Babies A to Z

HAEMOPHILUS INFLUENZAE B INFECTION

Haemophilus influenzae B (HiB) is a bacterial infection that in children causes meningitis or epiglottitis, and in adults may affect numerous organs. It is spread by close contact and can cause infections in any age group, but is far more serious in children.

In children it may cause:- Meningitis, which is an infection of the meninges (covering of the brain) that results in a fever, irritability, lethargy, seizures and coma. The onset of meningitis may be so rapid that the child may be permanently affected (eg: by deafness, learning difficulties and other forms of brain damage) before any treatment can work.

- Epiglottitis, which is a life threatening infection of a piece of cartilage at the back of the throat that may swell and block the airways.

Blood and fluid from the spinal cord can be tested to confirm the diagnosis.

In children potent antibiotics are needed for treatment, and they must be given by injection. The swollen epiglottis (piece of cartilage at the back of the throat) may choke the child before the antibiotics can work, so urgent hospitalisation and intubation (placing a tube into the throat to permit breathing) is essential.

Good recovery occurs if the infection is diagnosed and treated early, but permanent damage or death are possible in children if treatment delayed.

A vaccine for infants has been available since 1993 to prevent HiB infections. It is given as three or four doses, two months apart, starting at two months of age. It is not recommended for use in adults, but is unlikely to cause problems if given accidentally. Common: side effects may include redness and soreness at the injection site, while unusual effects may include irritability, tiredness, sleeplessness, diarrhoea and a rash. It should be used with caution in fever, acute infection or immune system problems. It must not be inject into a vein.

See also EPIGLOTTITIS; MENINGITIS; PNEUMONIA

HEAD CIRCUMFERENCE

The circumference of the head in infants is often measured to detect an abnormally small or large skull, and to allow the medical treatment of any underlying cause (eg. hydrocephalus, microcephaly) at an early stage. A tape measure is placed around the head from front to back and manoeuvred until the maximum possible reading has been obtained.

Charts (see below) have been prepared which enable head circumference to be compared against a normal standard for each age, and variations from the normal to be plotted.

HEIGHT GRAPHS

HYDROCEPHALUS

The brain and spinal cord are surrounded by cerebrospinal fluid (CSF). In the brain are a number of cavities, one of which contains a network of veins (the choroid plexus) that secretes the CSF, which passes through small ducts to the outside of the brain. From there it flows down and around the spinal cord in the back, from where it is absorbed into the blood. Hydrocephalus occurs when excess CSF accumulates in or around the brain.

There are three types of hydrocephalus:- Obstructive hydrocephalus occurs if CSF cannot escape from the cavities within the brain due to a blockage in the draining tubes, and the brain is blown up by the fluid it contains.

- Communicating hydrocephalus occurs when there is a blockage of the circulation down the spinal cord and the fluid cannot be absorbed back into the bloodstream.

- Normal pressure hydrocephalus may occur in the elderly after a stroke, bleed into the brain or changes in brain structure with dementia.

The first two types are usually caused by a developmental abnormality of the foetus, or may develop in later life because of brain infections, tumours in the brain or skull, a colloid or other form of cyst in the brain, blood clots and other rarer conditions.

In babies with hydrocephalus, the soft skull is grossly dilated by the excess fluid. In older children or adults, a severe headache, personality changes, partial paralysis and loss of consciousness may be symptoms, as the harder skull is unable to expand. Other symptoms will depend upon the effect of the increased fluid pressure on the brain. It is diagnosed by a CT or MRI scan.

Treatment involves inserting a tube (ventriculoperitoneal shunt) into the skull to drain away the excess CSF. The tube has a one way valve allowing the CSF to escape, but preventing other fluids or infection from entering the brain. The far end of the tube is inserted into a vein in the neck or chest, or is run all the way through the chest, and allowed to drain into the abdominal cavity. Shunts can become blocked and require replacement or clearing occasionally. Any brain or intellectual damage that occurs before the condition is treated may be permanent.

Treatment is usually very successful in controlling the condition and allows the patient to lead a normal life with minimal impairment of body function or intelligence.



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