Malaria interesting case study with negative peripheral blood smear

Malaria interesting case study with negative peripheral blood smear

Interesting case study of Malaria

A 5 years old boy had complained of fever with chills and extreme lethargy for 5 days.

For these complaints routine investigations with complete blood counts (CBC) done multiple times. CBC reports showed thrombocytopenia around 70000. But malarial parasites not detected on peripheral smear examination. Other investigations such as sonography of abdomen also done which revealed mild splenomegaly.

The patient was not improving and the anxious parent came for OPD consultation with Dr. Pratik Savaj for the complaint of persistent fever.

On examination no specific findings except a lethargic look found.

The patient was investigated for tropical fever panel and the following results came in the investigation shown in the below image.

real time tropical fever panel

You can see in the image that Real-Time PCR results for dengue, chikungunya, leptospira, rickettsia, salmonella, West Nile fever were negative but it detected Plasmodium spp.

Final diagnosis: Malaria

His peripheral blood smear slides were reviewed but no malarial parasites were seen.

The treatment started with falcigo (artesunate) and he became afebrile within 24 hours with lethargy got improved by the next day.

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Discussion of the case

Why malarial parasites not seen on peripheral smear?

The reason may be the following:

  1. Microscopy may not reliably detect very low parasitemia that is less than 5 to 10 parasites/mcL.
  2. Total 3 negative smears required to rule out malaria.
  3. At least 300 oil immersion fields should be examined before giving results on microscopy.
  4. Parasites may also be missed by pathologists.

When to send tropical fever panel PCR?

It should be sent on following conditions:

  1. Fever without localization
  2. Fever with thrombocytopenia
  3. Fever with multi-organ involvement

Remember this is valuable in the first 7 to 10 days of illness because it is the antigen-based test.

After 10 days, antibody-based tests should be advised such as dengue duo, lepto IgM, Weill Felix test, etc.

What is the cost for tropical fever panel PCR?

This investigation costs about 4500 to 5000 rupees in India. But it may vary in different states and areas.

Learning point

Only one or two CBC (Complete Blood Counts) with negative smear examination of malarial parasites can’t rule out malaria. You may also require other investigation choices to detect the disease.

In our case studies section, we discuss these kinds of educational medical cases that help to improve awareness and knowledge base. This case was shared with us by

Dr. Pratik Savaj

Infectious disease physician

DNB Medicine,

FID, FNB infectious disease (Hinduja Hospital, Mumbai)

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