Info
🌱 來自: Huppert’s Notes
Tick-Borne Illnesses🚧 施工中
Tick-Borne Illnesses
Lyme disease
• Etiology: Borrelia burgdorferi spirochete is spread by the Ixodidae scapularis tick in the Northeastern United States, Northern Midwest.
• Stages**:**
- Stage 1: Early localized (1–4 wks) – single erythema migrans target-shaped skin lesion
- Stage 2: Early disseminated infection (weeks-months) – multiple erythema migrans skin lesions, fever, headache, heart block/myocarditis, cranial nerve palsy, meningitis
- Stage 3: Late infection (mo-yr later) – oligoarticular arthritis, encephalopathy or encephalomyelitis
- Post-Lyme disease syndrome: There is no biologic evidence for “chronic Lyme” infection and there is no benefit to antibiotics for this syndrome
• Diagnosis: Two tier testing with ELISA and Western blot confirmation
• Treatment: PO doxycycline; use IV ceftriaxone for more severe stage 2 and 3 disease (e.g., meningitis)
Other tick-borne illnesses
• Ehrlichiosis: Bacterial illness transmitted by the Lone Star tick. Can cause leukopenia, thrombocytopenia, and rash (less common). Treatment: Doxycycline
• Anaplasmosis: Bacteria transmitted by the Ixodes tick (same tick that transmits the Lyme spirochete and babesiosis – so can get co-infection!). Causes fever, rash. Treatment: Doxycycline
• Babesiosis: Parasite transmitted by the Ixodes tick. Can cause hemolytic anemia, jaundice, hemoglobinuria, renal failure. Typically, the patient does not have a rash (unlike other tick-borne illnesses). Patients are at particular risk if they are asplenic. Diagnosis: Smear with intra-erythrocytic parasites that look like a Maltese cross. Treatment: Atovaquone + azithromycin OR quinine + clindamycin if severe infection
• Rocky Mountain Spotted Fever: Bacteria transmitted by the Dermacentor tick. Can cause fever, nausea/vomiting, and then a rash that starts on the palms and soles and spreads to the rest of the body. Can also cause, interstitial pneumonitis, elevated LFTs, thrombocytopenia. Treatment: Doxycycline
FIGURE 8.3: Antibiotic coverage map. This image depicts a simplified way to visually organize antibiotic coverage. See also Tables 8.11, 8.12 and “Principles of antibiotic selection and infection management” at the beginning of this chapter. For each drug, the generic name is listed first and then the trade name follows in parentheses for some drugs. Antibiotics with stronger Gram-positive (Gram+) coverage are positioned on the left of the figure in red and antibiotics with stronger Gram-negative (Gram–) coverage are positioned on the right of the figure in blue. The further left or right an antibiotic is positioned generally reflects broader Gram-positive or Gram-negative coverage respectively. At the bottom, antibiotics with atypical coverage are in green boxes and those with anerobic coverage are in a brown box. Please note that this is a simplified way to depict the relative coverage of antibiotics, as many of these antibiotics cover multiple classes of organisms with some caveats listed in the figure below each box. Please refer to other resources for a more complete overview of antibiotic sensitivities. Abbreviations: (P) indicates antibiotics that cover Pseudomonas aeruginosa (also see text in the bottom right of the figure), +MRSA indicates antibiotics that cover methicillin-resistant Staphylococcus aureus; +VRE indicates antibiotics that cover vancomycin-resistant enterococcus; +ESBL indicates antibiotics that cover extended-spectrum beta lactamase producing bacteria; IV, intravenous; PO, per os.