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Chickenpox (Varicella)

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Presentation on theme: "Chickenpox (Varicella)"— Presentation transcript:

1 Chickenpox (Varicella)
Dr. Harivansh Chopra DCH, MD PROFESSOR Department of Community Medicine, LLRM Medical College, Meerut.

2 Objectives To study the epidemiology of Chickenpox.
To study the differential diagnosis and treatment of the disease. To study the prevention of Chickenpox.

3 Chickenpox (Varicella)
It is characterised by vesicular rash that may be accompanied by fever and malaise. It is worldwide in distribution and occurs in both epidemic and endemic forms.

4 Agent The causative agent of chickenpox, V-Z virus is also called “Human (alpha) herpes virus 3”.

5 Agent Varicella-zoster virus (VZV) causes primary, latent, and recurrent infections. The primary infection is manifested as Varicella (chickenpox) and results in establishment of a lifelong latent infection of sensory ganglion neurons. Microscopic view of sensory ganglion neurons: Common site of latent infection by Varicella

6 Agent Reactivation of the latent infection causes Herpes Zoster (shingles).

7 Herpes Zoster Reactivation of Varicella zoster virus. Associated with:
Aging. Immunosuppression. Intrauterine exposure. Varicella at < 18 months of age.

8 Chickenpox transmission occurs mainly from the oropharyngeal
Source of Infection Usually a case of chickenpox. The virus occurs in the oropharyngeal secretions and lesions of skin and mucosa. Rarely the source of infection may be a patient with Herpes Zoster. Chickenpox transmission occurs mainly from the oropharyngeal secretions of a case.

9 Infectivity The period of communicability of patients with Varicella is estimated to range from 1 to 2 days before the appearance of rash, and 4 to 5 days thereafter.

10 Incubation period Usually 14 to 16 days, although extremes as wide as 7 to 21 days have been reported.

11 Age Chickenpox occurs primarily among children under 10 years of age.

12 Immunity One attack gives durable immunity. Second attacks are rare.
The acquisition of maternal antibody protects the infant during the first few months of life. Hemorrhagic Varicella in infant : One attack of Varicella gives durable immunity.

13 Structure of an IgG antibody: Antibody against Varicella is
Immunity The IgG antibodies persist for life and their presence is correlated with protection against Varicella. The cell- mediated immunity appears to be important in recovery from V -Z infections and in protection against the reactivation of latent V-Z virus. Structure of an IgG antibody: Antibody against Varicella is protective

14 Pregnancy & Varicella Infection during pregnancy presents a risk for the fetus and the neonate.

15 Environmental Factors
Chickenpox shows a seasonal trend in India, the disease occurring mostly during the first six months of the year. Overcrowding favours its transmission.

16 Transmission Chickenpox is transmitted from person to person by droplet infection and by droplet nuclei. Most patients are infected by "face-to-face" (personal) contact.

17 Transmission The portal of entry of the virus is the respiratory tract. Since the virus is extremely labile, it is unlikely that fomites play a significant role in its transmission. Main portal of chickenpox transmission is respiratory


19 Transmission Contact infection undoubtedly plays a role when an individual with Herpes Zoster is an index case. The virus can cross the placental barrier and infect the foetus, a condition known as Congenital Varicella. Mother-to-Child transmission of Varicella can cause Congenital Varicella

20 Congenital Varicella Syndrome
Results from maternal infection during pregnancy. Period of risk may extend through first 20 weeks of pregnancy. Risk appears to be small (< 2%). MRI scan of foetus in-utero: Risk of transmission of Varicella extends through first 20 weeks.

21 Congenital Varicella Syndrome – Features
Damage to Sensory Nerves : Cicatricial skin lesions. Hypopigmentation. This neonate suffering from Congenital Varicella died at 6th day: Typical skin lesions seen at autopsied body

22 Congenital Varicella Syndrome – Features
Damage to Optic Stalk and Lens Vesicle : Microphthalmia. Cataracts. Chorioretinitis. Optic atrophy. Fetus with Congenital Varicella at autopsy (26 weeks). Note the collapsed cranium, disproportionate Necrosis of the ocular globes and flattened midface.

23 Congenital Varicella Syndrome – Features
Damage to Brain/Encephalitis : Microcephaly. Hydrocephaly. Calcifications. Aplasia of brain. Brain sonograph of a fetus with Congenital Varicella at 18 weeks. Note the appearance of the falx cerebri, choroid plexus and cerebral hemispheres.

24 Congenital Varicella Syndrome – Features
Damage to Cervical or Lumbosacral Cord : Hypoplasia of an extremity. Motor and sensory deficits. Absent deep tendon reflexes. Neonate with Congenital Varicella: Note hypoplasia of lower extremity. The extremity had sensory and motor deficits.

25 Congenital Varicella Syndrome – Features
Damage to Cervical or Lumbosacral Cord : Anisocoria. Horner syndrome. Anal/urinary sphincter dysfunction. Pictoral representation of anisocoria. (this case is not Congenital Varicella) Pictoral representation of Horner Syn. (this case is not Congenital Varicella)

26 Anisocoria: Both pupils are usually of equal size
Anisocoria: Both pupils are usually of equal size. If they are not, that is termed anisocoria (from "a-", not + "iso", equal + "kore", pupil = not equal pupils)

27 The clinical features of Horner's syndrome can be remembered using the mnemonic, "HornyPAMELa" for Ptosis, Anhidrosis, Miosis, Enophthalmos and Loss of ciliospinal reflex.

28 Clinical features of Chickenpox –
The clinical course of chickenpox may be divided into two stages: Pre-eruptive Stage. (B) Eruptive Stage.

29 Pre-Eruptive Stage Onset is sudden with mild or moderate fever, pain in the back, shivering and malaise. This stage is very brief, lasting about 24 hours. Pre-eruptive phase in Varicella is very brief – characterised by Fever, pain in back, shivering, and malaise

30 Pre-Eruptive Stage In adults, the prodromal illness is usually more severe and may last for days before the rash comes out.

31 Eruptive Phase In children the rash is often the first sign.
It comes on the day the fever starts.

32 Eruptive Phase – Fever The fever does not run high but shows exacerbations with each fresh crop of eruption.

33 Eruptive Phase – Rash The rash is symmetrical.
It first appears on the trunk where it is abundant, and then comes on the face, arms and legs where it is less abundant.

34 Eruptive Phase – Rash Mucosal surfaces (e.g. buccal, & pharyngeal mucosa) are generally involved.

35 Eruptive Phase – Rash Axilla may be affected, but palms and soles are usually not affected. The density of the eruption diminishes centrifugally.

36 Eruptive Phase – Evolution of Rash
The rash advances quickly through the stages of macule, papule, vesicle and scab. In fact, the first to attract attention are often the vesicles filled with clear fluid and looking like "dew-drops" on the skin.

37 Eruptive Phase – Evolution of Rash
Superficial vesicles Unilocular Vesicles; Dew-drop like. Inflammation around vesicles They are superficial, with easily ruptured walls and surrounded by an area of inflammation. Usually they are not umbilicated.

38 Eruptive Phase – Evolution of Rash
The vesicles may form crusts without going through the pustular stage. Many of the lesions may abort. Scabbing begins 4 to 7 days after the appearance of rash.

39 Eruptive Phase – Pleomorphic Rash
A characteristic feature of the rash in chickenpox is its “Pleomorphism”, i.e. all stages of the rash (Papules, Vesicles and Crusts) may be seen simultaneously at one time, in the same area.

40 Varicella – Differential Diagnosis
Herpes simplex. 2. Enterovirus. Staphylococcus aureus (Bullous impetigo)

41 Varicella – Differential Diagnosis
Drug reactions. 5. Contact dermatitis. Insect bites.

42 Varicella – Differential Diagnosis
Severe Varicella was the most common illness confused with smallpox before the eradication of this disease.

43 Differences between Smallpox and Chickenpox
During the first day or two of rash it may be impossible, from the rash alone, to differentiate smallpox from chickenpox.

44 Differences between Smallpox and Chickenpox
On day 3, the rash associated with each of the diseases continues to look very similar.

45 Differences between Smallpox and Chickenpox
By day 5, all of the smallpox lesions are at the same stage of development. However, the patient with chickenpox shows several different stages of rash – There are papules, vesicles and pustules present.

46 Differences between Smallpox and Chickenpox
The smallpox lesions are large : 5 – 10 mm in size; firm and deeply embedded in skin. Most of the chickenpox lesions are smaller : 1 – 5 mm in size; lesions are much superficial.

47 Differences between Smallpox and Chickenpox
By day 7, no formation of scabs in smallpox lesions. Most of chickenpox lesions have already formed scabs, and some scabs, in fact, have already seperated.

48 Differences between Smallpox and Chickenpox
By day 10, smallpox scabs have just begun to form. In chickenpox, most of the scabs have fallen off by day 10. (In chickenpox, scabs begin to form as early as day 3 or 4, and fall off by day 14).

49 Differences between Smallpox and Chickenpox
Smallpox – pocks are more dense on the arms and legs than on the trunk. Chickenpox – many pocks on back but very few on arms or hands.

50 Differences between Smallpox and Chickenpox
In chickenpox there may be few or no lesions on the palms of the hands. In smallpox, pocks are usually present on palms of hands.

51 Differences between Smallpox and Chickenpox
In smallpox, many lesions are present on the soles of feet. In chickenpox, patient may have very few or no lesions on soles of feet.

52 Differences between Smallpox and Chickenpox
In smallpox, death occured 1 in 10 cases. In chickenpox, death is very uncommon.

53 Varicella Complications
Secondary bacterial infection of lesions. Cellulitis, Lymphadenitis, and Subcutaneous abscess. Varicella gangrenosa from S.pyogenes – a life-threatening infection.

54 Varicella Complications
Bacteremia causing pneumonia, arthritis, and osteomyelitis. CNS manifestations – Encephalitis & Cerebellar ataxia. Varicella hepatitis.

55 Varicella Complications
Acute thrombocytopenia, accompanied by petechiae, purpura, hemorrhagic vesicles, hematuria, and GI bleeding. Nephritis, Nephrotic syndrome, and HUS.

56 Groups at Increased Risk of Complications of Varicella
Healthy adolescents & adults. Immunocompromised persons. Pregnant women.

57 Groups at Increased Risk of Complications of Varicella
Newborns of mothers with rash onset within 5 days before delivery to 48 hours after delivery. Children with malignancy if chemotherapy was given during the I.P.

58 Laboratory diagnosis Examination of vesicle fluid under the electron microscope, which shows round particles (brick-shaped in smallpox) and may be used for cultivation of the virus.

59 Laboratory diagnosis Scrapings of floor of vesicles show multinucleated giant cells coloured by Giemsa stain (not in smallpox). Serology is used mainly for epidemiological surveys.

60 Treatment of uncomplicated Varicella
Oral therapy with Acyclovir – mg/kg/dose maximum: 800 mg/dose doses per day X 5 days should be used to treat uncomplicated Varicella

61 Treatment in high-risk patients
Acyclovir guanine – 500 mg/m2 8 hourly I.V. X 7 days. Given within 72 hrs. prevents progressive Varicella and visceral dissemination in high-risk patients. Drug therapy does not interfere with induction of immunity.

62 Treatment of Herpes zoster
Acyclovir also useful for treatment of Herpes zoster in dose of 500 mg/m2 or 10 mg/kg 8 hourly.

63 Prevention VZV transmission is difficult to prevent because the infection is contagious for hr before the rash appears. Infection control practices, including caring for infected patients in isolation rooms with filtered air systems, are essential.

64 Prevention – Varicella Vaccine
Composition : Live virus (min PFU) (Oka/Merck strain). Efficacy : 95% (65%-100%). Duration of : > 7 years. Vaccination Schedule : 1 Dose subcutaneous (<13 years of age). May be administered simultaneously with measles, mumps, and rubella (MMR) vaccine.

65 Prevention – Varicella Vaccine for children
Routine vaccination at months of age. Recommended for all children without evidence of Varicella immunity by the 13th birthday.

66 Prevention – Varicella Vaccine for adolescents and adults
Recommended to all persons >13 years of age without evidence of Varicella immunity. Two doses separated by 4-8 weeks. Do not repeat first dose because of extended interval between doses.

67 Varicella Vaccine – Adverse Reactions
Injection site complaints – % (children) % (adolescents and adults). Rash – 3 – 4% of vaccinees. Rash may be maculopapular rather than vesicular. Average 5 lesions. Systemic reactions not common.

68 Zoster following Vaccination
Most cases in children. Risk from vaccine virus less than from wild virus. Usually a mild illness without complications.

69 Transmission of Varicella Vaccine Virus
Transmission of vaccine virus not common. Asymptomatic seroconversion may occur in contacts without evidence of Varicella immunity. Risk of transmission increased if vaccinee develops rash.

70 Varicella Vaccine – Contraindications and Precautions
Severe allergic reaction to vaccine component or following a prior dose. Immunosuppression. Pregnancy. Moderate or severe acute illness. Recent blood product transfusion.

71 Conclusions Varicella or Chickenpox is a vaccine preventable disease occuring commonly in children. It is characterized by fever & pleomorphic rash in centripetal distribution. It causes many complications if it occurs in adults.

72 Thank you

73 MCQs “Pleomorphism” is the characterstic of rash of : Measles.
HHV – 3. Smallpox. Fifth disease. Ans. – 2.

74 MCQs A child presenting with fever and Varicella rash on day 1 :
Has already transmitted the virus to other children. Is infectious to his siblings. Will continue to infect others for 4 – 5 days. All of the above. Only 1 & 2 are correct. Ans. – 4.

75 MCQs Following are not false about “Congenital Varicella Syndrome” except: (multiple choice) Risk of transmission is maximum in the 2nd trimester of pregnancy. Extensive involvement of neurological system of foetus. Hyper-pigmentation of skin is pathognomic sign. If fetus is born alive, may have problem in defecation and micturition. Ans. – 1,3.

76 MCQs Complications of Varicella : (multiple choice)
Occur more commonly in children infected within first 5 years of life. Pnuemonia is more common in adults. Can be prevented by early administration of Acyclovir. Varicella gangrenosa is a life-threatening infection caused by superadded Clostridium infection. Ans. – 2,3.

77 MCQs All are false about Varicella vaccine except : (multiple choice)
It may be given along with MMR vaccine (live vaccine). AIDS patients, not having previous history of Varicella, should receive this vaccine. The child is 100% protected for his entire life. A susceptible female should be immunized in the first trimester of pregnancy itself . Ans. – 1.

78 Differences between Smallpox and Chickenpox
Incubation – About 12 days (range 7-17 days) Prodromal symptoms - Usually mild Distribution of rash – - palms and soles frequently involved - axilla usually free - rash predominant on extensor surfaces and bony prominences Chickenpox About 15 days (range 7-21 days) Usually mild - seldom affected - axilla affected - rash mostly on flexor surfaces

79 Characteristics of the rash
superficial - unilocular; dew-drop like appearance - rash pleomorphic, I.e. different stages of the rash evident at one given time, because rash appears in successive crops - an area of inflammation is seen around the vesicles - deep-seated - vesicles multilocular and umbilicated - only one stage of rash may be seen at one time - No area of inflammation is seen around the vesicles

80 Evolution of rash evolution of rash is slow, deliberate and majestic, passing through definite stages of macule, papule, vesicle and pustule - scabs begin to form days after the rash ap evolution of rash very rapid - scabs begin to form 4-7 days after the rash appears

81 Fever - Fever subsides with the appearance of rash, but may rise again in the pustular stage (secondary rise of fever) Temperature rises with each fresh crop of rash

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