Setting: ED
CC: “Fever, cough, sputum, weight loss”
VS: BP: 112/70 mm Hg; T:101.4°F; R: 18 breaths/minute
HPI: A 34-year-old immigrant from Asia comes to the ED with fever, cough, and sputum with some hemoptysis developing over a few weeks. The patient has lost 15 pounds unintentionally over the past few weeks.
PMHX: alcoholism
Medications: none
PE:
Head, Ears, Eyes, Nose, Throat (HEENT): normal, no adenopathy
Chest: scattered rales, no consolidation
Cardiovascular: no murmurs, rubs, gallops
Initial Orders:
Chest x-ray
Oxygen
Oximeter
A patient with these symptoms can also be put on isolation from the beginning. You will not lose points for doing so.
Report:
Chest x-ray: apical infiltrate (Figure 7-5)
Oximeter: 95% saturation on room air
Orders:
Respiratory isolation
Sputum acid fast stain
Mycobacterial culture
Figure 7-5. Advanced pulmonary tuberculosis involving the apex and upper lobe. (Reproduced with permission from Tintinalli JE, et al. Tintinalli’s Emergency Medicine, A Comprehensive Study Guide, 7th ed. New York: McGraw-Hill; 2011.)
Purified Protein Derivative (PPD) Skin Testing
• Not for acute diagnosis
• Not for symptomatic persons
• Not with fever, cough, sputum, abnormal x-ray
PPD screens asymptomatic groups.
PPD detects previous exposures in high-risk groups.
The patient is placed on respiratory isolation. Some providers, based on the x-ray and the clarity of the diagnosis, may choose to add ceftriaxone and azithromycin. Do not start empiric tuberculosis (TB) medication until you have obtained sputum acid-fast cultures. You will want to give the sample every chance to grow.
Obtain sputum acid-fast cultures before starting anti-TB medications.
Acid-fast culture is the only way to determine the sensitivity of an organism.
The patient is placed on respiratory isolation. His fever persists at 101°F and then 101.5°F.
Report:
Acid-fast stain: positive (Figure 7-6)
Once the acid-fast stain is positive, order four TB medications and vitamin B6 (pyridoxine).
Orders:
Rifampin
Isoniazid
Pyrazinamide
Ethambutol
Vitamin B6
Liver function tests (LFTs) (aspartate aminotransferase [AST], alanine aminotransferase [ALT])
Figure 7-6. Note the rounded granuloma. This biopsy shows old tubercle bacilli walled off in the lung. (Reproduced with permission from Ryan KJ, et al. Sherris Medical Microbiology, 5th ed., New York: McGraw-Hill; 2010.)
Isoniazid increases urinary loss of pyridoxine (vitamin B6).
Move the clock forward to get the results of LFTs and see if there is a change in them by the use of TB medication.
TB medications are eliminated by hepatic p450 systems.
The patient must remain on isolation until repeat acid-fast stains of sputum show that the TB has been cleared from the smear and the patient is not dangerous to others.
Results: baseline LFTs are normal.
What test will tell first if the acid-fast bacilli are the organism Mycobacterium tuberculosis or another species in the genus Mycobacteriaceae?
a. Culture
b. Polymerase chain reaction (PCR)
c. Response to therapy
d. No way to tell
Answer b. Polymerase chain reaction (PCR)
PCR takes infinitesimally small amounts of genetic material from an organism and multiplies it in order to detect the speciation of the organism before the cultures grow. Mycobacterial culture can take 4 to 6 weeks to grow. The PCR can speciate the organism in a day.
There is no difference in the appearance of mycobacteria on a smear.
The patient remains in the hospital on respiratory isolation. Respiratory isolation can be very lonely and depressing. Staff do not visit you as often, and when they do, it is briefer and there is much less discussion.
After 7 days in the hospital, you repeat the sputum smear because the patient states “I can’t stand it in isolation. I have to get out of here as soon as possible.”
Report:
The repeat acid-fast bacillus (AFB) stain at 7 days is positive.
What test can be done to prove whether the mycobacteria on the stain are alive or dead?
a. Nothing can be done.
b. Use a PCR assay.
c. Wait for the results of the culture.
d. Do interferon provocation testing.
Answer c. Wait for the results of the culture.
You cannot do anything right away to tell if the AFB are alive or dead. PCR will tell the species, but cannot tell if they are viable AFB that can spread disease, or just dead, old AFB.
After 10 days in isolation, the patient says that he is walking out of the hospital: “You can’t stop me!”
What can you do to control this potential TB transmission problem?
a. Arrest him and put him in prison.
b. Place a guard at the door to enforce isolation.
c. Consult the ethics committee.
d. You can do nothing; he is an adult who is free to go.
Answer b. Place a guard at the door to enforce isolation.
He does not have the right to leave the hospital as long as he has AFB in his sputum that may be viable. As long as a patient can transmit TB, you have the right to incarcerate him in the hospital. Because you are not a police officer, you do not have the right to arrest or imprison him. There is no point in consulting an ethics committee for a clear, straightforward problem. It does not matter what they say. It is not an ethics problem. It is an infection control problem.
Active TB in Sputum = Mandatory Respiratory Isolation
From whom you mainly isolating the patient?
a. General unexposed public
b. Household contacts
c. Friends and family
Answer a. General unexposed public
Interestingly, the family is not the biggest concern. They have already been exposed. You are isolating the patient from other patients and the general public who has never been exposed to TB. The patient is already on TB medications and is much less infectious now than he was before he came to the hospital. You are isolating him from new contacts.
After another week, the repeat AFB stain is negative, and the patient is released from the hospital. He will get all four TB drugs for the first 2 months, then continue isoniazid and rifampin alone for another 4 months.
Pulmonary TB
• Total therapy: 6 months
Bone, Central Nervous System (CNS), Miliary, or Pregnant Patient
• Total therapy: 9 months
Toxicity
• Pyrazinamide: hyperuricemia
• Rifampin: red secretions, body fluids
• Ethambutol: optic neuritis, color vision problems
When the final “Case will end in 5 minutes of real time” screen pops up, do not forget to order TB screening for the patient’s contacts. Either the PPD skin test or the in vitro interferon gamma release assay is used. Both tests indicate the need for 9 months of treatment with isoniazid and vitamin B6 to prevent possible reactivation of TB in those previously exposed.