Abdominal Abcess


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Abdominal Abcess

  1. 1. Differential diagnosis of brain abscess •Epidural and subdural empyema •Septic dural sinus thrombosis •Mycotic cerebral aneurysms •Septic cerebral emboli with associated infarction •Acute focal necrotizing encephalitis (most commonly due to herpes simplex virus) •Metastatic or primary brain tumors •Pyogenic meningitis
  2. 2. Dental infection Frontal or ethmoid sinuses Brain Direct abscess spread otitis media and mastoiditis Post neurosurgery Bullet wounds
  3. 3. Chronic pulmonary infections Skin infections Pelvic infection Brain Hematogenous Intraabdominal abscess spread infection Esophageal dilation and endoscopic sclerosis of esophageal varices Bacterial Cyanotic endocarditis congenital heart diseases
  4. 4. Microbiologic pathogens in brain abscesses, according to major primary source of infection Source of infection Pathogens Streptococcus (especially Streptococcus Paranasal sinuses milleri), haemophilus, bacteroides, fusobacterium Streptococcus, bacteroides, prevotella, Odontogenic sources fusobacterium, haemophilus Enterobacteriaceae, streptococcus, Otogenic sources pseudomonas, bacteroides Streptococcus, fusobacterium, Lungs actinomyces Urinary tract Pseudomonas, enterobacter Staphylococcus aureus, enterobacter, Penetrating head trauma clostridium Staphylococcus, streptococcus, Neurosurgical procedure pseudomonas, enterobacter Endocarditis Viridans streptococcus, S. aureus Congenital cardiac malformations Streptococcus (especially right-to-left shunts)
  5. 5. Viridans streptococci Streptococcus milleri Streptococcus pneumoniae Gram-positive cocci Staphylococcus aureus Aerobic Gram-negative Escherichia coli, rods Pseudomonas spp, Klebsiella pneumoniae, Proteus spp
  6. 6. The most frequent anaerobes cultured from a brain abscess •anaerobic streptococci. • Bacteroides spp (including B. fragilis). •Prevotella melaninogenica. • Propionibacterium. •Fusobacterium. • Eubacterium. • Veillonella. •Actinomyces
  7. 7. Immunocompromised hosts •Toxoplasma gondii •Listeria •Nocardia asteroides •Aspergillums' •Cryptococcus neoformans. •Coccidioides immitis. • Mucormycosis
  8. 8. CT-Scan Early cerebritis appears as an irregular area of low density that does not enhance following contrast injection. the lesion enlarges with thick and diffuse ring enhancement following contrast injection thin ring which may not be uniform in thickness
  9. 9. MRI •more sensitive for early cerebritis •more sensitive for detecting satellite lesions •More accurately •estimates the extent of central necrosis •ring enhancement, •cerebral edema •Better visualizes the brainstem
  10. 10. LP a lumbar puncture (LP) is contraindicated Decompression of the cerebrospinal fluid (CSF) pressure associated with brain stem herniation in 1.5 to 30 percent of cases
  11. 11. Culture and biopsy •Gram's stain • aerobic • anaerobic • mycobacterial •fungal culture
  12. 12. Antibiotics •Penicillin G covers most mouth flora including both aerobic and anaerobic streptococci. •Metronidazole readily penetrates brain abscesses, Given the excellent intralesional concentrations and the high probability of anaerobes. •Ceftriaxone covers most aerobic and microaerophilic streptococci also covers many Enterobacteriaceae •Ceftazidime should be used when brain abscess complicates a neurosurgical procedure or in cases where the abscess culture grows P. aeruginosa. •Vancomycin should be included when brain abscess follows penetrating head trauma or craniotomy or when S. aureus bacteremia is documented
  13. 13. Aspiration •preferred for speech areas and regions of the sensory or motor cortex and in comatose patients. •Not preferred for: •Early cerebritis without evidence of cerebral necrosis. •Abscesses located in vital regions of the brain or those inaccessible to aspiration
  14. 14. Surgery •indications for excision after initial aspiration and drainage: •Traumatic brain abscesses (to remove bone chips and foreign material) •Encapsulated fungal brain abscesses •Multiloculated abscesses