ACUTE FLACCID PARALYSIS

ACUTE FLACCID PARALYSIS

Acute flaccid paralysis = paralysis of acute onset (<4 weeks) , affected limb or limbs are flaccid, i.e. floppy or limp, tone is diminished , sensation not affected.

A case of AFP is defined as any child aged <15 years who has acute onset of flaccid paralysis

for which no obvious cause (such as severe trauma or electrolyte imbalance) is found, or

paralytic illness in a person of any age in which polio is suspected

Surveillance is carried out for all cases of acute flaccid paralysis (AFP) and not just for poliomyelitis.

All AFP cases should be reported, regardless of the final diagnosis.

2 specimens, at least 24 hours apart, collected within 14 days of paralysis onset volume (8-10 g) Arrive at a WHO accredited laboratory in good condition. = no desiccation, no leakage, adequate documentation and cold chain properly maintained.

Earlier the stool is collected the greater the chance of poliovirus detection

Stool sample -

children aged <15 years, are to be reported

AFP in a person aged >15 years is unlikely to be polio.

Any case of AFP, regardless of the age, should be reported and investigated if poliomyelitis is a possible cause.

At least one case of non-polio AFP occurs for every 1lakh population children aged <15 years per year.

non-polio causes of AFP, =

1.    Guillain-­Bane Syndrome (GBS)

2.    transverse myelitis (TM)

3.    traumatic neuritis (TN)

If an area has 10 lakh children <15 years of age, then at least 10 non-polio AFP cases should be reported each year

Obtain 2 stool specimens from AEP cases within 14 days of paralysis onset.

Late detection of AFP cases indicates surveillance failure.

CASE INVESTIGATION AND OUTBREAK RESPONSE IMMUNIZATION

Case Investigation: Each reported case of AFP should be investigated within 48 hours of being reported and the case investigation form completed.

An effort should be made to determine where polio infection might have been acquired,

Ask about travel to or visitors from outside the community during the month (33 days maximum) preceding onset of paralysis.

60-day follow-up to determine if residual weakness is present.

Outbreak response immunization (ORI):

Cover a minimum of 500 children less than 5 years old around the reported AFP case.

Trivalent OPV is the vaccine of choice

There are no contraindications to OPV.

Each case of paralytic poliomyelitis represents 1,000 infected persons.

VIRUS ISOLATION AND SPECIMEN COLLECTION PROCEDURES

Stool: Virus usually can be found in the feces from 72 hours to up to eight or more weeks after infection, with the highest probability during the first 2 weeks. Isolation of wild poliovirus from stool is the best way to confirm the diagnosis of paralytic poliomyelitis

Cerebrospinal fluid (CSF): Not likely to yield virus

CSF cell count, gram stain, protein, and glucose useful in eliminating other causes AFP.

Throat:       specimen collection not recommended.

Blood:         blood specimens not recommended.

Stool specimen should be placed in a clean container = a wide mouthed plastic or glass bottle with screw-on cap.

One “thumb sized” (8 Gm) amount of stool is adequate.

Storage = temperature below 8⁰C

Vaccine carrier with frozen ice packs can be used

Autopsy specimens -Neural tissues -collected using sterile instruments and placed in individual sterile containers. -Spinal cord is best - obtained at all levels of the cord, including the medulla, cervical, thoracic, and lumbo-sacral levels.

Maintenance of the cold chain - advance notice to the laboratory - regarding arrival time, site, mode, and the name of the person (courier) carrying the specimens.

Stools - inoculated into cell cultures - typical cytopathic effect -occurs within 48 hours

Specimen Collection and Handling

Specimen	8 grams of faeces (approximately one “thumb-sized”)
Number	Two specimens, taken 24 to 48 hours apart.
When	Within 2 weeks of onset, no later than 8 weeks.
Method	Voided faeces, preferably at least 8 grams.
Temporary storage	Less than +80C
Transportation	Less than +80C
Label	Properly
Collection Responsibility	Officials of WHO
Storage Responsibility	Officials of WHO
Transportation Responsibility	Officials of WHO
Responsibility for provision of specimen containers and specimen carriers	Officials of WHO

When poliovirus is isolated, special tests are conducted to differentiate vaccine-related from wild polioviruses. This process is called intratypic differentiation (ITD) and is important in determining whether the poliovirus was wild or vaccine-related. This procedure for lTD is available in two reference labs in India.

A minimum of 28 days are required to isolate and identify polioviruses

Factors influencing isolation results,

1.    intermittent excretion of the virus in the stool

2.    insufficient material collected

3.    collection too late in the course of illness

4.    inadequate storage and transport procedures of specimens

5.   Poor laboratory technique.

CLINICAL ASPECTS OF PARALYTIC POLIOMYELITIS

Paralytic poliomyelitis is still the most common cause of AFP in India.

Presents as asymmetrical lower motor neuron flaccid paralysis.

Age of onset of paralysis is 18 months and ranges from 3 months to 5 years,

The maximum number of cases occurring in - July to September.

Fever prior to the onset of paralysis.

malaise,

anorexia,

nausea,

vomiting, headache,

sore throat,

constipation, and abdominal pain.

signs of meningeal irritation, i.e. stiffness of neck and back muscles.

Tripod sign may be present i.e. the child finds difficulty in sitting and sits by supporting himself with hands at the back and by partially flexing the hips and knees.

paralysis reaches its maximum in less than 4 days;

paralysis starts from the trunk at the shoulder or hip and moving distally down the extremity.

muscle strength varies in different muscle groups of different limbs.

proximal muscle groups are more involved as compared to distal ones.

DTRs are diminished before the onset of paralysis.

Cranial nerve involvement is seen in bulbar and bulbospinal forms of paralytic poliomyclitis

facial asymmetry, difficulty in swallowing, weakness, or loss of voice.

Respiratory insufficiency can be life threatening and may lead to death.

Diagnosis - by isolation of wild poliovirus from the stool specimen.

In polio, the spinal fluid is inflammatory and it may or may not be under pressure. The fluid may be transparent or slightly turbid. Protein is increased moderately to 40-65 mg. From 20 up to 300 cells per mm are present with polymorphonuclear leukocytosis initially, but later shift towards lymphocytosis occurs.

DIFFERENTIAL DIAGNOSIS OF ACUTE FLACCID PARALYSIS (AFP)

Guillain-Barre Syndrome

Guillain-Barre Syndrome (CBS) another cause of AFP in childhood

an acquired demyelinating disease of the peripheral nervous system - weakness and areflexia.

History of fever about 2-3 weeks prior to illness.

The paralysis in CBS is flaccid symmetrical paralysis with absent or diminished DTR

Paralysis of CBS is ascending, affecting lower limbs first, followed by trunk, then upper limbs.

Bilateral cranial nerve involvement is common.

Facial nerve involvement is most common.

Pain and muscle tenderness at the onset.

Sensory deficit is frequently present but is difficult to elicit in children.

Tingling and burning sensations in the soles and palms

Cramps in peroneal muscles

Electrophysiological study is performed 3 weeks after onset of flaccid paralysis.

Electromyography in CBS remains normal

The demyelination of the peripheral nerves reduces conduction velocity

Sensory nerve conduction time is also slow.

A CSF white count of 50 or more is strong evidence against the diagnosis of GBS.

-- increase in protein up to 200 mg, with a cell count of usually 10 or fewer monocytes per mm³ of CSF. Albumino-cytological dissociation

Prognosis of CBS is good.

Complete recovery occurs in the majority of cases.

Sequelae may be present at 3 months after onset of paralysis

1.    bilateral foot drop

2.    weakness of grip

3.    wrist drop

4.    symmetrical atrophy of peroneal and anterior tibial muscles in legs

5.    Atrophy of hypothenar eminence in palms.

Differentiating features from paralytic poliomyelitis are:

·   Age: maximum number of cases of polio occur below 3 years of age, while in CBS more likely to occur above 2 years. There is age overlap at 3-4 years for both diseases. CBS is very rare in children < 1 year of age.

·   Fever: in polio, fever is typically present just prior to the onset of paralysis, while in CBS it is 2-3 weeks prior.

       ·   Paralysis: in polio, paralysis is asymmetrical and initially involves large proximal muscles. In CBS, paralysis is symmetrical and usually involves distal smaller muscles. In CBS the paralysis is ascending from the feet, while in polio it is descending from the shoulder or hip muscles.

·   CSF findings: in polio CSF shows 20-300 White blood cells (WBC) and protein is normal or minimally elevated, while in GBS, WBCs are usually < 10/mm³ while proteins are raised up to 200 mg (a/bumino-cytologic dissociation).

Although not routinely done, some hospitals are equipped with electrophysiological diagnostic equipment. The usual findings are:

·   Nerve: Nerve conduction velocity may be normal during the first two weeks in polio but during the third week it is abnormal showing evidence of anterior horn cell disease. In GBS, it is abnormal: slowed conduction, decreased motor amplitudes.

·   Electromyography (EMG): EMG is highly abnormal in polio with signs of denervation and giant action potential, while in GBS it is usually normal. However, a normal EMG does not rule out polio.

Transverse Myelitis

Age - from 4 years and above.

Fever may be present before the onset of AFP

Paralysis is symmetrical in the lower limbs

Profound anesthesia to all forms of sensation.

Site of involvement is - lumbar, thoracic, or cervical.

Arms paralysis not frequent.

There is hypotonia and DTRs are absent in TM.

Sequence of symptoms is flaccidity of legs, followed by loss of control of rectal and bladder sphincters.

Recovery is related to onset. When onset is rapid (within hours), recovery is slow

In contrast, children whose paralysis took several days to develop may recover completely.

Flaccidity usually changes to spasticity

areflexia may be replaced by hyperreflexia.

Differentiating features of transverse myelitis from polio are:

·   Age: Maximum cases of polio occur below 3 years of age, while TM is mostly above 4 years of age.

·   Paralysis: In polio, paralysis is asymmetrical and mostly involves large proximal muscles, while TM paralysis is symmetrical and may involve trunk and both lower limbs.

·   Sensory: In polio, there is no sensory loss, while in TM there is marked sensory loss.

·   Autonomic: In poliomyelitis bladder, dysfunction is usually absent; while in TM, there is marked dysfunction of the bladder and bowel sphincters.

·   CSF: In polio, it is abnormal, while in TM it is normal.

Traumatic neuritis

Traumatic neuritis (TN) caused by injections may lead to AFP of the lower extremity

Occurs from 1 hour to 5 days after injection in the gluteal region.

Fever is present before the onset of paralysis as the injection is given for a preexisting febrile illness.

Pain in the gluteal region or along the affected leg.

Atrophy may appear 40 to 60 days later.

Knee jerk is present. Ankle jerk is absent or diminished.

Hip and knee strength is normal.

The child walks with a foot drop.

Gradually recover with physiotherapy within 3 to 9 months.

Differentiating features of TN from polio are:

• Age: Polio occurs mainly below 3 years of age, while in TN there is no age limit.

• Paralysis: In polio, large proximal muscle groups are involved although any group of muscles may be affected and the DTRs are diminished. In TN only one leg is involved below the knee, knee jerk is normal but ankle jerk is diminished.

Differential Diagnosis of Paralytic Poliomyelitis

Signs and              Polio                            GBS                             Transverse myelitis     Traumatic neuritis symptoms

Progression of 24 —48 hours onset to From hours to 10 days From hours to 4 days From hours to 4 days paralysis            full paralysis

Fever onset           High, always present at Not common                Rarely present              Commonly present                             onset of flaccid                                                                                 before, during and after                             paralysis, gone the                                                                            flaccid paralysis                             following day

Flaccidity               Acute, asymmetrical,    Acute, symmetrical,      Acute, lower limbs,       Acute, asymmetric                             proximal                      distal                           symmetrical                 limb

Muscle tone           Diminished                   Diminished                   Diminished in lower Diminished in limb                                                                                                 limbs

DTRs                    Decreased or absent     Absent                         Absent in lower limbs Decreased or absent                                                                                                 early, hyper-reflexia                                                                                                 late

Sensation              Severe myalgia and      Cramps, tingling,          Anaesthesia of lower Pain in gluteal region                             backache, no sensory    hypoanaesthesia of       limbs with sensory                             changes                       palms and soles           level

Cranial nerve         Only when bulbar and   Often present, affecting Absent                        Absent                             bulbospinal                  nerves VII, IX, X, XI,                                                               XII

Respiratory           Only when bulbar and In severe cases              Sometimes                  Absent Insufficiency          bulbospinal

CSF: WBCs           High WBCs                   <10 WBCs                   Normal                       Normal

Protein         Normal or slightly         High                            Normal or slightly         Normal                    increased                                                       elevated

Bladder                 Absent                         Transient                     Present                         Never dysfunction

Nerve conduction   Abnormal, anterior       Abnormal,                    Normal or abnormal,    Abnormal in sciatic velocity: third        horn cell disease          demyelination               no diagnostic value       nerve week                    (normal during the first                             two weeks)

EMG — 3 wks        Abnormal                     Normal                        Normal                       Normal

Sequelae at 3        Severe, asymmetrical   Symmetrical atrophy     Flaccid diplegia,            Moderate atrophy, only months and up to   atrophy, skeletal           of distal muscles           atrophy after years        in affected lower limb a year                   deformities developing                             later

Other Non-polio Enteroviruses causing AFP are

1. Coxsackie A
2. Coxsackie B
3. ECHO viruses
4. Enteroviruses types 70 and 71
5. mumps virus

Other conditions causing AFP-

peripheral neuropathies due to --

1.    metabolic defects (diabetic)

2.    toxins (including lipid solvents and fish toxins)

3.    organophosphate pesticides

4.    raw metals (lead)

5.    Drugs

6.    hereditary disease (Charcot-Marie-Tooth)

7.    diptheria toxin

8.    tick bite

The clinical picture of post-diphtheritic paralysis is similar to GBS.

Tumours may lead to acute flaccid paralysis which is asymmetrical. Progression is usually slow and generally there is no fever associated with paralysis onset. Distribution of nerve involvement is dependent upon the anatomic location of the space occupying lesion.

Diagnostic dilemmas

To increase accuracy of diagnosis do the following

1) obtaining stools specimens for culture on all patients with AFP;

2) completing the 60 day follow-up examination on as many cases as possible;

3) repeating the examination more frequently looking for an opportunity when the child is less irritable;

4) establishing expert medical boards to evaluate case records of difficult patients.

“Pseudo” paralysis

Certain conditions present with “pseudo” paralysis, which may be confused with AFP. These conditions are not AFP and should not be reported as AFP.

          Unrecognized trauma from contusions, sprains, or fractures are common sources of confusion.

Hypokalemia = toxic, irritable, and present with generalized acute flaccid paralysis of all 4 limbs and neck flop. It is caused by diminished potassium level in blood, especially in children with diarrhea and vomiting a few days prior to onset of paralysis. Weakness is noticed first in limb muscles, followed by weakness in trunk and respiratory muscles. Parents often bring their children in when the child becomes floppy and sudden neck flop is noted. Areflexia, paralysis, death from respiratory muscle failure and cardiac arrest can occur. Intravenous potassium drip save lives when the alert clinician recognizes this condition.

Children with non-specific toxic synovitis present with unilateral limp. Hip or knee joints are commonly affected. There is usually swelling of the joint and movements are painful. Low grade fever may persist for several days. X-rays may show fluid in the joint space.

Acute osteomyelitis shows localized signs of inflammation of the affected bone. There is polymorphonuclear leukocytosis. X-rays are diagnostically helpful.

Scurvy may occur at any age, but the majority of cases occur between 6 months to 2 years of age (like polio). The onset of symptoms is gradual. There is generalized tenderness and child resents handling. Pain leads to pseudoparalysis and legs are kept in frog position. In some cases subperiosteal hemorrhage may be palpated at distal end of femur. Gums show bluish-purple spongy swelling of mucous membranes, especially when teeth have erupted. X-ray of knees is diagnostic. In early cases a white line is visible at the distal end of femur and proximal end of tibia and fibula. In advanced cases, a zone of destruction on the medial side of the distal end of the femur and the proximal end of the tibia is seen.

In acute rheumatic fever the clinical pattern is usually diagnostic. The arthritis is migratory and affects different joints, i.e. elbows, knees, ankles, and wrists. The affected joints are red, warm, and swollen.

Congenital syphilitic osteomyelitis is found only in early infancy. X-rays are diagnostic and include osteochondritis at wrists, elbows, ankles, knees, and periostitis of the long bones. Gsteochondritis is painful and refusal to move the limb leads to pseudoparalysis.

Other conditions such as meningitis or Meningo-encephalitis can initially be confused with paralytic poliomyelitis; however, their etiologies are clarified after diagnostic procedures, such as lumbar puncture and biochemistries.

Post polio syndrome (also called post polio residual paralysis and post polio muscular atrophy) refers to a group of disorders experienced by many poliomyelitis sufferers, typically starting 25-35 years after initial onset. Symptoms include renewed, usually gradual progression of muscle weakness, increased fatigability, joint pain, muscle cramps, intolerance to cold, and sometime increased difficulty in breathing (when respiratory muscles are involved or severe scoliosis is present). Post polio syndrome appears to be more frequent and severe in persons who had a more severe initial poliomyelitis illness. No single examination, procedure, or laboratory test can definitely diagnose this condition. There is no evidence to suggest that these patients are reinfected or have chronic infection; rather, they may be experiencing the consequences of long-term overuse or disuse to compensate for the original destruction of nerve cells.

CLINICAL MANAGEMENT OF POLIOMYELITIS

Management of paralytic poliomyelitis in the acute phase is symptomatic. The child needs rest and care to ensure that there is no stress on the affected muscles. Care is also required to see that the child does not get secondary infections.

Massage and injections during this period are contraindicated.

Uncomplicated cases of single lower limb or both lower limbs and trunk involvement can be treated at home. However, if poliomyelitis is suspected, such children should be examined by a physician as early as possible, to confirm diagnosis, rule out “high-risk” factors, such as early respiratory involvement, and for proper advice to parents on the care of the child at home.

Complete bed rest is essential during the acute phase. There should not be any stress on the muscles involved. The mother or other persons caring for the child should frequently change the posture of the child in bed every two to three hours. The child should be placed on prone position  for short periods each day, to avoid the risk of pneumonia.

The limb should be placed in the optimum position for relaxation of the paralyzed muscles. The affected limbs can be positioned with pillows or rolled towels. The recommended positions are: hip-slight flexion; knee — 5 degrees flexion; foot — 90 degrees (support against the sole of the foot). Both legs should be supported from the lateral sides with pillows or rolled towels to prevent external rotation. Rolled towels should also be placed under the knee for positioning of hips and knees.

The joints affected by the paralyzed muscles should be moved passively and gently through the full range of motion to prevent contractures. Such movements should be done for 10 minutes 2 to 3 times a day. The movements should involve all joints of the affected limb. The movement should be within the range of pain.

Warm water fomentation using hot packs with soaked towels wrapped around the affected parts for 10 minutes 2 to 3 times daily should be started as soon as possible and continued up to 6 weeks after onset of paralysis.

There is no restriction on diet and normal food may be given to the child if he accepts. Children may be constipated during this period. Transient urine retention may be noted which may be relieved by alternate hot and cold compresses over the suprapubic region. However, if constipation lasts for 3 days or if there is no urine for 24 hours, the child should be immediately taken to a hospital.

In 2 to 20% of the cases the outcome may be fatal due to involvement of muscles affecting vital functions, especially respiration. If the child shows any respiratory distress or if the paralysis is progressing or in cases of upper limb involvement in the first week of illness, the child should preferably be hospitalized. Indications for referral to the hospital are listed below.

As the acute phase of illness subsides and recovery of strength begins, the emphasis shifts to active rather than passive movements and a vigorous programme of physical therapy is initiated to regain muscle power. Management of the recovery phase begins with a careful assessment and recording of muscle power of the weak muscle groups to serve as a baseline. The degree of recovery ranges from minimal to complete. Maximum recovery of the affected muscles takes place in the first six months, but slow recovery continues up to two years. Physiotherapy is necessary to prevent deformities and contracture due to muscle imbalance or improper posture. Physiotherapy under a qualified physiotherapist is important for regaining muscle power and rehabilitation of the child.

Braces are used to compensate for weak muscle groups, e.g. foot drop or more severe leg weakness. Children are fitted with braces (calipers) depending upon the age and degree of involvement of the limbs. Unilateral brace is given in case of a single lower limb paralysis by the age of one and a half years, when the child begins to start walking. Bilateral leg braces are prescribed for both leg paralysis by the age of 2 ‘/2 to 3 years of age. Children with bilateral braces need crutches. Bracing above or below the knee depends on the extent of paralysis. It can be extended up to the trunk in the case of trunk muscle weakness. Infants and younger children are also given abdominal support and jackets to help in sitting up in case of trunk weakness.

Although further clinical recovery is not expected after two years, continued physiotherapy is required to prevent deformities. Contracture, denervation, or imbalance of muscle tension can lead to progressive skeletal deformities. Reduced growth of a denervated extremity is commonly seen. Tendon shortening can be largely prevented by active physical therapy in the weeks following acute poliomyelitis, but some cases will require orthopedic procedures. Tendon transplants may be considered to improve function of the hand or foot. Surgical interventions may be indicated for various forms of deformities. Grthotic appliances also need to be changed as the child grows.

Except for the physical handicap of residual weakness, children are otherwise normal and should be treated as such. They should be encouraged to take part in childhood activities and attend normal schools. The guidance of a paediatric physiotherapist, occupational therapist, social worker, and a vocational counselor are helpful in promoting a positive approach and adjustment.

Management of non-polio causes of residual paralysis is similar to that for polio. In cases of transverse myelitis where sensory loss is severe, special care should be taken while giving splints and braces; otherwise, trophic ulcers may develop. During the acute phase, special emphasis is also required for skin care and posture because sensory loss, bladder and bowel dysfunction will increase the likelihood of the development of bed sores.