and Spencer W. Beasley2
(1)
Department of Urology, Royal Children’s Hospital, Melbourne, Australia
(2)
Paediatric Surgery Department Otago, University Christchurch Hospital, Christchurch, New Zealand
Abstract
The first section is on assessing head size and hydrocephalus, with a discussion of how to judge raised intracranial pressure by papilloedema. Ventriculoperitoneal shunts are now common, so there is a description of how to assess their function. There is a description of facial lumps and anomalies, with sections on the ears and parotid region.
The Head
The rapidly growing postnatal brain must be accommodated by an increasingly large skull. The sutures allow adjacent bones of the vault to grow without compression of the brain. Abnormalities of the size and shape of the head are caused by neural tube defects, defects in cerebrospinal fluid (CSF) flow or brain growth, craniosynostosis or deformity secondary to abnormalities of the neck (Table 10.1).
Table 10.1
Abnormalities of the cranium according to aetiology
Condition | Frequency | Aetiology |
|---|---|---|
1. Hydrocephalus | Common | Intracranial haemorrhage |
Infection | ||
Tumour | ||
Congenital aqueduct stricture | ||
2. Plagiocephaly | Common | Intrauterine distortion |
Restricted neck movement (torticollis) | ||
3. Microcephaly | Common | Primary brain anomaly |
Secondary brain injury | ||
Premature fusion of sutures | ||
4. Encephalocele | Uncommon | Failure of neural tube fusion |
5. Craniosynostosis | Uncommon | Premature closure of suture lines |
Is the Head Big?
The absolute size of the skull is not as important as its relative size, compared with the size of the rest of the body and the age of the child. Standard growth charts allow for these changes with age but require the head to be measured accurately (Fig. 10.1). The maximum circumference is measured in the fronto-occipital plane, usually just above the ears. A non-elastic tape measure (e.g. paper) is used and serial measurements are plotted on a head circumference chart (Fig.10.2). Two common patterns suggest an abnormally large head: (1) a large circumference since birth, which remains relatively bigger than normal or may even increase with age, indicating a congenital or inherited abnormality and (2) a circumference within the normal range but increasing faster than expected, indicating an acquired abnormality.
Fig. 10.1
Measuring head circumference. 1. Record the maximum fronto-occipital length. 2. Use a non-elastic tape measure. 3. Plot the result on a head circumference chart
Fig. 10.2
The head circumference chart, showing the two common patterns seen in a child with a large head. Increase in size at a rate faster than normal is suggestive of hydrocephalus
If the head is too big or enlarging too quickly, hydrocephalus is likely to be the diagnosis, but other uncommon conditions can produce a big head (Table 10.2) and need to be considered.
Table 10.2
Causes of a big head
Common | Excess CSF (hydrocephalus) |
Cerebral haemorrhage (in the premature baby) | |
Spina bifida | |
Aqueduct stenosis | |
Uncommon | Large brain (macrocephaly) |
Thick skull bones (osteofibromatosis) | |
Subdural haematoma | |
Cyst | |
Cystic neoplasm |
To determine if the big head is caused by hydrocephalus, look for the following signs (Figs.10.3and 10.4). The anterior fontanelle can be seen and palpated, may be larger than normal and bulging with increased pressure from within. The sutures are widely placed, with a gap palpable between adjacent bones of the vault. The forehead tends to overhang the relatively smaller face, with the anterior horns of each dilated lateral ventricle pushing out the sides of the forehead to produce ‘bossing’. Superficial, congested veins are visible under an attenuated and tight scalp. Sutures not commonly open, such as the metopic and lambdoid sutures, may be palpated. The eyes appear to deviate downwards to give the so-called setting-sun appearance. The explanation for this is not completely understood but may be compression of brain stem oculomotor connections in the quadrigeminal plate of the fourth ventricle. Occasionally, the shape of the occiput is helpful since the size of the posterior fossa is determined by the type and site of the obstruction to CSF (Fig. 10.5). Percussion of the normal skull (Fig. 10.6) produces a high-pitched, drum-like resonance compared with the hydrocephalic skull which has a sound which has been likened to that of a cracked earthenware pot in the older child where the sutures are interdigitating, and a more hollow percussion note in the infant.
Fig. 10.3
The clinical signs of hydrocephalus (lateral view)
Fig. 10.4
The clinical signs of hydrocephalus (anterior view)
Fig. 10.5
The effect of dilatation of the fourth ventricle on the shape of the back of the head in communicating hydrocephalus (a) and aqueduct stenosis (b)
Fig. 10.6
The ‘cracked-pot’ sign: the wide gap in the sutures changes the resonance of the skull on tapping and produces a dull thud
The child should be taken to a dark room for transillumination of the skull (Fig. 10.7). A bright torch is needed, but it can provide useful information even before CT/ultrasound or MRI is undertaken. Extreme dilatation of all the ventricles with little brain present will make the entire vault transilluminate, whereas a localized cyst or subdural hygroma (haematoma which has been gradually replaced by CSF) will produce focal areas of transillumination.
Fig. 10.7
Transillumination of the skull for hydrocephalus. Water-filled, large ventricles transilluminate if the child is examined in a very dark room using a large, bright torch
All children with a proven or suspiciously large head should be referred to a paediatric centre for detailed investigation. Skull x-rays, cranial ultrasonography (if the fontanelles are open), computed tomography scan or magnetic resonance imaging may be performed.
The classic signs and symptoms of hydrocephalus are seen only in the infant, before closure of the sutures (Fig. 10.8). After closure of the sutures, the cranium cannot expand readily, and an increase in its contents leads to an increase in intracranial pressure. The sutures close at about 4 years of age or earlier if previous hydrocephalus has been treated with a ventricular shunt. This may have drained the CSF too well and allowed the bones to stick together before the brain tissue expanded to fill the space. The cardinal symptoms and signs of raised intracranial pressure are vomiting (often early in the morning), headache and papilloedema.
Fig. 10.8
The two presentations of hydrocephalus in childhood, depending on whether the sutures are open or fused
Assessment of possible raised intracranial pressure must take into account whether there is a CSF shunt already present (Fig. 10.9). If there is a shunt in situ, it is highly likely that malfunction of the shunt is the cause. If there is no shunt, the cause is likely to be a neoplasm, unless the child has had meningitis. Therefore, in taking a history of a child with headaches and vomiting, knowledge of previous shunt surgery is vital. It is also important to know whether there has been a delay or deterioration in milestones and mental development, or a change in recent behaviour, which suggests a slowly progressive lesion (e.g. tumour). Depression of the conscious state may be present, but often this is a late feature and a normal conscious state does not necessarily indicate that all is well. The falling pulse and rising blood pressure are classic signs of raised intracranial pressure. However, in childhood, these parameters may remain normal until the intracranial pressure is so high that the patient is unconscious and close to death.
Fig. 10.9
The presentation of hydrocephalus after fusion of the sutures: there may be a history of previous shunt surgery and/or mental impairment. Shunt blockage is the likely cause if hydrocephalus was treated previously. If there is no CSF shunt, localizing neurological signs should be sought to exclude a brain tumour
Examination of the retina will confirm the presence of papilloedema, the cardinal sign of raised intracranial pressure (see below). The sides of the head behind and above the ears should be palpated to find the ventriculoperitoneal shunt and test its function (see below). If there is no shunt present, a cerebral neoplasm is possible and localizing neurological signs should be sought.
Looking for Papilloedema
Small children are not able to keep their eyes still, which makes examination of the optic disc difficult. Since the disc and peripheral vessels are in the same focal plane, the ophthalmoscope is focused on the peripheral vessels first (Fig. 10.10). The examiner then waits for the disc to move into the field of view as the child’s eye moves.
Fig. 10.10
Examination of the eye in a child with possible papilloedema. Since the peripheral vessels and disc are in the same focal plane, get the vessels in focus first and wait for the disc to move into view. The child’s eye moves frequently because of the low level of concentration
When papilloedema is present, the disc is blurred at the normal focal length at which the peripheral vessels are clear (Fig. 10.11). The blurred image is easily mistaken for inadequate technique or an uncooperative child. If the peripheral retina is in focus, blurring in the region of the disc is a crucial sign and should not be ignored. Papilloedema can be confirmed by altering the focus to bring the top of the swollen disc into view, which allows the distended vessels and haemorrhages to be seen clearly (Fig. 10.12). Pharmacological dilatation of the pupil is useful if a clear view of the disc is not readily obtained.
