Parasitic & Fungal Infections

Question 1

Toxoplasmosis gondii

what animal is the defifinitive host?

Answer 1

cats but also found in birds and many other mammals

Question 2

toxoplasmosis gondii

Where do you get it from?

Answer 2

contaminated soil from cat feces, contaminated undercooked meat.

Question 3

toxoplasmosis gondii

What are dangers for pregnant mothers?

Answer 3

It passes through placenta, moms shouldnt clean cat litter

Question 4

toxoplasmosis gondii

symptoms

Answer 4

Can be asymptomatic
Fever, malaise, headache, sore throat.
Cervical lymphadenopathy

Question 5

toxoplasmosis gondii

Dx

Answer 5

Positive IgG and IgM serologic tests

Question 6

toxoplasmosis gondii

congenital infection

Answer 6

After acute infection of seronegative mothers, CNS abnormalities and retinochoroiditis seen in offspring.

eye issues for baby

Earlier infections more likely to have serious outcomes: SAb, stillbirth, neurologic problems,

Question 7

toxoplasmosis

infection in immunocompromised

Answer 7

Reactivation leads to encephalitis, retinochoroiditis, pneumonitis, myocarditis.
Positive IgG but negative IgM serologic tests.

Encephalitis with necrotizing brain lesions
Chorioretinitis
Pneumonitis

Question 8

toxoplasmosis

Dx through CT or MRI

Answer 8

*Multiple ring-enhancing lesions

Question 9

toxoplasmosis

Triad of Sx for congenital infection

Answer 9

Retinochoroiditis/chorioretinitis
Hydrocephalus
Intracranial calcifications

Question 10

toxoplasmosis gondii

Tx

for normal, compromised, pregnant

Answer 10

usually not needed for immunocompetent.

For AIDS full therapy for 4–6 weeks followed by maintenance therapy with lower doses of drugs.

Treat primary infection during pregnancy to reduce risk of fetal transmission.

Retinochoroiditis: treatment advocated if decrease in visual acuity, multiple or large lesions, macular lesions, significant inflammation, or persistence for over a month.

Question 11

toxoplasmosis gondii

Medications

Answer 11

Pyrimethamine orally once daily plus sulfadiazine(sulfonamide) orally four times daily, with folinic acid/leucovorin once daily.

Question 12

toxoplasmosis gondii

AIDS treatment/meds

Answer 12

HIV+ patents with low CD4+ counts may require prophylaxis with trimethoprim/sulfamethoxazole to prevent symptomatic disease

Question 13

toxoplasmosis gondii

Tx for pregnant

Answer 13

is spiramycin(macrolide) orally three times daily until delivery.
reduces frequency of transmission to fetus by 60%
does not cross placenta,

Question 14

Toxoplasmosis gondii

prevention

Answer 14

Cook meat until no longer pink inside

Cats
Change cat litter box daily (not if pt is pregnant or HIV+)
Hand hygiene
Feed cat well-cooked food

Garden soil: wash hands, wash produce

Question 15

Amebiasis

What are the infectious agents

Answer 15

Entamoeba dispar, Entamoeba moshkovskii, Entamoeba histolytica

Question 16

Amebiasis

how do you get infected?

Answer 16

Ingestion from fecally contaminated food or water by person to person spread
Present worldwide but most prevalent in tropical areas with crowding, poor sanitation and nutrition
Disease follows penetration of the intestinal wall

Question 17

Amebiasis

Dx

Answer 17

Diagnosis is most commonly made by finding organisms in stool
Serologic tests may also be utilized
Liver abscesses can by seen via U/S, CT, or MRI

Question 18

Amebiasis

Tx

Answer 18

metronidazole or tinidazole

Question 19

amebiasis

prevention

Answer 19

Safe water and fruit/vegetable supplies
Sanitary disposal of human feces
Adequate preparing of food
Avoidance of fly contamination
Handwashing

Question 20

malaria

Transmission and endemic areas

Answer 20

Exposure to (female) anopheline mosquitoes in a malaria-endemic area
South and Central America, Africa, the Middle East, Southeast Asia
Caused by Plasmodium parasites
Plasmodium falciparum responsible for nearly all severe disease

Question 21

plasmodium falciparum

Severe Sx

Answer 21

SEVERE
Cerebral malaria, severe anemia, hypotension, pulmonary edema, acute kidney injury, hypoglycemia, acidosis, and hemolysis.

Question 22

plasmodium

Dx

Answer 22

identified through blood smears or rapid test

Question 23

plasmodium

patho

Answer 23

goes to liver then blood infecting erythrocytes

Question 24

plasmodium

classical presentation
(3 stages)

Answer 24

Cold stage (sensation of cold, shivering)
Hot stage (fever, headaches, vomiting; seizures in young children); and
Finally sweating stage (sweats, return to normal temperature, tiredness).

Question 25

# plasmodium more common presentation

Answer 25

Fever Chills Sweats Headaches Nausea and vomiting Body aches General malaise

Question 26

# Plasmosium clinical manifestations

Answer 26

mainly P falciparum, can include severe anemia; hypotension and shock.(RBCs being blown apart) Hypoglycemia – diminished gluconeogenesis Acidosis – microcirculatory flow affected, anaerobic glycolysis Renal impairment - infarcts, capillary leakage Pulmonary edema - sequestration of parasitized RBCs in lungs and/or cytokine-induced leakage from pulmonary vasculature

Question 27

# plasmodium Tx

Answer 27

Chloroquine is first line P. falciparum is somewhat resistant, use Artemisinin (artesunate, artemether) generates free radicals that damage parasite proteins

Question 28

# plasmodium Tx for severe malaria

Answer 28

Medical emergency – IV Artesunate Maintenance of fluids and electrolytes Respiratory and hemodynamic support Potential blood transfusions/anticonvulsants/antibiotics/hemodialysis

Question 29

# Plasmodium prevention

Answer 29

Bed nets, insecticides Travelers to endemic areas: Chloroquine Malarone Mefloquine Doxycycline Primaquine Tafenoquine

Question 30

Pinworms

Answer 30

**Most common helminth infection in US** Enterobius vermicularis Usually children under 18 (typically 5-14), or those who are institutionalized

Question 31

# Enterobius vermicularis (pinworm) Main route of infection

Answer 31

oral after scratching or exposure to eggs from contaminated food/fomites

Question 32

# Enterobius vermicularis pathophys

Answer 32

Eggs hatch in duodenum and larvae migrate to cecum. Females mature in a month, and remain viable for about another month; migrate through anus nocturnally to deposit large numbers of eggs on perianal skin

Question 33

# Enterobius vermicularis Most telling Sx

Answer 33

**Perianal pruritus, particularly at night** INTENSE ITCHING AT NIGHT, possible bacterial infection from scratching

Question 34

# Enterobius vermicularis Dx

Answer 34

listen to hx and Characteristic eggs on perianal skin detected using clear sticky tape (**Scotch tape test**) Sometimes worms seen in feces

Question 35

# Enterobius vermicularis Tx

Answer 35

Oral single dose: albendazole, mebendazole Redose in 2 weeks because of frequent reinfection Treat family members and Washing clothes and bedding in hot water to kill eggs

Question 36

what are helminths

Answer 36

worm parasites

Question 37

hookworm agent

Answer 37

Ancylostoma duodenale and Necator americanus Found in feces of infected animals Look for patients who were walking barefoot common in tropic/subtropic regions

Question 38

hookworm life cycle

Answer 38

Eggs deposited on warm moist soil and hatch, releasing larvae that are infective for a week *Patient will sometimes report walking barefoot

Question 39

# hookworm life cycle

Answer 39

larvae penetrate skin and migrate in bloodstream to pulmonary capillaries. In lungs, larvae penetrate into alveoli and are carried by ciliary action upward to bronchi, trachea, mouth. After being swallowed, they reach & attach to small bowel mucosa and mature to adult worms.  Attach to intestinal mucosa and suck blood. Blood loss is proportionate to worm burden.

Question 40

# hookworm Signs and Dx

Answer 40

Transient pruritic skin rash and lung symptoms Anorexia, diarrhea, abdominal discomfort **Iron deficiency anemia** Characteristic eggs and occult blood in the stool

Question 41

# hookworm clinical manifestation

Answer 41

Often asymptomatic Anemia due to blood loss in gut Blood loss in stools not visibly apparent New infection: epigastric pain, anorexia, diarrhea Chronic infection: abd pain, anorexia, diarrhea, **iron-deficiency anemia,** protein malnutrition

Question 42

# hookworm Dx

Answer 42

characteristic eggs in stool possible blood in stool

Question 43

# hookworm Tx

Answer 43

ivermectin single dose or albendazole once daily for 3 days

Question 44

# tapeworms main beef and pork agent

Answer 44

*Beef: Taenia saginata (eating raw or undercooked beef) *Pork: Taenia solium (eating undercooked pork)

Question 45

# tapeworms Sx

Answer 45

Patient complains of GI symptoms, potentially including anorexia and weight loss

Question 46

# tapeworms Dx

Answer 46

egg in stool

Question 47

# tapeworms Tx

Answer 47

usually a single dose of praziquantel

Question 48

# Ascariasis Ascaris lumbricoides

Answer 48

most common intestinal helminth, LARGE white worms, common in children contaminated soil is ingested

Question 49

# Ascaris lumbricoides Sx and Dx

Answer 49

Most are asymptomatic Heavy infection may cause intestinal discomfort Malnutrition and/or even *obstruction Diagnosis made by ID of eggs in stool or after adult worm emerges from mouth, nose, or anus

Question 50

# Fluke spp and transmission

Answer 50

Clonorchis sinensis Opisthorchis viverrine Fascilla hippatica Undercooked fish, crabs, water plants in endemic areas

Question 51

Roundworm agent and transmission

Answer 51

Trichinella spiralis Trichinosis Muscle tissue damage Spread by ingestion of raw, most commonly pork

Question 52

# trichinosis Sx

Answer 52

are asymptomatic; however, GI complains may be present Can progress to fever, *myalgias, periorbital edema, headaches, cough, rash

Question 53

# Trichinosis Dx

Answer 53

elevated muscle enzymes, serological tests, proceeding to muscle biopsy only if necessary

Question 54

# trichinosis Tx with early detection

Answer 54

mebendazole, albendazole

Question 55

Filariasis

Answer 55

Wuchereria bancrofti

Question 56

# Wuchereria bancrofti Sx

Answer 56

Chronic progressive swelling of extremities and genitals (elephantitis)

Question 57

# Loiasis (Loa loa) transmission and Sx

Answer 57

Transmitted by chrysops flies Larvae develop into adult worms and ***migrates to eye**

Question 58

Rocky Mountain Spotted Fever Agent, transmission, endemic area, time of year

Answer 58

Rickettsia rickettsii Exposure to infected tick bite in an endemic area Half of cases are from 5 states: North Carolina, Tennessee, Oklahoma, Missouri, and Arkansas Usually seen in May-August when ticks are most active

Question 59

# Rickettsia rickettsii Patho

Answer 59

R. rickettsii likes to damage vascular endothelial cells. Direct vascular injury; endothelial cells produce prostaglandins that cause increased vascular permeability Hyponatremia from release of antidiuretic hormone as an appropriate response to hypovolemia/reduced tissue perfusion (leaky vasculature}

Question 60

# RMSF Sx

Answer 60

**fever/headache**/rash; fever/rash/history of tick bite rash is delayed **non blanching rash** Early phase, nonspecific signs/symptoms: fever, headache, malaise, myalgias, arthralgias Nausea is common. Children may have severe abdominal pain may be fatal

Question 61

# RMSF Rash

Answer 61

90% of patients, not usually at initial contact with clinician ***Rash on palms and soles is highly characteristic**

Question 62

# RMSF Rash first presentation

Answer 62

**First peripherally on wrists/ankles; spreads centripetally. Involvement of palms/soles is important Dx feature.**

Question 63

# RMSF CBC with diff

Answer 63

Usually normal WBC at presentation, left shift. May be anemia, thrombocytopenia, hyponatremia As illness progresses, thrombocytopenia becomes more severe

Question 64

# RMSF Tx

Answer 64

doxycycline 100mg twice daily for 5-7 days (10-14 days for severe cases); treat until afebrile for 2-3 days

Question 65

Lyme disease agent, transmission, region, time

Answer 65

most common Caused by Borrelia burgdorferi Infection transmitted to humans by blood-feeding anthropods: mosquitoes, ticks, fleas Most cases are reported from the northeastern and north central regions of the US Occurrence more common late spring and summer (May to July)

Question 66

# Lyme disease Early localized

Answer 66

ncludes erythema migrans **“bulls-eye” rash with central clearing**(EM – next slide) and nonspecific flu-like findings that can include myalgias, arthralgias, headaches, and fatigue.

Question 67

# lyme disease Early disseminated

Answer 67

(weeks to several months after tick bite): can include acute neurologic (aseptic meningitis with headache and stiff neck or facial palsy) or cardiac involvement (with arrhythmias); may be first manifestation of Lyme disease.

Question 68

# Lyme Disease Late stage

Answer 68

(months to few years after the onset of infection; may not be preceded by early localized or disseminated disease): arthritis in one/few joints is most common, neurologic manifestations (encephalopathy or polyneuropathy) can occur.

Question 69

# lyme disease Dx

Answer 69

Exposure to tick habitat + erythema migrans or at least 1 late manifestation of the disease + lab confirmation Dx confirmed by antibody testing using enzyme immunoassay or immunofluorescence assay; confirmation of positive result with Western blot

Question 70

# Lyme diseae Tx

Answer 70

Prophylactic antibiotics following tick bites in recommended in certain high-risk situations: doxycycline 200mg orally Doxycycline 100mg orally twice daily for 10 days

Question 71

# Histoplasma capsulatum Histoplasmosis transmission and region

Answer 71

**Exposure to bird and bat droppings; common along river valleys (esp. *Ohio River and Mississippi River valleys). Fungus isolated from soil contaminated** Infection presumably takes place by inhalation

Question 72

# Histoplasma capsulatum Sx

Answer 72

**More respiratory symptoms seen**

Question 73

Pts most at risk for parasitic or fungal infections

Answer 73

Cancer, children, AIDS, immunocompromised

Question 74

# Histoplasma capsulatum Clinical presentation

Answer 74

**More respiratory symptoms seen** Mostly asymptomatic, variable symptoms from mild to severe Usually have respiratory symptoms if present Past infection - pulmonary and splenic calcification noted incidentally More severe infections typically have symptoms as atypical pneumonia Can have a macular/papular rash

Question 75

Chronic Pulmonary Histoplasmosis Xrays:

Answer 75

**apical cavities, nodules, infiltrates**

Question 76

# Histoplasmosis who is affected?

Answer 76

normally immunocompromised pts

Question 77

# Histoplasmosis Dx

Answer 77

Sputum culture rarely positive, maybe in chronic disease Antigen testing in acute disease. Chest x-ray Combination of urine and serum antigen assays: 83% sensitivity for Dx acute pulmonary. Blood or bone marrow cultures (immunocompromised patients with acute disseminated disease) positive >80% of the time, take several weeks for growth.

Question 78

# Histoplasmosis Tx

Answer 78

Most cases resolve within 4 weeks Progressive localized disease and mild/moderately severe nonmeningeal disseminated disease, treatment of choice is  itraconazole (disrupts cell membrane integrity) Orally for up to 12 weeks depending on severity of illness Severe disease: IV amphotericin B for 1-2 weeks followed by itraconazole for total of 12 weeks Patients with AIDS-related histoplasmosis require lifelong suppressive therapy with itraconazole orally

Question 79

# Cryptococcosis Cryptococcosis

Answer 79

**Cryptococcus neoformans *Pacific northwestern region *Look at occupation (Farmer?) *Most common cause of fungal meningitis.**

Question 80

# Cryptococcosis where is it found?

Answer 80

**Found worldwide in soil and on dried pigeon dung**

Question 81

# Cryptococcosis Clinical presentation

Answer 81

Pulmonary Varies from mild/moderate cough to ARDS CNS Meningitis and encephalitis Altered mental status, ataxia, headache, coma Visual disturbance common Pustular skin rash

Question 82

# Cryptococcosis Dx

Answer 82

***Sputum culture (if having more pulm symptoms) *Lumbar puncture: ** increased opening pressure, variable ↑WBCs, increased protein, decreased glucose India ink stain of CSF reveals budding, encapsulated fungi.

Question 83

# Pneumocystitis PJP

Answer 83

Pneumocystis jirovecii pneumonia (PJP) Overt infection is a subacute interstitial pneumonia that occurs among older children and adults with altered immunity Cancer, transplants, AIDS, receiving corticosteroids ***Occurs in up to 80% of AIDS patients who are not receiving prophylaxis**

Question 84

# PJP Clinical presentation

Answer 84

Usually limited to pulmonary Onset may be subacute with only dry cough or shortness of breath Hard to cough anything up due to thick secretions May present with spontaneous pneumothorax and/or additional symptoms of fever, fatigue, weight loss Note decreased oxygen saturation on exam

Question 85

# PJP Dx

Answer 85

***Sputum cultures *Positive beta-D-glucan** (detects fungal cell wall) ***Chest x-ray & CT scan** (next slides) ***Ground glass opacification** Can start empiric therapy for PJP if disease is suspected clinically

Question 86

# PJP Tx

Answer 86

**Oral trimethoprim-sulfamethoxazole is the preferred treatment**

Question 87

Coccidioidomycosis

Answer 87

Valley fever Coccidioides immitis or C. posadasii ***Found in soil and causes infections when inhaled *Southwestern US and parts of Mexico and Central South America**

Question 88

# Valley fever Acute infection

Answer 88

: influenza-like illness, fever, backache, headache, fatigue, and cough. Erythema nodosum common

Question 89

# valley fever dissemination

Answer 89

Dissemination may result in meningitis, bony lesions, or skin and soft tissue abscesses Common infection in patient with AIDS

Question 90

# Aspergillosis Agent

Answer 90

Aspergillus fumigatus Inhalation of spores of fungus

Question 91

# Aspergillosis Predisposing factors

Answer 91

** leukemia, bone marrow or organ transplantation, corticosteroid use, advanced AIDS**

Question 92

# Aspergillosis Most common cause of non-candida invasive fungal infection

Answer 92

Most common cause of non-candida invasive fungal infection in ***transplant recipients and in patients with hematologic malignancies**

Question 93

# Aspergillosis what are the most common disease sites

Answer 93

Pulmonary, sinus and CNS are most common disease sites

Question 94

# Aspergillosis Tx

Answer 94

antifungal drugs

Question 95

Fluke Sx

Answer 95

Most aSx or mild GI If untreated progress to serious disease, advanced GI

Question 96

Fluke Dx and Tx

Answer 96

Clinical findings or eggs in stool Praziquantel