Preparing for NEET PG 2017: Chikungunya Update

While preparing for NEET PG, it is important to have updated information about various vector-borne diseases in the country, especially for the PSM section. With the outbreak of Chikungunya in various parts of the country, it is expected that students are going to get various questions about the disease in the forthcoming exam.

Following are the National Guidelines for Clinical Management of Chikungunya. It contains various important updates about the disease that aspirants should know

Introduction

Chikungunya fever is a viral disease transmitted to humans by the bite of infected mosquitoes. Chikunguny a virus (CHIKV) is a member of the genus Alphavirus, in the family Togaviridae. CHIKV was first isolated from the blood of a febrile patient inTanzania in 1953. Since then it has been identified repeatedly in west,central and southern Africa and manyare as of Asia, and cited as the cause of numerous human epidemics in those areas. The virus circulates through out much of Africa ,with transmission, thought to occur,mainly between mosquitoes and monkeys. In ‘Swahili’ language, Chikungunya means that which contorts or bends.This refers to the contorted (or stooped) posture of patients who are afflicted with these severe joint pain (arthritis), a most common feature of the disease.It is a debilitating, but non-fatal viralillness.

Since 1960 ,the outbreaks of the disease in South Eastern Asia were reported from India, Sri Lanka, Myanmar, Thailand, Indonesia, Philippines and Malaysia. Chikungunya outbreaks typically resulting large number of cases but death sarerarely encountered. Chikungunya cases start appearing in postmonsoon season period that is in the month of May onwards with a peak between them July and August as during this period vector density remains very high.

Chikungunya in India

In the Indian sub-continent, first isolation of the virus was done in Calcutta during 1963. Subsequently, there have been several reports of Chikungunya virus infection during 60’s in different parts of India viz: Kolkata, Pondicherry and Chennai inTamil Nadu, Rajamundry, Vishakapatnam and Kakinadain AndhraPradesh, Sagar in Madhya Pradesh and Nagpur in Maharashtra. There after, sporadic cases also continued to be recorded specially from Maharashtra. The last out break of Chikungunya infection in 20 the century occurred in India during 1973. There after, a quiescence of 23 decades during 2006 reports of large scale out breaks off ever caused by Chikungunya in several parts of India have confirmed there-emergence of this virus in the country with 13.9 million clinically suspected and 2001 laboratory confirmed cases(

www.nvbdcp.gov.in; Chhabra M 2008). Since then transmission is continuing in various parts of the country. There-emergence of Chikungunya maybe due to a variety of social, environmental, behavioral and biological factors.Lack of her immunity may have probably led to its rapid outbreak across several states of India.

Currently in 2016, big up surge/epidemic due to Chikungunya is being going on in the capital city of Delhi and reporting case from other States/UT’s too. Till 11th September, 2016 a total of 14656 clinically suspected cases(including1724in Delhi) from 18 states and2 UT’s have been reported.

DIAGNOSING CHIKUNGUNYA VIRUS

Laboratory criteria included increased lymphocyte count consistent with viremia.

1.Virus isolation provides the most definitive diagnosis, but takes one to two weeks for completion and must be carried out in bio safety level III laboratories to reduce the risk of viral transmission.

2.Serological diagnosis requires a large amount of blood than the other methods ,and uses an ELISA assay to measure chikungunya specific IgM levels in the blood serum. Chikungunya anti-body tests are generally appropriate after the first week of symptom on set and onward.

3.Reverse Transcriptase, (RT) PCR techniques ingested primer pairs issued to amplify several Chikungunya specific genes from whole blood, generating thousands to millions of copies of the genes in order to identify them. The Chikungunya virus reverse transcript (RT) PCR assay is appropriate in the early days of symptom on set, since CHIKV RNA can be detected during the acute phase of illness(≤8 days after symptom onset).

The technique issued for diagnosing CHIK virusus ingnested primer pair simplifying specific components of three structur0al generegions, Capsid(C), Envelope E2 and part of Envelope E1. A specimen for PCR is exactly similar to the one for virus isolation i.e. heparinized whole blood.

COMMON FEATURES OF DENGUE AND CHIKUNGUNYA

SL.NO	FEATURES	CHIKUNGUNYA	DENGUE
1.	Fever Onset Duration	Acute 24 days	Gradual 57 days
2.	Rash	Maculopapular	Petechiae maculopapular
3.	Arthralgia Frequency Duration	Frequent May last longer than a month	Less common Short duration
4.	Hypovolaemic shock	Rare	Common
5.	Leukopenia	Common	Infrequent
6.	Thrombocytopenia	Infrequent	Common
7.	Haematocrit	Normal	High

PRESENTATION OF CHIKUNGUNYA

Clinical presentation of Chikungunya is divided into three phases. In Chikungunya mostly symptoms have an abrupt onset with high grade fever, single or multiple joint pains, skin rashes, headache and myalgia. Clinical presentation of Chikungunya usually follows 3 phases which are as follows:

a)	Acute phase :	Less than 3 weeks
b)	Sub-acutephase:	>3 weeks to 3 months
c)	Chronic phase :	>3 months

Clinical presentation maybe mild, moderate or severe and most of the symptoms subside within 3 weeks from the onset of symptoms. Some of the symptoms may persist for 3 months and even more. Usually 10 –15%of the patient those who present with severe Chikungunya progress to Sub acute or chronic phase.

COMMON SYMPTOMS

• Fever


• Arthralgia/Arthritis


• Backache


• Headache


• Skinrash/Itching

RARE SYMPTOMS

• Photophobia


• Retroorbitalpain


• Vomiting


• Diarrhea


• Meningeal syndrome


• Acute encephalopathy

COURSE OF ILLNESS

• Symptoms and signs are generally self-limiting among most of the Some of the signs and symptoms progress to Sub acute or chronic phase.
  
  
  
  • Arthralgia
  
  
  • Myalgia
  
  
  • Arthritis
  
  
  • Persistent Joint stiffness
  
  
  • Restricted joint movement
  
  
  • Painful jointmovement
  
  
  • Enthesopathy
  
  
  • Tendinnitis
  
  
  • Skin pigmentation
  
  
  • Skin rash
  
  
  
  

CLINICAL CLASSIFICATION OF SEVERITY OF DENGUE

Based on clinical presentation severity of Chikungunya is classified into three categories, However this category may vary over time during the course of illness.

MILD

• Low grade Fever Mild Artharlgia Mild focal Myalgia General weakness Skin rash/itching

MODERATE

• Low to high grade persistent fever Moderate joint pain


• Generalized myalgia Hypotension


• Mild bleeding Retroorbital pain Oliguria

 



 

SEVERE

1. Persistent high grade fever


2. Severe Joint pain


3. Persistent vomiting /Diarrhoea


4. Altered sensorium


5. Bleeding(GI bleeding due to use of Analgesics)


6. Shock due to persistent vomiting and diarrhea

PRESENTATION OF ARTHRITIS

Arthralgias are poly articular and usually involve peripheral joints. The joint pain tends to be worse in the morning which gets better with mild physical activity. The pain may remit for 23 days and then reappear in a saddle back pattern in some patients.It is usually polyarticular, symmetrical involving predominantly small joints of hands and feet. Ankles, wrists and small joints of the hand are the worst affected. Larger joints like knee and shoulder may also be involved. There is a tendency for early and more significant involvement of joints with some previous trauma or degeneration.

IMPACT OF CHIKUNGUNYA IN PREGNANCY

Pregnant woman can get Chikungunya infection at any stage of pregnancy.Chikungunya virus can also be transmitted from the mother to the child.The time of greatest risk of Chikungunya virus transmission from a mother to a fetus appears to be during birth. Various preliminary studies showed that such a contamination is“rare lyserious”when the babies were infected during birth, signs of infection appeared around Day 4. and more than 90% of the infected newborns recovered quickly without sequelae. Immunoglobulin M[IgM], an antibody, generally appears between 4 and 7 days after the onset of clinical signs. IgM, however, does not pass through the placental barrier. The body starts producing Immunoglobulin G[IgG] around Day 15 and pass it through the placenta and confer immunity to the fetus. Fever, in general, can trigger uterine contractions, miscarriages or fetal deaths.

The chances of passing the infection to fetus is very less even though a recent research study in the French Reunionisl and demonstrated for the first time the maternal fetal transmission of Chikungunya virus, if the pregnant woman is infected at the time of delivery, the virus can be transmitted to the new born child. So it is important to ensure that in Chikungunya are as pregnant woman is protected from mosquito bite. Neonatal cases observations in French Reunion island outbreak in 2005 suggest possible fetal transmission during pregnancy. These study further revealed that though fetal contamination risks appear to be rare before 22 weeks of gestation, they are potentially dangerous. After 22 weeks gestation, newborns infection occurs if them other is viremia positive at delivery. Transplacental transmission is suspected, but the pathogenic mechanism remains unknown. As per the available literature there is no impact of Chikungunya infection on pregnancy outcomes except for the number of prenatal hospitalizations.

Chikungunya is a self limiting disease however in severe form of the disease sequelae can be seen. It has been observed that 90%joint symptoms resolve completely. However, some have either.

• Episodic stiffness and pain


• Persistent stiffness without pain

PATHOGENESIS

At present ,not many detailed studies are available on the pathogenes is of the Chikungunya fever. In humans, the bite of an infected mosquito leads to deposition of Chikungunia virus (CHIKV) in the subcutaneous tissue resulting in viremia. A febrile response signals viral replication with release of inflammatory cytokines. Lymphocytic peri vascular cuffing and extra vasation of erythrocytes from capillaries are seen in biopsies of the cutaneous rash. Animal studies on related flaviviruses have shown that replicating virus in the synovial fluid, endosteum and periosteum of the affected bones induce complement activated immune complex mediated arthritis.

CLINICAL MANAGEMENT OF CHIKUNGUNYA

• Management during Acute and subacute phase of the illness


• Management during Chronic phaseor
  
  
  
  • There is no antiviral drugs against CHKV
  
  
  • Most of the signs and symptoms are self-
  
  
  • Treatment for Chikungunya is purely symptomatic supportive care
  
  
  • Analgesics, antipyretics and fluid supplementation are important aspects in managing the disease
  
  
  • Supportive or Palliative Medical Care With Anti inflammatories
  
  
  • Supportive care with rest is indicated
  
  
  • Movement and mild exercise tend to improves tiffness and morning arthralgia ,but heavy exercise
  
  
  
  

Disabling peripheral Arthritis/Artropathy refractory to NSAID:Short term corticosteroid may be used.

Long term anti-inflammatory therapy Physiotherapy

Chloroquine phosphate

Management of Chikungunya with High riskgroup:

Proper management of Comorbid condition and co-infection.

ACUTE STAGE

Clinical Management of CF during acute stage can be in ambulatory settings. Hosptialisation is rarely indicated.

• Domiciliary(Homecare)


• Hospital based

HOME BASED

• Adequate rest or activity as tolerated


• Paracetamol 500 mg TDS/QID ( dose not to exceeds 3 Gm 24hours)


• Antacids likePPI/H2blocker to counter gastritis


• Antihistaminics, if required in consultation with doctors


• Tepid water sponging for highfever


• Ensure adequate intake of water orally to maintain urine output atleast more than a litre per day


• Cold compresses. Avoid hot fomentation in acute stages as it can worsen the joint symptom.


• Physiotherapy in form of mild exercises in recovering


• Avoidself-medication particularly antibiotics, steroids,and other painkillers specially overdosing


• Avoid Aspirin

MANAGEMENT OF CHRONIC ARTHRITIS

A short course of steroids may be useful. Non weight bearing exercises may be suggested. Contractures and deformities with physiotherapy/surgery

• NSAIDS


• Short course of steroid(In case of refractory to NSAID after 23weeks)


• HCQS (During sub-acute stage)


• Physiotherapy


• Surgery

SUMMARY

• Management is mostly symptomatic


• Paracetamol and NSAIDs are commonly used for symptomatic relief


• Avoid Aspirin


• During epidemic, every patient clinically suspected need not to Promptly refer the case to higher centre and when indicated (cited above)


• Protect against mosquito bite during febrile phase for prevention for transmission (mosquitonet, mosquito repellent etc.).


• Systemic manifestation is rare


• Relapse or reinfection is not seen


• Co-infection with Dengue and malaria can occur


• No specific anti-viral drug

Public health measures

Patient when infected can spread the infection by spreading the infection through mosquitoes. It is important to break this transmission by minimizing the vector density by community participation and taking appropriate control measures in the hospitalse thing by following measures.

Minimizing transmission

This can be done in the following ways:

• Minimizethe vector population


• Minimize the vector patient contact(Aedes mosquitoes bite during day time, mostly in the morning and late afternoon)


• Reporting to the nearest public health authority/orthe DPMO

Risk communication to household members

Chikungunya is a disease that is transmitted by mosquitoes. Household members may also come down with Chikungunya infection as they also share the same environment.Hence there is no need to isolate the patient

Minimizing vector population

• Intensify efforts to reduce larval habitats in and around the houses; remove stagnant water from all junk items lying around in the household and in the peridomestic areas


• Stagnating water in flower pots or similar containers should be changed daily or atleast


• Introduce larvivorous fish in aquaria,garden pools,etc


• Weeds and tall grasses should be cut short to minimizes hady spaces where the adult insects hide and rest during hot day light hours


• Drain all water stagnating after rains


• Fogging and street sanitation with proper waste management (fogging does not appear to be effective,yet it is routinely implemented in epidemic situation)

• Insecticide sprays: bed rooms, closets and crevices,bath rooms, kitchens, and corners; alternatively, coils, mats, vaporizers,etc.


• Have the patient as well as other members of the household wear full sleeves to cover extremities, preferably bright coloured clothes


• Wiremesh/nets on doors and windows

The author, Dr Mukesh Bhatia is a renowned medical educationist, having experience in the medical education sector for more than 35 years and is currently the Chairman of Dr Bhatia Medical Institute, one of the most prominent PG Medical Coaching Institutes in India.