2nd
most common cause of death by infection
Organisms
1.M.tuberculosis
2.M.bovis(Reservoir
is cattle/cow milk)
3.M.africanum(Reservoir
is human)
Pathogenesis
1.Primary disease(Children type)
Inhalation>Alveoli>Recruits macrophage>Transformed into epithelioid cell ,Langhan's cell>Aggregates with lymphocyte>Forms granuloma>Granuloma aggregates and forms initial lesion called Gohn focus>Gohn focus with regional lymphadenopathy is called Gohn complex/primary complex of ranke
Primary diseases affects middle and lower zone
Seconndary focus-Node/common ,serous membrane(pleura,pericardium ,peritoneum) ,meninges ,bones ,liver
Mediastinal node>Spread>Supraclavicular node(Clinical)
Tubercular node-Painless ,initially mobile ,matted , discharge/Collar stud formation
2.Post primary(Adult type)
Exogenous(New infection) or endogenous type(Reactivation of primary TB)
Affects
apical portion of upper lobes
May
causes bronchogenic spread ,called satellite lesion
Clinically lung TB is post primary
How TB causes collapse
More common in children when lymphoma is associated
In adult when endobrocnhiolar TB is associated
Miliary TB - Blood-borne dissemination gives rise to miliary TB, which may present acutely but more frequently is characterised by 2–3 weeks of fever, night sweats, anorexia, weight loss and a dry cough.
Differential diagnosis of miliary TB-Sarcoidosis
,pneumoconiosis/asbestosis ,pulmonary eosinophilia ,hemosiderosis ,carcinomatosis
Post tussive crepitation-Crepitation appears after
cough ,indicated TB
How a pulmonary TB
Presents
1.Chronic cough
> 3 weeks , often with haemoptysis
2.Pyrexia of
unknown origin
3.Unresolved
pneumonia
4.Exudative pleural
effusion
5.Asymptomatic
(diagnosis on chest X-ray)
6.Weight loss,
general debility
7.Spontaneous
pneumothorax
Investigation
CBC-Lymphocytosis ,high ESR
Chest X ray-Patchy opacity
Sputum for AFB-On the spot >Next day, early morning sample to be brought from home>On the spot during receiving home sample
Gene X pert(NA amplification test)-Sputum and node biopsy>If RPO gene is found ,it is Rifampicin resistant.Result within 1 day
Pleural fluid cytology-
Physical-Normally amber colour
Biochemical-Exudative(Protein
>30g/dl)
Treatment
Category-1(6 months regimen for new onset pulmonary/extra pulmonary TB)
1st line
2HRZE/Initial
or intensive phase-Reduce population
4HR/Continual
phase-Kills remainders
[TB meninges/pott's-12 months; 2HRZS ,10HR ]
2nd line-(For resistant TB)
Kanamycin
Amikacin
Ciprofloxacin
Category-2(When Category-1 fails ,when
-ve sputum become positive; 2 weeks)//8 months
2HRZES
1HRZE
5HR
Patient become non infective after 2 weeks of treatment
Follow up(How will you asses treatment is working/not)
Clinical S/S- S/S dissapears ,no fever ,weight gain ,reduced cough
Examination-No crepitations
Investigation-
CBC
ESR decreased
Sputum -ve
Category-1(2nd ,5th ,6th months)
-
Why not before
2 months?-Maximum drug action needs 2 months>If still +ve sputum>advise
to take drug further 1 months>If still sputum +ve>do gene Xpert
Category-2(3th ,5th ,8th months)
X ray chest
When will you know a treatment failure
+ve sputum at 5 months
MDR
TB
What
is MDR TB
+ve sputum after 2 months Rx OR , resistance to R/H with/without other DR
What
is DR TB
Resistance to any 1st line drug
What
is XDR TB
Resistance to R/H with any quinolones with 1 injectable 2nd line drug
Doses
of TB drugs
H(Isoniazide/INH)=5-10mg/kg
R(Rifampicin)=10mg/kg
Z(Pyrazinamide)=20-35mg/kg
E(Ethambutol)=15-25mg/kg
S(Streptomycin)=0.7 or 1g/kg
Single dose in morning in empty stomach
If can't tolerate ,give in full stomach
Ceftriaxone 2g BD injection in TB meningitis
Side effects of TB drugs
Rifampicin
1.Discoloration
of body secretion(e.g. orange urine)
2.Skin
rash
3.Hepatitis
INH
1.Peripheral
neuropathy-Tingling sensation ,numbness of limb(So add vitamin B6)
2.Skin
rash
3.Hepatitis
Pyrazinamide
1.Hyperuricemia
2.Gout(Joint
pain)
3.Hepatitis
Ethambutol
Retrobulbar
neuritis
Streptomycin
1.Nephrotoxicity
2.Ototoxicity
Advice
after Rx
1.ওষধ নিওমিত
খাবেন
2.ওষধ খেলে
পেসাব কম্লা রঙের হবে ,এতে ঘাবড়ানোর কিছু নেই
3.পেসাব
ও চোখের রঙ হলুদ(Hepatitis) ওষধ বন্ধ করে ডাক্তারের কাছে যাবে
4. ২ মাশ নিচের test গুল করতে হবে-
Sputum for AFB
CBC
,chest X ray
5.Use
barrier method along with OCP(Contraceptive failure with Rifampicin)
If Hepatitis occurs during treatment course, what to do?Stop drug>Sign-symptoms dissapear>Do Liver function test>If course gap is more than 1 month start treatment as new onset TB and if gap is less than 1 month ,then fillup those days
What
is DOTS
Directly observed treatment short course-Drugs taken in presence of an attendance 3 times weekly[For prevention of resistance]
What is FDC
Fixed drug combination-Rimstar 4 FDC (HRZE)
Question.50 years old male with fever for 2 weeks ,with walking difficulty for 10 days,associated with paraplegia.
Diagnosis-Spine TB(If gibbus->Pott's disease)
Here Disc space reduced-In TB
but disc space is normal in Secondary carcinoma from prostate
Prevention
BCG vaccine/Bacillus Calmette Guerin ,a live attenuated vaccine from M.bovis
Intradermal
vaccine
It
prevents dissemination including TB meningitis
MT
test
10 TU used ,given intracutaneously ,reading is taken
upto 2-4 days
It is supportive evidence of diagnosis of TB
In suspected case of sarcoidosis
CD4 is responsible for +ve test
If smear +ve
-No need for MT
Induration >10mm is +ve test(BCG ,recent/past
infection)
Induration >15mm is strongly +ve
False -ve in extreme age ,cytotoxic drugs
,immunosuppression ,sarcoidosis ,lymphoma
False +ve in BCG(>5mm) ,non tubercular mycobacterium
Indication of steroid in TB
1.Adrenal
TB
2.TB
of serous cavity
Pericarditis
Pleural effusion
Ascitis
3.Tubercular meningitis
4.Occular
TB
5.Genitourinary TB
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