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Tuberculosis, Emergency Medicine

Basics

Description

- Extrapulmonary TB: - CNS infections: - Meningismus - Cranial nerve defects, diplopia - Headache, fever, malaise - Confusion - Acute ischemic stroke

- Pericarditis: - Pleuritic chest pain increased with recumbency

- Renal infection: - Spinal TB (Potts disease): - Back pain/stiffness, point tenderness - Fever - Decreased range of motion

- Cervical lymphadenitis (scrofula): - Unilateral, painless - May form draining sinus tracts

- Lumbar puncture with CSF analysis: - For suspected TB meningitis - Elevated WBCs with lymphocyte predominance - Elevated protein - Low to normal glucose

- Chest radiograph: - May be normal - In primary disease, parenchymal infiltrates with unilateral hilar adenopathy are the classic findings. - Reactivation TB typically appears as cavitary lesions with or without calcification, usually in upper lung segments. - Miliary TB shows bilateral disseminated 2-mm nodules throughout lungs. - Chest radiograph may be nondefinitive in AIDS/immunocompromised patients. - Unilateral pleural effusion in both primary and reactivation TB - Tracheal deviation with scarring or atelectasis - Ghon focus " ”calcified scar/healed primary focus of infection - Ghon complex " ”primary infiltrate with associated unilateral hilar adenopathy

- >10-mm induration: - IV drug users - Immigrants from high-prevalence countries (within 5 yr) - Underlying disease (diabetes, renal failure, malignancies) - Healthcare workers - Prison inmates - Institutionalized (nursing home, homeless shelters)

  • Tuberculosis (TB) is an infectious disease with protean manifestations, causing significant global morbidity and mortality.

Mechanism

  • Infectious droplet nuclei are inhaled through the respiratory tract.
  • Bacteria are dispersed through coughing, sneezing, speaking, singing.
  • Primary TB/latent TB infection (LTBI):Initial infection occurs when organisms enter the alveoli, become engulfed by macrophages, and spread via regional lymph nodes to the bloodstream.Patients are usually asymptomatic.May be progressive/fatal in immunocompromised hosts.Positive reaction to purified protein derivative (PPD) indicates past exposure or infection.Negative PPD does not rule out active TB.May progress to active TB (5 " “10%).
  • Reactivation TB:LTBI becomes active TB.Systemic (15%) and pulmonary (85%) symptoms.
  • TB affects about one-third of the worlds population (90 million new cases in the past decade worldwide, with about 30 million deaths).
  • Centers for Disease Control and Prevention (CDC) statistics from 2011 show TB in US at an all-time low.
  • TB rates in US have continued to decline since 1993.
  • Increase in US foreign-born cases
  • Still an estimated 10 " “15 million people are infected in US alone.

Etiology

  • Infection with Mycobacterium tuberculosis, a slow-growing, aerobic, acid-fast bacillus resulting in disease.
  • Humans are the only known reservoir.
  • Recent TB epidemics:HIV-infected patientsMultidrug-resistant TB (MDR-TB)Extensively drug-resistant TB (XDR-TB):High mortality, few effective drugs

Diagnosis

Signs and Symptoms

  • Depending upon site of infection; all human tissues have potential for infection.
  • Pulmonary TB:CoughFever, night sweatsMalaise, weight lossHemoptysisPleuritic chest painShortness of breath
  • Extrapulmonary TB:CNS infections:MeningismusCranial nerve defects, diplopiaHeadache, fever, malaiseConfusionAcute ischemic strokePericarditis:Pleuritic chest pain increased with recumbencyRenal infection:Spinal TB (Potts disease):Back pain/stiffness, point tendernessFeverDecreased range of motionCervical lymphadenitis (scrofula):Unilateral, painlessMay form draining sinus tractsMiliary TB:Multiorgan system involvementDiffuse adenopathyHepatomegalySplenomegalyWeight loss, fever

History

Predisposing factors and conditions for TB: ‚

  • HIV infection and other immunocompromised states (organ transplant, renal failure, diabetes)
  • Drug and alcohol abuse
  • Poverty, homelessness (living in shelters)
  • Institutionalization (nursing homes, prisons)
  • Immigration from an endemic area
  • Positive PPD test/previous infection

Physical Exam

  • Fever
  • Tachycardia
  • Hypoxia
  • Cachexia
  • Abnormal breath sounds
  • Cervical lymphadenopathy

Essential Workup

  • Diagnosis difficult due to the variety of clinical presentations.
  • Chest radiography:Most valuable test for active pulmonary TB
  • Skin testing: PPD

Diagnosis Tests & Interpretation

Lab

  • CBC
  • Electrolytes, BUN, creatinine, glucose, LFTs
  • Hyponatremia (due to syndrome of inappropriate antidiuretic hormone)
  • ABGs for oxygenation/ventilation assessment
  • Sputum staining for acid-fast bacilli (Ziehl " “Neelsen stain):Provides a quick presumptive diagnosis
  • Sputum, CSF, blood, urine, or peritoneal fluid culture:Gold standard for diagnosis of TBAverage time for positive culture is 3 " “6 wk.DNA polymerase chain reaction (PCR) testing more rapid
  • Lumbar puncture with CSF analysis:For suspected TB meningitisElevated WBCs with lymphocyte predominanceElevated proteinLow to normal glucose

Imaging

  • Chest radiograph:May be normalIn primary disease, parenchymal infiltrates with unilateral hilar adenopathy are the classic findings.Reactivation TB typically appears as cavitary lesions with or without calcification, usually in upper lung segments.Miliary TB shows bilateral disseminated 2-mm nodules throughout lungs.Chest radiograph may be nondefinitive in AIDS/immunocompromised patients.Unilateral pleural effusion in both primary and reactivation TBTracheal deviation with scarring or atelectasisGhon focus " ”calcified scar/healed primary focus of infectionGhon complex " ”primary infiltrate with associated unilateral hilar adenopathy
  • Spine radiographs for Potts disease:May be normalAnterior wedging of 2 involved vertebral bodies and destruction of disk
  • CT chest:Better defines extent of disease

Diagnostic Procedures/Surgery

Skin testing: ‚

  • Inject 0.1 mL of PPD intradermally in the forearm.
  • Positive test indicates prior or current infection with M. tuberculosis.
  • Test results are read between 48 and 72 hr after administration.
  • Interpretation of positive: >5-mm induration:Close contacts with TB patientsPositive chest radiographs for TBHIV-positiveOrgan transplant or other immunosuppression
  • >10-mm induration:IV drug usersImmigrants from high-prevalence countries (within 5 yr)Underlying disease (diabetes, renal failure, malignancies)Healthcare workersPrison inmatesInstitutionalized (nursing home, homeless shelters)
  • >15-mm induration:

Differential Diagnosis

  • Bacterial pneumonia
  • Bronchiectasis
  • Coccidiomycosis
  • Histoplasmosis
  • Lung abscess
  • Lung carcinoma
  • Lymphoma
  • Pneumocystis carinii pneumonia
  • Pulmonary embolism
  • Sarcoidosis

Treatment

Pre-Hospital

  • Place patient in respiratory isolation (negative flow).
  • Place a mask on the patient to prevent respiratory spread of the disease.
  • Initiate treatment with an IV, oxygen, and pulse oximetry.
  • Endotracheal intubation may be required in patients with severe hemoptysis or respiratory compromise.
  • Providers should wear submicron particulate filter masks (N-95 designation).
  • Inform close contacts.

Initial Stabilization/Therapy

  • ABCs:Control airway as needed.Administer oxygen as needed.Place on patient cardiac monitor and pulse oximetry.Establish IV access with 0.9% normal saline
  • Isolate patients in negative pressure rooms with at least 6 air exchanges per hour.
  • Protection for healthcare workers (N-95 masks)

Ed Treatment/Procedures

  • Isolation and strict respiratory precautions
  • Treatment is augmented due to increasing multidrug resistance.
  • Any regimen must contain at least 2 drugs to which the TB bacillus is susceptible.
  • CDC currently recommends initial therapy that includes 4 1st-line drugs.
  • LTBI with normal chest x-ray given isoniazid (INH) for 9 mo or weekly combination of INH and rifapentine (RPT) for 12 wk.
  • Consult infectious disease specialists when treating HIV patients on antiretroviral therapies.
  • Add dexamethasone for TB meningitis.
  • Surgical drainage for TB empyema may be necessary; consult thoracic surgeon.
  • Directly observed therapy (DOT) may be necessary to ensure compliance in certain populations.
  • Intermittent (biweekly) regimen may demonstrate higher patient compliance.

Medication

First Line

  • INH: 5 mg/kg, max. 300 mg (peds: 10 " “15 mg/kg, max. 300 mg) PO/IM per day:Refractory seizures in overdose, treat with pyridoxine 5 g IV over 5 min or POCaution with alcohol coingestion, hepatitis
  • Rifampin (RIF): 10 mg/kg, max. 600 mg (peds: 10 " “20 mg/kg, max. 600 mg) PO/IV per day
  • Pyrazinamide (PZA): 20 " “25 mg/kg/d max. 2 g (peds: 15 " “30 mg/kg/d) or:<55 kg: 1 g PO per day56 " “75 kg: 1.5 g PO per day>75 kg: 2 g PO per dayNot recommended in pregnancy
  • Ethambutol (ETB): 15 " “20 mg/kg, max. 1,600 mg (peds: 15 " “30 mg/kg, max. 1 g) PO per day or up to TIDNot recommended <13 yr old, requires visual testing
  • RPT: 10 mg/kg, max. 900 mg (peds: Not recommended <12 yr old) PO once per week or 300 mg PO weekly for 10 " “14 kg, 450 mg PO weekly for 14.1 " “25 kg, 600 mg PO weekly for 25.1 " “32 kg, 750 mg PO weekly for 32.1 " “49.9 kg, 900 mg PO weekly for >50 kg
  • Rifabutin: 5 mg/kg, max. 300 mg (peds: Unknown) PO per day

Second Line

(Less Effective, More Toxic)

  • Streptomycin: 15 mg/kg/d, max. 1 g (peds: 20 " “40 mg/kg/d) IM/IV per day:Teratogenic: Contraindicated in pregnancy
  • Ethionamide: 0.5 " “1 g (peds: 10 " “20 mg/kg/d) PO div. QID
  • Levaquin: 750 mg (peds: Contraindicated) PO/IV per day

Follow-Up

Disposition

Admission Criteria

  • Respiratory compromise
  • Suspicion of diagnosis
  • Inability to comply with outpatient therapy
  • Unavailable outpatient resources (no PCP)
  • Involuntary admission for noncompliant outpatients occurs:Be aware of respective state laws concerning involuntary admission (consult infectious disease specialist).

Discharge Criteria

  • Without respiratory compromise
  • Home isolation procedure compliance
  • Ability and willingness to comply with long-term therapy
  • Appropriate outpatient follow-up and treatment available
  • Notification of the public health authorities is mandatory.

Issues for Referral

Referral to Department of Public Health for DOT ‚

Follow-Up Recommendations

  • Sputum analysis periodically to document clearance
  • Medication toxicity monitoring:INH, RIF, PZA: Monitor liver function tests for hepatitisPZA: Check uric acid levelsETB: Eye testing for color blindness

Pearls and Pitfalls

  • Early isolation and respiratory precautions
  • Careful history to establish risk factors
  • The chest x-ray and PPD are great diagnostic aids.
  • Initial 4-drug regimen for active disease
  • Nonadherent, active TB patients are considered a public health hazard:Specific state laws are applicable in numerous areas.

Additional Reading

  • American Thoracic Society; CDC; Infectious Diseases Society of America. Treatment of tuberculosis. MMWR Recomm Rep. 2003;52(RR-11):1 " “77.
  • American Thoracic Society; Centers for Disease Control and Prevention; Infectious Diseases Society of America. American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America: Controlling tuberculosis in the United States. Am J Respir Crit Care Med. 2005;172:1169 " “1227.
  • Centers for Disease Control and Prevention (CDC). Recommendations for use of an isoniazid-rifapentine regimen with direct observation to treat latent Mycobacterium tuberculosis infection. MMWR. 2011;60(RR-48):1650 " “1653.
  • Moran ‚ GJ, Talan ‚ DA.Tuberculosis. In: Wolfson ‚ AB, ed. Harwood-Nuss ' Clinical Practice ofEmergency Medicine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins: 2010:912 " “917.
  • Taylor ‚ Z, Nolan ‚ CM, Blumberg ‚ HM. Controlling tuberculosis in the United States. Recommendations from the American Thoracic Society, CDC, and the Infectious Diseases Society of America. MMWR Recomm Rep. 2005;54(RR-12):1 " “81. http://www.cdc.gov/tb/publications/factsheets/statistics/TBTrends.html. Accessed on February 28, 2013.

See Also (Topic, Algorithm, Electronic Media Element)

  • Pneumonia, Adult
  • Bronchiectasis
  • Coccidiomycosis
  • Histoplasmosis
  • Lymphoma
  • Pneumocystis carinii Pneumonia
  • Pulmonary Embolism
  • Sarcoidosis

Codes

ICD9

  • 010.90 Primary tuberculous infection, unspecified, unspecified
  • 011.90 Unspecified pulmonary tuberculosis, unspecified
  • 795.51 Nonspecific reaction to tuberculin skin test without active tuberculosis
  • 018.90 Miliary tuberculosis, unspecified, unspecified
  • 013.20 Tuberculoma of brain, unspecified
  • 017.90 Tuberculosis of other specified organs, unspecified

ICD10

  • A15.7 Primary respiratory tuberculosis
  • A15.9 Respiratory tuberculosis unspecified
  • R76.11 Nonspecific reaction to skin test w/o active tuberculosis
  • A19.9 Miliary tuberculosis, unspecified
  • A17.81 Tuberculoma of brain and spinal cord
  • A18.84 Tuberculosis of heart
  • A18.89 Tuberculosis of other sites

SNOMED

  • 56717001 Tuberculosis (disorder)
  • 63309002 Primary tuberculosis (disorder)
  • 441846005 Nonspecific tuberculin test reaction (finding)
  • 47604008 Miliary tuberculosis (disorder)
  • 302131003 Tuberculosis of heart (disorder)
  • 31112008 Tuberculous meningoencephalitis (disorder)