acute flaccid paralysis and surveillance

major causes of afp,surveillance,management

1. AFP AND SURVEILLANCE

2. AFP A clinical syndrome characterized by rapid onset of weakness of limbs accompanied by weakness of respiratory muscles and difficulty in swallowing progressing to maximum severity within 1 to 10 days.

3. AFP is defined as sudden onset of weakness of a limb or paralysis over a period of 15 days in a child less than 15 years. GLOBAL POLIO ERADICATION INITIATIVE

4. CAUSES Results from involvement at any point in the motor unit . Common causes include GBS,poliomyelitis,transverse myelitis,traumatic neuritis,nonpolio enteroviral illnesses,post diphtheritic neuropathy.

5. D/D OF AFP

6. POLIOMYELITIS Highly infectious enteroviral disease. Virus transmitted through faeco -oral route  multiplies in the intestine  invades the nervous system  causes paralysis. Age at onset <5 years. Presents as acute febrile viral meningitis syndrome with meningeal signs,headache,malaise,GI symptoms.

7. Motor signs develop within 1 to 4 days -start with severe myalgias . -asymmetric. -lumbar involvement > cervical. -spinal cord involvement > brainstem. -no sensory deficit. -paralysis within 1 – 2 weeks. -atrophy appears rapidly, progresses over several weeks.

8. Diagnosis by isolation of pathogen from stools. CSF – neutrophilic pleocytosis lymphocytes and monocytes Protein content raises over time,becomes normal by 6 weeks.

9. Electrophysiology studies to differentiate polio from GBS (acute denervation,reduced compound action potentials.) MRI shows increased T2 weighted signal in anterior horns and cord swelling.

10. Polio like illness due to non polio viruses Non-polio entero viruses like coxsackie A7,enterovirus 71,japanese B virus,westnile virus,tick borne encephalitis cause damage to anterior horn cells resulting in AFP.

11. GUILLAIN-BARRE SYNDROME Immune attack ( IgM,IgG,macrophages,complement activation) directed at schwann cells,myelin demyelination . Axonal injury is secondary to pathological events of demyelination ( bystander injury ) Synonymous with acute inflammatory demyelinating polyneuropathy ( AIDP )

12. Two patterns of axonal involvement Involving both sensory and motor neurons (acute motor-sensory axonal neuropathy) Involving only motor neurons (acute motor axonal neuropathy)

13. Age at presentation - >3years . M>F . An antecedent infectious disease with CMV,EBV,HIV,vaccinia virus, campylobacter jejuni diarrhoea , vaccinations precede AIDP. (3days – 6 weeks before the onset of symptoms)

14. Motor + sensory symptoms (hypo/hyperesthesia)+ ataxia. Autonomic symptoms in 30%. Present with pain in the back,thighs and legs along with motor weakness starting in legs and ascending upwards. Maximal weakness within 2 weeks. Areflexia / hyporeflexia . Atonia / hypotonia .

15. CSF shows albumino -cytological dissociation. Electrophysiology shows demyelination of peripheral nerves. S low or block of Nerve conduction velocity. MRI is normal.

16. Clinical variants 1–Polyneuritis cranialis Cranial nerve involvement 2–Miller fisher syndrome Ophthalmoplegia , ataxia, areflexia 3–Chronic progressive GBS Symptoms persisting more than 6 weeks 4- Chronic relapsing GB

17. Differentiation from spinal cord syndrome Absence of sensory level Lack of spinal tenderness Normal bowel and bladder function

18. Treatment IVIG given (2g/kg/day over 2 days). -As early as the diagnosis is made. -A/E : mild flu like symptoms,nausea,headache,malaise . Plasmapheresis is equally effective. - 5 exchanges of 50 ml plasma/ kg on alternate days (10 days course). -Cannot be done in patients with cardiovascular compromise. Trial of immunosuppressives,corticosteroids . Supportive treatment and treatment of complications.

19. Outcome Regressive : 90 % of patients make a good recovery Recovery begins 2 to 4 weeks after progression stops starting from the last muscles affected till lower limb ( descending pattern .) Chronic Relapsing : Less than 5% of patients. Mortality : 3% die from complications.

20. TRANSVERSE MYELITIS Caused by inflammation of the spinal cord. In 60% unknown In 40% , associated with autoimmune disorders such as: multiple sclerosis neuromyelitis optica systemic lupus erythematous Sjogren’s syndrome sarcoidosis

21. In children <3 years and between 5-14 years. H/O vaccination with OPV,MMR,Hep A,DPT,influenza,varicella,Jap B,HiB in the preceding month. Earliest symptom is sensory loss or pain in the back,thighs,legs . Sudden onset of progressive weakness of legs. Ascends leading to flaccid quadriplegia. Bowel bladder involvement in 70% .

22. Maximal weakness by 48hrs. 85% showed a sensory level. Cranial nerves not involved. Normal EMG,NCV. MRI shows focal areas of >> T2 signals in the cord. Elevated wbc’s , high IgG index in CSF.

23. Diagnostic criteria

24. Treatment Methyl prednisolone (1g/1.73 sq m) iv daily for a period of 3-5days Oral prednisolone tapered over 2-3 weeks. IVIG,immunosuppressants in non responders.

25. Outcome Residual disabilities of gait,numbness,bladder dysfunction persist in 40-75% of the cases even after many years. Better outcome if early time of diagnosis, lower anatomic level, involvement of only few spinal segments, older age at onset, lack of leucocytes in CSF.

26. TRAUMATIC NEURITIS Inflammation of a nerve following an injury. Sciatic nerve injury leading to paralysis of the foot and permanent sequelae following intramuscular injection in the gluteal region is common.

27. POST DIPHTHERITIC POLYNEUROPATHY Vaccine preventable illness caused by exotoxin producing strains of Corynebacterium diphtheriae . Initial symptoms of low grade fever,sore throat,neck swelling,nasal twang,ipsilateral palatal paralysis. Polyneuropathy occurs as a complication in 20% of patients. Due to higher release of exotoxin .

28. The time between initial symptoms and onset of polyneuropathy is termed as latency period. Classic features include acute flaccid paralysis,reduced /absent DTR,sensory symptoms. Onset of paralysis is 4 – 6 weeks after the onset of bulbar signs and symptoms.

29. Low fatality rate. Paralysis resolves with time. Early administration of antitoxin( im /iv) neutralizes the exotoxin .

30. AFP SURVEILLANCE Poliomyelitis is targeted for eradication. Highly sensitive surveillance including immediate case investigation and specimen collection are critical for the detection of wild poliovirus circulation and for documenting the absence of poliovirus circulation for polio-free certification.

31. All patients with acute flaccid paralysis should be reported to Surveillance Medical Officer of World Health Organization. Every case of AFP within the last 6 months has to be reported. Additionally, other conditions which need notification are: Isolated facial palsy Isolated bulbar palsy Unproved hypokalemia Neck flop Floppy baby Flaccid hemiplegia Encephalitis Postictal weakness (Todd’s paralysis) Postdiphretic polyneuritis.

32. After confirming the cases as AFP

33. Stool Specimen Collection For every cases of AFP, 2 stool specimens are collected (at least 24 hours apart) Ideally within 14 days of onset of paralysis (optimal time period for detection of polio virus) Should also be collected in any late-reported AFP case upto 60 days from the day of onset of paralysis.

34. Voided stool sample is preferred. Each specimen should be 8 g each. Enema or purgatives are not recommended. Collected in a clean, dry, screw-capped container. Labelled and transported in the ‘cold chain’

35. Poliovirus Isolation 2 types of cell lines are used: RD cell lines (derived from human rhabdomyosarcoma ; favour the growth of all enteroviruses ) L20B cell lines (favour the growth of only poliovirus) If cytopathic effects appears in L20B cell line, the isolate then goes for neutralization test to determine the serotype (type 1,2 or 3) of the poliovirus by using appropriate antisera

36. Intratypic differentiation test is done to determine whether the particular isolate is wild poliovirus or vaccine poliovirus. All wild poliovirus isolates undergo genetic sequencing.

37. A case is classified as polio if wild poliovirus is isolated from the stool specimen. Others undergo additional investigations & are classified as compatible with polio or discarded as nonpolio AFP .

38. THANK YOU !