Problem 19Problem 19

(1) A 35-year old man with fever, malaise, & weight loss. Final diagnosis was Fever of Unknown Origin (FUO).

Q. What is FUO ?

A. It is a fever of 38.5°C or higher for more than 3 weeks & aetiology was unknown despite thorough investigations .

Q. What investigations you may carry out ?

A. @ Blood culture

@ Urine microscopy+culture for TB, etc

@ Serology for infectious mononucleosis ,

Mycoplasma, Chlamydia, influenza,

typhoid, adenoviruses, Legionella, syphilis

brucellosis, leptospirosis, toxoplasmosis,

@ Skin test: TB, hydatid disease, Histoplasma

Q. Give the infective causes of FUO?

A.@ Hidden abscess (liver)

@ Endocarditis @ Hydatid disease @ Query fever @ Tuberculosis @ Enteric fever @ Histoplasmosis @ EB virus (Infectious mononucleosis) @ Leptospirosis @ Syphilis

@ Listeriosis @ Toxoplasmosis @ Influenza @ Legionellosis @ Rabies @ Brucellosis @ Mycoplasmosis @ Chlamydiosis @ Lassa fever @ Leishmaniasis

Problem 20Problem 20

(1) A 20-years old student with fever, malaise , headache , difficulty in sleeping , & healed scar on his arm due to dog bite. Final diagnosis was rabies .

Q. What is the aetiology?

A. Rabies virus .

Q. How do you confirm diagnosis ?

A.@ Virus detection by immunoflurescence in

corneal scraping & skin biopsy. @ Viral culture from saliva @ Antibody serology . @ detection of Negri bodies

in brain biopsy after death . @ Animal inoculation. Q. What is the reservoir of rabies ?

A. Bats, birds, dogs, foxes , other warm-blooded animals.

Q. How is rabies prevented ?

A.@ Rabies vaccine

from tissue culture.

@Passive immunization.

Problem 21Problem 21

(1) A 30-years old woman c/o nausea , vomiting , swelling of fingers, malaise, fatigue ,anorexia, upper abdominal pain , & dark urine. She was found to have hepatomegaly & tender liver .Lab. tests showed positive urine bilirubin , high serum bilirubin ,& raised ALT test. Final diagnosis was viral hepatitis .

Q. Which viruses are to blame ?

A. Hepatitis A, B , C, D viruses – EB virus – CMV– yellow fever virus

Q. Which tests you perform to establish the aetiology of viral hepatitis ?

A. *HAIgM antibody

*HBcIgM

*HBsAg

*HBsAb

*HCV IgG antibody

*Serology for other viruses .

(2) Results of serology were

:

*HAIgM-negative *HBsAg-positive , *HBcIgM-positive , *HBsAb-negative *HCV IgG – negative *Other tests negative.

Q. What is the diagnosis ?

A. Acute hepatitis B Q. What is the diagnosis if: *HAIgM –negative *HBsAg-negative *HBcIgM-positive *HBsAb-negative *Other tests negative ?

A. Acute hepatitis B (Recent infection ).

Q. What is the diagnosis if: *HAIgM-negative *HBsAg-negative *HBcIgM-negative *HbsAb-positve *Other tests negative ?

A. Past infection or immunity to hepatitis B

Q. How did the patient acquire infection?

A. May be blood transfusion, sexually, intravenous narcotics,

(3) Patient improved , & tests one year later showed positive HBsAg & HbsAb was negative

Q. What is the diagnosis?

A. Chronic carrier of HBV

Q. What test you do to show if she is infectious to others ?

A. HBeAg

Problem 22Problem 22

(1) An 18-year old woman c/o painful sore throat , malaise, anorexia, fever, & headache . She had DPT vaccine in childhood O/E : tonsils swollen & full of exudates, no membrane in pharynx , liver tender & enlarged

Q. Which lab. test you do to

reach a diagnosis ?

A. Throat culture for S. pyogenes + Monospot test.

(2) Throat culture revealed alpha hemolytic streptococci , Monospot test was negative , ALT & AST were raised , WBC 16000.

Q. So , what is your diagnosis ?

A. Early infectious mononucleosis (IM) with negative Monospot test. (supported by LFT)

(3) Several days later Monospot test was positive and lymphocytosis was detected (15% of lymphocytes were atypical ) . So final diagnosis of infectious mononucleosis was made .

Q.What is the causative agent ?

A. EBV. Diagnosis is confirmed by EBV IgM antibody .

Q.How is Infection transmitted?

A. Kissing (EBV is found in

saliva)

Q. In what age group is it more common?

A. Young adults.

Q. What are the heterophil antibodies?

A.They are nonspecific antibodies formed during EBV infection .

Q. Do you need to isolate EBV in tissue culture?

A. No, culture not done routinely.

Q. Can IM be contracted more than once?

A. No , only once – it gives life –long immunity .

Q. Is there any way of prevention ?

A. No vaccine or drug to prevent infection.

Problem 23Problem 23

A 45-year old man c/o behavioral changes & impaired consciousness . Final diagnosis was viral encephalitis

Q. What viruses involved ?

A. H.simplex types 1&2 , Mumps, Measles, Varicella-zoster, Polio, ECHO, Coxackie, Influenza , Rubella, Rabies, arthropod –borne viruses (St.Louis,Japanese B). Q. What are the human Herpes viruses ?

A.HSV-types 1 & 2 Varicella-zosterEBVCMVHerpes virus types 6 & 7 .

Q. Describe the lab. diagnosis of viral encephalitis.

A.* Brain biopsy in which virus is detected by IF * Electron microscopy * Tissue culture. *Serology for herpes. * CSF for herpes antibodies. *Throat swab for viral culture. * Stool for Enterovirus culture

Problem 24Problem 24

(1) A 32-year old woman with fever, headache ,shivering, cough, muscle pain, & painful eyes. Final diagnosis was influenza .

Q. What are the causative agents ?

A. @ Influenza viruses A & B

@ RSV (elderly )

@ Adenovirus

@ Parainfluenza viruses

@ Mycoplasma pneumoniae

@ Chlamydia spp.

Q. Give influenza serious complications?

A. Pneumonia : Viral or bacterial

Q. What specimens to collect ?

A. @ Throat swab or nasopharyngeal

aspirate for viral culture

@ Blood for serology

@ Sputum for both bacterial &

viral culture

@ Blood culture for bacteraemic

pneumonia

Q. What are the virological tests you perform ?

A. @ Tissue culture

@ Immunoflurescence for antigens of :

*Influenza viruses A,B

*RSV

*Parainfluenza viruses

*Adenoviruses

*Chlamydia spp.

Q. How are influenza viruses classified ?

A. @ Influenza A virus, divided into

many subtypes according to

neuraminidase (N) molecule &

haemaglutinin (H) molecule

@ Influenza B

@ Influenza C (not serious )

Q. Is influenza preventable ?

A. Yes, by :

@ An inactivated vaccine containing the 3 viruses 70% effective for one year only . Vaccine is recommended for people at risk e.g. those c/o asthma , heart diseases , renal failure, diabetes, old age , immunosuppression.

@ Amantadine drug for prophylaxis .

Problem 25Problem 25

(1) A 27-year old man attended the lab. for HIV test.

Q. How is HIV transmitted ?

A. @ Sexual

@ Mother to baby

@ Blood transfusion

@ Sharing of needles among

drug addicts

@ Needle stick injuries

Q. What is the basis of HIV test ?

A. Detection of HIV antibodies by Ag-Ab reaction Q. When does this test become positive?

A.3 months after exposure “window period “

(2) Following this period HIV test became positive. Q. How do you confirm the diagnosis ?

A. @ PCR @ Western blot

Q. What is the family of HIV?

A. Retroviruses

Problem 26Problem 26

(1) A 4-years old boy with skin rash , fever, running nose , cough , & Koplik's spots . Final diagnosis was measles.

Q. How can the diagnosis be confirmed ?

A.@ Collect throat swab for virus

culture

@ Collect blood for serology

Q. Is measles preventable?

A. By a live attenuated vaccine incorporated in MMR (measles-mumps-rubella)

Given at 12-18 months

of age

Problem 27Problem 27(1) An 8-year old girl with itchy skin rash , vesicles,& mild fever. Final diagnosis was chicken-pox.

Q. Give the aetiology & how can you confirm diagnosis ?

A. @ Varicella-zoster

virus (VZV)

@ Confirmation by isolation of virus from vesicles fluid or by serology

(1) A 48-year old man with painful skin rash localized on back & chest. Final diagnosis was herpes zoster (shingles – الحزام that involves ( الناريthoracic nerve roots. Q. What is the aetiology of this condition ?

A. Same VZV, in adults

Problem 28Problem 28(1) A 23-year old pregnant lady with fever, skin rash, & swelling of wrists. Final diagnosis was rubella .

Q. What investigations should you carry out ?

A. Two sera for virus serology

Q.How would you interpret the following :

1)Rubella IgG negative & IgM negative?

2)Rubella IgG negative & IgM positive?

3)Rubella IgG positive & IgM positive?

4)Rubella IgG positive & IgM negative?

A.1.No infection + No immunity2.Acute infection + No immunity 3.Acute infection + Past exposure 4.No infection + Immunity

Q. How may rubella be prevented ?

A. Live attenuated vaccine with MMR vaccine , given in 2nd.year of life.

Q. What other viruses causing skin rash in pregnancy ?

A. Parvovirus B19