Pregnancy

TORCH infections

•    Toxoplasma gondii:

o    From undercooked meat or cat faeces

o    Triad in neonate: chorioretinitis, hydrocephalus, intracranial calcifications

•    Others:

o    Syphilis: snuffles, saber shins, Hutchinson teeth

o    Varicella-zoster virus: limb hypoplasia, skin scarring

o    Parvovirus B19: hydrops fetalis (severe fetal anaemia)

•    Rubella:

o    Sensorineural deafness, cataracts, PDA

•    Cytomegalovirus (CMV):

o    Most common congenital infection

o    Periventricular calcifications, microcephaly

•    Herpes simplex virus (HSV):

o    Perinatal transmission → neonatal encephalitis, disseminated disease

Vaccination and screening

•    Avoid live vaccines (e.g., MMR, varicella, yellow fever) during pregnancy

•    Check rubella and VZV immunity pre-conception

•    Influenza and pertussis vaccines recommended during pregnancy

Alcoholism

Infections

•    Aspiration pneumonia:

o    Common organisms: anaerobes (e.g., Fusobacterium, Prevotella), oral streptococci

•    Klebsiella pneumoniae:

o    Classic “currant jelly” sputum

o    Associated with lung abscess and cavitation

•    Tuberculosis:

o    Higher risk due to immunosuppression, malnutrition

•    Listeria monocytogenes:

o    More frequent in alcohol-dependent patients

Other considerations

•    Malnutrition → impaired cell-mediated immunity

•    Thiamine deficiency (Wernicke’s risk) in sepsis settings

Splenectomy

Infection risk

•    High risk of overwhelming post-splenectomy infection (OPSI):

o    Rapidly fatal septic shock, especially from encapsulated organisms

•    Classic organisms: SHiN:

o    S. pneumoniae (most common cause of sepsis post-splenectomy)

o    H. influenzae type b

o    N. meningitidis

Prevention

•    Vaccination (ideally 2 weeks pre-splenectomy if elective):

o    Pneumococcal (both PCV13 and PPV23)

o    Meningococcal ACWY and B

o    Hib

•    Antibiotic prophylaxis:

o    Long-term penicillin V (especially in children)

•    Education:

o    Seek immediate medical help and start antibiotics at first sign of fever

Sickle Cell Disease

Infections

•    Salmonella osteomyelitis:

o    Classic association; S. aureus also remains common

•    Pneumococcal sepsis:

o    Functional asplenia from repeated splenic infarctions → reduced opsonisation of encapsulated bacteria

•    Other infections:

o    Parvovirus B19 → aplastic crisis

Prevention

•    Early pneumococcal and meningococcal vaccinations

•    Prophylactic penicillin in children

HIV/AIDS

CD4 thresholds and infections

•    CD4 <200 cells/mm³:

o    Pneumocystis jirovecii pneumonia (PCP): dry cough, hypoxia, ↑LDH

o    Oral and esophageal candidiasis

•    CD4 <100 cells/mm³:

o    Toxoplasma gondii encephalitis: ring-enhancing brain lesions

o    Cryptococcus neoformans meningitis: subacute onset, raised opening pressure

•    CD4 <50 cells/mm³:

o    CMV retinitis: "pizza pie" retinal appearance, vision loss

o    Mycobacterium avium complex (MAC): fever, diarrhoea, wasting

Prophylaxis

•    Co-trimoxazole: PCP and toxoplasmosis (CD4 <200)

•    Azithromycin or clarithromycin: MAC (CD4 <50)

Solid Organ Transplant / Neutropenia

Common pathogens

•    CMV:

o    Colitis, pneumonitis, retinitis

•    HSV, VZV:

o    Mucocutaneous lesions, disseminated disease

•    Fungal infections:

o    Candida (oropharyngeal, bloodstream)

o    Aspergillus (lung, sinus)

Neutropenic fever

•    Definition: single temp ≥38.3°C or sustained ≥38°C for >1 hour with neutrophils <0.5 × 10⁹/L

•    Emergency: start broad-spectrum empirical antibiotics immediately (e.g., piperacillin-tazobactam)

•    Consider adding antifungal if persistent after 4–7 days

Extra Revision Pearls

•    Listeria monocytogenes: avoid unpasteurised cheese in pregnancy and alcoholics

•    Parvovirus B19 in sickle cell: sudden severe anaemia + reticulocytopenia

•    Splenectomy patients: wear a medical alert bracelet or carry a card