Category Archives: Infectious Diseases
The daily educational pearl – Schistosomiasis
Schistosomiasis aka bilharziasis, snail fever
– caused by blood flukes of genum Schistosoma – 2 big groups, one that causes gastrointestinal disease and one that causes urogenital disease
The daily educational pearl – Jones criteria rheumatic fever
The diagnosis of rheumatic fever can be made when 2 major criteria, or 1 major criterion plus 2 minor criteria, are present as well as evidence of previous streptococcal infection. The are known as revised Jones criteria.
The daily educational pearl – Vincent’s Angina
Vincent’s angina or acute necrotizing ulcerative gingivitis (trench mouth)
= ulceration and necrosis of interdental papillae and gingivae
– usually caused by anaerobic organisms in patients who are immunosuppressed or have very poor oral hygiene
– can spread to involve the cheeks / lips / facial bones
DDx: herpes gingivostomatitis (usually interdental papillae not involved, more systemic symptoms)
Treatment:
– antibiotics – metronidazole, initially iv and then po
– chlorhexidine mouth rinses twice a day
– often need debridement
– protein-rich diet, fluids; treatment (if possible) of predisposing factors
They should be referred to / admitted under the Maxillo-facial team.
The daily educational pearl – retropharyngeal abscess
Retropharyngeal abscess
Common in children younger than 4 years of age because the retropharyngeal space contains lymph nodes that atrophy after the age of 6, but there is an increasing incidence in adults (different pathophysiology – initial cellulitis of the retropharyngeal space spreads rapidly to form an abscess).
Causes:
pharyngitis / otitis media / parotitis / tonsillitis / Ludwig’s angina
dental infections / dental procedures
extension from vertebral osteomyelitis / discitis
upper airway instrumentation / endoscopy
trauma + foreign bodies (e.g. fish bones)
haematologic spread
Pathogens: usually polymicrobial with a mixture of aerobic bacteria (Beta-hemolytic Streptococcus, Staphylococcus spp., anaerobic bacteria (Bacteroides), Gram-negative bacteria (Haemophillus). Mycobacterium tuberculosis can cause retropharyngeal abscesses as well, but they are “cold” abscesses, that rarely present with fever or systemic features.
Signs / symptoms: fever, drooling, sore throat, dysphagia, odynophagia, neck pain and stiffness, dysphonia (“duck quack” or “cri du canard” voice), stridor, trismus or respiratory distress; tenderness on moving the trachea and larynx sideways (“tracheal rock sign”).
These patients prefer to remain supine (to prevent the oedematous retropharynx from occluding the airway), as opposed to the patients with epiglottitis / severe croup who prefer to sit forward / tripod position.
Complications: airway obstruction, mediastinitis, abscess rupture + aspiration pneumonia, epidural abscess, sepsis, jugular venous thrombosis
Imaging options:
Xray lateral soft tissues neck: prevertebral soft tissue swelling (>1/2 vertebral body width at C2-C4 or > 1 vertebral body width at C6-C7); rarely gas, or air-fluid levels.
CT of the neck with IV contrast or MRI: definite diagnosis + size of abscess + local complications
Treatment: IV antibiotics (same regimen as for peritonsillar abscesses), with or without surgical drainage.
They all need urgent ENT review / management and admission to intensive care unit due to the potential for airway obstruction.
The daily educational pearl – suspected STDs
Management of suspected STDs
Investigations: depend on gender and clinical presentation
Male patients:
– 2 x urethral swabs
– one dry for Chlamydia / gonorrhoea PCR
– one to smear on glass slide, then place in charcoal transport medium for M/C/S
– first pass urine for chlamydia and gonorrhoea PCR
– clotted blood tube for serological tests (syphilis, hepatitis B, HIV serology) (after consent / counselling re: HIV)
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The daily educational pearl – Asymptomatic patient, positive urine culture
Asymptomatic bacteriuria
– screen and treat as acute cystitis in pregnant women because of the risk of developing pyelonephritis and adverse pregnancy outcomes
The daily educational pearl – Urine testing in UTIs
The daily educational pearl – Antibiotic therapy for UTIs
Current therapeutic guidelines for the management of UTIs in adults
First of all, just as a reminder, if you send the urine off for M/C/S for patients who are discharged home, please document under clinical comments in EDIS what antibiotic you prescribed so that we don’t have to recall the notes every time there is a positive urine culture.