1 Typhoid Fever

7/25/2019 1 Typhoid Fever

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Typhoid fever

Enteric fever is an acute systemic illness characterizedby fever , headache , and abdominal discomfort.

Typhoid ,the typical form of enteric fever ,is caused by

Salmonella typhi.A similar but generally less severe

illness known as paratyphoid is due to infection withS.paratyphi A,B,or C.Man is the only natural host for

S.typhi , which is transmitted in contaminated food or

water.The incubation period is !"# days.


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Clinical features

$After ingestion, the bacteria invade the small bowel wallvia %eyer &s patches, from where they spread to the

regional lymph nodes and then to the blood.

$The onset is insidious and non"specific , with

intermittent fever, headache ,and abdominalpain.%hysical findings in the early stages include

abdominal tenderness,hepatosplenomegaly,

lymphadenopathy , and a scanty maculopapular

rash'&rose spots ).


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$(ithout treatment' and occasionally even after

treatment) serious complications can arise , usually inthe third week of illness.These include*

.Meningitis

+.ober peumonia

-.steomyelitis

#./ntestinal perforation and hemorrhage

$The # th week of the illness is characterized by gradual

improvement , but in developing countries up to -!0

of the infected will die , and !0 of untreated

survivors will relapse


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$After clinical recovery 1"!0 of the patients will

continue to e2crete S.typhi for several months * these

are termed convalescent carriers.

$3etween 0 and #0 will continue to carry organism for

more than a year * this is called chronic carriage.Theusual site of carriage is the gallbladder,and chronic

carriage is associated with the presence of

gallstones.


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Diagnosis

$The definitive diagnosis of enteric fever re4uires the

cultureof S.typhi or S. paratyphi from the patient.$Blood cultureis positive in the first + weks.5ultures of

intestinal secretions ,faeces , and urine is alsoused , although care must be taken to distinguish

acute infection from chronic carriage.

$Bone marrow cultureis more sensitive than bloodculture , but is rarely re4uired except in patients who

have already received antibiotics.$.B!!serological tests such as the (idal antigen test

are of little practical value and are easilymisinterpreted.


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"anagement$5hloramphenicol , co"trimo2azole and amo2icillin may

still be effective in some cases , but #uinolones ' e.g

ciproflo2acin 1!! mg twice daily ) are now thetreatment of choice.

$Although increased resistance to 4uiolones is being

seen * in such cases azithromycin may be effective..B!!.the patient &s temperature may remain elevatedfor several days after starting antibiotics , and thisalone is nota sign of treatment failure.

$%rolonged antibiotic therapy may eleminate the carrier

state , but in the presence of gallbladder disease it israrely effective.5holycystectomy is not usually 6ustified

on clinical or public health grounds.


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$revention

$Mainly through improved sanitation and clean

water.

$Travellers should avoid drinking untreated water,ice in drinks and eating ice creams.

$7accination with in6ectable inactivated or oral liveattenuated vaccines gives partial protection.


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Brucellosis % "alta fever , undulant fever)is azoonosis and has a world 8wide distribution.

The organismsusually gain entry into human body viathe mouth 9less fre4uently they may enter via therespiratory tract , genital tract or abraded skin.

$The bacilli travel in the lymphatics and infect the lymphnodes .This is followed by haematogeneous spreadwith ultimate localization in the reticuloendothelialsystem.

$Spread is usually by the ingestion of raw milk from the

infected cattle or goats, although occupationale2posure is also common.%erson 8 to " persontransmissionis rare.


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Clinical features$The incubation period of brucellosis is "-

weeks. The onset is insidious , with malaise ,headache, weakness, generalized myalgiaand night sweats.

$The fever pattern is classically undulant ,although continuous and intermittent patternsare also seen.ymphadenopathy,hepatosplenomegaly and spinal tendernesssacro"iliitis'+!"-!0) may be present9arthritis , osteomyelitis ,epididimo"orchitis 'upto #!0 ) , meningoencephalitis and

endocarditis have all been described.


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$:ntreated brucellosis can give rise to chronic

infection, lasting a year or more.This is

characterized by easy fatiguability , myalgia ,and occasional bouts of fever and

depression.

$Splenomegaly is usually present.ccasionally

infection can lead to localized

brucellosis.3ones and 6oints , spleen

,endocardium , lungs , urinary tract andnervous system may be involved.Systemic

symptoms occur in less than one third.


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DIAGNOSIS

$Blood % or bone marrow ) cultures are

positive during the acute phase of illness in

1!0of patients % higher in B.meitensis ),

but prolonged culture is re4uired.

$/f using automated blood culture systems

'3A5TE5) incubate longer than the usual1";

days.This is less helpful in chronic disease

where serological tests of greater value.


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$$C& for the detection of 3rucella in blood

gives a rapid diagnosis ,and along with the

measurement of /g< and /gM antibodies

by E/SA , are highly sensitive andspecific


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"anagement

$3rucellosis is treated with a combinationof doxycycline +!!mg dailyandrifampicin=!!>?!! mg daily for '

wee(s, but relapses occur.

$Alternatively tetracycline can becombined with streptomycin , which isusually given for only the first + weeks oftreatment.


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$revention

$%revention and control involve carefulattention to hygiene when handlinginfected animals.

,vaccination with the eradication ofinfection in animals , and pasteurizationof milk.

$o vaccine is available for use in

humans.

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1 Typhoid Fever