Infectious diseases Flashcards
Brucellosis (aka Malta fever)
Epidemiology:
- Zoonosis caused by gram- coccobacilli
- Spread by untreated milk and raw beef
- Farm workers
Features:
- Fever
- Malaise
- Arthralgia/arthritis
- Depression
- Hepatosplenomegaly
- Spondylitis, sacro-ilitis
Investigations:
- Bloods - leucopenia
- Prolonged blood culture (6/52)
- Serology - brucella agglutination test
Management:
- 6 week course of doxycycline+ rifampicin + gentamicin/cotrimoxazole
Whipple’s disease
Multisystem infection which impairs fat metabolism and absorption
- Predominantly GI symptoms
Epidemiology:
- Caused by Tropheryma whipplei
- Gram+ bacilli
- M > F
- HLA-B27
Features:
- Weight loss + fever
- Diarrhoea
- Bloating
- Abdominal pain
- Arthritis (seronegative) - migratory, non-deforming, episodic
- Neurological involvement
Investigations:
- Bloods
- Coagulopathy
- Low albumin
- Raised ESR
- Duodenal biopsy
- PAS-positive foamy macrophages in the
lamina propria
- Positive PCR
Management:
- Long-term antibiotics - co-trimoxazole
- IV therapy if evidence of CNS involvement
Complications:
- Steatorrhoea
- Lymphadenopathy
- Protein-losing enteropathy -> ascites, enteropathy
- Neurological involvement
- oculomasticatory myorhythmia
- dementia
- IRIS
- symptom relapse in first few weeks,
managed with steroids
Paragonimiasis
Infection by Paragonimus westermani
- Trematode fluke
- Ingestion of metacercaria from infected
crustaceans
- Risk of self-reinfection
- Preferentially lives in the lungs
Features:
- Acute
- Abdominal pain
- Cough
- Low-grade fever
- Chronic
- Granulomatous, cavitating lung lesions
- Haemoptysis
- Weight loss
- Small risk of CNS disease
Investigations:
- FBC - eosinophilia
- Sputum microscopy for eggs
Management:
- Praziquantel TDS for 2 days
Sporotrichosis
Infection by Sporothrix schenckii
- Fungus
- Lives in soil and plant matter
Typically cutaneous infection with 10 weeks incubation period
- Reddish, non-tender maculopapular lesion
- Nodules then spread along lymphatics
- Eventual breakdown into ulcers
Investigations:
- Skin biopsy
- culture samples on Sabourad dextrose agar
Treatment:
- 1st line - PO itraconazole
- If severe or immunosuppressed, IV amphotericin B
Actinomycosis
Infection by Achtinomycosis israeli and other spp.
- Gram+ filamentous anaerobe
- Colonises human oropharynx, GI, GU tracts
- Causes chronic granulomatous disease
Cervicofacial:
- Most common manifestation
- Follows dental procedures or laceration of the oropharynx
- Initially either acute cellulitis/abscess or slowly growing hard, painless, red swelling.
- Investigation:
- Microscopy - sulfur granules
- Management:
- Acute - surgical lancing
- Chronic - at least 6 months amoxicillin
- Complications
- Spread to neck or meninges
CNS tuberculosis manifestations
Tuberculous meningitis
Intracranial tuberculoma
Intracranial vasculitis
Spinal tuberculous arachnoiditis
Cryptosporidiosis
Cryptosporidium parvum is an IC protozoa
- Ingested by humans
- Oocytes excreted in faeces, resistant to many
disinfectants and highly infectious
- Faeco-oral transmission via contaminated
water
- Infection seen in AIDS, children, dairy farmers
Features:
- Diarrhoea
- 7-10 days
- Watery
- Progresses to chronic diarrhoea in AIDS
patients
- Crampy abdo pain
- Low-grade fever
- Anorexia
- Dysphagia
- Biliary tract disease
- Bile malabsorption
Investigations:
- Stool
- Modified Ziehl-Neelson staining - acid-fast
cysts
- DFA testing - gold-standard
- PCR
Management:
- If AIDS, HAART
- Otherwise, supportive care + nitazoxanide or azithromycin for 7 days
Epstein-Barr Virus (EBV)
Part of the human herpesviruses
- Transmitted via bodily secretions
- Mainly affects 15-25 yrs
Features:
- Infectious mononucleosis:
- Fever
- Pharyngitis
- Lymphadenopathy incl. tonsillar enlargement
- Splenomegaly
- Maculopapular rash
- Jaundice
Investigations:
- Bloods:
- Lymphocytosis with atypical lymphocytes
- Serology:
- 1st line - Heterophile antibodies (monospot)
- 2nd line - EBV-specific antibodies
Management:
- Supportive
- Consider systemic steroids if airway obstruction, severe thrombocytopenia, haemolytic anaemia.
Complications:
- Haemolytic anaemia
- Splenic rupture
- Airway obstruction
- Pruritic drug reaction to penicillins
- Malignancy
- Associated with Burkitt’s lymphoma,
nasopharyngeal carcinoma etc.
Diffuse infiltrative lymphocytic syndrome
A rare complication of unmanaged HIV
- CD8+ lymphocytosis with visceral infiltration by CD8+ lymphocytes
- No positive autoantibodies
- Most commonly affects lungs
Features:
- Sicca symptoms
- Bilateral parotid enlargement
- Lymphadenopathy
- Lymphocytic interstitial pneumonia
- Neuropathies - [VII], aseptic meningitis etc.
Leishmaniasis
The syndromes of illness caused by unicellular kinetoplastids, Leishmania
- Transmitted by sandflies
- Promastigotes for XC, amastigotes for IC
- Disseminates in macrophages
Cutaneous:
- South India + South America
- Features:
- Ulcerated plaques
- Investigations:
- Skin biopsy
- Management:
- Sodium stibogluconate
Mucocutaneous:
- Typically at the mucocuntaneous junction of the nose
- Often has bacterial superinfection
- Investigations:
- Biospy
- Management:
- Sodium stibogluconate
Visceral:
- India (Bihar), Bangladesh, NE Africa, Brazil
- Incubation period 10 days - several years
- Features:
- Hepatomegaly
- Splenomegaly
- Fever
- Weight loss
- Anaemia
- Investigation:
- Biopsy of liver/spleen/lymph nodes
- Management:
- Liposomal amphotericin B
