Procalcitonin, intracellular precursor of calcitonin was first discovered in 1975 in chicken ultimo-branchial glands and later in human medullary thyroid Ca in 1981. In healthy individuals, PCT is broken down intracellularly and no PCT enters the circulation (1/n)
Bacterial LPS & inflammatory cytokines lead to PCT production from pituitary, neuroendocrine cells in the lungs, intestine, splanchnic area, liver, hypothalamus. (Even thyroidectomized patients had raised PCT in sepsis) Role of PCT in response to infection remains unknown (2/n)
⬆️Elevated 2-12 hrs after bacterial infection
⏳t1/2 of 24-30 hrs
⏳t1/2 of 24-30 hrs
Other causes of ⬆️ PCT
1. Medullary thyroid Ca or islet cell tumor (very high >10,000), SCLC lung
2. ESRD especially if on irregular HD
(presence of kidney injury should not preclude the use of PCT, use higher threshold & monitor trend)
3.tissue injury/physiological stress(4/n)
1. Medullary thyroid Ca or islet cell tumor (very high >10,000), SCLC lung
2. ESRD especially if on irregular HD
(presence of kidney injury should not preclude the use of PCT, use higher threshold & monitor trend)
3.tissue injury/physiological stress(4/n)
Falsely low PCT in localised infections like
⚪cellulitis
⚪appendicitis
⚪abscess
⚪empyema
(5/n)
⚪cellulitis
⚪appendicitis
⚪abscess
⚪empyema
(5/n)
MOSES study (Philipp Schuetz et al. Crit Care Med. 2017 May)
➡️ Independent predictor of mortality in sepsis
➡️Lack of reduction of PCT by 80% or increase in PCT denotes treatment failure
(6/n)
➡️ Independent predictor of mortality in sepsis
➡️Lack of reduction of PCT by 80% or increase in PCT denotes treatment failure
(6/n)
Use :
➡️to guide antibiotic discontinuation in sepsis/CAP
➡️Reduce antibiotic exposure
➡️Independent predictor of mortality (Moses study)
Not to be used to:
🔴Determine antibiotic initiation in sepsis/severe COPD exacerbations requiring ICU care
🔴Undifferentiated dyspnea
(7/n)
➡️to guide antibiotic discontinuation in sepsis/CAP
➡️Reduce antibiotic exposure
➡️Independent predictor of mortality (Moses study)
Not to be used to:
🔴Determine antibiotic initiation in sepsis/severe COPD exacerbations requiring ICU care
🔴Undifferentiated dyspnea
(7/n)
ProACT study (Huang DT et al, Procalcitonin-Guided Antibiotic Use. N Engl J Med. 2018)
🔻Failed to show a benefit in terms of ❗mortality or ❗antibiotic exposure for patients with suspected LRTI when PCT was used to guide antibiotic initiation. (8/n)
🔻Failed to show a benefit in terms of ❗mortality or ❗antibiotic exposure for patients with suspected LRTI when PCT was used to guide antibiotic initiation. (8/n)
CRP vs PCT
▶️CRP can't differntiate infective from non-infective causes of inflammation
▶️slow variation of CRP levels - delay in decision making
➡️ PCT has higher sensitivity and specificity in autoimmune & malignant diseases
🚩 Always use PCT with clinical correlation
(9/n)
▶️CRP can't differntiate infective from non-infective causes of inflammation
▶️slow variation of CRP levels - delay in decision making
➡️ PCT has higher sensitivity and specificity in autoimmune & malignant diseases
🚩 Always use PCT with clinical correlation
(9/n)
References :
#B58" target="_blank" rel="noopener" onclick="event.stopPropagation()">medsci.org
pulmcast.com
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pulmcast.com
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