inf intro + fever

7/27/2019 Inf Intro + Fever

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INFECTION

Dr. Mehrunnisa Umar Assistant Professor

Department of Medicine


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An Observation

In developed countries infection continues to beone of the most common causes of disease anddeath, particularly in children.

Infections like pneumonia, diarrhoea, malaria,tuberculosis, and conditions like malnutrition etc.have bad effects on health and growth of nation.

Vaccination and control of vectors transmittingdiseases has significant effect but diseases tend toreappear.


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Microbiology

Microbiology is the science of studying the microbes

Variety in the genes of microbes explain behavior aswell as how microbes are helpful and/or problematicto us.

These teeny, tiny dots that we may not even be ableto see with the highest power of our microscopes,are sometimes able to kill us.

Keep in mind that humankind has also been able toharness the power of the microbial world for ourbenefit using their versatility and success atadaptation.


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Microbiology

Given that pathogenic microbes are ubiquitous, whyaren't we sick all the time?

This is because;

Species and individual defense mechanisms

Artificial immunity through immunizations and herdimmunity.

Public health measures enacted to interrupt naturaltransmission cycles.


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A complex interaction b/w bacteria & host

Bacteria must overcome obstacles before diseaseoccurs

They must enter the host successfully and colonizetissue and then damage host tissue, and grow in thatlocation.

Microorganisms enter the body, for example, throughrespiratory tract, cuts or wounds, insect bites andconsumption of contaminated food.

Additionally, hospital procedures involving catheters,intravenous therapy or transplantation increase thechances of microorganisms entering a patients body.


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Effects of Infection on Human Body

Acute EffectsFever, lethargy, weakness, catabolism,WBC, anaemia,Inflammation (five signs)Mental disorientation

Shock Septicaemia, bleedingOrgan Failure


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Chronic EffectsWeight loss, wastingPhysical retardation in childrenMalnutrition

Chronic damage to organs

Post infection syndrome - fatigue


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Immune mediatedSkin rashes and nodulation

Arthritis e.g. RA, RF,SerositisNeuropathy herpes

Haematological immune damagesNephritis strep


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Toxic (Toxin Mediated)Erythematous strep rashesSTSSToxic diarrhoeasToxic membrane diphtheria

Bacterial toxins clostridia (tetanus,botulism), diphtheria


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Pathogenecity - Pathology

Pathogenicity is the ability to destroy tissueand cause a physiological or anatomicalchange and, eventually disease.

MECHANISMS OF PATHOGENESISMicroorganisms cause disease by certainbasic mechanisms:

Invasion of tissue

Production of toxins

Virulence


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Defense Mechanism Of The HumanBody

The body resists infection and disease in anumber of ways through nonspecificresponses and specific responses.

Four nonspecific defenses in the body

Skin

Mucous membranes

Phagocytosis

Inflammation


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Defense Mechanism Of The HumanBody

HUMORAL IMMUNITY Antibodies are highly specific protein molecule

Antibody mediated defenses include:

Antitoxins,

Bacteriolytic antibodies, Antibodies plus complement,Opsonizing antibodies


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Defense Mechanism Of TheHuman Body

CELL MEDIATED IMMUNITY

Specific immune response provided by T-

lymphocytes

Cell-mediated defenses include:

Cytotoxic T-lymphocytes,K & NK cells,

Activated macrophages


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Host Microbe Interaction

Host: Any organism that harbors a microbe is a host.

Mutualism: A relationship between a host and microbewhere they both benefit each other.

Commensalisms: a relationship between host and microbewhere one benefits and the other is neither harmed nor helped.

Parasitism: a relationship between host and microbewhere one benefits and the other is harmed.


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Disease: When an organism can't carry

out normal cell function, results in adisturbance in state of health.

Not just microbes that cause thesemalfunctions, but when microbes arethe cause, it's called infectious disease.Infection means the multiplication of apathogenic microbe in a host.


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Bacterial Diseases

Infection:During this stage the bacteria are introduced into the bodytissues

Incubation:During this stage the bacteria multiply in numbers, at timeseven before the body defense mechanism could come intoaction.

Prodromal Phase: During prodrome the symptoms of disease begin to appear.


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Clinical Phase:Characteristic clinical features of agiven disease

Resolution Phase:When diagnosed and appropriatetreatment with antibiotic is instituted,resolution is expected.

At times the disease complicates andthe patient may be killed by the diseaselike in severe pneumonia


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Fever

FEVER is a Diagnostic ClueIt is an essential host defense mechanismAssociated with or without localizing signsIt can be due to Infection, inflammation or neoplasm


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Fever

MONOKINES LYMPHOKINES CYTOKINES

FEVER

ENDOGENOUS PYROGENS

InfectionsToxinsInflammationImmunologic

responses

MACROPHAGES ENDOTHELIUM

HYPOTHALAMIC ENDOTHELIUM

THERMOREGULATORY NEURONSElevated Thermostat

MacrophagesEndotheliumLymphocytesOther cells

Behavioral changes

CORTEX

PGE2 and otherArachidonicAcid metabolites

PG

+

+ PG

Peripheral efferents

Muscle contraction

Heat production

Vasomotor center

Sympathetic chain

casoconstriction

Heat conservation


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Fever

Range 36.8 + 0.4 o C (98.2 + 0.7 o F)

Lowest at 6 A.M. 37.2 o C (98.9 o F)

Peak at 4 - 6 P.M. 37.7o

C (998.9o

F)


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Fever Development

It is controlled increase in body temperatureover normal values

It is regulated in the same manner as normaltemperature but the thermostat is set at adifferent (higher) level

Factors that are responsible for setting of thethermostat at a higher level are called

`Pyrogens`.


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Fever Development

PYROGENS:

Substances (chemicals, toxins or drugs) thatcan cause fever are called pyrogens

May be exogenous (outside the host) or endogenous (produced by the host)


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Fever Development

PYROGENS:

Exogenous pyrogensLlipopolysacchride found in the outer

membrane of Gram -ve organisms.Lipteichoic acidPeptidoglycans

Act primarily by inducing formation of endogenous pyrogens or sometimes acting

directly on the endothelial cells in the brain.


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Fever Development

PYROGENS:

Endogenous pyrogens are polypeptidesproduced by a variety of host cells, usuallymonocytes and macrophages. They include:

Interleukin-1 Interleukin - 1 Tumour necrosis factor (TNF )Interferon (IFN) Interleukin 6

.


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Fever Development

PYROGENS:

Endogenous pyrogens are polypeptidesproduced by a variety of host cells, usuallymonocytes and macrophages. They include:

Interleukin-1 Interleukin - 1 Tumour necrosis factor (TNF )Interferon (IFN) Interleukin 6

.


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Fever

EFFECTS OF FEVER ON THE BODY:

BENEFITS:

Improves survival in animalsImproves inflammatory responses to illness inhumans


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Fever

EFFECTS OF FEVER ON THE BODY:

COSTS:Each one degree Celsius rise in temperature

increases oxygen consumption by 13%.Increase in caloric and fluid requirement asmore heat and fluid is lost from the body infebrile condition.

Pyrogens accelerate muscle breakdown.Mental acuity and concentration is reduced.There may be state of delirium to coma.In children, fits may be present.


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Fever- Patterns

o Intermittent type temp return to normal onceduring most days

o

Remittent type

temp do not return to normaleach day

o

Sustained/Continuous temp do not vary more than 1

degree F /day

o Relapsing - recurrent over days to weeks


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Classical PUO

1. FEVER MORE THAN 101 F2. MORE THAN 3 WEEKS3. CAUSE NOT DIAGNOSED AFTER ONE WEEK OF

INTENSIVE HOSP INVESTIGN

TYPES OF PUO ACUTE,NOSOCOMIAL,HIV ASSOCIATEDNEUTROPENIC PUO


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PUO causes

INFECTIONS 30%MALIGNANCY 20%CONNECTIVE TISSUE D- 15 %OTHERS 20 %UNDIAGNOSED 15 %


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FEVER - Common Clues

RESPIRATORY SYMPTOMS URTI ,LRTI,TB,URINARY SYMPTOMS UTI,APN,CYSTITISABDOMINAL SYMPTOMS ABSCESS,ACUTEABDOMENARTHRITIS SYMPTOMS RA,SLE,ASTRAVEL HISTORY

DIETARY HISTORY

OCCUPATIONAL HISTORY


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TRAVEL History

MALARIA ENDEMIC AREASDENGUE FEVER - Eg )SINGAPOREVIRAL FEVERSTYPHOIDTUBERCULOSISSCHISTOSOMIASIS


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D ietary & Occupational History

BIRDS PSITTACOSIS

ANIMALS CONTACT- TOXOPLASMOSIS (CAT),

BRUCELLOSIS,LEPTOSPIROSIS (RAT)

UNCOOKED MEAT/SEA FOOD/ -

HEPATITIS

A & E,SALMONELLA

UNPASTEURIZED MILK

SALMONELLA,TB,BRUCELLOSIS


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Drug fever

All drugs can produce Drug INDUCED fever exceptDIGOXINBradycardia, hypotension, Skin rash, pruritus +,

Eosinophiliaeg) pencillin, sulpha, ATT


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THERE IS NO SUBSTITUTEFOR OBSERVING THE PATIENT,

TALKING TO HIM ANDTHINKING ABOUT HIM.


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FEVER & MYALGIA VIRAL FEVERS LEUCOPENIA &THROMBOCYTOPENIA

INFLUENZA URTI SYMPTOMS

POLYMYOSITIS PROXIMAL M WEAKNESS,MUSCLE PAIN & TENDERNESS, CPK HIGH

MENINGOCOCCAL INFECTION -Rash

SEPSIS


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Fever & Night Sweats

TUBERCULOSISLYMPHOMA

ABSCESSBRUCELLOSISINFECTIVE ENDOCARDITISALCOHOL WITHDRAWAL SYNDROME


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FEVER Brady, Tachycardia

RELATIVE BRADYCARDIA

TYPHOID FEVERMALARIAMENINGITISLEPTOSPIROSISVIRALDRUG FEVER


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RELATIVE TACHYCARDIA

TOXINS


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Fever & Eyes

EYE PAIN

TEMPORAL ARTERITIS WATERY EYES- PANDRY EYES SLE,RA

SC Hemorrhages SBECONJUNCTIVITIS TB,SLECONJUNCTIVAL SUFFUSION-LEPTOSPIROSISUVEITIS- TB,SLE,SARCOIDOSIS


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FEVER WITH JAUNDICE

LEPTOSPIROSIS RENAL FAILURE +HEPATITIS-DRUGS (ATT) ,VIRAL

ALCOHOLIC HEPATITISCIRRHOSIS OF LIVERHEPATOMA

VIRAL FEVERSMALARIA


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GENERALIZED LYMPHADENOPATH LEUKEMIA ALL , CLLLYMPHOMA MEDIASTINAL INVOLVEMENT

HIV INFECTION

ORAL CANDIDIASIS,THIN BUILTTOXOPLASMOSIS-WITH LIVER,SPLEENDISSEMINATED TUBERCULOSIS WITH LIVER

,SPLEENBRUCELLOSIS-WITH LIVER,SPLEEN


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FEVER WITH HEPATOSPLENOMEGALY

MALARIATYPHOIDLYMPHOMALEUKEMIADISSEMINATED TBINFECTIVE ENDOCARDITISBRUCELLOSISKALA AZAR


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FEVER WITH MENTAL CONFUSION

MENINGITISMENINGISM- TYPHOIDHIVBRUCELLOSISCNS NEOPLASMS


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LOCAL TENDERNESS

TONGUE - RELAPSING FEVERTRAPEZIUS SUB DIAPHRAGMATICABSCESSSTERNAL METASTASIS, PRE LEUKEMIASPINAL BRUCELLOSIS,TYPHOID,SBE,OM

THIGH - POLYMYOSITIS,BRUCELLOSISCALF POLYMYOSITIS, RMSF


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FEVER - ARDS

SARS INFECTIONCEREBRAL MALARIA (P FALCIPARUM )HANTA VIRUS INFECTIONSEPSIS


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HIGH ESR

TBTEMPORAL ARTERITISCARCINOMALYMPHOMASABSCESSMYELOPROLIFERATIVE DISORDER


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FEVER & LOW PLATELETS DENGUE FEVERVIRAL FEVERSLEUKEMIALYMPHOMAMYELOPROLIFERATIVE DISORDER

DRUG FEVERSLEHIV INFECTION


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CHEST X-RAY DIAGNOSIS

TB-ANY FORMLYMPHOMAS-MEDIASTINAL INVOLVEMENTSARCOIDOSIS BHLPNEUMONIASAUTOIMMUNE DISEASES


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DIAGNOSTIC TESTS ANA,ANTI DS DNA SLEBONE SCAN-OSTEOMYELITIS,METASTASISECHO HEART ATRIAL MYXOMA,IE,PCITIS

SMEAR TEST + VE MALARIA,ELISA IGM AB -LEPTOSPIRAVIRAL CULTURE + INEBV,CMV INFECTIONS

BLOOD CULTURE + INIE,SEPSIS,AGGLUTININ TEST + INSALMONELLA ,BRUCELLOSIS


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ULTRA SOUND

HEPATOMAABSCESSHYPERNEPHROMA (PHYSICIAN S TUMOUR)LYMPHOMAPELVIC TUMORS


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Blood cultures for aerobic and anaerobic pathogens.

maximum 6 sets of blood cultures are required.

Urine culture

Cultures of sputum

Stool Cultures

Perform cultures for - Bacteria,- Mycobacteria, and- Fungi

Cultures:


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Serologies are most helpful if paired samples show asignificant, usually 4-fold, increase of antibodies specificto an infectious microorganism.

Brucellosis, CMV, infectious mononucleosis, HIV,amebiasis, toxoplasmosis, and chlamydial diseases arediagnosed by serology.

These diagnostic tests are of limited value in mostpatients with FUO, but they are appropriate for evaluation of the above illnesses in the correct clinicaland epidemiological setting.

Serologies


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THANK YOU

ALL WE KNOW IS STILL INFINITELYLESS THAN ALL THAT REMAINS UNKNOWN

-WILLIAM HARVEY -

inf intro + fever

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