179: Lyme Borreliosis Flashcards
What is the primary causative agent of Lyme disease?
Lyme disease is caused by Borrelia burgdorferi, a tickborne spirochete.
T or F: B. garinii causes meningitis and rediculopathy more frequently than B. burgdorferi.
True.
What is the typical onset time for Erythema Migrans after a tick bite?
Erythema Migrans typically begins 3 to 30 days (average: 7 days) after the completion of tick feeding.
What percentage of infected individuals present with Erythema Migrans?
Erythema Migrans is present in 70% to 80% of infected individuals, and as high as 90% in patients diagnosed with Lyme disease.
What are the histopathological findings associated with Erythema Migrans?
Histopathology of Erythema Migrans shows a superficial and deep perivascular infiltrate of eosinophils at the center of the lesion, with plasma cells, lymphocytes, and histiocytes peripherally.
What are the characteristics of the classic EM rash?
The classic EM rash is typically large (>5 cm), expanding, erythematous, round or oval, with the longer axis along the lines of least skin tension (Langer lines) central clearing and a darker punctate center at the site of the tick bite (Bull’s-eye rash).
T or F: Central clearing may be more common in B. garinii infections compared to B. burgdorferi infections, indicating a potential difference in clinical presentation between the species.
True.
What are the common symptoms reported by patients with Erythema Migrans?
30% to 50% of patients report mild tingling, itching, or burning, and 50% report systemic manifestations that may appear before, during, or after the classic lesion.
What is the typical duration for a solitary EM rash to develop?
A solitary EM rash typically requires a minimum of 36 hours at the site of the tick bite to develop.
What is the relationship between Erythema Migrans and the dissemination of bacteria?
3 days after the presence of the EM lesion, bacteria can disseminate from the inoculation site, leading to multiple EM rashes scattered over the body.
A patient develops multiple erythema migrans (EM) lesions scattered over their body. What does this indicate about the stage of Lyme disease?
Multiple EM lesions indicate hematogenous dissemination of the spirochete, representing early disseminated Lyme disease.
What is the pathophysiological mechanism behind the ‘bull’s-eye’ appearance of erythema migrans (EM)?
The ‘bull’s-eye’ appearance is due to the host inflammatory response to the nascent Borrelia infection.
What is the most common dermatologic manifestation of hematogenous dissemination in Lyme disease?
The most common dermatologic manifestation is multiple erythema migrans (EM) lesions.
What is the primary vector for Borrelia burgdorferi in North America, and what stage is most responsible for human transmission?
The primary vector is the Ixodes scapularis tick, and the nymphal stage is most responsible for human transmission.
What is the significance of the ‘bull’s-eye’ rash in Lyme disease diagnosis?
The ‘bull’s-eye’ rash, or erythema migrans (EM), is the most distinctive clinical manifestation of Lyme disease and often allows for a clinical diagnosis without laboratory testing.
What is Acrodermatitis Chronica Atrophicans (ACA) and its demographic characteristics?
Acrodermatitis Chronica Atrophicans (ACA) is observed mainly in elderly patients in Europe, with a predilection for females. Rare cases are reported in children, and most patients do not recall the specific tick bite that initiated the disease.
What are the clinical phases of Acrodermatitis Chronica Atrophicans (ACA)?
ACA has two clinical phases:
-
Inflammatory Phase:
- Early clinical stages present as a bluish-red discoloration on the extensor aspects of fingers, hands, joints, and lower extremities.
- Involves joints such as elbows and knees, with infiltrated purple bands adjacent to involved joints.
- Associated findings include cushion-like swelling of the dorsum of hands and feet.
- Lesions extend from distal to proximal portions of the extremity, with erythema and swelling varying in intensity (waxes and wanes).
- Swelling of the posterior aspect of lower extremities is indicative of Lyme disease.
-
Atrophic Phase:
- Characterized by a ‘cigarette paper-like’ appearance and prominence of superficial veins.
- Chronic joint and bone involvement attributed to persistence of spirochetes in cutaneous lesions
What are the neurological and joint manifestations associated with Acrodermatitis Chronica Atrophicans (ACA)?
Neurological and joint manifestations associated with ACA include:
- CNS and peripheral nervous system involvement in 45% of patients with ACA.
- 30-45% of patients experience polyneuropathy, most pronounced in the limb with cutaneous involvement.
- Chronic joint and bone involvement is attributed to the persistence of spirochetes in cutaneous lesions, often seen in longstanding ACA or untreated EM or ACA.
What histopathological features are observed in Acrodermatitis Chronica Atrophicans (ACA)?
Histopathological features of ACA vary with the clinical phase:
-
Inflammatory lesions consist of three layers:
- An atrophic epidermis
- A zone of uninvolved papillary dermis
- A layer of inflammatory cells composed of lymphocytes and plasma cells.
- Plasma cells in the infiltrate are mainly documented from studies in Europe.
- Infiltrate may extend deep into the subcutis, with occasional reports of interface dermatitis.
- Unusual findings include vacuoles at different levels of the dermis, which may indicate lymphedema.
A patient presents with a bluish-red discoloration on the extensor aspect of their fingers and hands. What is the likely diagnosis, and what phase of the disease does this represent?
The likely diagnosis is Acrodermatitis Chronica Atrophicans (ACA), and this represents the inflammatory phase.
What is the histopathological hallmark of Acrodermatitis Chronica Atrophicans (ACA) in its inflammatory phase?
The hallmark is a three-layered inflammatory lesion with an atrophic epidermis, uninvolved papillary dermis, and a layer of inflammatory cells composed of lymphocytes and plasma cells.
What is the significance of the ‘cigarette paper-like’ appearance in the atrophic phase of ACA?
The ‘cigarette paper-like’ appearance is characteristic of the atrophic phase of ACA, indicating chronic skin changes.
What is the significance of the ‘waxing and waning’ swelling in the inflammatory phase of ACA?
The ‘waxing and waning’ swelling is indicative of the inflammatory phase of ACA and may help differentiate it from other conditions.
What is the clinical significance of the ‘doughy’ swelling in ACA?
The ‘doughy’ swelling is a characteristic finding in the inflammatory phase of ACA and is often seen on the dorsum of the hands and feet.
What are the clinical features of cutaneous scleroborrelioses associated with Lyme disease?
- Sclerotic skin lesions indistinguishable from primary lichen sclerosus et atrophicus or morphea.
- Develop in approximately 10% of patients with ACA and borrelial lymphocytoma, but also in the absence of other cutaneous manifestations.
- Present as hard nodules on the elbows and knees, and lateral aspect of the digits near joints.
- Provoked by trauma, surgery, and electromagnetic radiation.
- Associated with uncommon sclerotic disorders like progressive facial hemiatrophy (Parry-Romberg syndrome) and eosinophilic fasciitis (Shulman syndrome).
What histopathological findings are associated with borrelial fasciitis?
- Eosinophilic infiltration of the fascial planes, less impressive than in idiopathic Shulman disease.
- Variable dermal sclerosis, loss of appendages, and perivascular infiltrate predominantly of lymphocytes and plasma cells with scattered histiocytes.
What are the characteristics of cutaneous atrophoborrelioses?
- Atrophic lesions indistinguishable from primary anetoderma.
- May occur in the absence of other dermatoborrelioses.
- When associated with ACA, lesions are usually seen at the periphery of an extensive lesion.
- Histopathology shows abnormal elastic tissue fibers with a perivascular infiltrate of lymphocytes, occasional histiocytes, neutrophils, or eosinophils.
What is the significance of cutaneous lymphoborrelioses in Lyme disease?
- Least common of the cutaneous hallmarks of Lyme disease (1%).
- Present as single borrelial lymphocytoma (lymphadenosis benigna cutis) or multiple lesions.
- More common in children, with lesions typically found in ear lobes and scrotum in children, and nipple-areolar area in adults.
- Direct evidence of an infective etiology has been confirmed by immunofluorescence using species-specific monoclonal antibodies.
A child presents with a nodulopapular lesion on their earlobe. What is the likely diagnosis, and what is the causative organism?
The likely diagnosis is Borrelial lymphocytoma, and the causative organism is Borrelia burgdorferi.
What is the significance of high titers of antibodies in patients with Borrelia-associated lymphoma?
High titers of antibodies are a common denominator in patients with Borrelia-associated lymphoma, typical of the chronic stage.
What is the recommended treatment for Borrelial lymphocytoma?
The recommended treatment is antibiotic therapy, which resolves the lesions more rapidly than spontaneous resolution.
What are the characteristics of benign lymphocytic infiltrates of the skin / Jessner-Kanof?
- Discoid lesions starting as small papules that expand peripherally with central clearance.
- Wax and wane in association with borrelial infection.
- More common in men.
- Typically found on the face, neck, and upper trunk.
What is the clinical presentation of Borrelia-associated B-cell lymphoproliferative disease?
- Multiple ill-defined, slowly progressive plaques and nodules on the trunk, extremities, or both.
- Common in older patients.
- Highest frequency of infection found in marginal zone lymphoma (20% to 52%).
What are the common neurologic manifestations of Lyme disease?
- Meningitis
- Cranial neuropathy
- Radiculopathy
- Can manifest as soon as 1 week after EM lesion.
What is Bannwarth syndrome and its significance in Lyme disease?
- A triad of lymphocytic meningitis, cranial palsy (often facial), and radiculoneuritis.
- Pathognomonic for Lyme disease and frequently reported in Europe.
What are the cardiac manifestations associated with Lyme disease?
- Cardiac involvement can occur from 1 week to 7 months after onset of infection.
- B. burgdorferi has a predilection for the atrioventricular node, leading to atrioventricular block.
- Acute myopericarditis and left ventricular dysfunction can occur, usually self-limited and mild.
What are the musculoskeletal manifestations of late-disseminated Lyme disease?
- Inflammatory arthritis is the most frequent clinical sign, occurring in 60% of patients with untreated or incompletely treated infection.
- Presents as asymmetric monoarthritis or oligoarthritis of large joints, most often the knee.
- Migratory arthralgia is also common during disseminated Lyme disease.
What is the triad of Bannwarth syndrome, and why is it significant?
The triad of Bannwarth syndrome includes lymphocytic meningitis, cranial palsy (often facial), and radiculoneuritis. It is pathognomonic for Lyme disease.
What is the most frequent clinical sign of late-disseminated Lyme disease, and how does it typically present?
The most frequent clinical sign is inflammatory arthritis, which typically presents as asymmetric monoarthritis or oligoarthritis of large joints, most often the knee.
A patient presents with bilateral facial palsy. What should be the immediate clinical suspicion?
Bilateral facial palsy should immediately raise suspicion for Lyme disease.
What is the clinical significance of migratory arthralgia in Lyme disease?
Migratory arthralgia is a common manifestation during disseminated Lyme disease and may precede inflammatory arthritis.
What are some of the ophthalmic complications associated with Lyme disease?
Ophthalmic complications include conjunctivitis, keratitis, iridocyclitis, retinal vasculitis, choroiditis, and optic neuropathy. These complications are rare and are a direct result of tissue inflammation caused by B. burgdorferi.
What is the significance of B. burgdorferi crossing the placenta during pregnancy?
B. burgdorferi can cross the placenta during the initial spirochetemia, but evidence of a fetal immune response or adverse neonatal outcomes are not definitively established. Studies have not found a link between maternal infection with Lyme and subsequent birth defects.
What are the characteristics of Lyme disease in children compared to adults?
Pediatric Lyme disease is similar to that of adults, with EM lesions typically found in the head and neck. However, optic nerve involvement in children may lead to blindness.
What percentage of patients with Lyme arthritis treated with antibiotics may experience persistent arthritis, and what are some proposed mechanisms?
About 10% of patients with Lyme arthritis treated with antibiotics may have arthritis that persists for years. Proposed mechanisms include autoimmune syndrome and molecular mimicry of borrelial antigens with host proteins, although the latter remains unproven.
These patients respond to immunosuppressive agents (methotrexate and anti-TNF therapies).
What is Posttreatment Lyme Disease Syndrome and its associated symptoms?
Posttreatment Lyme Disease Syndrome involves symptoms that persist beyond a standard treatment course of 2 to 4 weeks, including profound fatigue, depression, myalgia, polyarthralgias without arthritis, paresthesias, and neurocognitive difficulties. The linkage of these symptoms with B. burgdorferi infection is controversial.
What are the risk factors associated with Lyme disease?
Risk factors for Lyme disease are almost completely dependent on exposure to the tick vector in areas where Lyme disease is prevalent. Avoidance of environments where ticks are likely to be found is effective in preventing the disease.
What are the characteristics of B. burgdorferi as an organism?
B. burgdorferi is the agent of Lyme borreliosis.
What are the characteristics of B. burgdorferi as an organism?
B. burgdorferi is the agent of Lyme borreliosis, belonging to the eubacterial phylum of Spirochaetales. It is a corkscrew-shaped, motile bacterium with a genome made up of a linear chromosome and more than 20 plasmids, the largest number known for any bacteria. It lacks biosynthetic machinery to produce many essential nutrients, making it highly dependent on its hosts.
Describe the life cycle of Ixodes ticks and their role in Lyme disease transmission.
Ixodes ticks have a 2-year, 3-stage life cycle (larval, nymphal, and adult). Larval ticks acquire B. burgdorferi by taking a blood meal from an infected animal and maintain the infection during subsequent molting. Each tick life stage takes 1 blood meal, with larval ticks feeding in late summer, nymphal ticks in spring and early summer, and adult ticks in fall and early winter. Major reservoirs for B. burgdorferi include small rodents and birds, while adult ticks feed on larger mammals like deer, which are not important reservoirs.
What are the two major regulators of borrelial gene expression and their pathways?
The two major regulators of borrelial gene expression are:
1. HK1/Rrp1 pathway: Activated as bacteria exit a mammalian host and enter a tick host.
2. Rrp2/RpoS/RpoN system: Activated as the bacteria readies itself for entry into a mammalian host.
What role does the tick salivary protein Salp15 play in the infection process of B. burgdorferi?
Salp15 is a tick salivary protein that helps B. burgdorferi evade the mammalian immune system during early infection by being present on the surface of the spirochete.
What is the gold standard for diagnosing Lyme disease and what are its limitations?
The gold standard for diagnosing Lyme disease is culture. However, it requires specialized media and the slow growth of the organism makes it impractical. B. burgdorferi can be cultured from biopsies of EM and ACA, but rarely grows in synovial fluid or cerebrospinal fluid samples.
How does the immune response to B. burgdorferi manifest in patients?
The immune response to B. burgdorferi causes the characteristic EM rash, and the bacteria enter the blood circulation, disseminating hematogenously within days to weeks after infection.
What are the characteristics of PCR assays in detecting B. burgdorferi?
PCR assays are very sensitive in detecting B. burgdorferi DNA in skin biopsy and synovial fluid specimens from patients with EM and Lyme arthritis. However, PCR testing for B. burgdorferi DNA has not been approved by the FDA, and its sensitivity in detecting the organism in synovial fluid is between 70% and 85%.
What are the limitations of ELISA tests in diagnosing Lyme disease?
ELISA tests are relatively sensitive but are associated with a high rate of false-positive results.
* Patients with lupus, RA , Epstein-Barr virus, bacterial endocarditis, and other tick-borne diseases are at an increased risk for false-positive IgM serologic testing.
* Patients with H. pylori, SLE, erlichiosis and babesiosis cause false-positive IgG serologic testing.
What is the role of antigenic variation in Borrelia burgdorferi’s immune evasion?
Borrelia burgdorferi changes the antigenic composition of its VlsE protein through recombination, helping it evade the host immune system.
What is the role of host proteases like plasmin in Borrelia burgdorferi’s pathogenesis?
Host proteases like plasmin assist Borrelia burgdorferi in moving through tissues during dissemination.
What is the role of the VlsE protein in Borrelia burgdorferi’s immune evasion?
The VlsE protein undergoes antigenic variation, allowing Borrelia burgdorferi to evade the host immune response.
What is the significance of the C6 peptide test in diagnosing Lyme disease?
The C6 peptide test is a newer ELISA test that uses a small peptide of the constant region of B. burgdorferi VlsE protein, which has greater specificity. It measures only IgG antibodies, and the sensitivity of the assay in patients with early disease is equivalent to that seen with IgM whole-cell ELISA tests.
What are the current recommendations for serologic testing in suspected Lyme disease cases?
Current recommendations for serologic testing in suspected Lyme disease cases include:
1. Start with a highly sensitive ELISA test.
2. If ELISA is negative, further testing is not recommended.
3. If the test is positive or indeterminate, confirm with a Western immunoblot assay with high specificity.
The specificity of the 2-step approach is 99% - 100% in late-stage Lyme disease.
What does a positive IgM Western blot with a negative IgG Western blot indicate in Lyme disease testing?
A positive IgM Western blot with a negative IgG Western blot is considered a negative result due to the high false-positive rate of IgM testing. This indicates that seronegativity in patients suspected of having late Lyme disease practically excludes the diagnosis.
What is the differential diagnosis for erythema migrans (EM) in Lyme disease?
The differential diagnosis for erythema migrans (EM) includes:
- Cellulitis or erysipelas
- Tinea
- Insect bites
- Fixed drug eruptions
- Erythema multiforme
Additionally, southern tick-associated rash illness (STARI) is a newer inclusion in the differential diagnosis, associated with the bite of Amblyomma americanum.
What is the management approach for Lyme disease?
The management approach for Lyme disease includes:
- Antibiotic treatment is indicated for all stages, even though most manifestations resolve without therapy.
- Patients may not be asymptomatic at the time of completion of the antibiotic course, but this is not an indication for extending the length of therapy.
- Symptoms generally continue to improve steadily over time.
This diagnostic method is more specific because it enables detection of antibodies to individual components of B. burgdorferi.
Western immunoblot assay.
What is the recommended diagnostic approach for a patient with suspected Lyme disease but no erythema migrans (EM)?
The recommended approach is two-stage serologic testing, starting with an ELISA test followed by a Western immunoblot if the ELISA is positive or indeterminate.
What is the pathophysiological basis for the high false-positive rate of IgM serologic testing in Lyme disease?
The high false-positive rate is due to cross-reactivity with other conditions like autoimmune diseases and other tick-borne illnesses.
What are the first-line and alternative first-line antibiotics for treating Lyme disease?
First-line antibiotics:
- Doxycycline: Excellent CNS penetration, effective against A. phagocytophilum, suitable for children and pregnant women.
Alternative first-line agent:
- Cefuroxime.
Second-line agents:
- Macrolides: Used for those who cannot tolerate first-line agents, requires close monitoring and follow-up.
What is the recommended duration of therapy for Lyme disease?
The recommended duration of therapy for Lyme disease is 10 to 14 days.
What preventive measures can be taken to avoid Lyme disease?
Preventive measures include:
1. Avoiding environments where ticks that carry B. burgdorferi are likely to reside.
2. Performing tick checks and bathing after activities where exposure to ticks is expected.
3. Removing crawling or attached ticks promptly, as there is minimal transmission of spirochetes before 36 hours of attachment and feeding.
4. Using insect repellents with active ingredients like DEET, IR3535, PMD, and picaridin to prevent tick bites.
What is the efficacy of DEET in preventing tick bites?
DEET has been in use for 70 years and has a strong safety record. DEET-treated clothing has been demonstrated to provide up to 92% protection against tick bites. However, the duration of efficacy is less than 2 hours, requiring frequent reapplication.
What was the outcome of the human vaccine developed against Lyme disease?
An effective human vaccine against Lyme disease was developed in 1998, which reduced the risk of infection by 76%. However, it was voluntarily withdrawn from the market in 2002 due to low demand, and there is currently no human vaccine available against Lyme disease.
A patient presents with erythema migrans (EM) but no systemic symptoms. What is the recommended first-line treatment?
The recommended first-line treatment is doxycycline.
A patient develops fever, chills and worsening arthralgi and myalgia after starting antibiotics for Lyme disease. What causes this reaction?
The patient is experiencing Jarisch-Herxheimer reaction. It is caused by the host’s immune response to the dying Borrelia organisms.
What is the recommended prophylaxis for Lyme disease, and under what conditions should it be administered?
A single dose of oral doxycycline is recommended as prophylaxis if an attached tick has been found.
What is the recommended treatment for Lyme disease-associated meningitis?
The recommended treatment is intravenous antibiotics, such as ceftriaxone.
What is the role of DEET-treated clothing in Lyme disease prevention?
DEET-treated clothing provides up to 92% protection against tick bites, reducing the risk of Lyme disease.
Incubation period and duration of intreated solitary lesion of cutaneous lymphoborrelioses?
- Weeks to 10 months.
- Months to years (average: 5 years).
What are some uncommon cutaneous manifestations of Lyme disease?
Uncommon Manifestation | Onset Time |
|———————–|————|
| Cutaneous sclerodermatoses | Months to years (late) |
| Cutaneous atrophoborrelioises | Months to years (late) |
| Cutaneous lymphoborrelioises | Months to years (late) |
With what two manifestations can the diagnosis of Lyme disease be made on clinical grounds alone?
Classic EM and Bannwarth syndome.
What is the initial approach to a patient presenting with solid or ring-shaped erythema migrans (EM)?
- If consistent with EM and in an endemic region or recent travel to an endemic region, treat.
- If possibly consistent with EM, determine if in an endemic region or recent travel to an endemic region.
- If no other symptoms or nonspecific symptoms for >2 weeks, test (1st step test: ELISA, C6).
- If other symptoms suspicious for Lyme disease (LD), treat.
- If in a nonendemic region and no travel to endemic region, observe and consider alternate diagnosis.
What are the distinguishing features to differentiate erythema migrans from other conditions in the differential diagnosis?
Diagnostic Entity | Description | Distinguishing Features |
|——————-|————-|————————-|
| Cellulitis, erysipelas | Erythematous painful, spreading rash, often with associated edema, most commonly on lower extremity | Generally painful, seldom round or ovoid |
| Hypersensitivity to tick bite | Red papule at bite site with surrounding pruritic erythema, edema, urticaria | Typically pruritic, seldom exceeds 5 cm |
| Tinea corporis | Erythematous, annular lesions | Scaly, often with tiny vesicles at the border |
| Contact dermatitis | Erythematous rash which may form papules, vesicles, scale; in chronic cases lichenification, fissuring and erosions may occur | Generally occurs in areas exposed to jewelry, clothing, often with unusual patterns; often pruritic |
| Southern tick-associated rash illness (STARI) | Clinically indistinguishable from erythema migrans rash | Generally occurs in the South and Southwestern United States, but the geographic range is spreading to overlap with Lyme disease |
| Urticaria | Multiple, small, localized cutaneous edema with blanching erythema, generally pruritic | Usually presents as a pruritic, erythematous wheal; lesions generally last for minutes to hours |
| Pityriasis rosea | Multiple, small 2- to 4-cm oval lesions, often preceded by a larger “Herald patch” | Scaly, often appear in a classic “Christmas tree” pattern, generally on the trunk |
| Erythema annulare centrifugum | Expanding erythematous, annular, migrating lesions | Generally chronic, with waxing/waning course |
| Erythema multiforme | Circular, erythematous plaques, generally not exceeding 3 cm, sometimes follows herpes simplex virus or Mycoplasma pneumoniae infection | Acral distribution, may involve mucous membranes; lesions often become confluent |
What is the recommended antibiotic and duration for treating Erythema migrans in adults with Lyme disease?
Doxycycline 100 mg by mouth twice daily for 10 days; alternatives include Amoxicillin 500 mg three times daily for 14 days or Cefuroxime axetil 500 mg by mouth twice daily for 14 days.
What is the treatment duration for Lyme arthritis in adults with Lyme disease?
Doxycycline 100 mg by mouth twice daily for 28 days; alternatives include Amoxicillin 500 mg by mouth three times daily for 28 days or Cefuroxime axetil 500 mg by mouth twice daily for 28 days.
What is the recommended antibiotic and duration for treating Erythema migrans in adults with Lyme disease?
Doxycycline 100 mg by mouth twice daily for 10 days. Alternatives include Amoxicillin 500 mg three times daily for 14 days or Cefuroxime axetil 500 mg by mouth twice daily for 14 days.
What is the treatment duration for Lyme arthritis in adults with Lyme disease?
Doxycycline 100 mg by mouth twice daily for 28 days. Alternatives include Amoxicillin 500 mg by mouth three times daily for 28 days or Cefuroxime axetil 500 mg by mouth twice daily for 28 days.
What are the treatment options for Lyme carditis in nonhospitalized adults?
Doxycycline 100 mg by mouth twice daily for 14-21 days. Alternatives include Amoxicillin 500 mg by mouth three times daily for 14-21 days or Cefuroxime axetil 500 mg by mouth twice daily for 14-21 days.
What is the recommended treatment for meningitis in nonhospitalized adults with Lyme disease?
Doxycycline 100 mg by mouth twice daily for 14 days. Alternatives include Ceftriaxone 2 g IV daily for 14 days.
What is the prophylaxis recommendation for Lyme disease after a tick bite?
Doxycycline 200 mg as a single dose. Watchful waiting is an alternative.
What are the predominant species of Borrelia in Asia?
B. garinii and B. afzelii
What tick is known to transmit the predominant Borrelia species in Asia?
Ixodes persulcatus tick
When does Erythema migrans typically begin after a tick bite?
Begins 3 to 30 days (average: 7 days) after completion of tick feeding.
In which parts of the body does EM rash appear in children?
Head and neck
What condition presents as bluish-red discoloration on the extensor aspect of fingers, hands, joints, and lower extremities?
Acrodermatitis Chronica Atrophicans (ACA), inflammatory phase
What condition presents as hard nodules on the elbows and knees, and lateral aspect of the digits near joints?
Cutaneous Scleroborrelioses
What is Borrelial lymphocytoma and where does it present?
It presents as a nodulopapular lesion in the ear lobes and scrotum, and the nipple-areolar area in children and adults.
What is the most characteristic neuropathy of early Lyme disease?
Facial palsy
What is the predilection of B. burgdorferi that can result in atrioventricular block?
Atrioventricular node
What is the most frequent clinical sign of late-disseminated Lyme disease?
Inflammatory arthritis
What is the tick salivary protein that helps the organism evade the mammalian immune system during early infection?
Salp15
What are the manifestations that antibiotic therapy can hasten resolution of?
Erythema migrans (EM) and arthritis. NOT facial palsy, radiculitis.
What is the first line therapy for Lyme disease?
Doxycycline
What are the alternative first line agents for Lyme disease treatment?
Cefuroxime and Macrolides
What are the two predominant Borrelia species in Asia, and what tick transmits them?
The two predominant species are B. garinii and B. afzelii, transmitted by the Ixodes persulcatus tick.
Demographic preference of Lyme borreliosis?
- Bimodal
- Peaks at 5-9 y.o. and 55- 59 y.o.
Early cutaneous finding of Lyme disease?
Erythema migrans is the 1st symptom to develop with infection as bacteria 1st multiply in the skin.
What is the IHC result of tissue samples of E. migrans and how does it differ for HIV-infected people?
Infiltrate is CD4+ T lymphocytes but CD8+ for HIV-infected patients.
What are body areas more likely to sustain tick bites long enough to go unnoticed and allow for transmission of spirochetes?
- Popliteal fossa
- Groin
- Axilla
- Back
- Head
Most common manifestation of hematogenous dissemination of the spirochete?
Multiple EM rashes scattered over the body.
What are late cutaneous findings of Lyme borreliosis?
- Acrodermatitis Chronica Atrophicans
- Cutaneous Scleroborrelioses
- Cutaneous Atrophoborrelioses
- Cutaneous Lymphoborrelioses
Unifying feature of lichen sclerosus et atrophicus-like and morphea-like scleroborrelioses in histopathology?
Abundance of plasma cells in the inflammatory infiltrate.
Late skin lesions that are indistinguishable from primary anetoderma?
Cutaneous atrophoborrelioses.
It is the agent of Lyme borreliosis.
B. burgdorferi sensu lato. They are spirochetes which are vigorously motile and corkskrew-shaped.
T or F: Humans are definitive hosts important in maintaining B. burgdorfei in the wild.
False. They are incidental hosts.
What strain of B. burgdorferi is likely to result in hematogenous spread of the organism?
OspV type A (RST1)
Factors for B. burgdorferi that help in escaping immune defenses?
- Motility
- Antigenic variation
- Proteins that bind a host complement protein, factor H
Its main use is detecting B. burgdorferi in synovial fluid where Lyme arthritis is suspected.
PCR.
It is the main laboratory modality used to support a clinical diagnosis of Lyme disease.
Immunologic diagnosis (ELISA, Western immunoblot assays).
T or F: Persistent seropositivity is not in itself an indication of treatment failure. There is no test that allows confirmaton of successful clearance of the organism after treatment.
True.
Recommended treatment for cutaneous manifestations that are accompanied by neurologic disease or high-degree heart block.
IV Antibiotics:
* ceftriaxone
* cefotaxime
* penicillin G
T or F: Doxycyline should be used in children and pregnant women for Lyme disease.
True! (Unlike in most cases.)
Duration of efficacy of insect repellents?
Less than 2 hours (require frequent reapplication).
