2. Introduction
infection by
Mycobacterium tuberculosis,
M. bovis and
occasionally by Bacillus Calmette-Guerin (BCG)
can be acquired either exogenously or endogenously
• The clinical manifestations depend on
• the site of infection,
• type of inoculum and the
• host's immunity
3. Etiological Agent
• Mycobacterium tuberculosis -
Weakly gram-positive,
strongly acid fast,
strictly aerobic,
non-motile,
non-spore forming,
curved rods
Cell wall has high content of mycolic acid-rich
Mycobacterium Bovis –
penetrate the gastro-intestinal mucosa and lymphatic tissue of the
oro-pharynx when ingested in milk.
11. Scrofuloderma
(Tuberculosis colliquativa cutis)
• Direct extension from underlying tuberculosis FOCUS
• Commonest form worldwide
• Commonest form in children and adolescents in India
• An asymptomatic bluish red subcutaneous swelling
• Breaks down to form undermined ulcers or fistulas
13. Lupus vulgaris
Most common form of cutaneous TB in India
reddish brown, plaque
Grows by slow peripheral extension
• APPLE JELLY NODULES ON DIASCOPY
14. Acute cutaneous miliary tuberculosis
haematogenous dissemination
Crops of minute bluish papules, vesicles, pustules, erythematous nodules, or
haemorrhagic lesions
15. Metastatic tuberculous abscess
(Tuberculous gumma)
• subcutaneous nodule or a non-tender fluctuant abscess
• Commonly on extremities
• May break down to form an undermined ulcer, with sinuses
16. Tuberculids
• Cutaneous hypersensitivity reaction to hematogenous dissemination of
M. tuberculosis or its products in patient with significant immunity
(earlier concept)
• Following criteria must be fulfilled to designate a condition as
tuberculid:
– Tuberculoid histology on skin biopsy
– Strongly positive Mantoux reaction
– Absence of M. tuberculosis in smear
– Negative culture
– Resolution of skin lesions with antituberculous therapy
17. • True tuberculids can be grouped as
• Micropapular: lichen scrofulosorum.
• Papular: papulonecrotic tuberculid.
• Nodular: erythema induratum of Bazin or nodular tuberculid
20. Erythema induratum of Bazin
(Nodular vasculitis, Bazin disease, Tuberculosis cutis indurativa)
• Tuberculosis‐associated panniculitis
• Usually calves, young or middle-aged women
• ill‐defined nodules or subcutaneous plaques
21. Atypical Mycobacteria
Causative agent Clinical features Investigations Treatment
M. Marinum
(Fish tank/
swimming pool
granuloma)
Nodule/pustule – break down into
ulcer/abscess. Sporotricoid pattern
Culture at 30-33° C
PCR DNA
Clarithromycin + Ethambutol ±
Rifampicin x3-4 months
(Resistant to isoniazid and
pyrazinamide)
M. Kansasii Papule/pustule/nodules/verrucous
plaques. Primarily pulmonary disease
Culture
PCR
Isoniazid + Rifampicin + Ethambutol
x18 months (Resistant to isoniazid)
M. Ulcerans
(Buruli ulcers)
Papule/nodule – ulcer -- Rapid spread
– Upto subcut, spare muscles
Smear. Culture at 32°
C. PCR
Rifampicin + Streptomycin
± Surgery (according to category)
M. Avium complex
(M. avium and M.
intracellulare)
Multiple ulcer, nodules, plaques,
abscess. Sporotrichoid spread. HIV
individuals more affected
Culture
(blood/marow)
AFB –ve. PCR
Clarithromycin + Ethambutol ±
Rifabutin ± Surgical excision
M. Haemophilum Erythematous/violaceus
papules/nodules – painful
abcess/ulcer. Panniculitis
Culture (30-32°C)
PCR
Clarithromycin + Ciproflox +
Rifamycin
M. Scrofulaceum Nodule/abscess/plaque/ulcer.
Swelling/sinus of submandibular and
submaxillary gland.
Culture
PCR
Surgery
Clarithro + Ethamb + Rifabutin
M. Szulgai Principally Pulmonary.
Cellulitis/nodules/sinus
Isoniazid, Rifampicin, Ethambutol,
Streptomycin
22. Laboratory Investigations
Absolute criteria-
• Demonstration of M. TB in either tissue culture or cytological smear
• Demonstration of mycobacterial DNA by PCR
Relative criteria-
• Presence of active, proven tuberculosis elsewhere
• Presence of acid‐fast bacilli in the lesion
• Positive reaction to tuberculin
• Positive IFN‐γ release assay
• Effect of specific therapy
26. Drug Daily Dose Thrice-Weekly Dose
Isoniazid 5 mg/kg, max 300 mg 10 mg/kg, max 900 mg
Rifampicin 10 mg/kg, max 600 mg 10 mg/kg, max 600 mg
Pyrazinamide 25 mg/kg, max 2 g 35 mg/kg, max 3 g
Ethambutol 15 mg/kg 30 mg/kg
First line drugs
• Rifampicin(R)– Bactericidal, all bacilli
• Pyrazinamide(Z)– Bactericidal, all bacilli
• Isoniazid(H)– Bactericidal, replicating bacilli
• Ethambutol(E)– Bacteristatic
28. WHO recommended drug regimens
• Culture and drug susceptibility testing (DST) for all previously treated TB
patients at or before the start of treatment
• In patients with HIV, treatment with isoniazid and rifampicin is continued for
seven months after the initial two months of quadruple therapy.
29. DOTS (directly observed treatment, short course)
• launched by WHO in 1995
• Category 3 regime under RNTCP abolished
• Only 2 regimes in effect (of 1st line drugs)
• Cat 1 for all new cases and Cat 2 for all retreatment cases
• Cat 1: 2 H3R3Z3E3 + 4 H3R3
• Cat 2: 2 H3R3Z3E3S3+ 1 H3R3Z3E3 + 5 H3R3E3
• Fixed drug combination (FDC) products such as
isoniazid/rifampicin, isoniazide/rifampin/pyrazinamide, and
isoniazid/rifampin/pyrazinamide/ethambutol are available as well
30. Multidrug-resistant (MDR) tuberculosis
• Defined as resistance to rifampicin and isoniazid with or without resistance
to other antituberculous drugs
• MDRTB found in lupus vulgaris, scrofuloderma, and tuberculosis cutis
• 3.6% of new and 20% previously tuberculosis (TB) patients in world have
MDR-TB
Extensively drug-resistant (XDR) TB
• XDR= HR + 1 FQ + 1 Injectable (KM or AMK or CM)
• 10% of MDR-TB cases are also extensively drug-resistant (XDR-TB)
31. Isoniazid and Rifampicin resistant-
• Pyrazinamide + ethambutol + quinolone (levoflox) + Streptomycin (or
another injectable) x 18-24 months
Resistant to all first line drugs-
• 1 injectable + 3 of the following
• Ethionamide, quinolone, cycloserine, PAS
x 24 months
Surgery
• Surgical excision of small lesions of lupus vulgaris or warty tuberculosis,
if diagnosed early
• Plastic surgery may help the disfigurement left by treated lupus vulgaris
32. Pregnancy-
• Ethambutol and streptomycin are contraindicated due to their teratogenic
effects
Renal Insufficiency-
• Interval or drug dosing should be adjusted in patients with creatinine
clearance <30ml/min
• Rifampicin - None
• Isoniazid - 50%
• Pyrazinamide 48 – 72h
• Ethambutol 25 – 50%
• Streptomycin 72 – 96h
33. Hepatic Insufficiency-
• Rifampicin, isoniazid and pyrazinamide have great hepatotoxicity potential
• Ethambutol can be fully utilized by patients with liver insufficiency
• To prevent isoniazid-related neuropathy, pyridoxine (10–25 mg/day)
should be added to persons at high risk of vitamin B6 deficiency such as
• Alcoholics, malnourished, pregnant and lactating women, chronic renal
failure, diabetes, HIV infection
