Allergy to amoxicillin causes a blotchy rash and, rarely, fever, swelling of the mouth and tongue, itching, and breathing difficulty.
Penicillin is a beta-lactam antibiotic, one of a group of drugs that also includes CEPHALOSPORINS. Drugs of this group have a four-part beta-lactam ring in their molecular structure and they act by interfering with the cell-wall growth of mutliplying bacteria.
Among the organisms to which it has been, and often still is, active are: streptococcus, pneumococcus, meningococcus, gonococcus, and the organisms responsible for syphilis and for gas gangrene (for more information on these organisms and the diseases they cause, refer to the separate dictionary entries). Most bacteria of the genus staphylococcus are now resistant because they produce an enzyme called PENICILLINASE that destroys the antibiotic. A particular problem has been the evolution of strains resistant to methicillin – a derivative originally designed to conquer the resistance problem. These bacteria, known as METHICILLINRESISTANT STAPHYLOCOCCUS AUREUS (MRSA), are an increasing problem, especially after major surgery. Some are also resistant to other antibiotics such as vancomycin.
An important side-e?ect of penicillins is hypersensitivity which causes rashes and sometimes ANAPHYLAXIS, which can be fatal.
Forms of penicillin These include the following broad groups: benzylpenicillin and phenoxymethyl-penicillin; penicillinase-resistant penicillins; broad-spectrum penicillins; antipseudomonal penicillins; and mecillinams. BENZYLPENICILLIN is given intramuscularly, and is the form that is used when a rapid action is required. PHENOXYMETHYLPENICILLIN (also called penicillin V) is given by mouth and used in treating such disorders as TONSILLITIS. AMPICILLIN, a broad-spectrum antibiotic, is another of the penicillins derived by semi-synthesis from the penicillin nucleus. It, too, is active when taken by mouth, but its special feature is that it is active against gram-negative (see GRAM’S STAIN) micro-organisms such as E. coli and the salmonellae. It has been superceded by amoxicillin to the extent that prescriptions for ampicillin written by GPs in the UK to be dispensed to children have fallen by 95 per cent in the last ten years. CARBENICILLIN, a semi-synthetic penicillin, this must be given by injection, which may be painful. Its main use is in dealing with infections due to Pseudomonas pyocanea. It is the only penicillin active against this micro-organism which can be better dealt with by certain non-penicillin antibiotics. PIPERACILLIN AND TICARCILLIN are carboxypenicillins used to treat infections caused by Pseudomonas aeruginosa and Proteus spp. FLUCLOXACILLIN, also a semi-synthetic penicillin, is active against penicillin-resistant staphylococci and has the practical advantage of being active when taken by mouth. TEMOCILLIN is another penicillinase-resistant penicillin, e?ective against most gram-negative bacteria. AMOXICILLIN is an oral semi-synthetic penicillin with the same range of action as ampicillin but less likely to cause side-effects. MECILLINAM is of value in the treatment of infections with salmonellae (see FOOD POISONING), including typhoid fever, and with E. coli (see ESCHERICHIA). It is given by injection. There is a derivative, pivmecillinam, which can be taken by mouth. TICARCILLIN is a carboxypenicillin used mainly for serious infections caused by Pseudomonas aeruginosa, though it is also active against some gram-negative bacilli. Ticarcillin is available only in combination with clarulanic acid.... penicillin
Patients found to have bacteriuria on SCREENING may never have consulted a doctor but nearly all have a few symptoms, such as frequency or urgency – so-called ‘covert bacteriuria’.
Men have longer urethras and fewer urinary tract infections (UTIs) than women. Risk factors include diabetes mellitus, pregnancy, impaired voiding and genito-urinary malformations. Over 70 per cent of UTIs are due to E. coli, but of UTIs in hospital patients, only 40 per cent are caused by E. coli.
Treatment Patients should be encouraged to drink plenty of water, with frequent urination. Speci?c antibiotic therapy with trimethoprim or amoxicillin may be needed.... bacteriuria
Examination of the ear includes inspection of the external ear. An auriscope is used to examine the external ear canal and the ear drum. If a more detailed inspection is required, a microscope may be used to improve illumination and magni?cation.
Tuning-fork or Rinne tests are performed to identify the presence of DEAFNESS. The examiner tests whether the vibrating fork is audible at the meatus, and then the foot of the fork is placed on the mastoid bone of the ear to discover at which of the two sites the patient can hear the vibrations for the longest time. This can help to di?erentiate between conductive and nerve deafness.
Hearing tests are carried out to determine the level of hearing. An audiometer is used to deliver a series of short tones of varying frequency to the ear, either through a pair of headphones or via a sound transducer applied directly to the skull. The intensity of the sound is gradually reduced until it is no longer heard and this represents the threshold of hearing, at that frequency, through air and bone respectively. It may be necessary to play a masking noise into the opposite ear to prevent that ear from hearing the tones, enabling each ear to be tested independently.
General symptoms The following are some of the chief symptoms of ear disease: DEAFNESS (see DEAFNESS). EARACHE is most commonly due to acute in?ammation of the middle ear. Perceived pain in this region may be referred from other areas, such as the earache commonly experienced after tonsillectomy (removal of the TONSILS) or that caused by carious teeth (see TEETH, DISORDERS OF). The treatment will depend on the underlying cause. TINNITUS or ringing in the ear often accompanies deafness, but is sometimes the only symptom of ear disease. Even normal people sometimes experience tinnitus, particularly if put in soundproofed surroundings. It may be described as hissing, buzzing, the sound of the sea, or of bells. The intensity of the tinnitis usually ?uctuates, sometimes disappearing altogether. It may occur in almost any form of ear disease, but is particularly troublesome in nerve deafness due to ageing and in noise-induced deafness. The symptom seems to originate in the brain’s subcortical regions, high in the central nervous system. It may be a symptom of general diseases such as ANAEMIA, high blood pressure and arterial disease, in which cases it is often synchronous with the pulse, and may also be caused by drugs such as QUININE, salicylates (SALICYLIC ACID and its salts, for example, ASPIRIN) and certain ANTIBIOTICS. Treatment of any underlying ear disorder or systemic disease, including DEPRESSION, may reduce or even cure the tinnitis, but unfortunately in many cases the noises persist. Management involves psychological techniques and initially an explanation of the mechanism and reassurance that tinnitus does not signify brain disease, or an impending STROKE, may help the person. Tinnitus maskers – which look like hearing aids – have long been used with a suitably pitched sound helping to ‘mask’ the condition.
Diseases of the external ear
WAX (cerumen) is produced by specialised glands in the outer part of the ear canal only. Impacted wax within the ear canal can cause deafness, tinnitis and sometimes disturbance of balance. Wax can sometimes be softened with olive oil, 5-per-cent bicarbonate of soda or commercially prepared drops, and it will gradually liquefy and ‘remove itself’. If this is ineffective, syringing by a doctor or nurse will usually remove the wax but sometimes it is necessary for a specialist (otologist) to remove it manually with instruments. Syringing should not be done if perforation of the tympanic membrane (eardrum) is suspected. FOREIGN BODIES such as peas, beads or buttons may be found in the external ear canal, especially in children who have usually introduced them themselves. Live insects may also be trapped in the external canal causing intense irritation and noise, and in such cases spirit drops are ?rst instilled into the ear to kill the insect. Except in foreign bodies of vegetable origin, where swelling and pain may occur, syringing may be used to remove some foreign bodies, but often removal by a specialist using suitable instrumentation and an operating microscope is required. In children, a general anaesthetic may be needed. ACUTE OTITIS EXTERNA may be a di?use in?ammation or a boil (furuncle) occurring in the outer ear canal. The pinna is usually tender on movement (unlike acute otitis media – see below) and a discharge may be present. Initially treatment should be local, using magnesium sulphate paste or glycerine and 10-per-cent ichthaminol. Topical antibiotic drops can be used and sometimes antibiotics by mouth are necessary, especially if infection is acute. Clotrimazole drops are a useful antifungal treatment. Analgesics and locally applied warmth should relieve the pain.
CHRONIC OTITIS EXTERNA producing pain and discharge, can be caused by eczema, seborrhoeic DERMATITIS or PSORIASIS. Hair lotions and cosmetic preparations may trigger local allergic reactions in the external ear, and the chronic disorder may be the result of swimming or use of dirty towels. Careful cleaning of the ear by an ENT (Ear, Nose & Throat) surgeon and topical antibiotic or antifungal agents – along with removal of any precipitating cause – are the usual treatments. TUMOURS of the ear can arise in the skin of the auricle, often as a result of exposure to sunlight, and can be benign or malignant. Within the ear canal itself, the commonest tumours are benign outgrowths from the surrounding bone, said to occur in swimmers as a result of repeated exposure to cold water. Polyps may result from chronic infection of the ear canal and drum, particularly in the presence of a perforation. These polyps are soft and may be large enough to ?ll the ear canal, but may shrink considerably after treatment of the associated infection.
Diseases of the middle ear
OTITIS MEDIA or infection of the middle ear, usually occurs as a result of infection spreading up the Eustachian tubes from the nose, throat or sinuses. It may follow a cold, tonsillitis or sinusitis, and may also be caused by swimming and diving where water and infected secretions are forced up the Eustachian tube into the middle ear. Primarily it is a disease of children, with as many as 1.5 million cases occurring in Britain every year. Pain may be intense and throbbing or sharp in character. The condition is accompanied by deafness, fever and often TINNITUS.
In infants, crying may be the only sign that something is wrong – though this is usually accompanied by some localising manifestation such as rubbing or pulling at the ear. Examination of the ear usually reveals redness, and sometimes bulging, of the ear drum. In the early stages there is no discharge, but in the later stages there may be a discharge from perforation of the ear drum as a result of the pressure created in the middle ear by the accumulated pus. This is usually accompanied by an immediate reduction in pain.
Treatment consists of the immediate administration of an antibiotic, usually one of the penicillins (e.g. amoxicillin). In the majority of cases no further treatment is required, but if this does not quickly bring relief then it may be necessary to perform a myringotomy, or incision of the ear drum, to drain pus from the middle ear. When otitis media is treated immediately with su?cient dosage of the appropriate antibiotic, the chances of any permanent damage to the ear or to hearing are reduced to a negligible degree, as is the risk of any complications such as mastoiditis (discussed later in this section). CHRONIC OTITIS MEDIA WITH EFFUSION or glue ear, is the most common in?ammatory condition of the middle ear in children, to the extent that one in four children in the UK entering school has had an episode of ‘glue ear’. It is characterised by a persistent sticky ?uid in the middle ear (hence the name); this causes a conductive-type deafness. It may be associated with enlarged adenoids (see NOSE, DISORDERS OF) which impair the function of the Eustachian tube. If the hearing impairment is persistent and causes problems, drainage of the ?uid, along with antibiotic treatment, may be needed – possibly in conjunction with removal of the adenoids. The insertion of grommets (ventilation tubes) was for a time standard treatment, but while hearing is often restored, there may be no long-term gain and even a risk of damage to the tympanic membrane, so the operation is less popular than it was a decade or so ago. MASTOIDITIS is a serious complication of in?ammation of the middle ear, the incidence of which has been dramatically reduced by the introduction of antibiotics. In?ammation in this cavity usually arises by direct spread of acute or chronic in?ammation from the middle ear. The signs of this condition include swelling and tenderness of the skin behind the ear, redness and swelling inside the ear, pain in the side of the head, high fever, and a discharge from the ear. The management of this condition in the ?rst instance is with antibiotics, usually given intravenously; however, if the condition fails to improve, surgical treatment is necessary. This involves draining any pus from the middle ear and mastoid, and removing diseased lining and bone from the mastoid.
Diseases of the inner ear
MENIÈRE’S DISEASE is a common idiopathic disorder of ENDOLYMPH control in the semicircular canals (see EAR), characterised by the triad of episodic VERTIGO with deafness and tinnitus. The cause is unknown and usually one ear only is affected at ?rst, but eventually the opposite ear is affected in approximately 50 per cent of cases. The onset of dizziness is often sudden and lasts for up to 24 hours. The hearing loss is temporary in the early stages, but with each attack there may be a progressive nerve deafness. Nausea and vomiting often occur. Treatment during the attacks includes rest and drugs to control sickness. Vasodilator drugs such as betahistine hydrochloride may be helpful. Surgical treatment is sometimes required if crippling attacks of dizziness persist despite these measures. OTOSCLEROSIS A disorder of the middle ear that results in progressive deafness. Often running in families, otosclerosis affects about one person in 200; it customarily occurs early in adult life. An overgrowth of bone ?xes the stapes (the innermost bone of the middle ear) and stops sound vibrations from being transmitted to the inner ear. The result is conductive deafness. The disorder usually affects both ears. Those affected tend to talk quietly and deafness increases over a 10–15 year period. Tinnitus often occurs, and occasionally vertigo.
Abnormal hearing tests point to the diagnosis; the deafness may be partially overcome with a hearing aid but surgery is eventually needed. This involves replacing the stapes bone with a synthetic substitute (stapedectomy). (See also OTIC BAROTRAUMA.)... ear, diseases of
Because it is a more powerful antibiotic than amoxicillin alone, co-amoxiclav is used to treat infections caused by amoxicillin-resistant strains of bacteria.... co-amoxiclav
Bacterial meningitis is life-threatening: in the United Kingdom, 5–10 per cent of children who contract the disease may die. Most cases of acute bacterial meningitis in the UK are caused by two bacteria: Neisseria meningitidis (meningococcus), and Streptococcus pneumoniae (pneumococcus); other bacteria include Haemophilus in?uenzae (a common cause until virtually wiped out by immunisation), Escherichia coli, Mycobacterium tuberculosis (see TUBERCULOSIS), Treponema pallidum (see SYPHILIS) and Staphylococci spp. Of the bacterial infections, meningococcal group B is the type that causes a large number of cases in the UK, while group A is less common.
Bacterial meningitis may occur by spread from nearby infected foci such as the nasopharynx, middle ear, mastoid and sinuses (see EAR, DISEASES OF). Direct infection may be the result of penetrating injuries of the skull from accidents or gunshot wounds. Meningitis may also be a complication of neurosurgery despite careful aseptic precautions. Immuno-compromised patients – those with AIDS or on CYTOTOXIC drugs – are vulnerable to infections.
Spread to contacts may occur in schools and similar communities. Many people harbour the meningococcus without developing meningitis. In recent years small clusters of cases, mainly in schoolchildren and young people at college, have occurred in Britain.
Symptoms include malaise accompanied by fever, severe headache, PHOTOPHOBIA, vomiting, irritability, rigors, drowsiness and neurological disturbances. Neck sti?ness and a positive KERNIG’S SIGN appearing within a few hours of infection are key diagnostic signs. Meningococcal and pneumococcal meningitis may co-exist with SEPTICAEMIA, a much more serious condition in terms of death rate or organ damage and which constitutes a grave emergency demanding rapid treatment.
Diagnosis and treatment are urgent and, if bacterial meningitis is suspected, antibiotic treatment should be started even before laboratory con?rmation of the infection. Analysis of the CEREBROSPINAL FLUID (CSF) by means of a LUMBAR PUNCTURE is an essential step in diagnosis, except in patients for whom the test would be dangerous as they have signs of raised intracranial pressure. The CSF is clear or turbid in viral meningitis, turbid or viscous in tuberculous infection and turbulent or purulent when meningococci or staphylococci are the infective agents. Cell counts and biochemical make-up of the CSF are other diagnostic pointers. Serological tests are done to identify possible syphilitic infection, which is now rare in Britain.
Patients with suspected meningitis should be admitted to hospital quickly. General pracitioners are encouraged to give a dose of intramuscular penicillin before sending the child to hospital. Treatment in hospital is usually with a cephalosporin, such as ceftazidime or ceftriaxone. Once the sensitivity of the organism is known as a result of laboratory studies on CSF and blood, this may be changed to penicillin or, in the case of H. in?uenzae, to amoxicillin. Local infections such as SINUSITIS or middle-ear infection require treatment, and appropriate surgery for skull fractures or meningeal tears should be carried out as necessary. Tuberculous meningitis is treated for at least nine months with anti-tuberculous drugs (see TUBERCULOSIS). If bacterial meningitis causes CONVULSIONS, these can be controlled with diazepam (see TRANQUILLISERS; BENZODIAZEPINES) and ANALGESICS will be required for the severe headache.
Coexisting septicaemia may require full intensive care with close attention to intravenous ?uid and electrolyte balance, control of blood clotting and blood pressure.
Treatment of close contacts such as family, school friends, medical and nursing sta? is recommended if the patient has H. in?uenzae or N. meningitidis: RIFAMPICIN provides e?ective prophylaxis. Contacts of patients with pneumococcal infection do not need preventive treatment. Vaccines for meningococcal meningitis may be given to family members in small epidemics and to any contacts who are especially at risk such as infants, the elderly and immuno-compromised individuals.
The outlook for a patient with bacterial meningitis depends upon age – the young and old are vulnerable; speed of onset – sudden onset worsens the prognosis; and how quickly treatment is started – hence the urgency of diagnosis and admission to hospital. Recent research has shown that children who suffer meningitis in their ?rst year of life are ten times more likely to develop moderate or severe disability by the age of ?ve than contemporaries who have not been infected. (See British Medical Journal, 8 September 2001, page 523.)
Prevention One type of bacterial meningitis, that caused by Haemophilus, has been largely controlled by IMMUNISATION; meningococcal C vaccine has largely prevented this type of the disease in the UK. So far, no vaccine against group B has been developed, but research continues. Information on meningitis can be obtained from the Meningitis Trust and the Meningitis Research Foundation.... meningitis
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