TB Flashcards
Sixth leading cause of mortality in Philippines
TB
T or f
Most of mdr tb cases are new cases
False
Most are retreatment
indicated by negative skin test
caused by malnutrition, hiv, steroid, severe TB
anergy
TB gene xpert used for what tissues
sputum, gastric lavage, csf, lymph node
TB gene xpert not applicable for
stool, blood, urine
difference between th1 and th2 response
th1 protective role
th2 produce cytokines (humoral immunity)
factors that promote latency TB
low oxygen and nutrients
local production of TNF alpha and nitric oxide
key factors for getting TB
household contact with newly diagnosed smear +
age <5
immunocompromised state
age with lowest risk of TB
5-10 years
transmission of tb
droplet
how many bacilli necessary for successful infection
5 to 200
lung lesion primary tb
ghon focus
time period after primary tb infectioon is highest risk for disseminated tb
1 to 3 months
mortality rate of TST (+) versus (-)
3 times
classification according to bacteriological status
bacteriologically confirmed
clinically diagnosed
most common extrapulmonary sites
lymph nodes, bones, joints, liver
which lobe prone to obstruction and atelectasis/hyperaration
right middle lobe
most common extrapulmonary tb and most common cause of chronic lymphadenitis in kids
tuberculous lymphadenitis
most common location in CLAD
anteriro cervical
followed by axillary and supraclavicular
fistula in CLAD seen in
10%
most severe form of extrapulmonary tb
tuberculous meningitis
CSF in TB meningitis
clear, opalescent
5-500 WBC with PMNs first then lymphocytes later
glucose may be low normal in 2nd stage then very low on 3rd stage
protein may be normal initially but becomes high
what do you see if high protein in csf
pellicle forms
common findings on CT/MRI
hydrocephalus meningeal enhancement hypodensities due too cerbral infarcts cerebral edema nodular enhancing lesion
most common location brain tuberculoma
infratentorial or at the base of the brain
why are children more prone to pott’s
have increased blood supply to growing bones
where is lesion of potts usually located
area of endarteritis in the metaphyisis of long bone
most common skeletal site affected by tb
spine
most frequent symptom in potts
back pain
abdominal lymph node most involved
ileocecal
most common form of cutaneous tb
scrofuloderma
most common ocular manifestation
choroiditis
most frequent GU location in women
fallopian tubes
followed by endometrium, ovaries, cervix
definition of congenital TB
infant with TB lesion plus ONE or MORE:
- present w/in 1st week of life
- primary hepatic complex
- tb infection of placenta or endometrial tb
how is tb classified
bacteriological status anatomical site history of treatment hiv status drug susceptability
laryngeal tb with smear positive but no infiltrates on xray
extrapulmonary tb
both pulmonary tb plus extrapulmonary component
still considered pulmonary tb
definition of new case
no tb treatment or has taken it <1 month
isoniazid prophylaxis not counted
definition retreatment case
previously treated or started at least 1 month
definition mdr tb
resistance to at least both isoniazid and rifampicin
definition xdr tb
resistance to any fluoroquinolone and to at least one of three second line drugs
gold standard for diagnosis of tb
culture
if absent bacteriologic evidence, may classify as tb if
THREE or MORE of ff:
- exposure to adult/adol with active tb disease (epidemiologic)
- signs and symptoms (clinical)
- postivite TST (immunologic)
- abnormal CXR (radiologic)
- lab findings suggestive of TB (histological, cytological, biochemical, immunological, molecular
definition presumptive TB
signs and symptoms of tb or those with cxr suggesting tb
in child below 15 years old, presumptive TB has
THREE or more of ff:
- cough for 2 weeks
- fever for 2 weeks (malaria/pneumonia ruled out)
- weight loss
- failure to respond to 2 weeks of appropriate antibiotic therapy
- failure to regain to previous state of health 2 weeks after viral infection/exanthema
- fatigue/lethargy
most important diagnostic in tb
tst
most widely used TST
Purified protein derivative
PPD RT 23
where to administer TST
2 inches below elbow joint in volar aspect of forearm
apply wheal 6-10mmin diameter
how to measure TST
measure induration (palpable raised hardened area) measure perpendicular to the long axis of forearm
causes of false positives
infection with nontuberculous mycobacteria previous bcg incorrect method incorrect measurement incorrect strength of antigen
dose of PPD
0.1ml 2TU of RT23 = 0.1ml 5TU PPD-S
when do expect kids with bcg vaccination to have waning TST
after 5 years
causes of false negatives
infection vaccination (MMR, polio, varicella) CKD malnutrition malignancy steroids newborns elderly overwhelming TB infection stress (surgery, burn) organ transplant improper use of tuberculin (storage, administration) improper reading
TST should be postponed __ weeks after live vaccine
4-6 weeks
TST should be delayed __ after bout of measles, mumps, varicella, pertussis
2 months
TST should be delayed __ in kids with scabies, impetigo
after skin lesions healed
positive TST
15mm if no risk factors 10mm in prevalent areas 5mm if: 1. malnourished 2. immunocompromised 3. CXR findings 4. organ transplant 5. close contact with TB
advantage of using IGRA (interferon gamma release assays)
requires only single visit
result affected by prior BCG
cxr findings in tb
parenchymal focus
lymphadenitis
lymphangitis
pleural effusion
most common cxr findings
parenchymal focus
lymphadenitis
bronchial obstruction due to tuberculous lymph nodes may present as
hyperaeration
segmental atelectasis
collapse consolidation
cxr of chronic ptb
most common
apical and posterior segment of upper lobes
right lung > left lung
cxr miliary tb
2mm nodules stipple both lungs
they may coalesce (snowstorm effect)
modality of choice for potts vertebra
ct
modality of choice for potts intervertebral space
mri
four types of tb osteomyelitis
cystic
infiltrative
foacl erosions
expansile lesion
most common type tb osteomyelitis in kids
cystic
spina ventosa
bone destruction and periosteal thickening and fusiform expansion of bone
modality of choice for tb osteolmyelitis
mri
t1 marrow changes low signal intensity
t2 high signal
triad of radiograph abnormalities
for TB arthritis
PHEMISTER TRIAD
juxtaarticular osteoporosis
peripherally located osseous erosions
gradual narrowing of interosseous space
modality of choice for TB meningitis
mri
predilection of TB in brain
interpenduncular and suprasellar cisterns
most common complication of tb meningitis
communicating hydrocephalus
majority of infarcts in brain seen
basal ganglia and internal capsule
due to occlusion of small vessels
mri for brain tuberculoma
T1 - hypointense relative to gray matter
T2 - hyperintense
gad - rim enhancement
solid center in caseous - isointense t1/t2
liquid center t1 hypointense, t2 hyperintense
complication of spinal tb meningitis
syringomyelia
most common radiologic manifestation of abdominal TB
lymphadenopathy
most commonly involved: mesentric, omental, peripancreatic
most common clinical manifestation of abdominal TB
peritonitis
thickening of the valve lips with narrowing terminal ileum in abdominal TB
Fleischner sign
earliest radiologic abnormality in GU TB
moth eaten calyx due to erosion
primary sign of tb pericarditis
pericardial thickening 3mm
volume gastric aspirate
5-10ml
volume gastric lavage
25 to 50ml
transportation of gastric lavage
within 1 hour in room temp
may add 100mg sodium bicarbonate
volume of sputum
3ml
how to collect sputum
- rinse mouth with water
- breathe 3x
- cough hard
- expectorate in steril vial
volume respiratory wash
3ml with up to 5ml steril saline
room temp 1 hr
may be stored in fridge if >1hr
specimen for tissue
add up to 3ml sterile saline
room temp 1 hr
may be stored in fridge if >1hr
specimen for blood
10ml in yellow top sodium polyanetholsulfonate or green top with heparin
specimen for body fluids
10-15ml
room temp 1 hr
may be stored in fridge if >1hr
specimen for bone marrow
10ml in yellow top sodium polyanetholsulfonate
room temp
do not put in fridge
specimen for urine
40ml, minimum 10-15ml
room temp 1 hr
may be stored in fridge if >1hr
most effective bactericidal drugs
isoniazid and rifampicin
pyrazinamide is only active in
acidic environment of macrophages
used in acute inflammation
ethambutol prevents
resistant bacilli
older kids and adolescents use adult dosing when
> 25kg
MOA of isoniazid
10mkday (10-15) max 300mg
bactericidal
inhibits mycolic acid synthesis
inhibits catalase peroxidase enzyme
side effect isoniazid
hepatitis
hemolysis g6pd def
peripheral neuropathy
MOA of rifampicin
15mkday (10-20) max 600mg
inhibits dna dependent rna polymerase
side effect rifampicin
hepatitis
red orange urine
hypersensitivity
MOA of pyrazinamide
30mkday (20-40) max 2g
disruption of membrane energy metabolism
side effect of pyrazinamide
hepatitis
hypersensitivity
arthralgia
MOA of ethambutol
20 (15-25) max 1.2g
inhibits transferase in cell wall synthesis
side effect ethambutol
reversible optic neuritis
moa amikacin kanamycin streptomycin
inhibit protein synthesis
side effect amikacin kanamycin streptomycin
nephro and ototoxic
moa capreomycin
inhibit protein synthesis
side effect capreomycin
psychosis
seizure
moa ofloxacin levofloxacin moxifloxacin
inhibit dna gyrase
side effect ofloxacin levofloxacin moxifloxacin
tendon rupture
prolonged QT
moa prothionamide ethionamide
block mycolic synthesis
side effect prothionamide ethionamide
neurotoxic
hepatotoxic
gynecomastia
reversible hypothyroidism
category I
pulmo or extra pulmo CNS, bones, jointsNEW
2hrze
4hr
category Ia
extra pulmo NEW CNS, bones, joints
2hrze
10hr
category II
pulmo or extra pulmo tb (except CNS, bones, joints)
- relapse
- treatment after failure (5mo still smear+)
- treatment after lost to f/u
- prev tx unknown
2hrzes
1hrze
5hre
category IIa
extra pulmo CNS, bones, joints
2hrzes
1hrze
9hre
isoniazid preventive therapy IPT
given to
- hiv
- <5yo with household contact smear (+) regardless of kids TST
- <5yo with household contact smear (-) but with kids TST (+)
for isoniazid preventive therapy IPT
repeat TST done after
3 months
if (-) give BCG
if (+) continue INH to complete 6 months
corticosteroids most beneficial when given
- tb menigitis
- tb pericarditis
- tb pleural effusion
- endobronchial tb
- miliary tb
how to give corticosteroids in tb
prednisone 2kday x 4-6weeks
then taper 1-2 weeks then d/c
for seriously ill give 4mkday MAX 60mg/day
definition CURED
treatment completed with no evidence of failure and three or more consecutive cultures take at least 30 days apart (-)
breastfeeding with TB
safe
breastfeed first before taking meds
supplement with pyridoxine
asymptomatic pregnant woman with positive TST, normal cxr, and contact with TB
isoniazid 9 months, begin after first trimester
newborn with asymptomatic mother but mom is TST (+) and normal xray
don’t separate
give BCG
mom has TB but has completed at least 2 weeks at time of delivery
DO NOT GIVE BCG
given ISONIAZID first for 3 months then do TST
if (-) STOP ISONIAZID and give BCG
if (+) and baby is well, continue ISONIAZID for another 3 months -> if after 6mo baby is well, give BCG
if no TST available, give ISONIAZID for 6 months then do BCG
mother has current tb but no Tx
give ISONIAZID
if mom is isoniazid resistant, give RIFAMPICIN
placenta sent for studies, workup baby
TST (-) then repeat after 3 mo
TST (+) but normal cxr, complete ISONIAZID/RIFAMPICIN 6 months
if TST (-) and CXR (-) and mom completed treatment may stop ISONIAZID/RIFAMPICIN and administer BCG
kid with liver problem with tb
monitor ALT 2x/week first 2 weeks
then WEEKLY until 2nd month
then MONTHLY until end of tx
if pyrazinamide cant be given
2mo INH, RIF, ETH
7mo INH RIF
or PZA can be substituted with fluoroquinolone
if with liver cirrhosis
aminoglycoside, fluoroquinolone, cycloserine for 18-24 months
should we stop if kid <5yo, with elevated transaminase 5x but asymptomatic
no
drug induced liver injury
AST 3x elevated with symptoms
or 5x elevated w/o symptoms
AST <5x mild
5-10x moderate
>10x sever
how to restart meds in drug induced liver injury
one at a time after AST returns to <2x
RIF first, then INH, then PZA
caution in renal impairment
PZA (metabolites accum) and EMB (cleared renally)
longer dosing interval is needed
drug efficiently removed by dialysis
pyrazinamide
when to administer drugs when ongoing dialysis
after dialysis
drug not removed by dialysis
rifampicin
primary prophylaxis in HIV kids
kids >12mo old
IPT, no known exposure at home but prevalent
6mo INH
t or f
all kids with HIV and TB after completing treatment shoudl received additional 6 mo isoniazied
true
increased risk smear (+) in DM at hba1c of
9% and above
interaction of DM drugs and anti kochs
need to increase hypoglycemic agents because of increased metabolism cyp450 by rifampicin
transplant patients
TST prior to transplantation
indication of IPT in transplant patients
- > 5mm before transplantation
- A. cxr of old tb, B. hx of inadequate tb tx, C. close contact to person w/ tb, D. recipient of donor with hx of inadequate tb tx
- newly infected
patient for gastrectomy with TST (+)
ideally give INH prophylaxis
patient for jejunoileal bypass with TST (+) >10mm
ideally give INH prophylaxis 6 mo
prior to anti TNF treatment
TST done first
prophylaxis prior to anti TNF tx
6mo INH
3mo INH RIf
AST baseline then q3mo
minor rash after taking drugs
rif and pza
give diphen, loratadine then continue meds
petechial rash after taking drugs
check cbc if thrombocytopenia
rifampicin stopped
generalized rash after taking drugs
stop all meds, give alternate drugs
can be restarted one by one interval 2-3 days
start with INH, rifampicin etc
vomiting after taking drugs
may give with food
check ALT
diarrhea while taking anti kochs
stop all
restart one at a time q4 days
jaundice after taking drugs
stop all
may give streptomycin and ethambutol
order of rechallenge: rif, inh, pza q4days
drug fever
check if no infection
stop meds, may give alternative
should resolve in 24 hours
adverse effect joint pain
pza
adverse effect flu
rifampicin
adverse effect neurotoxicity (drowsiness, dizziness, seizures)
inh
