Rocky mountain spotted fever: Difference between revisions
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==Background== | ==Background== | ||
*Most frequent rickettsial disease reported in the US. | *Most frequent rickettsial disease reported in the US.<ref>http://www.cdc.gov/rmsf/</ref> | ||
*Caused by Rickettsia rickettsii | *Caused by Rickettsia rickettsii | ||
**Obligate intracellular, gram negative bacteria | **Obligate intracellular, gram negative bacteria | ||
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==Clinical Features== | ==Clinical Features== | ||
*Symptoms generally begin 2-14 days after inoculation from an infected tick | *Symptoms generally begin 2-14 days after inoculation from an infected tick<ref>http://www.mayoclinic.com/health/rocky-mountain-spotted-fever/DS00600</ref> | ||
===Early symptoms=== | ===Early symptoms=== | ||
*'''Non specific and highly variable''' | *'''Non specific and highly variable''' | ||
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*Fatigue | *Fatigue | ||
*Conjunctivitis | *Conjunctivitis | ||
===Late symptoms=== | ===Late symptoms=== | ||
*Arthralgias | *Arthralgias | ||
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*Secondary to host response against infected endothelial cells | *Secondary to host response against infected endothelial cells | ||
**Vasculitis | **Vasculitis | ||
**Myocarditis | **[[Myocarditis]] | ||
**Interstitial pneumonitis | **Interstitial pneumonitis | ||
**Encephalitis | **[[Encephalitis]] | ||
==Diagnosis== | ==Diagnosis== | ||
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==Work-Up== | ==Work-Up== | ||
*EKG (Myocarditis) | *EKG (Myocarditis) | ||
*Chem 7 (Hyponatremia) | *Chem 7 ([[Hyponatremia]]) | ||
*CBC (Thrombocytopenia) | *CBC (Thrombocytopenia) | ||
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==Treatment== | ==Treatment== | ||
*[[Doxycycline]] 100mg BID for 5-7 days | *[[Doxycycline]] 100mg BID for 5-7 days<ref>Shandera WX, Roig IL: Viral & Rickettsial Infections, in Papadakis MA, McPhee SJ (eds): Current Medical Diagnosis and Treatment, ed 52. USA, McGraw-Hill, 2013, (Ch) 32: p 1412-1413.</ref> | ||
**Children - 2.2mg/kg BID | **Children - 2.2mg/kg BID | ||
*[[Chloramphenicol]] 50-100 mg/kg/day div Q6hr (Max dose = 4g/day) | *[[Chloramphenicol]] 50-100 mg/kg/day div Q6hr (Max dose = 4g/day) | ||
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*[[Tick borne illnesses]] | *[[Tick borne illnesses]] | ||
== | ==References== | ||
<references/> | |||
[[Category:ID]] | [[Category:ID]] | ||
Revision as of 17:17, 13 April 2015
Background
- Most frequent rickettsial disease reported in the US.[1]
- Caused by Rickettsia rickettsii
- Obligate intracellular, gram negative bacteria
- Predilection for vascular endothelial cells
- Spread by ticks
- American Dog Tick (Dermacentor variabilis) Most common vector
- Rocky Mountain Wood Tick (Dermacentor andersoni)
- Brown Dog Tick (Rhipicephalus sanquineus)
- Cayenne Tick (Amblyomma cajennense)
- Seasonal distribution with most infections occurring in the summer months
- Widely distributed in the US
- States with the highest incidence are Oklahoma, Nebraska, Arkansas, Tennessee and North Carolina
- Overall incidence is increasing while mortality is falling
Clinical Features
- Symptoms generally begin 2-14 days after inoculation from an infected tick[2]
Early symptoms
- Non specific and highly variable
- Fever
- Nausea/Vomiting
- Abdominal pain
- Myalgias
- Headache
- Fatigue
- Conjunctivitis
Late symptoms
- Arthralgias
- Rash
- Begins as a blanching maculopapular rash that evolves to become a petechial rash
- Usually 2-5 days after fever subsides
- Starts on extremities and spreads inward (centripetally)
- Can involve palms and soles (50% of cases)
- Positive Rumpel-Leede test
- Development of petechiae at the site of blood pressure cuff and distally after compression
Complications
- Secondary to host response against infected endothelial cells
- Vasculitis
- Myocarditis
- Interstitial pneumonitis
- Encephalitis
Diagnosis
- PCR (initially)
- Serial serologic examinations by indirect fluorescent antibody confirm the diagnosis
- Titers
Work-Up
- EKG (Myocarditis)
- Chem 7 (Hyponatremia)
- CBC (Thrombocytopenia)
Differential Diagnosis
- Other Tick Borne Illnesses
- Non-specific viral illness
Lower Respiratory Zoonotic Infections
- Psittacosis
- Anthrax (Bacillus anthracis)
- Brucellosis (Brucella species)
- Q fever (C. burnetti)
- Pasteurellosis (Pasteurella multocida)
- Melioidosis (Burkholderia pseudomallei)
- Rocky Mountain Spotted Fever (R. rickettsii)
- Pulmonic Plague (Yersinia pestis)
- Influenza A
- Hantavirus
Tick Borne Illnesses
- Babesiosis
- Colorado tick fever
- Ehrlichiosis
- Heartland virus
- Lyme
- Murine typhus
- Rocky mountain spotted fever
- Southern tick-associated rash illness (STARI)
- Tick paralysis
- Tularemia
Treatment
- Doxycycline 100mg BID for 5-7 days[3]
- Children - 2.2mg/kg BID
- Chloramphenicol 50-100 mg/kg/day div Q6hr (Max dose = 4g/day)
See Also
References
- ↑ http://www.cdc.gov/rmsf/
- ↑ http://www.mayoclinic.com/health/rocky-mountain-spotted-fever/DS00600
- ↑ Shandera WX, Roig IL: Viral & Rickettsial Infections, in Papadakis MA, McPhee SJ (eds): Current Medical Diagnosis and Treatment, ed 52. USA, McGraw-Hill, 2013, (Ch) 32: p 1412-1413.