Micro FA Mycology/Parasitology p151 -161 Flashcards
Systemic mycosis from
Mississippi and Ohio River Valleys
Mycoses from Eastern and Central US, Great Lakes
Usually NC/SC - gen E of Mississippi River
Systemic mycoses from Southwestern US, California
Systemic mycosis from Latin America
Sx of Histoplasmosis
Palatal/tongue ulcers, splenomegaly, pancytopenia
Patho signs of Histoplasmosis
Macrophage filled with Histoplasma (smaller than RBC
Where is histoplasma found?
bird (starlings) or bat droppings
Dx of Histoplasmosis
Diagnosis via urine/ serum antigen
Patho features of blastomycosis
Broad-based budding of Blastomyces (same size as RBC)
skin lesions of blastomycosis look like what neoplasm?
looks like SCC
Sx of blastomycosis
Inflammatory lung disease, can disseminate to skin/ bone
granulomatous nodules
Patho features of Coccidiodomycosis
Spherule (much larger than RBC) filled with endospores of Coccidioides
Sx of Coccidioidomycosis
Disseminates to skin/ bone Erythema nodosum (desert bumps) or multiforme Arthralgias (desert rheumatism) Can cause meningitis
Patho features of Paracoccidioidomycosis
Budding yeast of Paracoccidioides with “captain’s wheel” formation (much larger than RBC
3 dermatophytes - which infects what
Trichophyton - 3 skin, hair, and nails
Epidermophyton - skin and nails
(phyton - “fightin” tooth & nail)
Microsporum - skin and hair
Tinea corporis - acquired from?
contact with infected pets or farm animals
causative agent of tinea versicolor
Malassezia furfur
What leads to the different pigmentation pattern of tinea versacolor
Degradation of lipids produces acids that inhibit tyrosinase (involved in melanin synthesis) –> hypopigmentation
hyperpigmentation and/or pink patches can also occur due to inflammatory response.
Which mycoses is described morphologically as round yeast clusters with short curved hyphae?
Malassezia (“spaghetti & meatballs”)
Dx with Wood’s lamp or KOH skin scraping
Tinea
form pseudohyphae and budding yeasts at 20oC, germ tubes at 37oC
Candida albicans
Candida is NF of where?
mucous mem
septate hyphae that branch at 45o
Aspergillus
non dimorphic heavily encapsulated yeast
Cryptococcus
What does Candida cause in the immunocomromised?
oral and esophageal thrush
Candida vulvovaginitis is seen in what patient pop?
Diabetes pt (Fungi love sugar)
pt on inc antibiotic use
IV drug users can get what manifestation of candida?
endocarditis
Chronic mucocutaneous candidiasis seen in what pts?
Anyone with a Th1 defect
DB
Can form a ball like structure in pre-existing lung cavities, like after a TB infection
Aspergillus - aspergilloma (fungus ball)
Some species of Aspergillus produce _______ (associated with what neoplasm).
Some species of Aspergillus produce Aflatoxins (associated with hepatocellular carcinoma).
Tx of Aspergillus
voriconazole or echinocandins (2nd-line).
Patients with asthma or cystic fibrosis will have what response to Aspergillus
Allergic bronchopulmonary aspergillosis (ABPA)—hypersensitivity response to Aspergillus growing in lung mucus. Associated with asthma and cystic fibrosis; may cause bronchiectasis and eosinophilia.
Most sensitive/specific test for Cryptococcus
Latex agglutination test detects polysaccharide capsular antigen and is more sensitive and specific.
found in soil, pigeon droppings
Cryptococcus
What does Cryptococcus cause?
Acquired through inhalation with hematogenous dissemination to meninges.
therefore, leads to Cyptococcal pneumonia (cryptococcosis) and meningitis, encephalitis
At what CD count do you treat Candida, Histoplasma, Pneumocystis, Cryptococcus and Aspergillus
<500/mm3
- Candida albican oral thrush
<200/mm3
- Histoplasma
- Pneumocystis
<100/mm3
- Candida esophagitis
- Aspergillus
- Cryptococcus meningitis
irregular ribbon like broad non septate hyphae that branch at wide angles
Mucor/Rhizopus/Absidia
Mucormycosis seen in which pt pop?
Diabetes (ketoacidotic)
neutropenic pt (leukemia)
Pathogenesis of Mucor, Sx/
Inhalation of spores –> fungi proliferate in blood vessel walls, penetrate cribriform plate, and enter brain.
Rhinocerebral, frontal lobe abscess; cavernous sinus thrombosis.
Headache, facial pain, black necrotic eschar on face; may have cranial nerve involvement.
diffuse interstitial pneumonia caused by fungi in immune compromised pt?
Pneumocystis
disc shaped yeast seen on methenamine silver stain of lung tissue
Pneumocystis - honey comb like - dark colonies on a green background
Dx of Pneumocystis - why?
Diagnosed by bronchoalveolar lavage or lung biopsy
Pneumocystis - attaches to and kills type I pneumocytes –> leads to prolifer’n of type II –> alveoli fill with a dense exudate, can’t cough it up. Have to go in for it
Tx of Pneumocystis
TMP-SMX
Dimorphic, cigar-shaped budding yeast that grows in branching hyphae with rosettes of conidia
Sporothrix Schenckii
Typical presentation of Sporothrix
When spores are traumatically introduced into the skin, typically by a thorn (“rose gardener’s disease”), causes local pustule or ulcer with nodules along draining lymphatics (ascending lymphangitis
Immunocompromised pt with Sporothrix - presentation, common pt pop?
Disseminated disease possible in immunocompromised host. – pulm sprotrichosis
Seen in homeless, alcoholic pt inhaling infection form
Tx of sporthrix
itraconazole, KI (cutaneous)
bloating flatulence foul smelling diarrhea + camping/hiking
Giardia
bloody diarrhea + travel to tropics/mexico
Entamoeba histolytica
flask shaped ulcers on colon biopsy
entamoeba histolytica
What causes chronic watery diarrhea in an AIDS pt ? When do we Prophylactically tx?
Cryptosporidium
<50 (<100 CD4 count)
multiple ring enhancing lesions in CNS
brain abscesses of Toxoplasma - but look for AIDS
Also Glioblastoma
Congential Toxoplasmosis
chorioretinitis (neonatal blindness)
hydrocephalus
intracranial calcifications
Tx of Toxoplasma - what CD # do we prophylax?
Sulfadiazine, pyrimethamine
CD# <100
Primary sources of Toxoplasma
- undercooked pork
- Cat feces
In immunocompetent pt, how does Toxoplasma look?
Like mono - but heterophile Ab test (-)
Diving in warm water - what organism?
Naegleria fowleri
How does Naegleria lead to meningoencephalitis?
Crawling up the cribriform plate
why is there a recurring fever with Trypansoma?
antigenic variation
Covered in variant surface glycoproteins
Ab fight it —> fever –> new VSG
Transmission of Trypansoma from ?
Tsetse fly
Sx of Typansoma
African sleeping sickness
enlarged l.n., recurring fever, large red chancre at bite site –> somnolence –> coma
Diff b/w P. vivax/ovale and P malariae fever cycle
Vivax and ovale - 48 hr fever cycle
malariae - 72 hr fever cycle
What is p. falciparum fever cycle? why is it diff?
No regular fever spikes - Fever spikes due to RBC lysis, but unlike vivax/ovale/malariae the lysis of RBC is not synchonized, but occur individually - keeps the fever up
dormant form of p vivax/ovale - lives where?
How do we treat this form?
Liver - hypnozoite
Add Primaquine for radical cure
P falciparum infects what? leads to?
parasite infected RBC will occlude capillaries in brain, kidneys, lung —> tissue hypoxia, lactic acidosis, hypoglycemia
Transmission of Plasmodium
Anopheles mosquito
Vector for Babesia? Also transmits which other organisms?
Ixodes tick
same as Borrelia burgdorferi (Lyme) & Anaplasma
(Ehrlichia is Lone star tick Amblyomma)
Sx of Babesia
fever and hemolytic anemia
What can predispose one to more severe form of Babesia?
asplenia (thru op or practically)
Which people have natural immunity vs Plasmodium?
HbS heterozygote protected from p falciparum
Duffy blood group neg - from p. vivax
Thalassemia/Ab Normal Hgb - from plasmodium
unilateral periorbital swelling
Chagas disease - T cruzi
What cell type does T cruzi infect –> what are the consequences?
cardiac musc and smooth m. –> dilated cardiomyopathy, megacolon, mega esophagus
Vector for T Cruzi?
Reduviid bug (kissing bug)
Triatomine insect
vector of Leishmania?
sandfly
foul smelling, greenish discharge from vagina
Trichomonas vaginalis
Which nematodes do you get from ingesting them?
Enterobius
Ascaris
Toxocara
Trichinella
Trichuris
Which nematodes come thru the skin?
Strongyloides, Ancyclostoma, Necator
Nematode transmitted thru bite
Loa Loa, Onchocerca volvulus
Wulchereria bancrofti
Causes anal pruritus
Enterobius vermicularis
pin worm
May cause obstruction at ileocecal valve, biliary obstruction, intestinal perforation, migrates from nose/mouth
Ascaris lumbricoides (giant roundworm)
young child, can see larvae in sputum
Ascaris lumbricoides
causes microcytic hypochromic anemia
Ancylostoma , Necator
AN iron sucker
From wild game
Trichinella spiralis
fever, vomiting, nausea, periorbital edema, myalgia, splinter hemorrhages, eosinophils
Trichinella spiralis
loose stools, anemia, rectal prolapse in children
Trichuris trichiura (whipworm)
TrichuRIS - Rectum is Slipped