Ординатура / Офтальмология / Английские материалы / Pediatric Opthalmology_Mukherjee_2005

It is one of the most tenacious organism that is potentially destructive, difficult to destroy by sterilisation and has tendency to develop resistance to antibiotic.

The organism is a small, gram positive, non motile, non sproulating that is seen in various forms i.e. single, in chains or in bunches. It is easily grown. The growth is best at 30-37ºC. It is resistant to desiccation and many disinfectants. They are aerobic or facultative anaerobic.

Basically there are two types of organism i.e. coagulase positive and coagulase negative. Out of the two the former is pathogenic and the organism is called staphylococcus aureus, that produces golden coloured colonies. It produces many enzymes and toxins.

There are many species of coagulase negative staphylococci. They are known by various names i.e. S. albus, S. epidermis, S. hemolyticus, S. saprophyticus.

Coagulase negative staphylococci were thought to be only contaminants in the past, they are now considered as important opportunistic organism.

There are no known vaccines, anti toxins or toxoids that can be used as prophylaxis against all strains and species.

Systemic involvement - Almost all organs can be infected by staphylococci. Multiple organ involvement is common. It may develop in new born as toxic epidermal necrolysis to ripe old age as pneumonia. It may manifest as simple single boil, carbuncle, erysipelas. Other common systemic involvement’s are respiratory infection, rhinitis, otitis media, CNS infection, urinary tract infection, osteomyelitis, food poisoning and sepic shock syndrome.

Ocular involvement is common due to continuity of ocular surface with skin through lids and nasopharynx via lacrimal passage. Other sources of intra ocular infection are mostly intra operative and post operative.

Common ocular lesions are—Stye, lid abscess, boil on the lid, chronic blepharitis, dacryocystitis, orbital cellulitis due to generalised septicimia, there may be periostitis or orbital abscess.

Most common infection is acute or chronic conjunctivitis, other involvement in children is phlycten. Corneal involvement may be peripheral catarrhal keratitis due to staphylococcal toxin and suppurative keratitis.

Most dangerous infection is acute or delayed endophthalmitis following any intra ocular surgery, or penetrating injury. S. aureus causes acute endophthalmitis while coagulase negative strain cause delayed and chronic endophthalmitis.

Staphylococcal infection can cause anterior non granulomatous uveites, scleritis even dacryoadenitis.

Cavernous sinus thrombosis though basically a systemic CNS infection invariably report to the ophthalmologist.

Management

The infection may be caused by penicillin and methicillin resistant organism. Hence it is essential to find out the cultural character and sensitivity to antibiotic for complete eradication.

Ocular

Blepharitis: Lid hygiene, frequent application of erythromycin 0.5% ointment or bacitracin ointment for weeks. Oral doxycilin 100 mg OD × 10

Conjunctivitis—Sulphacetamide drop, ciprofloxacilin 0.3% drops, frequently.

Keratitis- Fortified cefazoline drops.

Vancomycin 50 mg/ml in phosphate buffered artificial tear is used in methicillin resistant staphylococci along with cycloplegic, may require sub-conjunctival injection.

Endophthalmitis is an emergency that requires early detection and management. Intra vitireal injection of proper antibiotic is the most effective method to combat endophthalmitis. Role of vitrectomy is doubtful.

Streptococcus

Human respiratory, gastro intestinal and genito urinary tracts commonly have colonies of streptococci. A person may be asymptomatic yet may harbour the organism. It is a major cause of neonatal sepsis, post infective acute rheumatic fever and post streptococcal glomerulonephritis. The enteroccocci cause mostly urinary tract infection while viridans cause endocarditis frequently.

The organism is gram positive, oval shaped, non motile, non sporulating. When grown in liquid media, they are seen in pairs or chains. The human pathogenic strains are facultative anaerobes. They are difficult to culture, requiringenriched media. Many strains cause hemolysis round the colonies. This property to causes hemolysis has been utilised to classify them into alpha and beta hemolyticus, when cultured on blood agar. About 20 percent of persons in a population may be asymptomatic carriers who are responsible for food borne infection and nosocomial infection.

Systemic involvement

All parts of the body can be infected by streptococci. The common conditions are pyoderma, cellulitis, erysipelas, necrotising fasciitis, scarlet fever, pharyangitis, tonsillitis, tonsilar abscess, pneumonia and empyema, streptococcal shock syndrome, neonatal sepsis and meningitis.

Ocular manifestation can be direct involvement of the conjunctiva, spreading from the skin, nasopharynx or metastatic.

Streptococcal conjunctivitis is generally self-limiting. It can cause membranous or pseudo membranous conjunctivitis that can lead to corneal infiltration, ulceration and even perforation. It can cause ophthalmia neonatorum.

Streptococci can cause preseptal cellulitis or frank orbital cellulitis. Preseptal cellulitis is common in children.

Endophthalmitis due to streptococci has uniformly poor prognosis. It is worst with S pyogenes and slightly better with S. viridans.

Mild to moderate anterior uveitis is also known to be due to streptococci.

Management

Most of the strains of streptococci are sensitive to penicillin. Alternate drugs include— Cephalosporins, erythromycin, clindamycine, tetracycline and chloramphenicol. Enterococci

are generally resistant to penicillin and cephalosporins. They respond well to vancomycin and aminoglycocides.

Spirochaetaceae8, 9

There are many organisms in this group. The most important out of them is treponema pallidum that causes syphilis. The other two are leptospira and Borrelia. The former cause leptospirosis, the latter results in relapsing fever, vincent angina and lyme disease.

Syphilis is one of the most widely spread chronic disease that can infect at any age and both the sexes in all races. It can be congenital or acquired.

The organism treponema pallidum is a spiral shaped, thin. delicate looking organism that has 6 to 14 spirals along its long axes. It is a motile organism. It is best seen on dark field examination. It can not be cultured invitro. Humans are the only known natural host.

The disease is mostly sexually transmitted though it can be acquired following blood transfusion with infected blood. Congenital syphilis is mostly due to transplacental spread from infected mother to the growing foetus generally in the third or fourth month of gestation. However, older children can acquire it following child abuse. In such cases they go through all the stages of adult acquired syphilis i.e. the primary, secondary, latent and tertiary stage.

Systemic involvement in congenital syphilis

The disease can be transmitted to the foetus any time during pregnancy if the mother is serologically positive. It develops more commonly by fourth month. Mothers in early stage of infection are more likely to infect the foetus than those who had infected period of more than two years. Early treatment of the mother before sixteen week is said to protect the foetus. Abortion and still births are two common modes of termination of congenital syphilis. It is a major cause of neonatal death.

The clinical presentation of congenital syphilis in surviving neonates can be divided into three stages:

1.Early features that appear within first two years of age.

2.Late manifestation that develop after two years

3.Residual effect of late manifestation

The systemic manifestations differ in infants and older children.

Infants—Presence of congenital syphilis is not felt at birth. They become obvious by second to tenth week post natal with hepato spleenomegaly, jaundice, anemia thrombocytopenia, lymphadenopathy. Skin rashes that may be bullae or vesicle, rhinitis, osteo chondritis.

The ocular signs are absent at this stage:

Older children—Anterior bowing of shin, periostitis, frontal bossing, Clutton joints, saddle nose, mulberry molars, peg shaped teeth, eighth cranial nerve involvement and ocular manifestation.

Ocular manifestations are late manifestation of congenital syphilis that has remained untreated for more than two years.

Commonest ocular manifestation of congenital syphilis is interstitial keratitis that develops between two to twenty years, is a bilateral condition.

It is always associated with sever anterior uveitis that is associated with endothelial edema, leading to generalised edema of the cornea and development of deep vascularisation. The deep vascularisation gives rise to salmon patch appearance, which gradually subsides to leave obliterated corneal vessels as ghost vessels. It takes years for the vessels to regress. A ground glass appearance of the cornea is common.

Other features are bilateral chorioretinitis, which gives an appearance of salt and pepper pigmentation also known as pseudo retinitis pigmentosa. Secondary glaucoma is common due to changes in the angle secondary to anterior uveites.

The differential diagnosis of interstitial keratitis include other condition of hazy cornea in children—Corneal birth injury, late corneal injury, congenital glaucoma, corneal endothelialdystrophy, congenitalrubellasyndrome, mucopolysaccharidosis, mucolipidosis.

Conditions that give pepper salt appearance of the retina besides congenital syphilis are rubella, cytomegalovirusretinitis, influenza.

Neonatal congenital syphilis should be differentiated from - Rubella, cytomegalo virus infection, toxoplasmosis, herpes simplex and erythroblastosis fetalis.

Management

The condition is preventable if the mother is adequately treated before sixteenth week of gestation. The infected child is treated with aqueous crystalline penicillin in consultation with pediatrician.

Ocular condition is treated with atropine and local steroid over months.

Leptospirosis

Leptospirosis as an organism that belongs to order spirochaetales. Leptospirosis is less frequent disease. It is seen as epidemics in certain parts of tropical and subtropical countries where financially less privileged persons live in unhygienic conditions in close contact the animals. The disease is zoonosis, is spreads commonly from certain animals to humans. Human to human spread is possible but less frequent. Drinking water contaminated by urine of infected animals or human beings is also a mode of spread. Many animals, fish or birds are the reservoir of the organism.

The organism is a spirocheate, it is a thin highly motile spiral organism that stain poorly but is clearly visible on dark field examination.

Systemic involvement

Many animals act as reservoir for the organism. These animals rarely develop the disease.

Humans acquire the disease by contact with urine or tissue of infected animals, or by drinking contaminated water. The organism commonly reaches the body through abraded skin or mucous membrane.

The incubation period is one to two weeks. The organism can be recovered from blood, CSF, aqueous within twenty four hours.

The virulence depends on toxin production. Clinically the disease has two stages-

1.Phase of leptospiracmia

2.Immune phase

The first phase consists of influenza like symptoms of pain all over the body, fever, chills, skinrashes, gastrointestinal disturbance, respiratory infection. One of common findings at this stage is conjunctival effusion.

The second phase lasts for several weeks. The child may become asymptomatic or may have serious complications like encephalitis, Guillain-Barre syndrome, multiple cranial nerve palsy, peripheral nerve involvement and myocarditis.

Ocular manifestations are common and variable. Commonest finding is conjunctival effusion without lacrimation or discharge. If there is discharge, it may contain leptospira.

Other ocular manifestations are—Iridocyclitis that may be mild and self limiting. Rarely may have chronic uveitis. Neovascularisation of iris, hypopyon, mutton fat KPs, broad posterior synechia, complicated cataract and secondary glaucoma. Retinal haemorrhage, choroiditis, chorio retinitis, vitreous membrane have also been reported.

Management consists of:

Prevention by personal hygiene, food hygiene, drinking potable water and chemo prophylaxis during epidemics by way of 100 mg doxycyclin once a day for a week in adults.

The organism is sensitive to ampicillin, erythromycin, doxycyclin, tetracyclin. Severe cases may require injection IV penicillin G.

Conjunctivitis does not require any separate treatment if the patient is on systemic antibiotic otherwise erythromycin ointment or fresh penicillin drops may be required.

Iridocyclitis is treated by standard method.

Lyme disease

The disease is spirochetal disease caused by Borreliaburgdorferi. It is a multi systemic disease. It is one of the arthopod related diseases that is spread by bite of tick ixodes. Many mammals are host of the tick.

Systemic involvement

The disorder involves multiple symptoms. Common are—Skin rash. neurological signs consist of Bell’s palsy, other cranial nerve palsy, meningitis, peripheral neuritis, late presentation are arthritis and peripheral neuropathy.

Ocular involvement—Any part of the eye may be involved. They can be divided into two groups i.e. secondary to neurological causes and those due to involvement of the eyeball proper. These are mostly immune mediated inflamations. The signs and symptoms of both the groups can run simultaneously. They are facial palsy, paralytic squint, optic neuritis, retrobulbar neuritis, optic atrophy, pseudo tumour cerebri, papilledema, conjunctivitis, symblepharon, keratitis, episcleritis.

Intra ocular manifestations are—Iritis, parsplanitis, and chorioretinitis.

The involvement may be unilateral or bilateral. One eye may be involved later than the other may. The lesion can be single or multiple.

Management

The disease mimic many diseases. It is relatively rare hence knowledge of the disease and high degree of suspicion is required. Elisa test and immuno fluorescent assays are the two investigations that may clinch the diagnosis.

The organism is sensitive to—Penicillin, amoxycillin, erythomycin, roxithromycin, tetracycline and doxycyclin.

Ocular management consists of management of Bell’s palsy, conjunctivitis, keratitis and episcleritis by standard methods.

Proteus

This is a saprophyte that is found in decaying organic matter, soil, water and GI tract of many animals and human beings. Generally infection by proteus is mild and may be asymptomatic unless they become opportunistic and cause wide spread infection.

The organism is gram negative, actively motile, non lactose fermenting. It possesses an enzyme urease, making it a potential urinary tract infective organism.

Systemic manifestation—Commonest infection is urinary tract infection. The urinary tract acts as portal of entry for other organs. Proteus invades immuno compromised individuals and debilitated individuals. It is a known contaminant of wounds, accidental or surgical and burns.

Other systemic manifestations are—Otitis media, mastoiditis, lateral sinus thrombosis, meningitis, even brain abscess.

Ocular manifestation—Though external ocular infections like conjunctivitis, keratitis is known to be caused by proteus, they are mostly due to trauma. However proteus is a potentially blinding organism following penetrating injury that may be accidental or surgical. Rarely it can cause dacryocystitis and scleritis.

Management

The organism is sensitive to many antibiotics i.e. ampicillin, third generation cephalosporin, all aminoglycocides.

Ocular treatment is by fortified gentamycin 14 mg/ml or tobramycin 14mg/ml frequently or by 0.3% ciprofloxacilin or ofloxacilin 0.3% drops hourly.

Endophthalmitis following either accidental or surgical is a serious condition requiring intra vitreal injection of gentamycin or amikacin. Vitrectomy may be required.

Salmonellosis—Typhoid (enteric fever)

Typhoid is one of the common acute febrile conditions in all ages. It is very common in children. It is a preventable public health problem that may cause death if not treated.

There are many organism in the salmonella group, only few cause human infection. The salmonella typhi the causative organism for typhoid fever is found only in humans.

The disease is transmitted by ingestion of contaminated drink or food. The disease also spreads due to person to person contact during acute phase. It can also spread from asymptomatic carriers. Faecal oral contact is commonest mode of spread in all ages, more so in children.

S. typhi is a gram negative, motile, facultative anaerobe. Incubation period varies between 3 days to 60 days.

Systemic involvement is basically enteritis, which is heralded by fever that is prolonged and persistent. There is step like rise of temperature, rose spots all over the body. Relative bradycardia is supposed to be a strong suggestive factor. There may be diarrhoea or constipation. The small intestine is commonly involved. There is hyperplasia of Peyers patches, mucosal ulceration, bleeding and perforation.

The child is generally delirious, has severe anorexia and loss of weight. The child may recover from these early phases or may pass into more widespread systemic involvement that includes almost all systems. There may be meningitis, encephalitis, paralysis of cranial nerve, pneumonia, bronchitis, myocarditis, cholecystitis, osteomyelitis, arthritis.

The child becomes afebrile with adequate antibiotic in four to seven days. In about 10% cases there is relapse. About 2% to 3% cases develop chronic carrier status and public health hazard.

Ocular manifestations are rare, when present are due to hematological spread of the organism. They are—Lid abscess, dacryoadenitis, hemorrhagic spots on the conjunctiva, keratitis, uveitis, vitreous and retinal haemorrhages, paralysis of extra ocular muscles.

Management : Prophylaxis—The disease is preventable if environmental, sanitation, water supply and sewage disposal could be improved. However if all children are supplied with potable water and instructed to follow proper food hygiene, the incidence falls sharply. Other prophylactic method is to give prophylactic oral vaccine and repeated every two years.

The first antibiotic found to be effective against typhoid was chloramphenical. The drug though very effective had many untoward side effects. The chloramphenical was followed by a long list of antibiotics that includes-Trimethoprim-sulphamethoxazole, ampicillin, amoxycillin, fluoroquinolones, third generation cephalosporins.

Ocular manifestations are treated by standard methods along with systemic antibi-

otics.

Ocular manifestation of systemic virus disease11, 12, 13, 14

Viruses are smallest infective organisms. They are called primitive organisms because they contain only one single nucleic acid either DNA or RNA. The viruses consist of nucleic acid surrounded by one or more proteins. The viruses themselves can not replicate for which they require a host-cell, hence they are called obligate intracellular parasites. Some of the viruses have an outer cover membrane that protects and stabilizes the nucleoid from environment outside and helps the virus to invade host cell. The outer cover, which is protein in nature, is responsible for antigenicity of the virus. On which depends the immunity and diagnostic tests. The antigenecity is usefully utilised to manufacture vaccine.

The invading viruses get attached to a special receptor site on the host cell membrane. The viruses are then pagocytosed.

The viruses do not possess enzyme required for reproduction and survival. They depend on the host cell for the enzyme, energy and precursor for multiplication.

The RNA viruses replicate in the cytoplasm of the host cell. The DNA replicate in the nuclei.

The RNA viruses that have ocular involvement are—

Entero virus (Picorna viruses)—They include—Poliomyelitis, Coxsackie virus and ECHO viruses.

Paramyxo viruses—Mumps, rubella and measles viruses.

Human immuno deficiency virus

The DNA viruses that have ocular involvement are— Pox viruses—Small pox virus (variola) and vaccinia virus.

Herpes viruses—Chicken pox (varicella), herpes simplex, herpes zoster, and cytomegalo viruses.

Other viruses—Molluscum contagiosum, human papilloma virus and human adeno viruses, Epistein-Barr virus.

Poliomyelitis

This viral disease has world-wide distribution. Though it has almost been eradicated in developed countries, it remains a major cause of death and physical handicap in developing countries. Its ocular manifestations are few and overshadowed by motor paralysis and deformity.

Like any other entero virus, poliovirus is transmitted by fecal-oral route. It has a short incubation period of three to six days. Most of the time it is asymptomatic. Only five percent of children have mild symptoms of fever, malaise, and body ache that is generally passed as influenza or other viral fever. Only one percent develops aseptic meningitis which is the cause of most visible sequel i.e. motor paralysis.

The central nervous system involvement has been divided anatomically intomeningeal, encephalic, bulbar, cerebellar and spinal.

The bulbar form is most likely to cause ocular involvement in the form of cranial nerve palsy. Commonest extra ocular muscle to be involved is lateral rectus. Involvement of fourth nerve is least common. Some children may develop seventh nerve palsy. Nystagmus is very frequent. Pupillary abnormalities are part of third nerve involvement. Horner’s syndrome develops rarely. Involvement of optic nerve is the cause of transient visual loss. The ocular involvements are self limiting.

Coxsackie virus

They cause less ocular manifestation than poliomyelitis. Systemic infection may lead to necrosis of skeletal muscles, tremor, spasticity, flacid paralysis, encephalo myelitis, aseptic meningitis.

The ocular involvement’s are either secondary to involvement of CNS or due to primary infection of conjunctiva and cornea resulting is kerato conjunctivitis, keratitis, phlycten, corneal pannus, pseudo membranous conjunctivitis.

ECHO viruses produce ocular manifestation similar to Cox sac kie virus.

Mumps

Mumps is common acute contagious disease of childhood. Commonest presentation is bilateral, almost symmetric painful swelling of parotid glands. The condition has a

prodromal stage of fever, body ache, anorexia, and malaise. It gives a life long immunity. Life long immunity is also acquired following immunisation.

The virus is a paramyxo virus, which is a RNA virus. It is one of the smaller viruses. It is pleomorphic.

The disease spreads as droplet infection via saliva and fomitis. The incubation period is 14-20 days.

Systemic involvement

After prodromal period that may last for one to two days, the child develops fast growing bilateral swelling, difficulty in swallowing and pain in the ear. It is common to develop similar swelling in the sub mandibular glands. Sub mandibular glands are always associated with parotitis. The swelling of the gland increases for two to three days and then subsides gradually leaving no trace of infection.

Other organs to be inflamed are testes, pancreas, ovaries. The orchitis is common in post pubertal patient. About 20% males are effected. The swelling is generally unilateral and painful. Late complication of orchitis is testicular atrophy. As testicular atrophy is unilateral it does not lead to sterility in men.

Oophoritis is less common, presents as pain in lower abdomen and does not cause steril-

ity.

More serious manifestations are

Aseptic meningitis, encephalitis, transverse myelitis, cerebellar ataxia, facial palsy.

Ocular involvement

Commonest ocular involvement is acute dacryoadenitis, which is bilateral, may cause narrowing of palpebral fissure and mild proptosis. Other ocular involvement’s are conjunctivitis, keratitis, scleritis, iridocylitis. There may be sub conjunctival haemorrhages and rarely interstitial keratitis. Bilateral optic neuritis is self limiting and has good prognosis. Rarely extra ocular palsy or pupillary abnormality may develop.

Management : Prophylaxis

An effective mumps vaccine is available that is administered as part of MMR vaccine that includes measles and rubella vaccine. It is generally administered after 12 months of age as subcutaneous injection. It gives life long immunity.

Therapeutic—There is no known antiviral drug effective against mumps virus. The management is symptomatic and supportive in the form of analgesic. Role of steroids is not established.

Ocular management is symptomatic by standard methods of antibiotic drops, cycloplegic’s and local steroids.

Rubella (German measles)

This RNA paramyxo virus causes a serious systemic infection that is fully preventable. It causes multiple crippling congenital anomalies in the foetus if the mother acquires the disease in first trimester. Infection of the mother after fourth month does not cause much damage to

the foetus but the foetus is not altogether safe. The infection gives a life long immunity, subsequent pregnancies are safe.

The disease occurs in endemics in population that have not been immunised. The disease spreads by droplet. The incubation period is 12 to 23 days. The infected droplets cause infection in the respiratory tract which is followed by hematogenic spread.

There are two modes of presentation

1.Common mild post natal infection that may go unnoticed.

2.More serious life and vision threatening congenital infection

Commonest age to get post natal infection is school going children. This does not mean that other ages are immune. It can occur at any age. Rubella is contagious in all ages even in asymptomatic cases.

The disease has a prodromal phase of malaise, fever and anorexia. The actual infection is always associated with suboccipital, postauricular lymphadenopathy, fever and rashes.

Congenital rubella—Maternal infection during first trimester is most important cause of severe multiple congenital anomalies in the developing foetus. The foetus is infected transplacentally. The classical signs of congenital rubella is rubella syndrome that includes cataract, heart disease and deafness. Other systemic involvement’s are—Low birth weight, retardation of growth, hepatospleeanomegaly, pneumonia, thrombocytopenia. The common cardiac anomalies are—Pulmonic stenosis and ductusarteriosus. Other anomalies are dental anomalies, cleftplate, and microcephaly.

The ocular manifestations are

There are hardly any ocular involvement in acquired rubella except catarrhal conjunctivitis and superficial keratitis.

Ocular manifestations of congenital rubella are many. They are—Microphthalmos, central cataract and retinopathy.

Less common ocular features are congenital glaucoma, corneal haze, iris hypoplasia, nystagmus and squint.

Late complications include progress in retinopathy, subretinal neovascularisation and maculopathy.

The rubella cataract is bilateral, almost symmetrical, slightly eccentric, dense, nuclear type. The lens is known to harbour live virus up to two years of age. Hence surgery should be followed by frequent and prolonged use of local steroids and cycloplegic with usual caution. Every effort should be made to aspirate the cortical matter as much as possible.

The congenital glaucoma develops later than cataract and is severe in nature. The cause of glaucoma is multifactorial i.e. spherophakia, microphthalmos, anomalies in the angle, secondary to uveitis or post cataract surgery status.

Measles (Rubeola)16

Measles is a common acute exanthematous respiratory disease, which is highly contagious resulting in epidemics. The disease is potentially fatal. It is met with all over the world,