SCRUB TYPHUS- POSSIBLE SIMPLE DIAGNOSTIC INDICATOR. Dr. Nikhil- DNB Pediatrics, Dr. Sarala Rajajee Dr S Thangavelu Dr. Ezhilarasi

Transcription

1 SCRUB TYPHUS- POSSIBLE SIMPLE DIAGNOSTIC INDICATOR Dr. Nikhil- DNB Pediatrics, Dr. Sarala Rajajee Dr S Thangavelu Dr. Ezhilarasi

2 Case Scenario 11 year old girl child referred with o High grade fever 8 days o Rigor + o Myalgia + o Prolonged menstrual bleed o Investigation revealed thrombocytopenia hence referred

3 Outside investigations Widal 1:80 Dengue serology Negative MPQBC Negative Platelets (74,000/ cu.mm.) Treatment received- Cefotaxime & Chloroquine for 4 days

4 13/11 14/11 15/11 16/11 (Morning) 16/11 (evening) 98,000 1,00,000 85,000 92,000 74,000

5 Examination Alert Afebrile Feeble pulses +++/+ BP- 100/60 mmhg Eschar (+) Right postero- lateral chest wall with axillary lymph node Systemic examination normal

6 ER Compensated shock was corrected with bolus Stabilized and shifted to ward Lab investigations- CRP Positive (54) TLC- 4500(P56 L42 E2) Platelets-18000/ cumm LFT- NORMAL

7 Treatment In view of eschar started on Doxycycline Gynaecologist opinion- tranexnamic acid for menstrual bleeding PLANNED FOR PLATELET TRANSFUSION in view of thrombocytopenia and prolonged menstrual bleed????

8 PERIPHERAL SMEAR ( EDTA) Normocytic normochromic RBC Polymorphs with toxic granules Large Platelet aggregates with normal platelet counts

9 PERIPHERAL SMEAR Low power High power

10 PERIPHERAL SMEAR

11 Course in hospital Cancelled transfusion. Dengue serology & MPQBC negative Scrub typhus IgM positive Continued on same line of management (Doxy)

12 Course in hospital Fever spikes settled & repeat platelet counts on counter increased to & menstrual bleeding stopped Remained stable & discharged

13

14 This child is being presented to highlight The importance of good clinical examination to detect eschar To always examine a peripheral smear in case of thrombocytopenia on counter to rule out Pseudothrombocytopenia Large platelet aggregates in PUO might indicate scrub typhus and should be evaluated further

15 We evaluated 20 other children referred to us as PUO with thrombocytopenia, dengue ruled out and later tests revealed scrub typhus positive. We found that all of them had large platelet aggregates on smear. Finding Cases Hepatosplenomegaly 20 Eschar 7 Platelets on Coulter counter Platelets on peripheral smear Scrub typhus IgM Case 1 50,000 6,50,000 Strong positive Case 2 10,000 6,10,000 Positive Case 3 25,000 2,20,000 Positive Case 4 5,000 2,80,000 Highly reactive Case 5 10,000 2,50,000 Positive

16 It generates an electrical pulse when a blood cell passes through a small aperture surrounded by electrodes. Each electrical pulse represents an individual cell, and the pulse height indicates the cell volume. Cells are identified depending on their volume. In the presence of large aggregates their volume increases and therefore not recognised as platelets

17 Standardization of Machine is necessary to ensure consistent results When accepting the platelet count and the automated WBC differential count it is always necessary to cross check it by the human eye. E.g: it is possible that the machine may show a platelet count and the Direct peripheral Smear show a Normal platelet count. This condition is known as Pseudothrombocytopenia. This is because the anticoagulant EDTA may clump the platelets and hence the coulter would record a decreased platelet count. Thus every low platelet count must be cross checked by peripheral smear before an elaborate investigation for thrombocytopenia is undertaken. But this is found out to be only in about 0.1% cases.

18 Enhanced platelet adherence and aggregation in Chagas' disease: a potential pathogenic mechanism for cardiomyopathy. Tanowitz, H. B. et al American Journal of Tropical Medicine and Hygiene 1990 Vol. 43 No. 3 Platelet Aggregation in Children With Helicobacter pylori Infection Published in SAGE Journals- Clinical & Applied Thrombosis/ hemostasis

19 Rickettsiae proliferate on endothelium of small blood vessels, release cytokines which damage cell integrity, with consequent fluid leakage and platelet aggregation. Vascular wall destruction consumes platelets leading to thrombocytopenia. Textbook of Pediatric Infectious Diseases edited by A. Parthasarath

20 Low platelet count should be verified on Peripheral Smear. Large platelet aggregates in EDTA sample may indicate scrub typhus & requires further evaluation. Thrombocytopenia in the background of platelet aggregatescould it be a bedside marker for scrub typhus?

21