common viral infections

COMMON VIRAL COMMON VIRAL INFECTIONS INFECTIONS

Dr.H.N.SarkerDr.H.N.Sarker

MBBS. FCPS.MACP(USA)MBBS. FCPS.MACP(USA)

Assistant professorAssistant professor

MedicineMedicine

TopicsTopics

IntroductionIntroduction

Clinical syndromes caused by virusesClinical syndromes caused by viruses

SYSTEMIC VIRAL INFECTIONS SYSTEMIC VIRAL INFECTIONS

IntroductionIntroduction

Viruses are simple infectious agents Viruses are simple infectious agents consisting of a portion of genetic material, consisting of a portion of genetic material, RNA or DNA, enclosed in a protein coat.RNA or DNA, enclosed in a protein coat.

They are essentially intracellular and They are essentially intracellular and cannot exist in a free-living state, needing cannot exist in a free-living state, needing to infect host cells to survive. to infect host cells to survive.

Clinical syndromes caused by virusesClinical syndromes caused by viruses

Classification/viruses involvedClassification/viruses involved Clinical Clinical syndromessyndromesDNA VIRUSES(PHAPH)DNA VIRUSES(PHAPH)

– Poxviruses(Poxviruses(Variola)Variola) SmallpoxSmallpox

– Herpes virusesHerpes viruses

Herpes simplex types 1 and 2Herpes simplex types 1 and 2Acute/recurrent Acute/recurrent

vesicular vesicular rash(Herpes rash(Herpes labialis)labialis)

Varicella zosterVaricella zoster

Chickenpox/shinglesChickenpox/shingles

Clinical syndromes caused by viruses Clinical syndromes caused by viruses

CytomegalovirusCytomegalovirusAcute/recurrent Acute/recurrent

hepatorenal infectionhepatorenal infection

Epstein-Barr virusEpstein-Barr virus Infectious Infectious mononucleosismononucleosis

Burkitt'slymphomaBurkitt'slymphoma Nasopharyngeal carcinomNasopharyngeal carcinom

Clinical syndromes caused by virusesClinical syndromes caused by viruses

– Human erythrovirus 19Human erythrovirus 19 Erythema Erythema infectiosuminfectiosum

– AdenovirusesAdenoviruses Upper respiratory tract Upper respiratory tract

infection/pharyngitisinfection/pharyngitis

Acute diarrhoeaAcute diarrhoea

– PapovavirusesPapovavirusesHuman papillomavirusHuman papillomavirus Common wartCommon wart

Polyoma (human BK and JC)Polyoma (human BK and JC) Progressive Progressive multifocalmultifocal

leucoencephalopathyleucoencephalopathy

HepadnavirusHepadnavirus Hepatitis BHepatitis B

Clinical syndromes caused by virusesClinical syndromes caused by viruses

– RNA VIRUSES(MRTCRP)RNA VIRUSES(MRTCRP)– MyxovirusMyxovirus- - OrthomyxovirusesOrthomyxoviruses InfluenzaA,BInfluenzaA,B

ParamyxovirusesParamyxoviruses MeaslesMeasles

MumpsMumps

Respiratory Respiratory syncytial virus syncytial virus

Clinical syndromes caused by viruses Clinical syndromes caused by viruses

– RetrovirusesRetroviruses HIV-1 and 2HIV infection HIV-1 and 2HIV infection

syndrome/AIDSsyndrome/AIDS

– TogavirusesTogaviruses RubellaRubella

German measles German measles 

  Dengue fever  Dengue fever  

Clinical syndromes caused by virusesClinical syndromes caused by viruses

CalicivirusCalicivirus Hepatitis-EHepatitis-E

RhabdovirusesRhabdoviruses

Rabies Rabies

PicornavirusesPicornaviruses

PoliovirusPoliovirus poliopolio

Coxsackie virusesCoxsackie viruses pericarditispericarditis

SYSTEMIC VIRAL INFECTIONS SYSTEMIC VIRAL INFECTIONS

INFLUENZA INFLUENZA

INFECTIOUS MONONUCLEOSIS (IM) INFECTIOUS MONONUCLEOSIS (IM)

ACQUIRED CYTOMEGALOVIRUS ACQUIRED CYTOMEGALOVIRUS INFECTION INFECTION

DENGUE DENGUE

YELLOW FEVER YELLOW FEVER

INFLUENZA INFLUENZA

A specific acute illness caused by a group A specific acute illness caused by a group of myxovirusesof myxoviruses

Aetiology:Aetiology:

Influenza A and B virusInfluenza A and B virus

INFLUENZA INFLUENZA

Clinical feature: Clinical feature:

Sudden onset of pyrexiaSudden onset of pyrexia

Generalized ache and pains , Generalized ache and pains , headache.headache.

Anorexia , nausea and vomitingAnorexia , nausea and vomiting

INFLUENZAINFLUENZA

Harsh nonproductive coughHarsh nonproductive cough

Acute symptoms subside within 3-5 days but Acute symptoms subside within 3-5 days but may be followed by post may be followed by post influenza influenza asthenia which may persist asthenia which may persist for several for several weeks.weeks.

INFLUENZAINFLUENZA

Complication: Complication:

Most patients donot develop Most patients donot develop complication.complication.

Trachitis, bronchitis, bronchiolitis , Trachitis, bronchitis, bronchiolitis , BronchopneumoniaBronchopneumonia

Secondary bacterial invasion by Secondary bacterial invasion by Streptococcus pneumoniae, H. Streptococcus pneumoniae, H. influenzae, Staph. aureus.influenzae, Staph. aureus.

INFLUENZAINFLUENZA

Complication: Complication:

Rare Rare

Toxic cardiomyopathy may cause Toxic cardiomyopathy may cause sudden deathsudden death

EncephalitisEncephalitis

Demyelinating encephalopathyDemyelinating encephalopathy

Peripheral neuropathy Peripheral neuropathy

INFLUENZAINFLUENZA

Management: Management:

Bed rest till fever subsidesBed rest till fever subsides

Parectamol .5-1 gm(1-2 tab) 4-6 hrlyParectamol .5-1 gm(1-2 tab) 4-6 hrly

Pholcodine 5-10 mg 6-8 hrlyPholcodine 5-10 mg 6-8 hrly

Antibiotic if secondary bacterial Antibiotic if secondary bacterial infection. infection.

INFECTIOUS MONONUCLEOSIS (IM)INFECTIOUS MONONUCLEOSIS (IM)

INFECTIOUS MONONUCLEOSIS (IM) INFECTIOUS MONONUCLEOSIS (IM) is caused by the is caused by the Epstein-Barr virus (EBV), a gamma herpes virus.Epstein-Barr virus (EBV), a gamma herpes virus.

Virology and epidemiology Virology and epidemiology

Epstein-Barr virus (EBV) is a B Epstein-Barr virus (EBV) is a B lymphotropic human herpes virus which is lymphotropic human herpes virus which is worldwide in worldwide in distribution.distribution.

Primary infection with EBV which occurs Primary infection with EBV which occurs during childhood is usually subclinical. during childhood is usually subclinical.

Between 25-70 % of adolescents are Between 25-70 % of adolescents are usually subclinical. usually subclinical.

Virology and epidemiologyVirology and epidemiology

Between 25-70 % of adolescents and adults who Between 25-70 % of adolescents and adults who undergo a primary EBV infection develop the undergo a primary EBV infection develop the clinical syndrome of infectious mononucleosis.clinical syndrome of infectious mononucleosis.

Saliva is the main means of spread, either by Saliva is the main means of spread, either by droplet infection or environmental contamination droplet infection or environmental contamination in childhood, or by kissing among adolescents in childhood, or by kissing among adolescents and adults.and adults.

Clinical features Clinical features

Infectious mononucleosis is defined by the Infectious mononucleosis is defined by the clinical triad of fever, lymphadenopathy, clinical triad of fever, lymphadenopathy, and pharyngitisand pharyngitis

combined with the transient appearance of combined with the transient appearance of heterophil antibodies and an atypical heterophil antibodies and an atypical lymphocytosis.lymphocytosis.

Clinical featuresClinical features

Other features-Other features-

splenomegaly, palatal petechiae, splenomegaly, palatal petechiae, periorbital oedema, clinical or biochemical periorbital oedema, clinical or biochemical evidence of hepatitis, and a non-specific evidence of hepatitis, and a non-specific rash. rash.

Diagnosis Diagnosis

Diagnosed by the clinical triad of fever, Diagnosed by the clinical triad of fever, lymphadenopathy, and pharyngitis in lymphadenopathy, and pharyngitis in typical age group(10-30 yrs).typical age group(10-30 yrs).

combined with an atypical lymphocytosis.combined with an atypical lymphocytosis.(20% or more of peripheral lymphocytes (20% or more of peripheral lymphocytes must have an atypical morphology).must have an atypical morphology).

andand

DiagnosisDiagnosis

the transient appearance of heterophil the transient appearance of heterophil antibodies byantibodies by

1.the classical Paul-Bunnell titration1.the classical Paul-Bunnell titration

OrOr

2. a more convenient slide test such as the 2. a more convenient slide test such as the 'Monospot'. 'Monospot'.

DiagnosisDiagnosis

Specific EBV serology Specific EBV serology (immunofluorescence) can be used to (immunofluorescence) can be used to confirm the diagnosis if necessary.confirm the diagnosis if necessary.– antiviral capsid (VCA) antibodies in the IgM class antiviral capsid (VCA) antibodies in the IgM class – antibodies to EBV early antigen (EA) antibodies to EBV early antigen (EA) – absent antibodies to EBV nuclear antigen (anti-absent antibodies to EBV nuclear antigen (anti-

EBNA). EBNA).

COMPLICATIONS COMPLICATIONS

CommonCommon– Severe pharyngeal oedema Severe pharyngeal oedema – Antibiotic-induced rash Antibiotic-induced rash – Chronic fatigue syndrome (10%) Chronic fatigue syndrome (10%)

COMPLICATIONSCOMPLICATIONS

UncommonUncommon

NeurologicalNeurological

Cranial nerve palsies Cranial nerve palsies

Polyneuritis Polyneuritis

Transverse myelitis Transverse myelitis

Meningoencephalitis Meningoencephalitis

HaematologicalHaematological

Haemolytic anaemia Haemolytic anaemia

Thrombocytopenia Thrombocytopenia

COMPLICATIONSCOMPLICATIONS

RenalRenal Glomerulonephritis Glomerulonephritis Interstitial nephritis Interstitial nephritis

CardiacCardiac Myocarditis Myocarditis Pericarditis Pericarditis

PulmonaryPulmonary Interstitial pneumonitis Interstitial pneumonitis

COMPLICATIONSCOMPLICATIONS

RareRare

Ruptured spleen Ruptured spleen

Respiratory obstruction Respiratory obstruction

Arthritis Arthritis

Agranulocytosis Agranulocytosis

Agammaglobulinaemia Agammaglobulinaemia

Management Management

Treatment is largely symptomatic: Treatment is largely symptomatic:

aspirin gargles to relieve a sore aspirin gargles to relieve a sore throat. throat. If a throat culture yields a β-If a throat culture yields a β-haemolytic haemolytic streptococcus, a course of streptococcus, a course of

erythromycin should be prescribed. erythromycin should be prescribed.

ManagementManagement

Amoxicillin and similar semi-synthetic Amoxicillin and similar semi-synthetic penicillins should be avoided because they penicillins should be avoided because they commonly induce a maculo-papular rash commonly induce a maculo-papular rash in patients with IM.in patients with IM.

ManagementManagement

When pharyngeal oedema is severe a When pharyngeal oedema is severe a short course of corticosteroids, e.g. short course of corticosteroids, e.g. prednisolone 30 mg daily for 5 days, may prednisolone 30 mg daily for 5 days, may help to relieve the swelling.help to relieve the swelling.