6. extent of tb problem

Amha Mekasha, MD, MSCDPCH, AAU

Extent of TB problem

• 2.3 million deaths/yr• Illness in 8.4 m/ year• 1 m are children• 6% increase annually• WHO estimates

– 159 & 370/100,000 new smear positive PTB & all other forms of TB respectively

– 40% of adult cases are HIV positive

Childhood TB among Children at TAH

• It is a neglected disease, “Orphan disease.”• Accounts for 20% or more of TB case-load in

many countries with high TB incidence.• It accounts for 4.3% of the admissions. (Damte

2007)• Accounts for 3.9% of the deaths. (Damte

2007)

Etiology

• 53 different species of mycobacterium

• 3 species cause TB in humans– M.tuberculosis– M.bovis– M. africanum

Transmission

• Inhalation• Ingestion of milk• Skin• Transplacental

Factors affecting transmission

• Crowding, poverty• UV light• Genetics• Close contact

– Dark & humid area– Indoors– Large # of bacilli in

sputum

Disease development

• Factors affecting disease development– Immunity status– Nutritional status– Intercurrent illness– Length of time of

exposure– # of bacteria inhaled– Age at infection

• Primary infection• Healing• Reactivation• Cavitation

Cellular response to M.tuberculosis

Pathogenesis

• Primary complex• Rupture of focus into pleural space• Ring or coin shadow• Lymph node complications

– Extension into bronchus– Consolidation– Hyperinflation– Blood spread of bacilli

Pathogenesis cont’d

• A cavity is formed when– Lesions do not control bacterial growth– Infection damages the lung tissue– Lesion eats into a bronchus

A cavity is an ideal ground for bacteria:– Oxygen level is high– Dead tissue is source of food– No longer walled off by a ring of immune cells

Outcome of primary infection

• No clinical disease, PPD positive• Hypersensitivity e.g erythema nodosum• Pulmonary complications e.g collapse,

effusion• Disseminated TB

Timetable of tuberculosis

Types of TB at TAH(Endale & Mekasha)

Type No. %Lymph nodes 253 16

Pulmonary 722 45.6

Disseminated 452 28.6

Abdominal 26 1.6

Bones/joint 114 7.2

CNS 11 0.7

Skin 3 0.2

Total 1581 100

Diagnostic methods

• X-rays• Tuberculin skin test• Culture• Biopsy• PCR• DNA finger printing• Stains

– Ziel Nielson– Flourochrome

• T-cell based interferon-gamma assays– QuantiFERON-TB gold– T-SPOT.TB

PPD Test

• < 5mm Negative• 5-10mm considered

positive in immune- compromised(diabetes, steroid therapy etc..)

• >10mm positive

False negative PPD test

• Severe PEM• Measles• Overwhelming TB• Wrong techniques• HIV• Steroids• Cancer

False positive PPD test

• Atypical mycobacterial infections• Hypersensitivity to constituents• BCG vaccination

Criteria for TB Dx in children• Positive PPD• Compatible radiology• Contact history• Symptom complex• AFB

• Miliary pattern on CXR• Biopsy• Culture• Positive PPD in unvaccinated < 5 years of age

Lymph glands• Common sites are cervical LN, occasionally axillary and groin

LN may be involved.• The progression of TB of the LN: • Firm,discrete LN >> Fluctuant LN>> matted LN>> Abscess>>

skin breaks>> chronic sinus>>Healing with scar. • In severely immuno -compromised patients may be acute in

presentation resembling acute pyogenic lymphadenitis. • DDX includes pyogenic LN, cat scratch disease, Burkitts

lymphoma, actinomycosis and LN swelling due to BCG in armpit.

Bones and joints

• Most occur in the first three years of life. The most commonly affected bones and joints are the spine, hip, knee and feet. The joints are swollen but not tender or hot.

Spinal TB• Most common in lower thoracic and lumbar spine.• Affects the anterior superior or inferior angle of the vertebral

bodies and spreads to the adjacent one destroying the vertebral discs.

• In the neck region patient may remain from turning his head• The abscess may manifest as a mass on side of the neck. • In thoracic area stiffness of the back may be noted and

angular deformity of the back (gibbus). • Abscess formation causing cord compression causing

paraplegia. The commonest site of cord compression is T8-11 where the vertebral canal is anatomically narrowest

• In the lumbar area in addition to the deformity of the bone there may be pus draining down to the groin forming psoas abscess.

Bone Tb…

• Arthritis: Hip, knee, shoulder and elbow• Pannus develops which erodes the cartilage and the

joint space is filled with granulation tissue leading to ankylosis.

• Difficulty of walking ( limping). If advanced there may be shortening of the affected side with wasting of the muscles.

• Radiologically in the early phase there is narrowing of the joint space but later on there may be changes in the bones.

Abdominal TB• Abdominal TB can begin in three ways. From un

pasteurized milk, foods contaminated with bacilli or through hematogenous spread.

• Primary lesion could be in the intestine with mesenteric lymphadenopathy. If the LN ruptures, it may result in peritonitis. TB peritonitis can also be blood bone. The LN may stick together the intestinal loops forming mass which may result in attacks of obstruction.

• Symptoms: tenesmus, chronic diarrhea associated with some bleeding. There may also be some abdominal pain. Fistulae may develop between bowel, bladder and abdominal wall.

Abdominal TB…• TB peritonitis: low grade fever and abdominal pain. Signs of

free fluid in the abdomen or it could also be dry type. • Diagnosis can be made by ascitic tap or peritoneal biopsy.• Ultra-sound of the abdomen may show features suggestive of

TB including enlarged mesenteric or retroperitoneal LN.• TB can also spread to the pelvis and involve the fallopian tube

and the ovaries in girls. These may lead to infertility in later life.

TB of the nervous systemMeningitis• It commonly results from:

– Military TB or disseminated TB– In the course of spread from primary focus; – It may also arise from a contiguous focus. – It arises from caseous foci in the brain or the meninges. The

foci discharge bacilli directly into the subarachnoid space. – The predilection of the exudates for the base of the brain

accounts for the frequent involvement of 3rd, 6th and 7th cranial nerves and the optic chiasma. There is vasculitis due to the inflammation of the vessels. Arteritis and thrombosis cause cerebral infarction. The ensuing edema and infarction may give rise to focal convulsions and hemiplegia.

•

• In summary the tubercles rupture into the subarachnoid space causing.1.Inflammation of the meninges2.Formation of a grey jelly-like mass at the

base of the brain3.Inflammation and narrowing of the

arteries to the brain

TB meningitis• The clinical onset is insidious. • Stage 1. None specific manifestations such as apathy,

lassitude, anorexia, low grade fever and vomiting, headache and behavioral changes. Lasts 1-2 weeks.

• Stage 2. Early meningeal symptoms with signs of intracranial pressure

• Stage 3. Severe CNS involvement: hemiplegia or paraplegia, decerebrate rigidity and coma.

• The duration of untreated TB meningitis is about three weeks.

Meningitis..• Appearance: Ground glass, may form a “spider

web” clot on standing• Cell count: 60-400 cells with predominance of

PMN cells in the early phase. Later on the lymphocytes predominate.

• Protein: Elevated above 400mg/dl• Sugar: Reduced, but may be normal in the early

phase• Stain: Smear positive in only about 10% of the

cases• Culture: Can be positive but it will be too late for

decision to initiate treatment.

Tuberculoma

• Tuberculous lesions in the brain may increase in size without rupturing causing tuberculoma. The onset is insidious manifesting as brain tumor. There may be cranial nerve palsies or hemiplegia. In general neurological deficits depend on the tract involved.

• Skull X-ray: may show signs of increased intracranial pressure.

TB Pericarditis• hematogenous spread or due to rupture of a mediastinal LN

into the pericardium space. • Dry pericarditis: with acute pain behind the sternum, friction

rub of the pericardium. EKG: Wide T-wave.• Pericardial effusion : Breathlessness, fever, distant heart

sound, pulsus paradox us, raised JVP, hepatomegaly and ascites.

• Constrictive pericarditis: The pericardium is thickened, sometimes with calcifications preventing cardiac dilatation. X-ray: small heart shadow with or without calcifications.

• Pericardiocentesis & Culture of the pericardial fluid is 60% positive.

• Echocardiography: fluid and strands crossing between the two layers of the serosa.

Principles of treatment There are 3 types of

population of bacteria1. Population in cavities

– Contain mutants– Multiply rapidly– Needs at least 2 drugs2. Inside macrophages– Multiply & grow slowly– Needs prolonged

treatment3. Closed lesion

– Dormant– Never completely killed

Regimen

Category I– 2(ERZH) – 4RH or 6HE

• Category III– 2(RHZ)– 4RH or 6HE

• Category II– 2HRZES/1HRZE– 5HRE

• Category IV…..

Indications for steroids in TB

• Meningitis• Pericarditis• Pleural effusions• Hypoadrenalism• Laryngitis• Severe hypersensitivity• Renal tract Tb• Massive LN enlargement

Defaulters• Reasons:

– Family problems– Lack of money for

transport– Absence from work

of the caretaker– Side effects

TB control

• Case finding– Passive case-finding– Active case-finding

• Case treatment• Chemoprophylaxis (IPT) All HIV-infected individuals without

active TB are eligible for IPT. • Health Education• BCG vaccination