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Potentially life-threatening emergency
Bacterial sepsis in Adult
See also in: Cellulitis DDx
Other Resources UpToDate PubMed
Potentially life-threatening emergency

Bacterial sepsis in Adult

See also in: Cellulitis DDx
Contributors: Sylvia Yeh MD, Art Papier MD, Noah Craft MD, PhD
Other Resources UpToDate PubMed


This summary discusses bacterial sepsis in adults and children. Bacterial sepsis in neonates is addressed separately.

Broadly defined, sepsis refers to the clinical situation in which there is evidence of bacteremia with associated systemic response: fever, tachycardia, increased respiration, and hypotension. At the far end of the sepsis spectrum, there is septic shock with inability to respond to fluid administration, advanced organ compromise, and changes in mental status. The common findings in sepsis include chills, rigors, fever, tachypnea, hypotension, skin lesions, and shock. Both gram-negative and gram-positive organisms can cause septic shock, as can systemic fungal and parasitic infection. Factors predisposing to poor outcome include diabetes, renal failure, alcohol use disorder, neutropenia, and advanced age. Individual infectious organisms have variations in the clinical presentation, and gram-positive organisms commonly can lead to toxic shock syndrome (TSS), described below.

Staphylococcal TSS – Staphylococcal TSS is caused by Staphylococcus aureus strains that can produce the toxic shock syndrome toxin-1 (TSST-1) and more commonly has the typical erythrodermic skin findings as compared to streptococcal TSS.

Streptococcal TSS – Streptococcal TSS is also caused by exotoxins that cause massive stimulation of T-cells via a superantigen mechanism. Clinically, the most common presenting symptom is severe pain in an extremity with or without underlying soft tissue infection. A prodrome of fever, diarrhea, and myalgias is often seen. The macular exanthem seen in staphylococcal TSS is much less commonly found in streptococcal TSS. Approximately 48-72 hours after the initial onset, shock and multiorgan failure follow. In this form of TSS, risk factors include varicella infection, bites, and lacerations.

Meningococcal disease – Meningococcal disease is a rapidly progressive infection caused by Neisseria meningitides, a gram-negative diplococcus bacterium. Symptoms may begin with a nonspecific viral-like illness that rapidly evolves (within hours) into one of two main presentations: meningitis or septicemia. Most cases are acquired through exposure to asymptomatic carriers via respiratory droplets. Children aged younger than 5 years and teenagers aged 15-19 are predominantly affected.

Sepsis with other bacteria may cause skin lesions in the immunocompromised host. 
  • Pseudomonas aeruginosa sepsis will occasionally present with skin lesions called ecthyma gangrenosum.
  • Listeria monocytogenes infection is well documented in HIV-infected and renal transplant patients and neonates. In these patients, pneumonia and meningitis dominate the picture, but purpuric skin lesions may occur. 
  • Patients with complement deficiencies (late phase components C5-C9) or alcohol use disorder are susceptible to N meningitidis
  • Capnocytophaga canimorsus is a commensal in the saliva of dogs and cats.
Note: Many of the individual bacterial and fungal causes of sepsis are covered as separate diagnostic concepts in VisualDx. See also gonococcemia, Candida sepsis, Trichosporon beigelii sepsis, and septicemic plague.


A41.9 – Sepsis, unspecified organism

10001005 – Bacterial sepsis

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

  • Acute meningococcemia
  • Necrotizing fasciitis
  • Toxic shock syndrome
  • Disseminated candidiasis
  • Aspergillosis
  • Pseudomonas sepsis (Ecthyma gangrenosum)
  • Subacute bacterial endocarditis usually does not have as many skin lesions.
  • Purpura fulminans
  • Leukocytoclastic vasculitis
  • Septic Vasculitis
  • Endemic typhus
  • Rocky Mountain spotted fever (RMSF) lesions appear first distally on the extremities, including the wrists, ankles, palms, and soles; exposure to RMSF usually occurs in an endemic region.
  • Thrombotic thrombocytopenic purpura
  • Enteroviral infections (Echovirus infection and Adenovirus infection)
  • Leptospirosis
  • Erythema multiforme
  • Disseminated gonorrhea
  • Cocaine levamisole toxicity
Other causes of bacterial sepsis:
  • Enteric fever
  • Q fever
  • Epidemic typhus
  • Fulminant hepatic necrosis
  • Hemorrhagic fever with renal syndrome
  • Shigellosis
  • Hemolytic uremic syndrome

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Drug Reaction Data

Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.

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Last Updated:07/08/2020
Copyright © 2024 VisualDx®. All rights reserved.
Potentially life-threatening emergency
Bacterial sepsis in Adult
See also in: Cellulitis DDx
A medical illustration showing key findings of Bacterial sepsis (Early) : Altered mental state, Chills, Fever, Cyanosis, Mottled configuration, Pain out of proportion to exam findings, Respiratory alkalosis, Ecchymosis, HR increased, RR increased, WBC elevated
Clinical image of Bacterial sepsis - imageId=276067. Click to open in gallery.  caption: 'A close-up of a hemorrhagic vesicle and surrounding pink erythema.'
A close-up of a hemorrhagic vesicle and surrounding pink erythema.
Copyright © 2024 VisualDx®. All rights reserved.