Travel historyFood poisoning organisms - Salmonella
- Shigella
- Campylobacter
Parasites - Investigations
- Haemolysis
- Very high bilirubin
- Low Hb
- May have slightly raised ALT, but not enough to explain the bilirubin
- Thrombocytopaenia
- Low glucose
- DIC
- Acidosis
- Parasites are transient and correlate with fever
- Do the blood film at the appropriate time
- Do three before deciding it's negative
HIV - Common infections are CD4-dependent ones
- Viruses
- Protozoa
- Fungi
- Mycobacteria
- Some bacteria too
- Parameters
- CD4 => Disease stage
- >200 => Only high-grade infections
- <200 => Low-grade infections
- <100 => Very low grade infections
- Viral load => Speed of progression
- Acute seroconversion
- Treatment is not helpful
- Extremely infectious
- TB
- CD4 <200 => Probably reactivation
- Consolidation with cavitation
- Air bronchograms
- CD4 <100 => Probably primary
- Adenopathy
- Loss of paratracheal stripe
- Low zone
- No cavitation
Low-grade infections in HIV - PCP
- CXR often normal early on
- Fine reticular (ground-glass) appearance later on
- Thin-walled cysts
- Predispose to pneumothoraces
- Alveolar exudate
- Candida
- Oral candida can invade oesophagus
- Cryptosporidium
- Colitis - "Dilated, featureless bowel)
- Thickened bowel wall (check opposed bowel loops)
- Thumb printing
- Loss of haustra
- Remember to check for HIV before you diagnose IBD, as they can look similar
- CMV retinitis
- Reactivation of latent herpesvirus
- Prevalence approx. equal to age in the healthy population
- Haemorrhagic retinitis
- Crytococcal meningitis
- May not see any white cells in CSF, despite bacteria due to immunosuppression (sinister sign)
- Check India Ink stain or CrAg in blood/CSF
- Toxoplasma
- Ring-enhancing lesions on MRI
- Similar to bacterial pyogenic abscess
- Distinguish by clinical presentation
- Especially in unusual places
- Primary cerebral lymphoma
- Looks very similar to toxoplasma
- Treat as if toxoplasma and see if it changes
- TB meningitis
- Tends to affect the basal system rather than peripheral structures
- Basal cisterns etc
- => Cranial nerves often involved
- Chronic/insidious onset
- Progressive multifocal leucoencephalopathy (PML)
- White matter lesions - Look a bit like MS
- Malignancy
- Karposi sarcoma
- Viral leukaemia
Notes - Information website - nathnac.org
- Typhoid test is a blood culture, not stool
- Cutoff for CD4-dependent infection = 200
- Lobar pneumonias are often pneumococcal
- Aspiration pneumonia usually goes to the right middle lobe
- First seizure in an adult = SOL UPO
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