INSTRUCTION

Examine the lower limbs of this patient who has had this abnormality since childhood.

SALIENT FEATURES

History

· History of trauma to'the spine and/or leg.

· History of poliomyelitis.

· History of weakness and fasciculations.

· Bladder and bowel symptoms.

Examination

· Wasting and deformity of one lower limb (or both, with one side being more affected than the other).

· Fasciculations.

· Normal tone in both lower limbs.

· Check the sensory system (L5 and/or S1 sensory loss in spina bifida).

· Examine the spine:

-Kyphoscoliosis (seen in poliomyelitis, indicating involvement of trunk

muscles).

-Tuft of hair in the lower lumbosacral spine (closed spina bifida).

· Comment on bony deformity in the affected leg.

Note. Always check the gait and test for Romberg's sign.

DIAGNOSIS

This patient has unilateral wasting and deformity of the R/L leg (lesion) due to poliomyelitis in childhood (aetiology) and wears

calipers on that leg (functional status).

QUESTIONS

What is the differential diagnosis?

· Old poliomyelitis.

· Spina bifida.

What are the causes of lower motor neuron signs in the legs?

· Peripheral neuropathy.

· Prolapsed intervertebral disc.

· Diabetic amyotrophy.

· Poliomyelitis.

· Cauda equina lesions.

· Motor neuron disease.

ADVANCED-LEVEL QUESTIONS

What is the cause of polio?

Polio is caused by a picornavirus of the genus Enterovirus; there are three antigenic types - type I (Brunhilde), type 11 (Lansing) and

type III (Leon).

Is the muscular involvement of polio in childhood progressive?

Paralytic polio usually remains stable after the initial attack. However, in some patients new muscle weakness and atrophy involving

previously affected muscles or even unaffected muscles occurs and this deterioration can occur as long as 30 years after the first

attack - known as postpoliomyelitis muscular atrophy (PPMA). The

progressionof this involvement is slow and is said to be distinct from motor neuron disease. It is not entirely clear why only some

patients are affected but it has been reported that it is more likely to occur in those with widespread paralysis and poor immune

status (N Engl J Med 1986; 314: 959).

Is poliomyelitis preventable ?

Yes, three types of polio vaccine are available (each containing all three strains of the virus):

· Oral polio vaccine of Sabin consists of live attenuated virus.

· Killed or inactivated vaccine of Salk.

· Enhanced potency vaccine of van Wezel.

With which vaccine is paralytic poliomyelitis associated?

Vaccine-associated paralytic poliomyelitis (VAPP) is associated with oral polio vaccine, particularly in immunodeficient individuals

(N Engl J Med 1995; 332: 500-6). Such individuals and their household contacts should be given inactivated vaccine.

What do you know about 'provocation poliomyelitis'?

Provocation poliomyelitis is caused by the administration of intramuscular injec-tions during the incubation period of wild-type

poliovirus or shortly after exposure to oral polio vaccine (either as a vaccine recipient or through contact with a recent recipient).

What do you understand by the term 'spina bifida'?

Spina bifida means an incomplete closure of the bony vertebral canal and is com-monly associated with a similar anomaly of the

spinal cord. The commonest site is the lumbosacral region but the cervical spine can be involved. It may be associated with

hydrocephalus.

What are the features of closed spina bifida?

· Cutaneous: lumbosacral lipoma, hypertrichosis, sinus or dimple above the sacrum, naevus or scarring.

· Unilateral shortening of one leg and foot with a deficiency of the muscles below the knee. There may be calcaneovalgus or

equinovarus deformity. Sensory loss in the fifth lumbar and first sacral dermatome is common.

· Neuropathic bladder, enuresis.

· Bony changes on radiography: sacral dysgenesis, scoliosis, laminar fusion of vertebral body, pedicle erosion and bony spurs.

Is the neurological deficit in closed spina bifida progressive?

This issue is contentious as much of the deficit is fixed antenatally and any pro-gression occurs as a result of growth and posture. In

some patients, however, the late appearance of bladder dysfunction indicates that the neurological deficit is pro-gressive in these

individuals.

Mention some teratogenic factors responsible for neural canal defects.

· Maternal diabetes and sacral dysgenesis.

· Sodium valproate in pregnancy and neural tube defects (Lancet 1982; ii: 1282).

Mention some prenatal screening tests for spina bifida.

· Amniotic alpha-fetoprotein levels.

· Amniotic acetylcholinesterase estimation.

· High-resolution diagnostic ultrasonography.

M.H. Romberg (1795-1873), German neurologist and Professor of Medicine in Berlin.

The 1952 Nobel Prize was jointly awarded to John E £nders (1897-1985), Thomas H. Weller (1915-) both of Children's Medical

Center and Harvard Medical School, Boston, and Frederick C. Robbins (1916-) of Western Reserve University, Cleveland, Ohio, for

their discovery of the ability of poliomyelitis viruses to grow in cultures of various types of tissue.