Imaging of fulminant infections in diabetic patients
Imaging of fulminant infections in diabetic patients Dr/Ahmed Bahnassy Assistant Professor of RadiologyCollege of Medicine- Qassim University
Diagnostic considerations in fulminant infections in diabetic patients. Low immune state of these patients. Susceptibility to infections ..including fungi, and virulent gram negative organism Extension to surrounding soft tissues and bones . Similarity to malignant diseases . Potential lethal outcome.
Therefore :diagnostic evaluation of an infection in diabetic patient is three folds: 1.To locate the primary site of infection. 2.To study the local extension of this infection. 3.To suggest the causative organism to take into consideration its behavior and its appropriate treatment .
A-Malignant Otitis Externa Severe life threatening infection of external auditory canal and surrounding tissues. Most common organism is Pseudomonas Aeruginosa C/O: unrelenting otalgia,headache.purulent otorrhea unresponsive to topical antibiotics. Location : at bone cartilage junction of EAC.
Extension of infection Inferiorly into soft issues inferior to temporal bone, parotid space and nasopharyngeal masticator space
B-Mucormycosis Mucormycosis is an aggressive, opportunistic infection caused by fungi . In individuals who are immunocompromised, germination and hyphae formation occur, and this allows the organism to invade the patients blood vessels.
D-Orbital infections Orbital infections most often occur secondarily to an underlying paranasal sinusitis; The two paranasal sinuses most often involved in orbital infections are the ethmoid and maxillary sinuses. Spread of infection from the sinuses to the orbit may occur directly through extension via the osseous structures or indirectly through the valveless venous plexus surrounding the orbit and paranasal sinuses .
Subperiosteal abscess Infection from the sinus may extend into and involve the subperiosteum, intraconal and extraconal spaces, and the globe. A subperiosteal abscess (SPA) results from the development of purulent material between the orbital bones and periorbita.
A-Aspergillosis Pulmonary aspergillosis is a spectrum of mycotic diseases caused by Aspergillus species, usually Aspergillus fumigatus. This intensely antigenic and ubiquitous soil fungus is commonly found in the sputum of healthy individuals. However, in susceptible hosts, its ability to invade the arteries and veins facilitates its hematogenous spread.
Forms Pulmonary aspergillosis may take any of 4 forms: Allergic bronchopulmonary aspergillosis (ABPA) is caused by a hypersensitivity reaction to the fungus . Saprophytic aspergillosis, or aspergilloma, is the most common form. This form is noninvasive and involves colonization of preexisting cavities. Chronic necrotizing aspergillosis, also called semi- invasive aspergillosis, is a chronic cavitary pneumonic illness that often affect patients with preexisting chronic lung disease. Angioinvasive aspergillosis which is often fatal.
Aspegillosis :Invasive Aspergillosis -Halo Sign Patchy consolidations with surrounding area of ground glass opacity describes the halo sign in Angio-invasive form of aspergillosis
Angio -invasive Aspergillosis with air crescent sign.
Semi-Invasive Aspegillosis Mild immunocompro mise Consolidation , cavitation ,Pleural thickening ,+/- mass within the cavity )
A-Emphysematous cholecystitis Ischaemia +infection with gas producing organisms. Organism:Clostridium Welchii,Ecoli. 1/3 show normal WBC. Point tenderness is rare due to diabetic neuropathy 15% mortality
B-Emphysematous Pyelonephritis Emphysematous pyelonephritis (EPN) is a life-threatening, fulminant, necrotizing upper urinary tract infection associated with gas within the kidney and/or perinephric space. organisms : E. coli (68%), Klebsiella pneumoniae (9%), and Proteus mirabilis.
C-Emphysematous cystitis UT infection by gas forming organism almost pathognomonic of poorly controlled diabetes . Organism: E.coli,E.aerogenes. CT is the most sensitive examination.
D-Xanthogranulomatous Pyelonephritis Xanthogranulomatous pyelonephritis (XGPN) represents an unusual suppurative granulomatous reaction to chronic infection, often in the presence of chronic obstruction . Two forms of XGPN are described, namely, a diffuse or global form (83-90% of patients) and a focal form (10-17%).
E-Fournier Gangrene a polymicrobial necrotizing fasciitis of the perineal, perirectal or genital area . 500 reported cases in literature .
Radiological diagnosis Radiographs can show the presence of soft tissue gas in patients suspected of having necrotizing fasciitis. Sonographic evaluation of the scrotum, scrotal contents, and surrounding structures shows a thickened and oedematous scrotal wall, gas within the scrotal wall, and unilateral or bilateral peritesticular fluid. Subcutaneous gas within the scrotal wall is the sonographic hallmark.
Radiological findings Air loculi seen as highly reflecting ring shadows. Note gas lucencies in scrotal subcutaneous tissue
Conclusion Infections in diabetic patients have many specific considerations in their diagnosis. Their extensions increase the seriousness of the condition . The potential lethal outcome of these cases must prompt a rapid and accurate diagnosis .
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