Isolation (scarlet fever):

• 21 days from the beginning of the disease (term of possible complication development)

• On the 21^st day – urinalysis and ECG

Chicken pox

Definition :

Acute infectious disease caused by Varicella-Zoster virus (VZV) from Herpesviridae with airborne way of transmission, with predominant involvement of epithelium and nervous system and presented with syndromes of intoxication and exanthema

Classification of Herpesviridae (CHICKEN POX):

1. HSV-1

2. HSV-2

3. VZV

4. EBV

5. CMV

6. Herpesvirus – 6 type

7. Herpesvirus – 7 type

8. Herpesvirus – 8 type

Disease forms (CHICKEN POX):

1. Varicella - primary infection, with virusemia

2. Herpes Zoster – reactivation of virus from neural ganglia

Etiology (CHICKEN POX):

• Varicella-Zoster virus (VZV)

• DNA-containing

• Carriage can be life-long

• Very unstable (15 minutes at room air)

• Very volatile and highly transmittable

Pathogenesis (CHICKEN POX):

• Entry of infection – upper respiratory mucous

• Virusemia → skin and mucus epithelium → characteristic rash

• All the mucous membranes of the body: macula → papula → erosion. Clinical presentations – croup, dyspepsia, dysuria

• Tropism to nervous system:

• Vertebral ganglia → Herpes Zoster

• Brain cortex → encephalitis

• Cerebellum → cerebellitis

• Immunodeficiencies → visceral forms (hepatitis, pneumonitis, carditis, etc.)

Pathogenesis of rash (CHICKEN POX):

1. Capillary dilation → macula

2. Serous edema → papula

3. Damage of spike layer of the skin → cell dystrophy and necrosis → intercellular fluid collection → vesicles. Basement of vesicles is infiltrated with monocytes and lymphocytes → typical hyperemia around vesicles

4. Resorption of exudate → crusts

Clinics – periods (CHICKEN POX):

1. Incubational period - 9-21 day

2. Rash period - depends on severity, from 3-4 days to 2 weeks

3. Convalescence period (“crusts period”)

Clinics – syndromes (CHICKEN POX):

• Intoxication syndrome – spikes of fever with every new rash elements. Fever, fatigue, malaise, irritability, vomiting

• Exanthema syndrome

Clinics – rash characteristics (CHICKEN POX):

1. Character of the elements – false polymorphism (macula → papula → vesicle → crust)

2. Prevalent localization – all over the body, including hair part of the head and excluding palms and feet

3. Background skin color – normal

4. Time of appearance – first days of the disease

5. Connection to fever – fever spikes with waves of new elements appearance

6. Itching – yes

7. Fusion of rash elements – no

8. Step-wise appearance – no, but repetitive waves

9. Presence of enanthema – on all mucous membranes

10. Disappearance of the rash – temporal depigmentation or mild scars after pustules or crusts removal

Classification (CHICKEN POX):

Type	Severity	Course
Typical	Mild	Without complications
Atypical: Rudimentary Hemorrhagic Gangrenous Generalized (visceral) Bullious Pustulous	Moderate Severity	With complications

Complications (CHICKEN POX):

1. Primary (caused by VZV)

2. Secondary (caused by bacterial infections)

Primary Complications Encephalitis Meningoencephalitis Myelitis Nephritis Myocarditis

CNS complications Early complications Develop on the first days of the disease Severe encephalitis with high mortality Hyperthermia, seizures, loss of consciousness, focal signs Late complications Develop at the “crusts” period Do not depend on the severity of the previous varicella Most often – cerebellitis

Secondary complications Cellulitis Pustulous and bullous forms Phlegmona Abscess Impetigo Bullious pyodermia Erysipelas Lymphadenitis Stomatitis Conjunctivitis Croup (seldom)

Chicken Pox in Newborns :

• If mother develops chicken pox within 5 days before delivery or few days after, the newborn will develop severe forms with generalization and high mortality rate. Incubation period in newborns is 6-16 days.

• If mother develops chicken pox earlier than 5 days before delivery, the newborn will produce mild or rudimental forms.

Laboratory diagnosis (CHICKEN POX):

1. In typical clinical forms, laboratory confirmation is not required

2. If the diagnosis is in doubt:

• “Tzanck” smear with sensitivity of about 60% (from a vesicle).

• VZV antigen from vesicular fluid (IFA)

• PCR of vesicle fluid, CSF or blood

• Serology – 4-fold increase in repeated titers in10 days

Treatment (CHICKEN POX): Mouth washing after every meal; Skin bathing without scratching; Topic antiseptic paints are contraindicated unless secondary infection develops; Corticosteroids are contraindicated, except in late encephalitis. Mild and moderate cases in immunocompetent children – symptomatic therapy: NSAIDs for fever (absolutely exclude aspirin – risk of Reye syndrome!) (avoid ibuprofen – risk of necrotizing fasciitis) Anti-hystaminic drugs for itching Indications for etiotropic therapy: Severe course Visceral, gemorrhagic forms Patients with immunodeficiencies (HIV, primary immunodeficiencies, oncology, hematologic diseases, patients on steroids or chemotherapy, after organ transplantation) Newborns, first two years of age children (if mother did not have chicken pox) Patients older than 12 years Eiotropic therapy – acyclovir Start within first 24 hours! IV: 10-30 mg/kg/day in 100 ml of infusion PO: 400mg qid for 2-6 years old 800 mg qid for older children Course 5-7 days Polyvalent IV Immunoglobulin (0,2-0,5 ml/kg) or specific VZV Immunoglobulin Antibiotics – for secondary complications, gangrenous form Encephalitis: Acyclovir Corticosteroids Pathogenic treatment

Prophylaxis (CHICKEN POX):

Chemoprophylaxis with acyclovir is not effective

Active prophylaxis – live attenuated VZV-vaccine

Children from 1 to 13 years – once

Older children and adults twice in 4-8 weeks (after previous testing for VZV-IgG)

Passive prophylaxis : VZIG –1,25 ml/10 kg, IM, once, at first 48-96 hours of incubation. Incubation period can prolong till 28 days. VZIG circulates in the body 2-4 weeks.

Indications:

1. Immunodeficiences,

2. Pregnancy (after previous testing for VZV-IgG),

3. Newborns from mothers who developed varizella within 5 days before and 2 days after delivery.