A 73-year-old female presented with 5 days of fever, vomiting, and an eschar on her neck. She was diagnosed with scrub typhus based on her symptoms and physical exam findings. Scrub typhus is a rickettsial illness caused by Orientia tsutsugamushi transmitted through chigger bites. It typically causes high fever, rash, and lymphadenopathy. Diagnosis involves serologic testing, PCR, or biopsy of lesions. Doxycycline is the treatment of choice and prevents complications like pneumonia or multi-organ dysfunction. Prevention involves protective clothing and insect repellent to avoid chigger bites.

1. DIAGNOSIS AND TREATMENT OF SCRUB
TYPHUS.
NETHAJI

2. CASE DISCUSSION:
A 73 year old female admitted with complaints of
fever x 5 days,vomiting x 2 episodes for 2 days.No other complaints.
past hx:DM X 10 years taking reg medicines and HTN x 10 years.
On examination:Bp:110/70mmhg HR:92bpm.RR:24min.Temp:101 f.
PICCL-
B/L pitting pedal edema present till knee.
Eschar noted on left side of the neck.
Investigations showed platelet count :1,61,0000. Dengue was
negative, scrub typhus negative, blood culture shows coagulase
negative staphylococcus.
How we will diagnosis?

3. INTRODUCTION:
• Scrub typhus infection is an aetiology of acute undifferentiated
fever in India.
• It is a zoonotic rickettsial illness caused by Orientia
tsutsugamushi .
• Reservoirs are chiggers (larva of trombiculid mite) and rats and
humans are accidentally infected.
• Transmitted by trombiculid mites in long grasses and in dirt-floor
homes.

4. Epidemiology
• O. tsutsugamushi is maintained by transovarial transmission in
trombiculid mites.
• After hatching, infected larval mites inoculate organisms into the
skin.
• Infected chiggers to be found in areas of heavy scrub
vegetation during the wet season.
• in some areas, >3% of the population is infected or reinfected
each month.

5. PATHOPHYSIOLOGY
• Chigger inoculates O.tsutsugamushi pathogens.
• Bacteria multiply at the inoculation site,and a papule forms the
ulcerates and becomes nectroic,evolving into an eschar,with
regional lymohadenopathy that may progress to generalized
lymphyadnopathy within a few days.
• O.Tsutsugamushi stimulates phagocytosis by the immune
cells,and then escapes the phagosome.it replicates in the
cytoplasm and then buds fromthe cell.

7. CLINICAL MANIFESTATIONS:
COURSE OF ILLNESS
• Mild and self-limiting to fatal.
• Incubation period of 6-21 days.
• Scrub thypus lasts for 14 to 21 days without treatment.
• Death may occur end of 2nd week due to complications.

8. Clinical symptoms:
• Fever is high grade(>104 f)
• Severe headache,profuse sweating,conjunctival injection.
• Myalgia,cough,and gastrointestional
symptoms(nausea,vomiting,diarrhea)
• Fever lasts for long periods in untreated patients.

9. SYMPTOMS AND SIGNS:
The classic case includes
1) eschar present ,
2)regional lymphadenopathy,
3)transient maculopapular rash.
- 40%develop a rash(on day 4-6 of illness)
-comprises 5 to 40 macular,then papular and vesicular spots.
-Non-pruritic..

10. ESCHAR
Painless papule often at
the site of the infecting
chigger bite.
Subsequent central
necorsis then occurs
forming eschar with
black crust.

11. • SIGNS:
• Relative bradycardia.
• Lymphadenopathy-Tender lymph node.
• Hepatomegaly anad splenomegaly can be observed.

12. Respiratory :
• cough
• ARDS
• Pathogenesis of ARDS in scrub typhus not known, immunological
response of the lung to the infection without direct invasion of the
organism and diffuse alveolar damage without evidence of
vasculitis.
• NEUROLOGICAL:
• Involvement of bood vessels in the CNS may produce meningitis.
• Mental changes from slight intellecutal blunting to coma or
delirium.
• In severe cases,to a multiple organ dysfunction syndrome.

13. COMPLICATIONS:
-Over whelming pneumonia with ARDS.
-Acute kindy injury.
-Atypical pneumonia.
-Myocarditis,CHF.
-Pulmonary edema.
-Circulatory collapse
-Disseminated intravascular coagulation.

14. DIFFERENTIAL DIAGNOSIS:
• The most common signs are similar to a variety of the other
infectious diseases.
• Typhoid fever.
• Malaria.
• Leptospirosis.
• Dengue fever.
• Brucelosis.
• Chickungunya.

15. Lab parameters
• Leucocytosis or leucopenia may be present,but mostly
normal wbc count.
• Liver enzymes levels are increased in 60% of cases.
• Thrombocytopenia may be sufficient to cause bleeding.
• Hyperbilirubinemia and increased creatinine.

16. Diagnosis evalution:
• Serologic assays
- Indirect fluorescent antibody(gold standard)
-indirect immunoperoxidase.
-enzyme immunoassays.
-Serological methods are reliable when a four-fold rise in antibody
titre is looked.
-When a single measurement is performed,the most common cut
off titre is 1:50
-PCR amplificatiton of orientia genes from eschar,lymphnodes
and blood.

17. WEIL FELIX TEST:
• The weil-felix test detects cross-reacting antibodies to proteus
mirabilius OX-K. The weil-felix test its a low cost.
• Fifty percent of patient have a positive test result during the
second week.
• Weil felix test is based on cross reactons which occur between
antibodies peoduced in acute rickettsial infecttions with antigens
of OX(OX19, OX 2 and OX K)

18. • Biospy of an eschar or generalized rash.
-pathological hallmark-lymphohistiocytic vasculitis.
-Endothelial injury causes loss of vasular integrity.Egress of
plasma and plasma proteins and microscopic and macroscopic
hemorrhages.
-Histologic change in biopsies of eschars shows focal intense
vasculitis with perivascular collection of lymphocytes and
macrophages.

19. • Isolation of O.tsutsugamushi can be done in cell culture or in
inoculated mice.
• Chest radiography may reveal pneumonitis especially in the
lower lung fields.
• In meningitis,there is apredominant mononuclear response.

20. TREATMENT:
ADULT TREATMENT:
• Doxycycline (100mg bd orally for 7-15 days)
-but can also be given in a single dose or short periods (3 to 7
days)although relapse can occur.
-Azithromycin (500mg orally for 3 days) especially for the
pregnant patients.

21. PROPHYLAXIS:
• Single oral dose of chloramphenicol or tetracycline given every
five days for a total of 35 days,with 5-day non-treatment
intervals(for endemic regions).
• No vaccine is available for scrub typhus.

22. PREVENTION:
• Protective clothing.
• Insect repellents containing dibutyl phthalate,benzyl
benzoate,diethyl toluamide etc applied to the skin and clothing
to prevent chigger bits.
• Do not sit or lie on bare ground or grass.
• Clearing of vegetation and chemical treatment of the soil may
help to break up the cycle of transmission from chiggers to
humans to other chiggers.

23. TAKE HOME MESSAGE:
• Scrub typhus is a re-emerging disease in india.
• An important cause of community acquired undifferntiated
febrile illness in india.
• It has to be considered in the differential diagnosis of sepsis and
multi organ dysfunction syndrome.
• Failure of early diagnosis is associated with significant mortality
and morbidity .
• Search for an eschar in hidden areas of body.
• Screening by weil felix and diagnosis is done by IgM scrub
typhus ELISA.
• DOC: Doxycycline.

24. REFERENCE:
• PMC ARTICLE
• Indian J Dermatol. 2017 Sep-Oct; 62(5): 478–485.
• Sayantani Chakraborty and Nilendu Sarma1
• From the Department of Dermatology, R. G. Kar Medical
College, Kolkata, West Bengal, India
• Harrison’s principles of internal medicine 21st edition.

25. THANKYOU.