ID Ix Buzz Flashcards
Acute convalescent 4x rise in titre
Dengue Fever
Gram negative diplococci on stain
Neisseria meningitidis (osce!)
Positive cysts on blue tolludine stain
PJP
Pneumocystic jiroveci pneumonnia
PCR for NPA
Influenza virus
Acid fast bacilli on Ziehl-Neeson stain
Tuberculosis
Pus containing sputum on culture with mixed oral flora
Pneumonia
Urinary antigen for pneumonia
Legionella
Strep O titre
Western Blot Test
Confirming test for HIV - highly specific
Do HIV Antibody test first - highly sensitive
Urine antigen test, sputum staining withdraw I react fluorescent antibody (DFA), culture
Legionella
Serologic testing, PCR polymerase chain reaction (pneumonia)
Chalmydophila / Chlamydia
Clinical diagnosis. Serum cold agglutinins and serum __ antigen can be used. (Pneumonia)
Mycoplasma
Urine pneumococcal antigen test + culture
Strep pneumoniae
Nasopharyngeal aspirat,e rapid molecular tests for pathogen (influenza, respiratory syncytial virus), DFA, viral culture
Viral pneumonia
Diagnosis of active TB disease
Mycobacterial culture of sputum (or blood, tissue) is the gold standard but can take weeks to obtain.
Sputum acid fast stain can yield rapid results - but lacks sensitivity
(red colour ‘red snapper’ of tubercle bacilli on acid fast staining)
CXR: cavitation infiltrate in upper lobe + calcification of lymph nodes (Ghon complex)
Diagnosis of latent TB (asymptomatic and previous exposure)
Dagnose with a positive PPD (purified protein derivative aka Mantoux test) or Quantiferon -TB test.
- immunocompromised individuals with latent TB may have negative PPD
- patients with + PPD should be evaluated with CXR
How to diagnose Influenza
Rapid viral antigen test with nasopharyngeal swab. (low sensitivity)
More definitive dx with DFA test, viral culture of PCR assay.
Investigation for Meningitis
Obtain LP for CSF Gram stain and culture ideally before initiation of antibiotics. Check glucose, protein, WBC count, RBC count, opening pressure (in absence of papilloedema or focal neurological deficits).
Viral PCR (HSV), cryptococcal antigen (HIV patients)
CT or MRI for pt with altered mental state, papilloedema, or focal neurological deficits. If CT is being ordered, empirical antibiotics should be started.
Blood culture
FBE: leukocytosis.
Investigation for encephalitis
CSF: lymphocytic pleocytosis, moderately high protein, low glucose for TB, fungal, bacterial, amebic infection.
LP: cell count, glucose, protein, culture for bacteria, fungi, mycobacterium, Gram stain, acid fast stain, INdia ink stain (Cryptococcus)
Order PCR: for HSV
ELISA test and Western Blot test for what disease?
What further tests to help Diagnosis
HIV
ELISA test (high sensitivity, moderate specificity) Detects anti HIV Ab in bloodstream. Can take up to 6 months to appear
Western blot test: (low sensitivity high specificity) Confirmatory
Baseline evaluation -
*HIV RNA PCR (viral load)
*CD4+ cell count
* CXR
*PPD skin test of interferon gamma release assay (Quantiferon)
*Pap smear
*mental state exam
*VDRL/RPR
*Serology for CMV
AIDS defining illnesses + opportunistic
The Major Pathogens Concerning Complete T Cell Collapse
Toxoplasma Gondi Mycobacterium avium intracellulare Pneumocystis jirovecii Candida albicans Cryptococcus neoformans Tuberculosis CMV Cryptosporidium parvum
Gram stain shows budding test and or pseudohyphae
Candidiasis (thrush)
Presents with soft white plaques that can be rubbed off with an erythematous base. DDx is oral hair leukoplakia - lateral borders of tongue hard to rub off)
Treat with clotrimazole or fluconazole
Cryptococcal antigen testing in CSF and or blood, CSF India ink stain and fungal culture
Cryptococcal meningitis
- Exposure to pigeon droppings,
Treat with amphotericin
Urine and serum polysaccharide antigen test,
Fever weight loss, hepatosplenomegaly, lymphadenopathy, non productive cough, palatial ulcers, pancytopenia.
histoplasmosis (fungus)
Spelunking, caving, HIV patients = risk factor
HIV patient with non productive cough and dyspnoea
Ix: cytology of induced sputu or bronchoscope specimen with silver stain and immunofluorescence
CXR: diffuse bilateralinsterstitialinfiltarate with ground glass appearance
Pneumocystis Jirovecii Pneumonia
- LUng tissue stained with silver uncovers cysts containing comma shaped spores
Treat with high dose TMP - SMX = aka BACTRIM
Associated with retinal detachment - pizza pie. Retinopathy, floaters and visual field change
HEpatobiliary involvement.
PNeuomonitis
CNS involvement
Cytomegalovirus
Diagnose with heterophil antibody (mono spot test)
Specific antibodies
FBE with mild thrombocytopenia, lymphocytosis and atypical T lymphocytes
Infectious mononucleosis
EBV
