Tick Borne diseases and Malaria

Question 1

Three major diseases from Ticks

Answer 1

Lyme disease, Rocky mountain, spotted fever, Human monocytotropic ehrlichiosis

Question 2

Lyme disease organism and vector

Answer 2

Borrelia Burgdorferi; Ixodes tick(Deer tick or Blacklegged ticks)

Question 3

RMSF organism and vector

Answer 3

Rickettsia rickettsii; American dog tick

Question 4

Ehrlichiosis organism and vector

Answer 4

Ehrlichia chaffeensis; Lone star tick

Question 5

Description of Borrelia burgdorferi

Answer 5

Spirochete

Question 6

Reported cases of lyme disease

Answer 6

Endemic to parts of the Northeast and Upper Midwest

Question 7

Stage 1 of Lyme disease

Answer 7

• localized(incubation 3-32 days)

- rash(Erythema migrans)

Question 8

Stage 2 of Lyme disease

Answer 8

• disseminated
• multiple annular skin lesions
• meningitis(headache, fever, stiff neck)
• cranial neuritis(CN 7)
• carditis(AV block)
• arthralgia

Question 9

Stage 3 of Lyme disease

Answer 9

• persistent
• oligoarticular arthritis(knee joints)
• encephalopathy(mood, memory, sleep disturbance)
• axonal polyneuropathy(tingling feet, weakness)
• acrodermatitis

Question 10

Description of an erythema migrans

Answer 10

central clearing and a necrotic center

Question 11

Vesicular erythema migrans

Answer 11

-vesicles may appear near the center of erythema migrants lesions

Question 12

Physical findings of Cranial nerve 7 palsy

Answer 12

• inability to raise the left eyebrow or generate wrinkles on the left side of the forehead
• difficulty closing the left eye and inability to raise the left corner of mouth
• demonstrates drooping at the left corner of mouth, loss of the left nasolabial fold, and inability to complete close the left eye

Question 13

Differential diagnosis of CN 7 palsy

Answer 13

• idiopathic(Bell’s Palsy)
• HSV(herpes simplex virus); usually no rash
• herpes zoster(ramsay hunt syndrome); vesicles in the external auditory canal
• lyme disease

Question 14

Post lyme syndrome

Answer 14

• “Chronic lyme disease”
• pain syndrome(arthralgias), chronic fatigue, neurocognitive symptoms
• symptoms occur for years after eradication of infection
• symptoms may be indistinguishable from chronic fatigue or fibromyalgia

Question 15

Serologic testing of lyme disease

Answer 15

• IgM and IgG
• often retrospective diagnosis using paired sera
• acute and convalescent, draw at presentation and 2-4wks later

Question 16

ELISA and Western blot verification

Answer 16

-similar to older HIV testing methods

Question 17

PCR

Answer 17

• arthrocentesis of joint fluid done in patient with arthritis
• low sensitivity in CSF

Question 18

Treatment of Lyme disease

Answer 18

Doxycycline

Question 19

Prevention of Lyme disease

Answer 19

• no human vaccine available

- examine self, use insecticides with DEET, tuck pants into socks, permethrin insecticides, insect shieldEpid clothing

Question 20

Description of Rickettsia rickettsii

Answer 20

-small, obligate intracellular gram - bacilli

Question 21

Tropism of Rickettsia rickettsii

Answer 21

vascular endothelial cells

Question 22

Epidemiology of Rickettsia rickettsii

Answer 22

Generally widespread, concentrated in mid america

Question 23

Incubation period of Rickettsia rickettsii

Answer 23

-1 week

Question 24

Pathophysiology of Rickettsia rickettsii

Answer 24

• increased vascular permeability
• edema, hypovolemia
• hyponatremia following compensatory ADH release
• thrombocytopenia
• DIC rare

Question 25

Clinical presentation of Rickettsia rickettsii

Answer 25

Classic triad = Fever, rash, history of tick exposure | -fever, headache, malaise, myalgia

Question 26

Rash of RMSF

Answer 26

- begins as faint merciless - progresses to vasculitis rash - petechiae - palms and soles potential

Question 27

Progressive disease of RMSF

Answer 27

- hypovolemia, hypotension, fluid third spacing - respiratory failure - cardiac dysrhythmia - CNS symptoms(confusion, lethargy, encephalopathy) - ATN(acute tubular necrosis) - shock - elevated transaminase(acute hepatitis/liver failure)

Question 28

Definition of thrombocytopenia

Answer 28

low platelets

Question 29

Definition of hyponatremia

Answer 29

low sodium

Question 30

Definition of azotemia

Answer 30

-increased BUN, potentially increased creatinine if ATN develops

Question 31

Testing for R. rickettsii

Answer 31

- no completely reliable test in early stages of disease - skin biopsy of lesion with direct immunofluorescence staining(obtain before or within 12hrs of antibiotic therapy) - serologic testing of IgM and IgG(first set of sera after 5days of illness, second set 14-21days after symptoms onset)

Question 32

Limited differential diagnosis of patient with fever, petechial rash on palms and soles, potential tick exposure

Answer 32

- meningococcal disease - Tick borne disease, RMSF - enteroviral disease - secondary syphilis - rubella - drug eruption - kawasaki disease - coxsackie virus(hand foot and mouth disease)

Question 33

Treatment of RMSF

Answer 33

Ceftriaxone and Doxycycline therapy for both meningococcal disease and RMSF

Question 34

Treatment of RMSF

Answer 34

- doxycycline for adults and children - not for pregnant women - dental staining in children

Question 35

RMSF and chloramphenicol

Answer 35

-pregnant women

Question 36

Description of Ehrlichia chaffeensis

Answer 36

obligate intracellular organism

Question 37

Incubation period of ehrlichiosis

Answer 37

~ 8 days

Question 38

Symptoms of Ehrlichiosis

Answer 38

fever, headache, mylagias

Question 39

Lab findings of ehrlichiosis

Answer 39

leukopenia, thrombocytopenia, elevated transaminases

Question 40

Treatment of ehrlichiosis

Answer 40

Doxycycline

Question 41

Area for Malaria

Answer 41

-tropical climates

Question 42

Organism and vector of Malaria

Answer 42

Plasmodium species; Anopheles mosquito

Question 43

Interesting fact about Pathological Hb disorder

Answer 43

Hemoglobinopathy map echoes malaria map

Question 44

Review chart of malaria species

Answer 44

Go to notes

Question 45

Plasmodium life cycle

Answer 45

1. Sporozoites have trophism for hepatocytes 2. asexual reproduction in hepatocytes 3. release into bloodstream 4. hijacking of RBC and degradation of hemoglobin, formation of ring forms 5. lyse RBC and release merozoites to invade more RBC, or gametocytes to reinfect mosquitos(hemolytic anemia => direct hyperbilirubinemia = jaundice) 6. Pvivax and Povale can produce dormant hypnozoites in hepatocytes, can reactivate in 3-12months

Question 46

Clinical features of patient presentation

Answer 46

headache, fatigue, myalgias, abdominal pain, fever, seizures(Pfalciparum), paroxysmal chills(Pvivax, ovale)

Question 47

Clinical presentation malaria

Answer 47

fever, mild hepatomegaly, mild icterus(jaundice), palpable spleen, rash is unusual

Question 48

Complications of P falciparum

Answer 48

- sequestration and agglutination in vasculature, including CNS - cerebral malaria(seizures, encephalopathy, coma) - hypoglycemia - metabolic acidosis(hypoperfusion and lactic acidemia) - noncardiogenic pulmonary edema(ARDS) - renal impairment(ATN) - hematologic abnormalities(anemia) - liver dysfunction(cholestasis, acute hepatitis)

Question 49

Diagnostic testing for malaria

Answer 49

- light microscopy of giemsa -stained blood smear - thick and thin blood smears, pathologist evaluation for ring forms and estimation of parasite load - thick blood smears concentrate parasites, increases diagnostic sensitivity - rapid diagnostic test, antigen detection

Question 50

Lab findings

Answer 50

- normocytic normochromic anemia | - increased acute phase reactants(ESR and CRP)

Question 51

Treatment of malaria

Answer 51

- non falciparum and chloroquine sensitive = chloroquine - p falciparum and chloroquine sensitive = chloroquine - chloroquine insensitive = Arteminsin-based combinations

Question 52

Preventive drugs

Answer 52

- malarone - doxycycline - chloroquine - mefloquine - CNS side effects