VASCULITIC DISORDERS IN CHILDREN/ IMMUNIZATION😊

• Largest of Herpesviridae

• SRK (salivary, resp, kidney) → Largest → lives in mannat (Monocytes) → big muscle fibre (human fibroblast culture)

• Reservoir: Humans only

• Transmission:
• Common: oral, respiratory, body secretions
• Less common: transplacental, sexual

• Multiplication sites (mnemonic SRK in Mannat):
• Salivary gland
• Respiratory tract
• Kidney

• Latent in: Monocytes

• M/c infection during 1st 4 months of organ transplant

Infections

Features`

• 1st CMV infection — 30%.

• 2nd CMV infection — 1-2% (Developing countries like India).

• Congenital CMV
• 90% of → asymptomatic
• No use of routine screening.
• Most important long-term sequelae in SYMPTOMATIC CMV
• Sensorineural hearing loss.
• Most common non syndromic causes of hearing loss.

Clinical features in Congenital CMV

• Microcephaly
• < 3 SD of HC

• Chorioretinitis.

• Hepatosplenomegaly.

• Jaundice.

• Petechiae.

• Periventricular calcifications.

Brain lesions with calcification

1. Craniopharyngioma

2. Oligodendroglioma

3. Meningioma.

4. Congenital CMV
• Periventricular calcification

5. Congenital Toxoplasmosis
• Cerebral calcification

6. Neurocysticercosis.

• Mnemonic: Brain calcifiy () → when Old (Oligodendroglioma) → start saying Meaningful (Meningioma) Crap (Craniopharyngioma)

• Most common cause of vision loss in ocular HIV.

• Mnemonic:
• CMV → Come we have Pizza, scrambled egg and ketch up,
• So brush and come

Features:

• "Pizza pie" appearance.

• "Scrambled egg and ketchup" appearance.

• "Brushfire extension" pattern.

• Causes focal chorioretinitis.

Diagnosis

• Congenital CMV
• Demonstrate replicating virus within the first 3 weeks.
• PCR/Viral culture:
• Best sample - urine sample.
• It can be done using saliva or blood sample.
• CMV IgM:
• ELISA
• Cannot demonstrate replicating virus

• Owl eye inclusion bodies (intra-cytoplasmic + intra-nuclear)

• Virus isolation:
• human fibroblast cell lines (secondary)
• specimen = urine washing

• Detection: PP65 antigen

• PCR

NCCT

Treatment for symptomatic patients

• DOC: Ganciclovir
• Resistance d/t U97 phosphotransferase gene

• Resistance: Foscarnet

• Note:
• UL 57 (DNA Polymerase) causes resistance to Ganciclovir, Foscarnet and cidofovir

• Primary toxoplasma infection during pregnancy.
• Severity → more if affected earlier (11 weeks)

• Mnemonic: Toxic killing → Kanni kude (chorioretinitis) thalayilott (cerebral calcification) inject cheyth (↑ size → hydrocephalus)

• Definitive host: Cat.

• Intermediate host: Human.

Mode of transmission

• Ingestion
• Sporulated oocyst via contaminated soil/food/water.
• Bradyzoites via undercooked meat.

• Blood transfusion & Vertical
• Tachyzoites.

• Blood and sex - tachy

• Relax (Brady) and eat meat
• Beef - brady

• spores from soil

• Cat → Oocyst
• Infective Stage.
• Diagnostic Stage.

• Diagnosis
• Serological diagnosis.
• Direct identification of parasite from:
• Peripheral blood.
• Amniotic fluid.
• Tissue sections.

Variants of toxoplasmosis

• Adult toxoplasmosis
• Asymptomatic.
• LN enlarged.

• HIV+ toxoplasmosis
• Encephalitis.
• Most commonly brainstem is affected.

• Congenital Toxoplasmosis
• More severe in trimester I.
• More common in trimester III.
• Chorioretinitis.
• Intracerebral calcification.
• Convulsions.
• Microcephaly
• Mental retardation.



• Mnemonic: CHC
• Small for gestational age.
• Prematurity.
• Hydrops fetalis, i.e., generalized anasarca.
• Persistence jaundice.
• Thrombocytopenia.
• Focal Chorioretinitis
• Most common manifestation
• HYDROCEPHALUS.
• Macrocephaly due to hydrocephalus.
• Cerebral calcification
• On NCCT

Important Information

• Toxoplasma → intracerebral calcification.

• CMV → periventricular calcification.

Diagnosis

• Frenkel test

• Sabin Feldman test: Gold standard.
• Test uses Methylene blue and tachyzoite stage
• If colorless - antibodies present.
• If color is present - antibodies absent.

Prevention and Treatment

• Pyrimethamine + Sulfadiazine.

• Early diagnosis of infection

• Treatment of mothers is by sulphadiazine.

CD4 Count vs Opportunistic Infections

CD4 Count	Infections/Findings	ㅤ
~600	• Lymph node enlargement	6 swellings → LNs
~500	• Herpes Zoster Virus • Pneumococcus (lobar consolidation)	ㅤ
~400	• Kaposi Sarcoma (any CD4) • Tuberculosis (snowstorm/hazy)	4K TB
~300	• Oral Hairy Leukaemia	300 Hairs
<200	• PCP (perihilar opacities), • Miliary TB, Candida, Cryptosporidium • Mucocutaneous Herpes	ㅤ
<100	• Cerebral Toxoplasmosis, • Cryptococcal Meningitis, • CNS Lymphoma, HIV Dementia, PMLE	100 = Brain
< 50	• CMV Retinitis • MAC	ㅤ

Congenital toxoplasmosis CT

• Eccentric target sign.
• M/c site: basal ganglia

• Most common infectious cause

• Mnemonic: Toxic guy () saw a headlight in a fog () and got a punch ()

Cryptococcosis:

• Soap bubble appearance.

• Cry when bathing with soap

CNS lymphoma:

• Solitary enhancing peripheral lesion.