
- Shoulder weakness, head-lag, weak cough and swallowing difficulties are an indication for respiratory support.
- To determine fluid losses from autonomic instability, monitor urine output and degree of sweating.
- Provide adequate nutrition.
- Provide bladder and bowel care as well as pressure-point care.
- Routine physiotherapy for chest and limbs, keep ankles in neutral position (90°) (may require foot/hand splints).
- Protect eyes and keep moist.
- Communicate with child as awareness is maintained. Staff should remember that children may be very frightened but unable to express their emotions and needs.
MEDICINE TREATMENT
Substantial pain is present (in up to 90%) in the severely affected patients.
Pain in this setting is often unrecognised and underestimated.
Pain management is essential. See Management of pain .
For neuropathic pain:
- Carbamazepine, oral, 5 mg/kg/dose 12 hourly.
- Immunoglobulin, IV, 1 g/kg/day, slowly over 12–16 hours on two consecutive days or 0.4 g/kg as a single daily dose on 5 consecutive days early in the disease process.
- Use under specialist supervision.
REFERRAL
- Chronic inflammatory demyelinating polyradiculoneuropathy.
- Guillain-Barré syndrome with bulbar paralysis and/or early signs of respiratory failure.
- Patients who have lost or are losing ambulation for management in consultation with a paediatric neurologist.
- Patients with complex Guillain-Barré syndrome.
MYASTHENIA GRAVIS
G70.0
DESCRIPTION
An auto-immune disorder resulting in muscle fatigue. Mild cases involve the eyes alone, i.e. ptosis and ophthalmoplegia, and severe cases involve proximal muscle groups, respiratory and bulbar control.
DIAGNOSTIC CRITERIA
Clinical
- Muscle fatigability with exercise and demonstration of this in the clinic setting:
- Lid-lag test, i.e. failure to maintain upward gaze for 1 minute.
- Arm-raising test, i.e. failure to maintain the arms at 90° from the trunk for 1 minute.
Note:
Myasthenia gravis patients not uncommonly present in a myasthenic crisis, with bulbar and respiratory compromise. Sometimes this may be the first mode of clinical presentation.
MEDICINE TREATMENT
- Pyridostigmine, oral, 1–5 mg/kg/day in 4–6 divided doses. (Specialist initiated).
REFERRAL
- All for confirmation of diagnosis and initiation of treatment (consideration of steroids, immuno-modulation therapy).
- Myasthenic crisis.