TB 2013_Diagnosis and clinical presentation

الرحمن الله بسمالرحيم

Clinical Presentation of Tuberculosis

Dr. Ramadan Fouad ArafaMBBCh, MSc, MRCP

Physician, Fujairah Hospital

Introduction

• TB is one of the world’s deadliest diseases

• 1/3 of the world’s population is infected with TB.

• In 2011, nearly 9 million people around the world

became sick with TB disease. There were around

1.4 million TB-related deaths worldwide.

• Over 95% of TB deaths occur in low- and middle-

income countries, and it is among the top three

causes of death for women aged 15 to 44.

• TB is a leading killer of HIV infected people.

• A total of 9,945 TB cases (a rate of 3.2 cases per

100,000 persons) were reported in US in 2012.

• The TB death rate dropped 41% between 1990

and 2011.

• An estimated 20 million lives saved through use

of DOTS and the Stop TB Strategy recommended

by WHO.

• Early diagnosis and prompt effective therapy form

the key elements of the TB control programme.

• Delay in diagnosis results in increased infectivity

in the community and it is estimated that an

untreated smear-positive patient can infect 20

contacts before being diagnosed.

Situation in UAE 2011New cases No. % Retreatment No. %

Smear-positive 46 45 Relapse 0 0

Smear-negative 25 24 Treatment after failure

0 0

Smear not done 2 2 Treatment after default

3 100

Extrapulmonary 30 29

Total treatment 103 Total retreatment 3 100

Total new and relapse

103 Total cases notified

106

Factors affecting transmission of TB1. Degree of infectiousness of the case:

a. Smear positive sputum:Pts with cavitatory lesions are more infectiousTB with HIV is less infectious20 cases may be infected from smear positive sputum

case before the index case is diagnosed.

b. Smear negative / culture + ve casesLess infectiousResponsible for up to 20% of transmission of TBc. Sputum – ve / culture –ve: not infectious

2. Duration of the contact with the index case

3. Shared environment:

Class mates

Office workers

Sharing living or bed room

Crowding in poorly ventilated rooms is one of the

most important factors affecting TB transmission.

Risk factors for active TBPrimary TB: • less transmissible even if severe and

disseminated.• 10% of 1ry TB will develop active TB in their life

time.• 50% of them will be in first year after infection• Reinfection• HIV• Age: late adolescents and early adults, 25-34 y

and old age.

Risk factors for active TBFactor RR /OddsRecent infection 12.9Fibrotic lesions (spontaneously healed) 2 - 20Comorbidities

HIV -----------------------------------------Silicosis -----------------------------------CRF / HD ----------------------------------DM ----------------------------------------IV drug use -------------------------------Immunosuppressive treatment ------Gastrectomy -------------------------Jejunoileal bypass ---------------------Posttransplant period -------------------

21 - 303010 - 252- 410- 30 102- 530- 6020 - 70

Tobacco smoking 2 - 3

Malnutrition and severe underweight 2

Case I

• A 35 year old housemaid,

• C/O chest pain with deep breathing with

blood stained sputum for last 2 weeks

• DM II +ve

• CXR

Case 2• Mr V from Philippines was admitted in August

2013• Fever• Chest pain in Lt upper part of chest• Pain is more with breathing• Lost weight• Productive cough• Occasional hemoptysis

• Febrile 39.5 ⁰• HR 112 bpm• RR 22 breaths/min• Chest : left bronchial breath sounds, pleural rub• CVS and abdomen: Unremarkable• CXR• CBC• Electrolytes• Sputum AFB +ve• PCR for MTB + ve

Case 3

• A 70 year old lady, local• Admitted with hemoptysis for 1 day• She has similar attack 4-5 months ago in KSA,

was diagnosed as URTI• No fever, chest pain, loss of weight, anorexia

or night sweats• No contact with chesty patients

Clinical manifestations of TBPrimary TB

•Asymptomatic•Fever•Pleurisy•More in children•CXR: middle and lower zones infiltrates•Hilar and paratracheal lymphadenopathy•Erythema nodosum •Pleural reaction

• In patients with impaired cell mediated immunity, primary PTB progress rapidly to clinical illness.

• Pleural effusion presents in 2/3 of cases.

• Primary lesion enlarges and undergoes cavitation (progressive primary TB).

• Hilar or paratracheal lymphadenopathy

• Enlarged LN may compress bronchi

• Lymph nodes may also rupture into the airway with development of pneumonia

• Bronchiectasis.

• Hematogenous dissemination

POSTPRIMARY (ADULT-TYPE) DISEASE• Reactivation of LTBI• Re-infection• Apical and posterior segments of the upper lobes• The superior segments of the lower lobes are also

more frequently involved.• It ranges from small infiltrates to extensive

cavitary disease.• Cavitation results in satellite lesions within the

lungs that may in turn undergo cavitation.• Massive involvement may cause pneumonia.

• Most patients respond to treatment, with defervescence, decreasing cough, weight gain, and a general improvement in well-being within several weeks.

Symptoms of PTB

• Nonspecific and insidious

• Diurnal fever and night sweats, weight loss,

anorexia, general malaise, and weakness.

• Cough.

• Hemoptysis develops in 20–30% of cases

• Dyspnea, ARDS, and chest pain

Gray zone cases

• Typical symptoms with normal CXR• CXR finding is asymptomatic patient• Symptoms and CXR findings with no sputum

production• Symptoms and CXR finding with negative AFB

smear• Exudative pleural effusion with negative

smear• Suspected TB meningitis. What to do?

Diagnosis of TB

• High index of suspicion

• Not difficult with high risk cases

• The longer the delay, the more typical CXR

findings

• Immunosuppressed patients always present with

atypical findings.

Diagnosis

• Sputum smear for

AFB x 2 times

• Sputum culture

Diagnosis

• Collection of specimens

Proper 2 sputum specimens

In sterile universal container or wide

mouthed screw-capped container

Sent for microscopy & culture

Sputum collection

• Sputum induction

–With 5ml of 3% saline given through nebulizer

–Order for sputum culture

• Gastric aspiration

• Bronchoscopy

–On high suspicion for PTB

Sputum exam

• Storage & transportation

Should be examined in maximum 5-7 days

If a delay to send the specimen to lab is

unavoidable, it should be stored in a

refrigerator until sent in a cool box

Other tests

• IGRA

• NAAT

• Tuberculin skin test

• Chest X-ray

• CBC, ESR

• For EPTB: appropriate sampling

IGRA Testing• IGRAs are used as aids in diagnosing TB infection

• Neither IGRA nor TST can distinguish LTBI from active TB.

• IGRA sensitivity 81% (100% in some studies)

• IGRA specificity 99%

• No cross reaction after BCG or non-TB Mycobacteria

• Persons with a +ve IGRA result should be evaluated for

the likelihood of TB infection, for risks for progression to

active TB, and for symptoms and signs of active TB.

NAAT

• Approved by WHO for smear +ve cases.

• Not recommended for smear negative cases.

• An automated molecular test for the detection of

M.TB and resistance to rifampicin

• Sensitivity for TB was 98.2% for smear + ve

sputum sample and 72.5% for smear -ve sputum

Automated liquid cultures

• Automated liquid cultures are more sensitive

than solid cultures

• Time to detection is more rapid than solid

cultures

• It can be used to detect Rifampicin resistance.

Tuberculin skin testing

• most widely used in screening

• limited value in the diagnosis of active TB.

• Low sensitivity and specificity.

• False-negative reactions are common

• Positive reactions are obtained in BCG –

vaccinated persons and LTBI.

Three cutoff points of clinical significance:

• Larger than or equal to 5 mm

Close contacts to persons with newly diagnosed TB

Persons with HIV infection

Patients with organ transplant

Patients taking the equivalent of more than 15 mg/d

of prednisone for one month or more

Patients with fibrotic lesions on chest radiography

• Larger than or equal to 10 mm Patients with medical conditions that increase the

risk of TB Recent converter - At least 10-mm increase in skin

test in past 2 years (regardless of age) Recent immigrants (within 5 y) from a high-

prevalence countryChildren younger than 4 years exposed to adults at

high risk for TBResidents and employees of facilities for long-term

care, including correctional institutions, nursing homes, homeless shelters, and mental institutions

• Larger than or equal to 15 mm - Persons

with none of the above

Case definitions

• Tuberculosis suspect.

Symptoms suggestive of PTB:

• productive cough

• other respiratory symptoms

• constitutional symptoms

Symptoms related to EPTB involvement

• Definite Case of TB:

Positive AFB smear, culture, histologic

features or by newer methods as NAAT

No therapeutic trial to diagnose TB

PTB: one or more sputum sample +ve for AFB

Definitions … continued • NEW CASE: A patient who has never had

treatment for TB or who has taken ATT < 1month.• RE-TREATMENT CASE: A patient previously

treated for TB, who – is started on a re-treatment regimen after

previous treatment has failed (treatment after failure),–who returns to treatment having previously

defaulted, or–who was previously declared cured or

treatment completed and is diagnosed with bacteriologically positive (sputum smear or culture) TB (relapse).

Pulmonary TB

• TB involving the lung parenchyma.

• Miliary TB is classified as pulmonary TB

• TB intrathoracic lymphadenopathy, or TB pleural

effusion, without radiographic abnormalities in the

lungs, constitutes a case of extrapulmonary TB.

• A patient with both pulmonary and extrapulmonary

TB should be classified as a case of pulmonary TB.

Extrapulmonary tuberculosis (EPTB)

• TB involving organs other than the lungs, e.g.

pleura, lymph nodes, abdomen, genitourinary

tract, skin, joints and bones, meninges.

• Diagnosis should be based on same criteria of

definite PTB.

• Sputum smear negative PTB:

Diagnostic criteria should include:

1.at least 2 sputum smear -ve for AFB;

2. and CXR consistent with active PTB; AND

3. a decision by a clinician to treat with a full course

of ATT and either:

— laboratory or strong clinical evidence of HIV infection or: — if HIV-negative (or unknown HIV status living in an area

of low HIV prevalence), no improvement to AB (excluding ATT, fluoroquinolones and aminoglycosides).

• Pulmonary TB cases without smear results

are no longer classified as smear- negative

(smear not done or Unknwon).

• In settings with an HIV prevalence >1% in

pregnant women or ≥5% in TB patients, sputum

culture should be performed in patients who

are sputum smear-negative to confirm the

diagnosis of TB.