An investigation into the causes of disabilities is beneficial both to the disabled individual and to the society at large. It provides the basis for planning rehabilitation services for the afflicted persons and for formulating and administering adequate measures for the prevention of the impairment.
While socio-economic rehabilitation is the ultimate goal, an understanding of the causes and types of disabilities and diseases is the first step towards the solution of the problem.
The causative factors of disabling conditions are manifold and varied. They may broadly be classified into:
(A) Hereditary;
(B) Congenital; and (C) Adventitious (Acquired)
Each of these factors is again attributable to a number of contributory causes.
In the first instance we will analyse the general causes of various disabling conditions. In the subsequent sections of this chapter we will deal with the specific causes of orthopaedic disabilities, blindness, deafness and speech handicap.
General Causes
(A) Hereditary
In the mind of the common man, a great confusion prevails regarding the nature of hereditary defects. Common man normally mixes up the terms hereditary, congenital and familial. Thefact, however, remains that the three terms are quite different fromone another. A defect which is congenital (that is, present at birth) or familial (running in a family) may not be hereditary at all. Ahereditary defect is one that passes down from generation to generation because of some sort of disturbance in the working of inherent gene mechanism.
It is, however, noteworthy that a particular condition may be hereditary and yet, it may not manifest itself at birth, or formany years to come, or might not have appeared before in the individual's immediatefamily.
This may appear paradoxical in view of the implication that a hereditary defect passes on from one generation to the other. But it does happen in mutation, that is, when rare recessive genes arepooled together or when new black genes come into being.
We know that recessive genes produce their full effectsonly when they flow in a double dose, from both the parents. But there are dominant genes also, which manifest themselves by direct transmission from either of the parents, in a single dose. This discovery has now led to a revolutionary change in our outlook on the nature of hereditary defects. There was a time when it was believed that every characteristic was either strictly hereditary or environmental. But, todaywe know that very few diseases or disabilities are purelyhereditary. Behind every defect, both hereditary and environmental factors operate.
Hereditary defects are comparatively infrequent, in spite of the common belief to the contrary.
Regarding the incidence of hereditary defects in India,
unfortunately, we have very little factual data. Among the Hindus, who form a majority of the Indian population, the practice of exogamy, which debars an individual from marrying within his immediate circle of kith and kin (SAGOTRA and SAPINDA) may, perhaps, be the governing factor in minimising the incidence of hereditary defects.
(B) Congenital
Congenital defects are those that are present at birth. Not all congenital defects are hereditary. Most of them are the result of
34
infections, nutritional deficiencies, chemical factors and other environmental conditions. The following are some of the causes for congenital deformities as enumerated by Dr. Usha Bhatt.
(a) Maternal Malnourishment: Recent reseach has
demonstrated that more important than the genetic factor is the pre- natal environment of the embryo. The first eight weeks are very important for the structural development of the embryo, as most of the congenital malformations of a non-hereditary nature are established
during this period. If maternal starvation takes place during the earlier period of gestation, the embryo dies, but if it were to occur at a later stage, i.e. organo-genetic period, malformations take place. If certain
nutritives, such as vitamins and minerals, are omitted from the diet of the expectant mother, congenital defects may appear. For example,
lack of iodine results in cretinism, whereas lack of vitamin A' invariably results in defective eyes, and in some cases, in cleft lip and palate.
(b) Maternal Infection: Rubella and German measles in the first two months of pregnancy may cause congenital defects, such as, microcephalia, deaf-mutism, hydrocephalia, cataract, etc. Other maternal infections may be mumps, chicken-pox, scarlet fever etc.
(c) The Rh Factor: Parent Rh blood incompatibility is also responsible for congenital disorders.
(e) X Rays: Radiation has an adverse effect on the embryonic growth. It was, incidentally, Murphy,1 who first drew attention to this fact. In a group of 75 children born to mothers whose pelvis was irradiated during pregnancy, 16 were microcephalics and, in all 28 showed some defect or other of the central nervous system.
35
(d) Disease: It has been found that amongst the offspring of diabetic mothers, there is a higher incidence of congenital defects like club foot, claw hand, missing fingers, etc.
(f) Chemical Agents: Certain congenital deformities are also due to an erroneous use of certain high potency chemical agents or ingredients.
(g) Glandular Disorders of the Mother: The effects of
endocrine disorders in the pregnant woman are not fully known, but hypo-functioning of her thyroid gland is associated with cretinism in the infant.(h) Mechanical Factors: A few congenital defects can be traced to abnormal pressure or other mechanical factors. The abnormal
position of the foetus may result in club foot, club hand or dislocation of wrists and knees.
(C) Adventitious (Acquired)
The term 'acquired defects' includes many conditions. The defects may be acquired due to (a) birth injuries; (b) pathological condition and diseases;(c) accidents; (d) nutrition definiencies, (e) defective postures, (f) consequences of war, (g) poverty, and (h) other causes.
(a) Birth Injuries: Many of the brain disabilities result from birth injuries. Premature birth, caesarean birth, long and difficult labour, precipitate birth, haemorrhage, improper use of forceps and of anaesthetics and drugs, such as morphine, may result in severe brain injuries like brachial palsy or cerebral palsy. Difficult labour in Eastern countries due to ignorance and incompetence of midwives may account for cerebral palsy and other brain injuries which in the West, are usually caused by the above mentioned factors.
(b) Pathological Conditions and Diseases: Infectious
diseases like whooping cough, measles, scarlet fever, meningitis,encephalitis, tuberculosis of bones and joints, small-pox and
poliomyelitis are likely to result in physical disabilities.(c) Accidents: In most of the Western countries permanent disablement as a result of industrial and highway accidents, outnumbers war casualities. In the last World War the United States of America registered a total of 17,000 service amputees, during the four years of its participation. But during the same period in America a total of 120,000 civilians suffered amputations, of which 44,000 were due to industrial accidents.
(1) Industrial Accidents: Industrial accidents are caused by three main factors:
(i) Lack of adequate safeguards about the machines; (ii) External factors such as poor ventilation, bad lighting arrangements, insufficient room, unclean conditions and unusual temperature; (iii) Individual or human factor known as accident proneness.
36
In India, the number of industrial accidents is increasing due to rapid expansion of industries.
(2) Traffic Accidents: The incidence of this group of accidents is rising by leaps and bounds with the growth of roadways, railways and airways. An expert in the field, Dr. Leslie G Norman of London, estimates that there are 100,000 deaths on the roads of the world every year and for every death there are 30-40 light injuries and 10- 15 serious injuries.2
Records of traffic accidents in developed countries like U.S.A., Canada, Great Britain, Australia etc. are of alarming numbers.
The incidence of traffic accidents in Indian cities has also increased considerably during the last four decades. Unplanned cities with narrow roads and poor traffic control arrangements have been responsible in increasing the number of road accidents. Railway accidents and other accidents such as falling from trees, house tops etc., also cause disabilities.
(d) Nutrition Deficiencies: Nutritional deficiency leads to low resistance against diseases, which may ultimately result in disablement.
The problem of nutrition resolves itself into two parts: (1) Production of sufficient quantity of food to meet the basic needs of the population;
and (2) Raising the standard of living. In India, dietary and nutrition surveys made from time to time have recorded both quantitative and qualitative deficiency.
(e) Consequences of War: In the West, war is the largest single factor responsible for causing permanent disablement not only to combatants on the battlefield but also to civilians who are forced to bear the hazards of war. The number of those permanently disabled and suffering from the consequences of war runs into millions. It has been estimated that 25 per cent of the world population is even now suffering from the scars of the World Wars. India was one of the fortunate countries that were not directly involved in the two wars. So the number of our war disabled due to the World Wars was low.
However we had our toll of war disabled as a result of our encounters with China and Pakistan.
(f) Poverty: Poverty with ignorance and disease, forms a most formidable trio. Poverty results in disablement and disablement leads to poverty.
37
(g) Other Causes: In addition to those mentioned above, illiteracy, shortage of medical personnel, want of requisite institutions, traditional fatalism of the masses and fear of the surgeon's knife etc., are some of the causes contributing to physical disabilities.
After examining the general causes of physical disabilities we shall now investigate the specific causes of different categories -of physical disabilities and their types.
Orthopaedic Disability
(A) Hereditary
Some of the abnormalities which are transmitted as dominants are: brachyphalangia, polydactylism, claw hands, spider hands, fused fingers, double joints, cleft palate, cleft lip etc. Abnormalities which are transmitted in a recessive mode are: club foot, dislocation of hip, spina bifida, Friedreich's spinal ataxia etc. It is interesting to find that some of the anomalies such as cleft lip and cleft palate are transmitted in both the dominant and recessive ways.3
(B) Congenital
The most common among congenital defects are: hare lip and cleft palate, webbed fingers, club foot, bow leg, dislocation of the hip, missing bones and amputations.4
(C) Adventitious (Acquired)
(a) Birth Injuries: As has been mentioned earlier in this chapter brain injuries at the time of birth result in such defects as brachial palsy or cerebral palsy.
(ID) Diseases: The classical causes of crippling are cerebral palsy, poliomyelitis and tuberculosis of the bones and joints. Other widely prevalent conditions are: rheumatism, arthritis, paraplegia,
hemiplegia and osteomyelitis. Some diseases which are rare but significant are: multiple sclerosis and muscular dystrophy.5 We shall now briefly examine each of these diseases or conditions.
(1) Cerebral Palsy: Cerebral palsy is perhaps the most important
single cause of a large number of orthopaedic disabilities. A
considerable number of children who are orthopaedically handicapped
38
have suffered from early brain damage to the motor area of the brain.
This damage results in motor disturbances and incoordination of various degrees of severity. People exhibiting these motor disturbances as the result of brain damage are said to be suffering from spastic paralysis.
Spastic paralysis or cerebral palsy was first described by Little in 1843. Hence it has been referred to as "Little's disease".
Cerebral palsy has been defined as "a motor defect present or appearing soon after birth and dependent on pathological abnormalities in the brain".6
Fay described cerebral palsy as "any abnormal alteration of movement or motor function arising from defect, injury, or disease of the nervous tissues contained in the cranial cavity".7
'Cerebral' means anything connected with the brain, whereas the word 'palsy' indicates lack of control of muscles or joints. 'Cerebral palsy' is a term used to designate any paralysis, weakness, inco- ordination, or functional aberration of the motor system resulting from brain pathology. It is perhaps unique among crippling conditions in that, ft may include all the functions of the brain. It may not only represent a motor handicap but may also include sensory and mental deviations as well. Visual, auditory and speech defects, and epilepsy are some of the other accompaniments of this brain disorder.8
Causes: Causes of cerebral palsy are mainly (i) ante-natal factors, accounting for 30 per cent of the cases. Some of these factors are: intra-cerebral haemorrhage of the foetus, maternal and foetal anoxia, parental Rh incompatibility, infection of the mother during pregnancy with rubella or syphilis, maternal diabetes, and maternal gonadal irradiation, (ii) natal factors, associated with birth itself accounting for 60 per cent of the cases. They are: oxygen deficiency, haemorrhage or precipitate birth, (iii) post-natal factors, accounting for 10 per cent of the cases. They are: infections like meningitis or encephalitis, head-injury due, to accidents, drugs, neoplasms and vascular diseases.
Types: The following are the six main types of cerebral palsy:
(i) spastic, (ii) athetoid, (iii) ataxic, (iv) tremor, (v) overflow, (vi) rigidity.
39
Wyllie has suggested a sixfold classification according to the number and manner in which the limbs are involved:
(I) Congenital symmetrical diplegia, paralysis in all limbs.
(ii) Congenital paraplegia, in which only the legs are involved.
(iii) Quadriplegia or bilateral hemiplegia, in which the
disturbance is greater in the arms than in the legs.(iv) Triplegia, a very rare condition in which three limbs are involved.
(v) Hemiplegia, in which both limbs on the same side are involved.
(vi) Monoplegia, an extremely rare condition in which only one limb is affected.
(2) Poliomyelitis: Poliomyelitis, one of the commonest diseases of childhood is a leading cause of orthopaedic disabilities among children.
The cause of poliomyelitis in man is a virus so small in size that it can be detected only, by the use of the electron microscope.
There are three recognised strains: Lansing, Brunhilde and Leon.
Each of these strains has its own characteristics. Consequently the immunity which may result from exposure to one strain may not confer immunity to the other two types.
Those who develop the disease are for the most part, children.
About 75 per cent of those reported annually as having polio are between 1 and 15 years of age. The remainder are usually in an age group from 16 to 40.
There are three types of poliomyelitis: (I) spinal, (ii) bulbo- spinal and (iii) bulbar. This disease has three phases: (i) acute, (ii) convalescent, and (iii) residual.
The general symptoms of polionlyelitis infection are sore throat, nausea and vomiting, headache, fever and drowsiness. Stiffness of back and neck are more specific signs. Pain associated with movement of the body occurs and, still later, paresis or paralysis of voluntary muscles may take place. Usually several days elapse before the clearly defined paralysis of muscle groups which are going to be
40
involved, takes place. This is a very brief description of the typical 'spinal' polio.
Some individuals will be found to have more involvement of their upper extremities, the muscles of respiration, the muscles of swallowing and speech. They have the 'bulbo-spinal' type of polio and the involvement is centered maximally in the motor neurons of the upper portions of the cervical cord and extending up to the bulbar portions of the brain. When such involvement occurs, the muscles of the chest, the diaphragm, the shoulders, arms, and hands are affected.
Many of these patients become the 'respirator' inhabitants during a portion of their illness.
A third and smaller group has 'bulber' polio. It is characterised by the maximum involvement of the 'higher centres' or the vital centres of the brain, plus the 7th, 10th and 12th cranial nerves and some involvement of the meninges. This group has the most severely involved patients and the mortality of polio is to be accounted for as deriving mainly from this group and the 'bulbospinal' type.1°
(3) Tuberculosis of bones and joints: Tuberculosis of bones and joints usually results in orthopaedic disability, because it affects the joints and causes loss of motion. In the spine, it causes rigidity or stiffening, loss of motion and, if untreated, hunchback. In many of the western countries, its incidence has been considerably lowered by vaccination and public education. In India, and other Asian countries, pulmonary tuberculosis as well as tuberculosis of bones and joints still continue to rage wild. The spread of the disease is favoured by insanitary and overcrowded conditions obtaining in cities and
malnourishment due to poverty.
(4) Arthritis and Rheumatism: In the West, arthritis is the most disabling of all chronic diseases. Arthritis means inflammation of joints and of all other structures around the joints. The causative factors
may be bacteria, injury or metabolic disturbance. It is most common in those individuals who have passed their middle age.11
Chronic arthritis is of many types, such as: rheumatoid arthritis, ankylosing spondylitis, gouty arthritis and osteoarthritis.
Rheumatoid arthritis is a systemic disease affecting primarily the connective tissues with joint inflammation dominating the clinical and pathological cases. Early in the disease, the patient may experience
41
fatigue, anorexia, weight loss, stiffness and fever. This is followed by joints involvement, often symmetrical, with pain on motion, tenderness, swelling, heat and redness. Hands, wrists, knees, ankles and feet are commonly affected. Subcutaneous nodules may appear over pressure points (for example, just distal to the elbows). Range of motion is
almost always limited in one or more joints, It may vary from slight and correctable in early cases to severe with contractures and fixed deformities in the advanced cases.
Ankylosing Spondylitis or Rheumatoid Spondylitis (known as Marie-Strumpell disease) is a chronic form of arthritis which affects the spine and sacroiliac joints, but may also involve peripheral joints, especially shoulders and hips. Early symptoms, usually aching and stiffness, appear in the low back. The sedimentation rate is elevated but tests for rheumatoid factor are negative. X-ray changes are seen earliest in the sacroiliac joints which show condensation of bone; later there is narrowing of articular space and finally bony fusion. Calcification of the paravertebral ligaments results in the bamboo spine' appearance in X-rays.
Gouty arthritis or Articular gout is a metabolic disorder
characterized by increased serum uric acid resulting from an inborn error of metabolism or secondary to another disease such as polycythemia vera or leukemia. It occurs mostly in the third, fourth and fifth decades, predominantly in men, and constitutes a small percentage of all patients with arthritis.Hypertrophic arthritis or esteoarthritis is the result of mechanical wear and tear of the human system consequent upon old age. It affects weight bearing joints, particularly knees, hips and lumbar spine,
and the distal interphalangeal joints of the fingers. The cervical spine and shoulders may also be involved. It affectè both men and women, and of all rheumatic conditions it is the least disabling and most static.
Symptoms, which come on in middle age or later, are predominantly joint pain and stiffness.
(5) Hemiple.gia: It is a crippling condition in which there is a paralysis of one side of the body from head to toe. It may be the result of an injury of the brain or some degenerative diseases like arteriosclerosis, severe organic heart disease or hypertension. More than half the cases have vascular origin. The condition is more prevalent
among males than females. In severe cases, however, it is
42