E-Book, Englisch, 352 Seiten
ISBN: 978-1-4831-9371-7
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark
Autoren/Hrsg.
Weitere Infos & Material
2 Some presenting symptoms and signs
Publisher Summary
This chapter discusses some presenting features of the varied problems of childhood. Pain is a difficult symptom to assess at any age and in the case of small children, it may have to be inferred from associated signs, for example, the limp resulting from a painful disorder of the hip joint. The nervous child is more likely to suffer from, and complain of, pain and under these circumstances, a period of careful observation may be more important than a battery of complicated investigations. Headaches are relatively uncommon in childhood. However, in the early years, so-called migraine equivalents quite often take the place of headache. These are sometimes referred to as the periodic syndrome, but this probably contains a number of recurrent conditions. Cyclical vomiting, which may only be associated with headache as age increases, is perhaps more often an early manifestation of migraine. It is suggested that when the vomiting is severe, it may be caused by a partial deficiency of ornithine transcarbamylase or other enzymes in the Krebs–Henseleit urea cycle in a heterozygote. This chapter can only be a brief review of a few presenting features of the varied problems of childhood. Each chapter will contain many of these, and too much repetition must be avoided. However, it should be emphasized that children come to the clinic with symptoms and signs, and not with disease entities. It is in this context that experience can sometimes outweigh knowledge, essential as both may be. It will be stressed in a later chapter that perception depends, among other factors, on memory, imagery, attention and concepts; and diagnosis is skilled perception. The importance of obtaining a careful description of symptoms and the need to question the child as well as the parents cannot be over-emphasized. For example, terms such as ‘fits’ and ‘seizures’ are often loosely used, and after a detailed discussion it may become apparent that the child is having temper tantrums and not epilepsy. Also, if a mother is asked about a child’s migraine she may deny any prodromal symptoms, but these can be elicited easily from the child by questions phrased in the right manner. Symptoms
Pain
Pain is a difficult symptom to assess at any age, and in the case of small children it may have to be inferred from associated signs, for example the limp resulting from a painful disorder of the hip joint. The nervous child is more likely to suffer from, and complain of, pain, and under these circumstances a period of careful observation may be more important than a battery of complicated investigations. The most acceptable theory of pain appreciation at present is the gate theory (Melzack and Wall, 1965). Most of the nerve fibres conducting pain are small, slowly conducting fibres, and there are relatively few large, rapidly conducting fibres. Cells of the substantia gelatinosa of the spinal cord are claimed to act as a control system affecting the afferent pattern before it passes on to the next relay of fibres conducting the impulses to the sensory cortex. Increased activity of the large fibres enhances the inhibitory effect of the substantia gelatinosa on the first central transmission cells in the dorsal horn, whilst increased activity of the small fibres lessens it. If gentle pressure is applied suddenly to the skin, large fibres fire the first central transmission cells and partially close the gate and shorten the barrage generated by these cells. If stimulus intensity is increased the effects of large and small fibres tend to counteract each other, and the output of the transmission cells increases. If the stimulation is prolonged, the large fibres start to adapt with a relative increase of small fibre activity, and the gate opens further with a rise in the output of the transmission cells. This can again be decreased by artificially raising large fibre activity, for example by scratching, which overcomes their adaptation. This may be the main gate, but there may be gates at other levels of the nervous system. Although this is only a hypothesis, there is no doubt that it has played its part in stimulating research (Nathan, 1976), even if certain aspects may be incorrect, for example pain is not invariably the result of stimulation of small non-myelinated fibres, the inhibitory effect of large myelinated fibres cannot always be demonstrated and the role of the substantia gelatinosa in pain is very conjectural. The discovery that the brain can synthesize pentapeptides which produce analgesia may well increase the understanding of the subject. The term endorphin is now used for naturally occurring substances having the properties of opiates, and three effective ones are ß-endorphin, leucine enkephalin and methionine enkephalin. They all have other than anti-nociceptive functions. They may also be linked with the apparent effects of acupuncture, as at slow rates of stimulation endorphin appears in the cerebral spinal fluid (Nathan, 1982), and may be the chemical basis for the ‘gate theory’. These substances, and an increasing number of neurotransmitters, are being found to have a part in the mechanisms by which painful stimuli are processed in the CNS. It is hoped that this knowledge will lead to more effective treatment. The distribution of the pain is most helpful in diagnosis. If it is of obvious root distribution this may be the first evidence of a focal lesion such as extra-dural abscess of the spine or a spinal neurofibroma. Neuralgias of any kind are very rare during childhood, but very occasionally pain of atypical distribution can be a symptom of depression. The quality of pain can be important. When pain is a feature of a focal sensory fit it is hard to describe, as are most sensory epileptic phenomena, because they are distorted sensations. However, one is often left in no doubt that it is a very unpleasant sensation. If the pain is described as severe and long-standing, and yet does not appear to affect the child in any other way, the possibility of a psychogenic origin must be considered. Aching pains in the muscles can be the first sign of weakness, for example such pain can be the first symptom of myasthenia gravis, and perhaps the condition thought to be of rheumatic origin. Muscular aching occurs in hypothyroidism, and shooting and aching pains in the limbs can also be early symptoms of a polyneuritis. Paraesthesia is a more common presenting symptom of peripheral nerve involvement, and, if sympathetically questioned about it, even very young children can describe such sensations. Headaches
The symptom of headache at any age may be of great importance, but especially so in childhood, if only because tension headaches from which so many people suffer are not so common. The clue to the correct diagnosis is often given by the character and timing of the headaches, and this information is available if time is taken in eliciting the history from the child and mother. Tension headaches When the headache is a symptom of anxiety the pain is often described as a feeling of pressure or tightness which increases as the day wears on. The scalp can be tender, even combing the hair being uncomfortable. The symptoms are rarely relieved by analgesics and are more likely to respond to such drugs as diazepam, chlordiazepoxide or chlorpromazine derivatives. However, this is symptomatic treatment, and the main task is to find out the cause of the anxiety and attempt to remove it. Migraine Accepting that headaches are relatively uncommon in childhood, one of the most frequent is migraine. Also, in the early years, so-called ‘migraine equivalents’ quite often take the place of headache; these have sometimes been referred to as the ‘periodic syndrome’, but this probably contains a number of recurrent conditions. Cyclical vomiting, which may only be associated with headache as age increases, is perhaps more often an early manifestation of migraine. It is suggested that when the vomiting is severe it may be caused by a partial deficiency of ornithine transcarbamylase or other enzymes in the Krebs-Henseleit urea cycle in a heterozygote. As this is a partial lack of the enzyme, the person is able to cope under normal circumstances, but under stress, for example during an infection, hyperammonaemia results. If the diagnosis can be confirmed by finding a significant elevation of the blood ammonia level, it may be possible to prevent the attacks by giving a low protein diet, for instance by using gluten-free products (Russell, 1969). The diagnosis can sometimes only be made for certain by using an ammonium tolerance test, using an oral dose of ammonium chloride (1.75 mg/kg). A diagnosis of migraine can usually be made by taking a careful history. Although hereditary factors play an important part in causation, it must not be forgotten that the symptoms can sometimes be caused by organic lesions, such as arterio-venous malformations. It has been suggested that the warning symptoms of a headache may be due to ischaemia. This may result from spasm of certain intracranial arteries. If these are arteries supplying the retina and visual pathways the defects will vary from scotoma to hemianopsia. Transient ischaemia of the occipital cortex will result in the characteristic spectrum of various colours which gradually expands in a zig-zag crescent from a central area, or takes the...
