pharyngeal arches

1. PHARYNGEAL ARCHES
DR. SRAVAN
E.N.T 1ST year Resident

2. Pharyngeal apparatus
Consists of :
• pharyngeal arches
• pharyngeal clefts
• pharyngeal pouches
• pharyngeal membranes

5. • During the 4th week ,splanchnic part of lateral
plate of mesoderm of the ventral foregut region
becomes segmented to form five distinct bilateral
swellings called pharyngeal arches or branchial
arches.
• Mesoderm consists of mesenchymal cells along
with neural crests cell give pharngeal arch
derivatives.
• Mesoderm gives rise to muscle myoblasts and
neural crest cells give rise to skeletal and
connective tissues.

6. • derivatives of pharyngeal arch consists of
following components :-
1.cartilage
2 .bone
3.Connective tissue
4.Muscles
5.Nerves
6. artery

7. Pharyngeal 1st arch derivatives

8. INTRODUCTION
• Dengue is the most common and important
arthropod-borne viral illness in humans.
• It is transmitted by female ,daytime biting
Aedes aegypti and Aedes albopictus.
• National dengue
day – 16th May.

9. ETIOLOGY
• Dengue virus belongs to family FLAVIVIRIDAE.
• positive sense ss-RNA.
• Four serotypes – DENV( 1,2,3,4 )
• Subsequent infection by another serotype
results in severe dengue.

10. EPIDEMIOLOGY
• Each year an estimated number of 50-100 million cases
occur over world wide anually in more than 100
endemic countries.
• There is 30 fold increase in Global incidence over the
last five decades.
• Every year Upsurge in cases seen in India from July to
November.
• Mortality – early detection - < 1%
severe dengue – 2-5%
Untreated – 20%

11. PATHOGENESIS

12. CLINICAL CLASSIFICATION
• WHO classification based on severity
1) Dengue fever
 Probable dengue / DHF
 Confirmed dengue
2) Dengue with warning signs
3) Severe dengue
* Expanded dengue syndrome

13. 1) Dengue fever :
C/F – Biphasic fever ( 2-7 days ) with 2 or
more features: Headache, Retro-orbital pain,
myalgia/arthralgia
Rash, positive tourniquet test
 probable dengue – Non-ELISA NS1/IgM
positive
 confirmed dengue – Isolation of dengue virus by
culture
ELISA NS1/IgM positive
PCR for Dengue virus
IgG seroconversion in paired sera after
> 2 weeks with four fold increased titre.

14. 2) Dengue with warning signs
• Abdominal pain or tenderness
• Persistent vomiting > 3 episodes
• Clinical fluid accumulation
• Mucosal bleed
• Lethargy, restlessness
• Liver enlargement >2 cm
• Laboratory: Increase in hematocrit (HCT) concurrent with
rapid decrease in platelet count

15. 3) Severe Dengue
Any one of three
• Severe plasma leakage leading to
- Shock (DSS)
- Fluid accumulation with respiratory distress
• Severe bleeding.
• Severe organ involvement:
- Liver: Aspartate transaminase (AST) or alanine
transaminase (ALT) ≥1,000
- Central nervous system (CNS)—impaired
consciousness
- Heart and other organs involvement

16. Expanded Dengue syndrome
Mild or Severe organ involvement may be found in DF/DHF.
Unusual manifestations of DF/DHF are commonly associated
with co-morbidities and with various other co-infections.
Clinical manifestations observed in EDS are as follows

17. PHASES OF DENGUE
FEBRILE PHASE:
• lasts for 2 to 7 days ,highgrade temperature ,facial
flushing,skin erythema headache ,myalgias and
arthralgias and other constitutional symptoms.
• May have sorethroat, cough.
• Liver enlargement >2cms below the right subcostal line.
• Progressive decrease in WBC and platelet count.
• Positive tourniquet test . The tourniquet test is part of
the new WHO case definition for dengue.

18. How to do a Tourniquet Test ?
1. Take the patient’s blood pressure and Inflate the cuff to a point
midway between SBP and DBP and maintain for 5 minutes. Reduce
and wait 2 minutes.
2. Count petechiae below antecubital fossa. . The test is considered
positive when 10 or more petechiae per square inch area over
forearm are observed.
In DHF, the test usually gives a definite positive test with 20
petechiae or more. The test may be negative or only mildly positive
during the phase of profound shock.

19. • CRITICAL PHASE:
Defervescence phase lasting for 3 to 7 days from onset
of fever .this phase is characterized by increase in
capillary permeability leading to polyserositis
,decrease platelet count ,increase in Hct.
Most frequent symptoms in india according to studies
are fever ,abdominal pain ,headache and vomiting.
Some children may have organ dysfunction with severe
hepatitis ,myocarditis or encephalitis in this phase
and profound shock.

20. • RECOVERY PHASE:
• This phase last for 48 to 72 hrs .
• Plasma starts coming back to intravascular
compartment from third space.
• Generalized well being, improvement in urine output
and appetite is seen.
• In some patients may have rash of “ isles of white in
the sea of red”.
• Few patients may have bradycardia and hypertension
in this phase.
• Hct stabilizes, WBC count starts increasing,
thrombocytopenia may take 7 to 10 days to normalize.

23. Admission criteria
• Warning signs.
• Signs and symptoms of hypotension.
• Spontaneous bleeding independent of platelet
count.
• Organ impairment.
• Co existing co morbid conditions.
• Social circumstances.

24. MANAGEMENT OF DENGUE
 HISTORY TAKING
 CLINICAL EXAMINATION
 INVESTIGATIONS
 DIAGNOSIS
 TREATMENT

25. HISTORY AND EXAMINATION
• Emphasis on history of onset of fever, urine
output ,oral intake and physical activity during
illness ,assessment of warning signs .
• Clinical examnination done to assess mental
state, hydration, hemodynamic assessment,
signs to assess extent of shock, abdominal
tenderness, hepatomegaly, bleeding
manifestations, tourniquet test is must.

26. INVESTIGATIONS
COMPLETE HAEMOGRAM:
1)Increasing Hct.( > then 20% )normal 45%.
Hct should be repeated for every 72 hrs and for every 24hrs in
severe dengue.
2) Leucopenia with lymphocyte predominance.precedes the
onset of critical phase.
3) thrombocytopenia seen in 50% of the children with dengue
infection .( <1 lakh /micro L indicates onset of critical
phase.platelet count should be monitored every 24hrs
initially.

27. • SEROLOGICAL DIAGNOSIS:
• ELISA based NS1 antigen detection test .
• NS1 antigen is a nonstructural glycoprotein secreted during
initial phase has specificity of 100% sensitivity of 90% done
in from day 1 to day 5.
• Dengue IgM by Mac ELISA .rapid kit test are available .IgM
Ab levels start raising from day 5 increases to 99% by day
10 and gradually decreases by day 14 and undetectable by
2 to 3 months.
• Dengue IgG appears by 1 to 2weeks start raising gradually
subsequently peaks and declines and persist for life.
• Molecular tests :Stand alone dengue PCR or MULTIPLEX
PCR panel can be used .sample for PCR need to be
collected within first 5 day of fever.
• Culture :Virus isolation by culture should be done day 1to
day 5 of fever

29. OTHER TESTS :
• Liver function tests.
• Renal function tests.
• Serum electrolytes.
• ECG
• CHEST X RAY
• USG ABDOMEN

30. Differential diagnosis of dengue
• Other haemorraghic fever.
• Chikungunya infection.
• Influenza.
• malaria.
• Enteric fever.
• Leptospirosis.
• Meningococal infection.
• Rickettsial fever.

32. Management
INCLUDES :
• Management of dengue based of severity.
• Management of severe bleeding.
• Management of fluid overload.
• Management of dengue with co morbidites
• Management of dengue with co infections.

36. Management of severe dengue

38. Management of severe bleeding
• Patient should be admitted and investigated to look for the
site of bleeding.
• Blood tranfusion can be life saving here,if
thrombocytopenia is severe ,first correct shock by PRBC
transfusion later followed by platelet transfusion .
• Indications of blood transfusion in severe dengue:
Loss of blood (overt blood)—10% or more of total blood
volume
• Refractory shock not responding to 40 to 60 ml/kg of fluid
despite adequate fluid administration.
• declining Hct and worsening metabolic acidosis
• Replacement volume should be 10 ml/kg body weight at a
time and coagulogram should be done

39. • Indications of platelet transfusion in dengue:
Platelet transfusion is not the mainstay of treatment in
patients with DF. In general, there is no need to give
prophylactic platelets even if at platelet count <
40,000/mm3.
• Prophylactic platelet tranfusion may be given when P/C is
<10,000/mm3 in the absence of bleeding manifestations.
• Haemorrhage with or without thrombocytopenia.
• Prolonged shock with coagulopathy with abnormal
coagulogram.
• Prophylactic Platelet transfusion neither shown to prevent
progression to severe bleeding nor does it shortened the
bleeding time and may instead be associated with severe
side effects.

40. MANAGEMENT OF FLUID OVERLOAD
• Fluid overload occurs because of excessive iv fluids, use of
hypotonic fluids, inappropriate use of platelets and fresh
frozen plasma and also continuation of iv fluids even in
recovery phase .
• These patient may have symptoms and signs of pulmonary
edema and congestive cardiac failure.
• Management:
• Oxygen therapy
• Discontinuation of fluids/reduction of rate.
• Fruosemide @0.1 to 0.5 mg/kg/dose OD or BD can be
given.
• Look for occult blood haemorrhage and transfuse packed
blood cells.

41. Discharge criteria
• Generalised well being.
• Fever free for atleast 24 to 48 hrs.
• Stable vitals.
• Platelet count >50,000 cu/mm

42. PREVENTION AND CONTROL
• Preventive measures directed against adult and
larval form of mosquitoes.
• During epidemics –aerial spraying/fogging with
malathion is recommended for adult mosquitoes.
• Mesocyclops,shell fish are credited to eat and
effectively eliminate Aedes larvae.
• Use of mesh to doors and windows.
• Avoid stagnation of water .
• cover storage water.

43. Surveillance
• DISEASE SURVEILLANCE : done by tracking the number
of suspected and confirmed infected human cases.
• It also includes recording of circulating serotypes of
dengue and number of deaths due to dengue.
• VECTOR SURVEILLANCE: tracking mosquitoes
population in areas of potential risk mainly by
• 1)house index-defined as percentage of houses
positive for the Aedes larvae.
• 2)Breteau index-number of containers positive for
larvae 100 houses
• Epidemic spread of Aedes has been reported with
house index of as low as <!% in indian settings.

44. VACCINES
• DENGVAXIA -A tetravalent ,live
attenuated,chimeric dengue vaccine in yellow
fever 17D backbone developed by sanofi
pasteur(CYD-TDV).
• The schedule of vaccine that have been evaluated
in phase 3 clinical trails include 3 doses taken
@(0,6,12 months) have been approved in 14
countries in age group of 2 to 16 yrs and showed
50% reduction in hospitalization and severity of
dengue infection in Vaccinated individuals.

45. OTHER VIRAL HAEMORRHAGIC FEVERS
• Crimean congo HF
• Kyasanur forest disease.
• Haemorrhagic fever and renal syndrome.
• Nipah virus infection
• Chandipura viral infection
• Ebola
• Zika virus infection

46. • Yellow fever
• Omsk haemorrhagic fever
• Rift valley fever
• Argentine, bolivian,venezuelan haemorrhagic
fever
• Lassa fever
• Marburg disease

47. Crimean congo fever
• RNA virus
• Usually infect cattle.highly contagious and human to
human spread by tick bite.
• It was first reported in india in Gujarat in 2011.
• Clinical features: fever, body pains, profuse bleeding.
disease mimics dengue with salient differences being
early and rapid platelet fall and rhabdomyolysis.
• Diagnosis by specific PCR.
• Treatment is supportive ,ribavarin is beneficial.
• Strict isolation.

48. Kyasanur forest disease
• Caused by KFDV, with incubation period of 3 to 8 days.
• Spread by tick bite (ixodidae tick) and contact with
infected animal.
• Clinical features : biphasic fever
mayalgias,prostration,bronchilar
involvement,meningoencephalitis in second phase of
fever.
• Severe leucopenia and thrombocytopenia is seen.
• Diagnosis is PCR of virus.
• Traeatment is supportive-hydration and W/F bleeding
manifestations.

49. Hemorrhagic fever and renal
syndrome
• Caused by rodent borne -hanta virus of bunya viridae
family presents as
• 1)heamorrhagic fever and renal syndrome
• 2)cardiopulmonary syndrome in india.
• Spread by inhalation of aerosols /contact of water
contaminated with rodent excreta/saliva.
• Clinical features:fever,body pains,bleeding,renal failure,
thrombocytopenia,diffrentiated from dengue by
leukocytosis
• Diagnosis is by specific IgM Ab detection.
• Treatment includes ribavarin and supportive care.

50. Nipah virus
• Causes encephaltis .
• Its natural asymptomatic host fruit bats
transmits infection to humans and pigs.
• Clinical features:fever f/b encephaltis and
respiratory distress.
• Mortality is 70%.sequelae in survivors.

51. Chandipura virus
• Causes viral encephalitis in children in several
states in india.
• Transmitted by infected sandflies .
• Associated with high mortality and sequelae.

52. Ebola
• It’s a RNA virus ,fruit bat as natural reservoir.
• Transmission to humans occurs by direct contact with
bat or consumption of plant /products contaminated
with bat feces or body fluids.
• It has incubation period of 2 to 21 days initially present
with non specific symptoms like headache ,vomitings,
fever, abdominal pain then followed by bleeding from
multiple sites and multiorgan failure.
• Diagnosis is by IgM ELISA ,PCR and virus isolation.
• Treatment is supportive.
• Prevention by strict isolation.

53. Zika virus
• It’s a RNA virus similar to dengue and chikungunya
transmitted by Aedes aegypti mosquito .
• Vertical transmission and sexual ,blood transmission
possible.
• Clinical features:low grade fever with arthralgia, myalgia,
rash ,conjunctivtis more prominent than dengue and
chikungunya.
• Two major complications :acute ,Guillain barre syndrome,
myelitis,meningoencephalitis.
• Teratogenic effects with an incidence of 30%,microcephaly
in 13%,stillbirths,IUDs and occular abnormalities.
• Diagnosis: first 7 days by RTPCR later by IgM MAC ELISA.
• TREATMENT is supportive and symptomatic.

54. REFERENCES
• Nelson textbook of paediatrics 21st edition.
• Piyush Gupta textbook of paediatrics 3rd edition.
• O.P ghai textbook of paediatrics 9th edition.
• IAP standard treatment guidelines.
• Guidelines by national health mission and
NVBDCP.
• Guidelines by centers of disease control and
prevention (CDC).