Chikungunya Fever: Investigations & Treatments

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Laboratory Diagnosis

The confirmation of Chikungunya fever is through any of the following:

  • Isolation of virus
  • PCR
  • Detection of IgM antibody
  • Demonstration of rising titre of IgG antibody

(Contribution of PCR and blood tests for the diagnosis of Chikungunya)

IgM antibodies demonstrable by ELISA may appear within two weeks. It may not be advisable to do the antibody test in the first week. In some persons it may take six to twelve weeks for the IgM antibodies to appear in sufficient concentration to be picked up in ELISA.

No significant pathognomonic hematological finding is seen. Leucopenia with lymphocyte predominance is the usual observation. Thrombocytopenia is rare. Erythrocyte sedimentation rate is usually elevated. C-Reactive Protein is increased during the acute phase and may remain elevated for a few weeks.

Interpretation of Results

Sero-diagnosis rests on demonstrating a fourfold increase in CHIK IgG titer between the acute and convalescent phase sera. However, getting paired sera is usually not practical. Alternatively, the demonstration of IgM antibodies specific for Chikungunya virus in acute-phase sera is used in instances where paired sera cannot be collected.

A positive virus culture supplemented with neutralization is taken as the definitive proof for the presence of Chikungunya virus. In addition, Positive polymerase chain reaction for E1 and C genome either singly or together from the specimen (serum, cerebrospinal fluid, etc) also constitutes a positive evidence of Chikungunya virus infection.

Overlap and confusion with Dengue Fever

Chikungunya fever has to be distinguished from dengue fever. In the former, shock or severe Haemorrhage is not observed. Moreover, The onset is more acute and the duration of fever is much shorter in Chikungunya fever. In Chikungunya fever, maculopapular rash is more frequent than in dengue fever .

In the early stage when rashes are absent have tested positive for rheumatoid factor during and after clinical episode. malaria has to be ruled out. With the presence of rashes, measles or German measles need to be ruled out. Differential diagnosis with other arthropod-borne viruses of the Alphavirus genus (Ross River, Barmah Forest, O’nyong nyong, Sindbis, and Mayaro viruses) is difficult, but these are comparatively rare.

Treatment

Currently, no specific treatment for Chikungunya is available. Supportive care is recommended, and symptomatic treatment of fever and joint swelling includes the use of non-steroidal anti-inflammatory drugs such as

  • Naproxen,
  • Non-aspirin analgesicssuch as paracetamol (acetaminophen) and fluids.
  • Aspirinis not recommended due to the increased risk of bleeding.
  • Despite anti-inflammatory effects, corticosteroidsare not recommended during the acute phase of disease, as they may cause immunosuppression and worsen infection.

Passive immunotherapy has potential benefit in treatment of Chikungunya. Studies in animals using passive immunotherapy have been effective, and clinical studies using passive immunotherapy in those particularly vulnerable to severe infection are currently in progress.

Passive immunotherapy involves administration of anti-CHIKV hyper-immune human intravenous antibodies (immunoglobulins) to those exposed to a high risk of Chikungunya infection.

No antiviral treatment for Chikungunya virus is currently available, though testing has shown several medications to be effective.

Guiding principles for managing chronic phase Management of Osteoarticular Problems

The osteoarticular problems seen with Chikungunya fever usually subside in one to two weeks’ time. In approximately 20% cases, they disappear after a gap of few weeks.

Moreover, In less than 10% cases, they tend to persist for months. In about 10 % cases, the swelling disappears; the pain subsides, but only to reappear with every other febrile illness for many months. Each time the same joints get swollen, with mild effusion and symptoms persist for a week or two after subsidence of  the fever. However, Destroyed metatarsal head has been observed in patients with persistent joint swelling.

Management of osteoarticular manifestations follow the general guidelines given earlier. Since an immunologic etiology is suspected in chronic cases, a short course of steroids may be useful. Care must be taken to monitor all adverse events and the drug should not be continued indefinitely to prevent adverse effects. Moreover, Even though NSAIDS produce symptomatic relief in majority of individuals, care should be taken to avoid renal, gastrointestinal, cardiac and bone marrow toxicity.

Cold compresses have been reported to lessen the joint symptoms. Disability due to Chikungunya fever arthritis can be assessed and monitored using one of the standard scales. As discussed above, proper and timely physiotherapy will help patients with contractures and deformities.

Non-weight bearing exercises may be suggested.; example, slowly touching the occiput (back of the head) with the palm, slow ankle exercises, assisted exercises, milder forms of yoga etc.

Management of Neurological Problems

Various neurologic sequelae can occur with persistent Chikungunya fever. Approximately 40% of those with CF will complain of various neurological symptoms but hardly 10% will have persistent manifestations. However, Peripheral neuropathy with a predominant sensory component is the most common (5 to 8%).

Paresethesias, pins and needles sensations, crawling of worms sensation and disturbing neuralgias have all been described by the patients in isolation or in combination. Worsening or precipitation of entrapment syndromes like carpal tunnel syndrome has been reported in many patients. Motor neuropathy is rare.

Occasional cases of ascending polyneuritis have been observed as a post infective phenomenon, as seen with many viral illnesses. Seizures and loss of consciousness have been described occasionally.

Anti-neuralgic drugs (Amitryptyline, Carbamazepine, Gabapentin, and Pregabalin)may be used in standard doses in disturbing neuropathies. Moreover, Ocular involvement during the acute phase in less than 0.5% cases as described above may lead to defective vision and painful eye in a small percentage. Progressive defects in vision due to uveitis or retinitis may warrant treatment with steroids.

Reference:

World Health Organization. Chikungunya in South-East Asia-Update, New Delhi: Regional Office for South-East Asia, 2008.

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