Infectious Diseases Flashcards
Describe malaria, it’s features, investigations, and treatment.
Malaria can be grouped into non-falciparum and falciparum as the the later is a species which causes a more severe disease.
Features: commonly a relapsing fever, chills, rigors, anaemia, hepatosplenomegaly, jaundice, headache, myalgia
Tests:
- serial thin and thick blood films
- FBC, U+E, LFTs, Glucose G6PD activity for prognostic factors
Treatment:
- uncomplicated non-falciparum malaria - chloroquine (quinine if resistant) and primaquine for liver stage (not needed in p.malariae also screen for G6PD defiency as can induce haemolysis)
- uncomplicated falciparum malaria - combination therapy preferably using artemisinin derivatives oral if able
- severe falciparum malaria - IV antimalarials as above and ITU involvement
Describe the malaria life cycle
Humans acquire malaria after being bitten by an infected female Anopheles mosquito. The sporozoites in the saliva of the mosquito enter the host and travel via the bloodstream to the liver where they mature (or in some species remain dormant where they are known as hypnozoites e.g Ovale & Vivax. The mature sporozoites then erupt releasing merozoites in to the bloodstream when they invade RBCs and undergo asexual reproduction. Mosquitoes ingest these and the organism undergoes sexual reproduction to produce thousands of sporozoites which then migrate to the salivary gland repeating the cycle.
What is the CURB-65 score?
CURB-65 is a score used to assess severity of pneumonia score 1 point for each:
C onfusion (abbreviated mental test 8 or less)
U rea greater than 7mmol/L
R espiratory Rate 30/min or more
B lood pressure less than 90mmHg systolic and/or 60mmHg diastolic
65 or greater age.
Score:
0-1 home management possible
2 indicates hospital therapy
3 or more indicates severe pneumonia with mortality 15-40% consider ITU.
Describe pneumonia, its common causes, clinical features, diagnostic tests and management.
An acute lower respiratory tract illness associated with consolidation on chest x-ray.
Community acquired pneumonia (CAP) most commonly caused by Streptococcus Pneumoniae followed by Haemophilus Influenzae, and Mycoplasma Pneumoniae. Hospital acquired pneumonias tend to be gram-negative enterobacteria or Staphylococcus Aureus.
Clinical features: Fevers, rigors, malaise, anorexia, dyspnoea, cough, purulent sputum, haemoptysis, and pleuritic pain. Signs: pyrexia, cyanosis, confusion, tachycardia, hypotension.
Tests: CXR, O2sats, Bloods (FBC, U+E, LFT, CRP, blood cultures), sputum culture.
Management: Antibiotics, orally if not severe or vomiting. severe needs IV. Oxygen to maintain sats at 94-98% and IV fluids as necessary. VTE prophylaxis. Consider ITU if shock, hypercapnia, or uncorrected hypoxia.
Describe Pneumococcal Pneumonia and its treatment
It is the commonest bacterial pneumonia. It affects all ages, but is commoner in the elderly, alcoholics, post-splenectomy, immuno-suppressed, and patients with chronic heart failure or pre-existing lung disease.
Treatment: Amoxicillin, Benzylpenicillin or Cephalosporin
Describe Staphylococcal Pneumonia, it’s features, and treatment
It may complicate influenza infection or occur in the young, elderly, IVDUs, or patients with underlying disease e.g. leukaemia, lymphoma, cystic fibrosis.
Features: it causes a bilateral cavitating bronchopneumonia.
Treatment: flucloaxacillin +/- rifampicin, MRSA (vancomycin).
Describe Klebsiella Pneumonia, it’s features, and treatment.
It is rare, it occurs in elderly, diabetics and alcoholics.
Features: Causes a cavitating pneumonia, particular of the upper lobes, often drug resistant.
Treatment: cefotaxime or imipenem
Describe Pseudomonas Pneumonia
Pseudomonas is a common pathogen in bronchiectasis and Cystic Fibrosis. It is a cause of hospital-acquired infections, particularly on ITU or after surgery.
Describe Mycoplasma pneumonia, it’s features, and treatment
It occurs in epidemics about every 4yrs. It is an atypical pneumonia.
Features: It presents insidiously with flu-like symptoms (headache, myalgia, arthalgia) followed by a dry cough. CXR shows reticular-nodular shadowing or patchy consolidation often of 1 lower lobe.
Treatment: clarithromycin or doxycycline.
Describe legionnaire’s disease, it’s symptoms, investigations, and management
Legionella pneumophilia colonizes water tanks kept at less than 60degreesC (e.g. Hotel air-conditions and hot water systems) causing out breaks of Legionnaire’s disease.
Symptoms: Flu-like symptoms (fever, malaise, myalgia) precede a dry cough and dyspnoea. Extra-pulmonary features include anorexia, D+V, hepatitis, renal failure, confusion and coma.
Investigations:
- CXR shows bi-basal consolidation
- Bloods shows lymphopenia, hyponatraemia, and deranged LFTs.
- Urinalysis may show haematuria
- Diagnosis made by legionella urine antigen/culture
Treatment:
-fluoroquinolone for 2-3wks or clarithromycin
Describe chlamydophila pneumonia, it’s features, and treatment
It is the commonest chlamydial infection, Person to person spread occurs.
Features:a biphasic illness: pharyngitis, hoarseness, otitis, followed by pneumonia.
Treatment: doxycycline or clarithromycin
Describe psittacosis, it’s features, and treatment
Chlamydiophila psittaci causes this ornithosis acquired from infected bird typically parrots.
Features: headache, fever, dry cough, lethargy, arthalgia, anorexia and D+V. CXR shows patchy consolidation.
Treatment: doxycycline or clarithromycin
Describe pneumocystis pneumonia, it’s features, and treatment.
This pneumocystis jiroveci causes this pneumonia in the immunosuppressed e.g. HIV.
Features: It presents with dry cough, exertional dyspnoea, decreased PaO2, bilateral crepitations. CXR may be normal or show bilateral perihilar shadowing. Diagnosed through visualisation of organism in culture.
Treatment:
- high dose co-trimoxazole first line, if not tolerated oral dapsone. If this is not tolerated or inappropriate e.g. patients with g6pd then thirdly line prophylaxis is nebulised pentamidine
- A role for methylprednisolone in severe cases i.e. pO2 less than 9.3
Describe Tuberculosis, its risk factors, symptoms, tests and management
TB is a notifiable disease, at risk populations often screened via Mantoux test or Interferon gamma testing (t-spot-TB)
Risk factors: poverty, alcohol, tobacco, contact with TB, immunosuppression ( HIV, DM, malignancy, extremes of age) and renal disease
Symptoms: cough, sputum, malaise, weight loss, night sweats, pleurisy, haemoptysis. May disseminate and appear in other systems causing symptoms
Tests: CXR and sputum samples, if disseminated try to get a sample, send for MC&S for Acid Fast Baccili on Ziegler-neelsen stain. Culture can take up to 12 weeks on Lowenstein-Jensen medium, PCR allows for rapid identification if rifampicin (and so likely multi-drug) resistance
Management: before treatment test colour vision (with ishihara charts) and acuity as ethambutol may cause ocular toxicity. 16 weeks on iosoniazid and rifampicin and 8 weeks on ethambutol and pyrazinamide. Monitor LFTs and FBC
What are some causative agents in bacterial meningitis?
Meningococcal (Nisseria meningitidis) Pneumococcal (Strep Pneumoniae) (elderly) Haemphilus influenzae ( very young) Listeria monocytogenes (extremes of age) E.coli + Group B strep (newborns)
Describe necrotising fasciitis and its management
It is a rapidly progressive infection of the deep fascia causing necrosis of subcutaneous tissue. In any atypical cellulitis get early surgical help. There is intense pain. Group A B-haemolytic streptococci is a major cause although infection is often polymicrobial
Management: urgent surgical debridment and IV antibiotics e.g benzylpenicillin and clindamycin
What is fourniers gangrene?
Necrotising fasciitis localised to the scrotum and perineum
Describe infective endocarditis, it’s risk factors, symptoms, tests, and management.
Fever + new murmur is endocarditis until proven otherwise. Follows an acute course and presents with acute heart failure and emboli. Usually due to Staph A or Strep Viridians, more rarely HÁČEK organisms (Haemophilus, Aggregatibacter, Cardibacetirum Hominis, Eikenella Corrodens, Kingella).
Risk Factors: IVDUs, aortic or mitral valve disease, prosthetic valves, VSD, patent ductus arteriosus, coarctation
Symptoms and signs:
- Septic signs: fever, rigors, night sweats, malaise, weight loss, anaemia, splenomegaly and clubbing.
- New murmur (usually regurgitive)
- immune complex deposition may give vasculitic symptoms, microscopic haematuria is common, Roth spots, splinter haemorrhages, janeway lesions, osler nodes
- embolic phenomena e.g abscesses in other organs, in the skin they are termed janeway lesions and together with Osler nodes are pathognomic for IE
Tests:
- blood cultures, bloods (FBC may show normochromic normocytic anaemia, neutrophilia, high ESR/CRP, check U+E, LFT for end-organ damage)
- Urinalysis may show microscopic haematuria
- CXR may show cardiomegaly
- ECG may show long PR interval due to aortic root abcess
- diagnosis made with dukes criteria and requires TOE which may show vegetations
Management:
- vancomycin +/- gentamicin if septic pre-culture
- Benzylpenicillin +/- gentamicin if strepOr flucloxacillin if staph
- echo +/- surgery if valve incompetence
What are Roth spots?
Boat shaped retinal haemorrhage with pale centres caused by microinfarcts e.g from IE, hypertension, HIV, connective tissue disease, anaemia, Behcet’s, viraemia, hypercoagulability
Describe Herpes Simplex virus
HSV is the cause of the common cold sore and genital herpes though it may cause other primary infections.
Dormant HSV in ganglion cells may be reactivated by illness, immunosuppression, menstruation, or sunlight.
Describe chickenpox
Caused by Varicella Zoster virus, it is an contagious febrile illness with crops of blisters at various stages. Usually self-limiting in children complications such as purpura fulminans/DIC, pneumonitis, and ataxia are commoner in pregnancy and adults than in children.
Incubation is 11-21days and patients are infective 4days before the rash until all lesions are scanned over.
After infection, virus is dormant in dorsal root ganglia. Reactivation causes shingles
Describe shingles
Shingles is caused by reactivation of VZV, causing pain in dermatomal distribution followed by fever, malaise and rash.
Treat with aciclovir, be aware of post-herpetic pain in affected dermatomes which can last years, try amitriptyline
What are coryzal symptoms?
Cold-like symptoms such as sneezing, coughing, sore throat, watery eyes, nasal congestion, runny nose
Describe Cellulitis, it’s presentation, and management.
Acute infection of skin and soft tissues (commonly legs). Usually due to beta-haemolytic strep, or staph A.
Presentation: Pain, swelling, warm erythematous skin, systemic upset, local lymphadenopathy.
Management:
- elevate the legs
- flucloxacillin 500mg/6h PO
- Benzylpenicillin 600mg/6h IV if systemically upset.
- Erythromycin 500mg/12h PO if pen-allergic
Describe Urinary Tract Infections (UTIs), its risk factors, symptoms, investigations, and management.
May be upper (renal pelvis) or lower (urethra bladder, prostate), complicated (abnormal renal tract/GU tract, voiding difficulty/obstruction, decreased renal function) or uncomplicated (normal renal tract + function. E. coli is the main organism, others include proteus, klebsiella.
Risk factors: Female sex, sexual intercourse, exposure to spermicide in women, pregnancy, menopause, immuno-suppressed/compromised, urinary tract obstruction, stones, catheter.
Symptoms: Burning sensation when urinating, foul-smelling urine, fever rigors, vomting, loin pain, supra public pain, urgency, frequency.
Investigations:
- urinalysis +ve leucocytes and nitrites.
- MSU for MC+S
Management:
- prevention, drink more water, cranberry juice,
- empirical treatment e.g. Trimethoprim, or nitrofuratoin adjust on culture and local sensitivities.
Describe Osteomyelitis, its symptoms, tests and management.
Infection of the bone most commonly caused by Staph A, except in patients with sickle-cell where salmonella predominates. At risk groups include, diabetics, sickle-cell, IVDUs, immunosuppression, alcohol abuse.
Symptoms: gradual onset of pai with tenderness, warmth, erythema, unwillingness to move, effusion in neighbouring joints, signs of systemic infection.
Tests: MRI, blood cultures, ESR/CRP raised, WCC raised.
Management:
-flucloxacillin for 6 weeks (clindamycin if pen-allergic)
Describe Leptospirosis (Weils Disease), its symptoms, and management.
Commonly seen in questions referring to sewage workers, farmers, vets or people who work in an abattoir. It is caused by the spirochaete Leptospira interrogates which is classically spread by contact with infected rat urine.
Symptoms: Fever, flu-like symptoms, renal failure, jaundice, subconjunctival haemorrhage, headache (beware meningitis
Management:
- high dose benzylpenicillin or doxycycline.
- IV penicillin G if severe.
Describe Kaposi’s sarcoma and it’s types
A spindle cell tumour derived from capillary endothelial cells or from fibrous tissue caused by Herpes hominis virus (HHV-8).
Presents as Purple macules, papules, nodules and plaques affecting the skin associated with HIV infections an AIDS defining illness can also affect the mucosa of any organ.
Types:
- Type 1 classic especially in elderly Jewish or Mediterranean males
- type 2 endemic, in forms 1 and 2 peripheral slow growing lesions are found and visceral involvement is rare, but node involvement may cause oedema
- Type 3 KS in immunisupression e.g. Organ transplants
- Type 4 AIDs related organ involvement is more common and disease is widespread optimise HAART
Describe Tinea, its symptoms, and management
A ringworm (fungal) infection. Named depending on the area affected e.g. Tinea pedis (foot), Tinea cruris (groin), Tinea capitis (scalp), Tinea unguim (nail), Tinea corporis (body).
Symptoms: a round, scaly, itchy lesion whose edge is more inflamed than its centre.
Management:
- skin scrappings from edge (active region), nail clippings, hair pulls, for microscopy and culture.
- 1% terbinafine cream.
Describe onychomycosis (Fungal Nail Infection), it’s causes, symptoms, and management.
Causes: mostly dermatophytes, mainly trichophyton rubrum (90%). Also yeasts such as candida. And non-dermatophytes moulds.
Symptoms: unsightly nails are a common reason for presentation, they appear thickened, rough, opaque.
Management:
- nail clippings and scrapings of affected nail
- confirm microbiology before treatment
- if dermatophyte infection oral terbinafine is currently first line with oral itraconazole as an alternative. Treatment need for 6-12wks for fingernails and 3-6mths for toenails
- candida infection should be treated topical if mild e.g. Amorolfine or oral intraconazole for 12wks if more severe.
What treatment should be given to those found to be carriers of MRSA.
Nose swab +ve = mupirocin 2% in white soft paraffin TDS 5days
Skin swab +ve = chlorhexidine gluconate OD 5days
Vancomycin, telco planing and linezolid are used in treatment of MRSA.
Describe Schistosomiasis, it’s presentation, investigations, management, and complications.
Also known as swimmers itch, caused by a worm.
Presentation: Can present Acutely, or with chronic infection.
- Acute syndrome (Katayama syndrome) is due to sudden release of antigenic eggs. Symptoms include swimmers itch (urticaria like rash after parasite has penetrated skin), malaise, arthralgia, myalgia, cough, Diarrhoea, and RUQ pain, fever, hepatomegaly.
- Chronic disease may present months to years after exposure, symptoms include bloody diarrohoea, abdominal pain, RUQ pain, haematemesis, haematuria, frequency, dyspnoea on exertion, cough, chest pain.
Investigations: Microscopic examination of stool or urine for eggs. Serology can detect less advanced infections.
Management: Praziquantel is treatment of choice.
Complications: Secondary infection, renal stones, bladder carcinoma, hydronephrosis, CKD, portal hypertension, pulmonary hypertension
Describe Rheumatic Fever, it’s diagnostic criteria, and management.
Systemic infection caused by sensitivity reaction to Group A beta-haemolytic streps which can lead to permanent damage to heart valves.
Diagnostic Criteria: Requires evidence of Group A strep infection + 2 major or 1 major and 2 minor criterion.
- Evidence of Group A Strep infection e.g. Positive throat culture, recent scarlet fever, +ve rapid streptococcal antigen test, elevated ASO
- Major Criterion: Carditis, Polyarthritis, Subcutaneous nodules, Erythema Marginatum, Sydenham’s Chorea
- Minor Criterion: Fever, Raised ESR/CRP, Arthralgia, Prolonged PR interval, Previous Rheumatic fever.
Management:
- Bed rest until CRP normal for 2wks, helps joints and heart
- Benzylpenicillin IV stat plus Penicillin for 10days
- High dose aspirin for carditis
- Haloperidol or diazepam for chorea
- Secondary Prophylaxis
Describe Rubella, it’s symptoms, and complications.
An RNA virus, live vaccine available. Screened for antenatally due to risk of malformation. infective 5days before and 5days after rash.
Symptoms: may be asymptomatic, or macular rash, suboccipital lymphadenopathy.
Complications: in utero malformations. Most at risk in first 16wks gestation. Cataracts with in infection at 8-9wks, deafness with infection at 5-7wks, cardiac lesions at 5-10wks.
Describe Cytomegalovirus, its presentation, and management.
Thought that 50% have been exposed but usually only causes disease in the immunocompromised e.g. HIV. Infected cells have an ‘Owl’s eye’ appearance due to intranuclear inclusion bodies.
Presentation: similar to glandular fever (sore throat, fever, splenomegaly) or hepatitis (fever, jaundice), also retinitis and colitis.
Management:
-Ganciclovir IV 5mg/kg/12h
Describe Toxoplasmosis, it’s presentation, and management.
Protozoan Toxoplasma Gondii found in poorly cooked meat, soil-contaminated vegetables. High risk in Pregnancy and HIV.
Presentation:
- Similar to Infectious mononucleosis e.g. Sore throat, lymphadenopathy, petechial palate, fever. CNS signs if immuno-comprised
- Cerebral: accounts for 50% of cerebral lesions in patients with HIV, headache, confusion, drowsiness, CT shows ring enhancing lesions.
- Congenital: Abortion, seizures, choroidoretinitis, hydrocephalus, microcephaly, cerebral calcification.
Management:
-sulfadiazine and pyrimethamine
Describe Cryptococcal Meningitis, its symptoms, investigations, and management.
HIV associated disease, most common fungal infection of CNS.
Symptoms: Headache, fever, malaise, nausea/vomiting, seizures, focal neurological signs.
Investigations: CSF high opening pressure, India ink test +ve, CT shows meningeal enhancement and cerebral oedema.
Management:
- amphotercin B IV + 5-Flucytosine
- secondary prophylaxis of fluconazole until CD4 over 150 and cryptococcal antigen -ve.
Which antibiotics are associated with high risk of C.diff infection?
Cephalosporins, broad-spectrum antibiotics.
What type of bacteria is Neisseria Gonorrhoeae?
Gram -ve intracellular diplococcus
What type of bacteria is propionibacterium acnes?
Gram +ve baccilus (rod)
What type of bacteria is pseudomonas aeruginosa?
Gram -ve baccilus(rod)
What type of bacteria is staphylococcus aureus?
Gram +ve coccus in clusters (Grapes)
What type of bacteria is streptococcus pneumoniae?
Gram +ve coccus in chains
Describe Whipple’s disease, its features, investigations, and management.
A rare cause of malabsorption due to infection with the bacteria tropheryma whipplei.
Features: Mostly occurs in white middle aged men who present with arthralgia, diarrhoea, weight loss and abdominal pain. CNS feature include reversible dementia and oculomasticatory myorhythmia (which describes a pendulum vengeance of oscillations of the eyes with concomitant contractions of the muscles of mastication it is pathgnomic of whipples)
Investigations: Small bowel biopsy reveals the presence of magenta coloured periodic acid-Schiff macrophages, and the presence of trilaminar-walled tropheryma whipplei arterial.
Management:
- IV Ceftriaxone for 2 weeks and oral co-trimoxazole for 1 year
Describe Chagas’ disease and its features.
Aka American Trypanosomiasis is caused by T.cruzi. Spread by blood sucking triatomine bugs in Latin America and southern USA.
Features: a red infuriated nodule (Chagoma) forms at the site of infection. Fever, myalgia, rash, lymphadenopathy, hepatosplenomegaly, unilateral conjucintivitis, periorbital oedema (Romanas sign) myocarditis, Meningoencephalitis. Can cause dilated cardiomyopathy, mega-oesphagus, mega-colon.
Describe typhoid fever, its features, management, and complications.
Caused by Salmonella Typhi and S.parathyphi. Incubation 3-21days. Spread is faecal-oral e.g. drinking local tap water (acid suppression from PPIs increase risk)
Features: Malaise, headache, high fever with relative bradycardia, cough, constipation, CNS signs (coma, delirium, meningism, cerebellar signs, seizures). Splenomegaly and brushing may occur.
Management:
-Ciprofloxacin 500mg BD for 10DAYS
Complications: osteomyelitis, GI bleed, cholecystitis, myocarditis, pyelonephritis, meningitis, abscess.
Describe Waterhouse-Friderichsen syndrome, its features, causes, and management.
Aka haemorrhagic adrenalitis, adrenal gland failure due to bleeding commonly caused by bacteria infection typically meningococcal disease.
Features: Fever, rigors, vomiting headache, hypotension, hypoglycaemia, hyponatraemia and hyperkalameia.
Causes: Neisseria meningitidis, pseudomonas aeruginosa, TB, Strep pneumonia, staph aureus in paediatric populations, Haemophilus influenxae rarely.
Management:
-Treat cause, hydrocortisone
Describe Leishmaniasis, its main types , and management,.
Leishmaniasis is caused by the intracellular Protozoa leishmania, usually being spread by sand flies.
Types:
- Cutaneous Leishmaniasis, caused by Liesmania tropical or mexicana presents as crusted lesion at site of bite and there may be underlying ulcer.
- Mucocutaneous leishmaniasis caused by leishmania braziliensis, skin lesions may spread to involve mucosal of the nose, pharynx
- Visceral Leishmaniasis, most caused by leishmania Donovani, presents with fever, sweats, rigors, massive splenomegaly, hepatomegaly, poor appetite weight loss, pancytopenia and grey skin.
Management:
- Sodium Stibogluconate (Pentostam)
- resistant cases Miltefosine, Paramycin, amphotercin b
What are the features of severe C.difficile Infection?
WCC over 15 Temp over 38.5 Creatinine over 150% baseline Tender, distended abdomen Colonic dilatation on AXR
What are the new Sepsis-3 definitions of sepsis?
Sepsis is life-threatening organ dysfunction due to a dysregulated host response to infection. The clinical criteria of organ dysfunction is defined as an increase of 2 points or more in the sequential Organ Failure Assessment (SOFA) score. Patients with suspected sepsis can be quickly identified at the bedside with qSOFA score of 2 or more in HAT, hypotension (systolic less than 100mmHg), Altered mental status, and Tachypnoea (RR 22 or over)
Septic Shock is a subset of sepsis in which underlying circulatory and cellular/metabolic abnormalities are profound enough to substantially increase mortality. Septic shock criteria are defined by sepsis as above + Persistant hypotension requiring vasopressin to maintain MAP gather than or equal to 65mmHg and Lactate greater than or equal to 2.
Describe Leprosy, its features, and management.
Leprosy is a ganulomatous disease primarily affecting the peripheral nerves and skin caused by Mycobacterium Leprae.
Features: Patches of hypopigmented skin typically affecting the buttocks, face and extensor surfaces of limbs, and sensory loss. The degree of cell mediated immunity determines the type of leprosy a patient will develop:
- Low degree of cell mediate immunity = Lepromatous Leprosy (Multibacillary) extensive skin involvement and symmetrical nerve involvement
- High degree of cell mediated immunity = Tuberculoid leprosy ‘Paucibacillary’ limited skin disease and asymmetric nerve involvement.
Management:
-Who- recommend triple therapy: Rifampicin, Dapsone and clofazimine
Describe Post Exposure Prophylaxis of Hepatitis A.
Human Normal Immunoglobulin or Hepatitis A vaccine maybe used depending on the clinical situation
Describe Post-Exposure prophylaxis for Hepatitis B.
HBsAg positive source: If the person exposed is a known responder to HBV vaccine then a booster dose should be given. If they are in the process of being vaccinated or are a non-responder they need to have Hepatitis B immunoglobulin (HBIG) and the vaccine.
Unknown source: For known responders the green book advises considering a booster dose of HBV vaccine. For known non-responders HBIG + Vaccine should be given whilst those in the process of being vaccinated should have an accelerated course of HBV Vaccine.
Describe Post-Exposure Prophylaxis of Hepatitis C
Monthly PCR if seroconversion then interferon +/- Ribavirin
Describe Post-exposure prophylaxis for HIV
A combination of oral antiretrovirals (previously recommended Truvada (Tenofoir and emtricitabine) and Kaletra (Lopinavir and ritonavir) but now recommend raltegravir instead of kaletra as is it better tolerated) as soon as possible (i.e. writhing 1-2hrs, but may be started up to 72hrs following exposure) for 4 weeks.
Serological testing at 12 weeks following completion of post-exposure Prophylaxis
This reduces risk of transmission by 80%.
Describe Post exposure prophylaxis for Varicella zoster
VZIG for IgG negative pregnant women/immunosuppressed.
What are the estimated transmission risks for blood-bourne disease for single needlestick injury.
Hepatitis B 20-30%
Hepatitis C 0.5-2%
HIV 0.3%
Describe Discitis, its features, risk factors, investigations, and management
Aka Vertebral Osteomyelitis, most often occurs as a result of haemtogenous seeding of one or more vertebral bodies from a distant focus. May also occur through contigous spread from a adjacent soft tissue infection.
Features: Chronic worsening back pain, exacerbated by physical activity and painful to touch often worse at night. Fevers and rigors. Peripheral neurological symptoms
Risk factors: IE, Diabetes, IVDU, Degenerative spinal disease, prior spinal surgery, corticosteroids.
Investigations:
- Raised inflammatory markers
- MRI spine
- CT Guided biopsy / aspiration of abscess
Management:
- Analgesia
- 6 weeks antibiotics
Describe Katayama Fever and its features, and management
Acute schistosomiasis, a syndrome that typically occurs 4-6 weeks following the initial infection with the parasites, as they begin to mature and lay eggs. It is thought to be an serum sickness type illness due to immune complex formation to the egg laying process rather than an effect of the worms themselves. The disease can be caused by an schistosomal species but is worst when caused by S. Japonicum and in these cases can cause severe illness and fatality.
Features: Fatigue, Cough, Fever, Urticarial Rash, Eosinophilia.
Management: Prazinquantel
What are the main organisms found in pyogenic liver abscess and the management?
Most common is Staph Aureus in children and E.coli in adults.
Management:
- Amox + Cipro + Metro
- If pen allergic Cipro + Clindamycin
Describe Clostridium Difficile infection, its risk factors, features, and management.
C.Diff is a gram positive rod often encountered in hospital practise. It produces an exotoxin which causes intestinal damage leading to a syndrome called pseudomembranous colitis.
Risk factors:
- Broad spectrum antibiotics e.g. cephalosporins
- Use if PPI and H2 receptor antagonists
- Exposure to c.diff
Features:
- Diarrhoea
- abdominal pain
- Raised WCC
- Toxic megacolon may develop
- Stool sample +Ve for CD toxin
Management:
- First line therapy is PO Metronidazole for 10-14 days
- if severe then PO Vancomycin is used
- Patients who do no respond to vancomycin may respond to PO Fidaxomicin
- Patients with severe and unremitting colitis should be considered for colectomy.
What is Loffler’s syndrome?
A disease in which eosinophils accumulate in the lung in response to a parasitic infection.
Describe Meliodosis, its features and management
Caused by Burkholderia Pseudomallei, a gram-negative, motile, soil dwelling bacterium. It is endemic in many parts of south East Asia and northern Australia. Classical history is of a worker in a paddy field who has regular contact with wet soil.
Features: Febrile illness, cough, pleuritic chest pain, bone pain, cellulitis, cutaneous abscesses.
Management:
IV Ceftazidime for at least 10days
Describe the different mechanisms of bacterial antibiotic resistance.
New Delhi metallo-beta-lactamase 1 is the mutation that leads to carbapenem resistance. Typically found in Klebsiella pneumoniae, Escherichia Coli (E. Coli), Enterobacter cloacae and others. First line of management is the old antibiotic colistin and second line may be tigecycline.
D-alanyl-D-lactate variation leading to loss of affinity to antibiotics is the mechanism of VRE (vancomycin resistant enterococci). Vancomycin binds to D-ala-D-ala.
The presence of MexAB-OprM efflux pumps is one of the mechanisms by which pseudomonas aeruginosa is resistant to -lactams, chloramphenicol, fluoroquinolones, macrolides, novobiocin, sulfonamides, tetracycline, and trimethoprim.
Alteration to the penicillin binding protein 2 is the mechanism behind methicillin-resistant staphylococcus aureus. Mutations in the MEC gene which codes the penicillin binding proteins give staphylococcus aureus its resistance.
Describe Loa Loa and its features
A nematode, aka the african eye worm. Worms occasionally make slow passage across the eye and can actually be sensed by patients.
Features:
- Skin lesions condoned to extremities i.e arms and legs. known as Calabar swellings represent overlying areas of urticaria where muscle cysts occur around tendon shearths
- Systemic symptoms include itching, myalgia, arthralgia, tiredness, urticaria
Describe Actinomycosis and its features
A rare infectious bacterial disease caused by Gram +ve Rod actinomyces. Usually associated with dental work or poor oral hygiene.
Features: Painful abscesses in the mouth, lungs breast or GI tract. They grow until they break open realising characteristic sulphur granules.
Describe Rocky Mountain Spotted Fever (RMSF), its features, and management.
RMSF is a febrile illness caused by infection with Rickettsia rickettsii. It is most prevalent in central, south and south-eastern US.
Features:
- There is history of tick bite in 65%, fever in 100% and rash in 90% of cases. Incubation period is 3-12 days. the first symptoms are fever, headache malaise and myalgia.
- A macular rash typically starts on the hands and feet and processes proximally towards the trunk, the face is not normally affected. The macule evolve to papules, petechiae, and ecchymoses, sloughing of the skin may occur and in severe cases necrosis and gangrene.
- Mild hepatitis, myocarditis, glomerulonephritis and encephalitis may also occur.
- Antibody tirres to Rickettsia may provide the diagnosis which is confirmed with a 4-fold rise in titres over a 2 week period.
Management:
-Tetracycline antibiotics
Describe Anthrax, its features, and management
Caused by animal products such as raw meat contaminated with Bacillus Antracis. It can occur in familial clusters. Incubation period is typically 2-5days.
Features:
- Oropharyngeal anthrax, fever, severe pharyngitis (ulcerative), neck oedema, lymphadenopathy, particular in consuming raw meat.
- Intestinal Anthrax is rare, typically causes severe abdominal pain, vomiting, and diarrhoea.
- Cutaneous Anthrax (Hide Porter’s disease, presents with boil-like skin lesion that progresses to an ulcer with black centre (Eschar) often painless).
Management:
- Combination of 2-3 antibiotics
- Notifiable disease
- Infection control ++
Describe Paragoinimiasis, its features, and management.
A food-borne parasitic infection caused bu the lung fluke, most commonly paragonimus westermani. It is particular common in east Asia. Infection usually occurs by easting inadequately prepared crab or crayfish.
Features:
- Acute Phase (invasion and migration): diarrhoea, abdominal pain, fever, cough, urticaria, hepatosplenomegaly, pulmonary abnormalities, eosinophilia.
- Chronic phases: Cough, expectoration of discoloured sputum contains clumps of eggs. Haemoptysis.
Management:
-Praziquantel.
What is the management of Cholera?
Supportive, if dehydration present oral tetracycline may help
Describe Tick-Borne Relapsing Fever, its features, and management
A bacterial infection caused by a certain species of Borrelia Hermsii, Parkeri, Turicata. linked with sleeping in rustic cabins in mountainous areas of western United States.
Incubation period is 7 days.followed by 3 days symptomic periods interspersed with 7 days afebrile periods. Characterised by recurring episodes of fever, headache, muscle and joint aches and nausea.
Management:
-Oral tetracyclines.
What is Immune Reconstitution Inflammatory Syndrome?
A condition seen in some cases of AIDs or immunosuppression, in which the immune system begins to recover, but then responds to a previously acquired opportunistic infection with an overwhelming inflammatory response that paradoxically makes the symptoms of infection worse.
Describe Hydatid Disease (Echinococcosis), its features, and management
A parasitic disease of tapeworms of the Echinococcus type. Two main forms are Cystic and Alveolar. The disease is spread when food or water that contains the eggs of the parasite are consumed. Commonly affected animals dogs, foxes, wolves, sheep.
Features: Asymptomic, Abdominal pain, weight loss, jaundice, SOB, cough.
Investigations: U/S Abdomen shows liver cysts. Antibodies against parasite.
Management: Albendazole.
Describe Epidemic Typhus, its features, and management
A form typhus caused by Rickettsia Prowazekii, transmitted by the human body louse.
Features: Headache, fever (39C), cough, rash, muscle pain, rigors, sensitivity to light (Rash beings on chest about 5 days after the fever appears and spreads to the trunk and extremities. Can have black Eschar at site of bite
Management:
- Oral tetracyclines
- IV Fluids.
Describe Dengue Fever, its features, and management
A mosquito-borne (aedes type) tropical disease caused by the dengue virus. Symptoms being 3-14 days after infection. A viral haemorrhage fever.
Features: High fever, headache, vomiting, muscle and joint pains(Breakbone fever), petechial rash (described as islands of white in a sea of red). Bleeding, thrombocytopenia Hypotension (Dengue shock syndrome)
Management:
- Vaccine available
- supportive
Describe Chikungunya Fever, its features, and management
An mosquito-borne infection caused by the chikungunya virus.
Features: Fever and joint pain are main symptoms, also associated with headache, muscle pain, rash, conjunctivitis.
Management:
-Supportive.
What are the different types of Viral Haemorrhagic fever?
Five main families of RNA viruses:
- Arenavirdae: Lassa fever, Lujo virus, Junin virus, Machupo virus, Sabiá Virus, Chapare Virus, Guanarito virus.
- Bunyaviridae: hantavirus (causes haemorrhagic fever with renal syndrome HFRS), Nairovirus (Causes Crimean-Congo Haemorrhagic fever) Garissa virus, Orthobunyavirus, Phlebovirus (causes Rift Valley fever)
- Filoviridae: e.g. Ebola, Marburg virus
- Flaviviridae: e.g. dengue, yellow, Omsk haemorrhagic fever Kyasanur Forset disease virus.
- Rhabdoviridae
What is the typical length of treatment for TB?
Non - CNS TB = 6 months
CNS TB = 12 months
Which Antibiotic is used for treatment of tetanus?
Metronidazole
Describe Cyclospora Cayetanesis infection
A protozoan that causes disease in humans, linked to face ally contaminated produce.
Features: Gastroenteritis, watery diarrhoea, weight loss, abdominal cramping, low grade fever, flatulence.
Describe African Trypanosomiasis, its features, and management.
Aka sleeping sickness, an insect-borne parasitic disease caused by the species Trypansoma Brucei (Gambiense (98%) and Rhodesiense). Both transmittedby the bite of an infected Tsetse fly. Time of onset is 1-3 weeks post exposure.
Features:
- Stage 1 ( occurs within 1-3 weeks)fevers, headache, itchiness, joint pains, Lymphadenopathy (Winterbottom’s sign Lymphadenopathy at back of neck). Chancre may occur at location of bite.
- Stage 2 (occurs weeks to months alter) trouble sleeping, confusion poor coordination.
Management:
- Diagnosed by microscopy of chancre fluid, lymph node aspirate, blood, bone marrow or CSF.
- first stage = Pentamidine, suramin
- Second stage = eflornithine.
Describe Blackwater Fever
A complication of malaria infection in which red blood cells burst in the bloodstream (haemolysis) releasing haemoglobin into blood vessels and into urine leading to kidney failure. It caused by heavy parasitazation of red blood cells with plasmodium falciparum and is thought that quinine may play a role in triggering the condition.
Describe tropical splenomegaly syndrome.
Aka hyperactive malarial splenomegaly occurs due to immunological over stimulation due to repeated attacks of malarial infection over a long period of time. Seen in malaria endemic countries characterised by massive splenomegaly and hepatomegaly and marked elevations in serum IgM and anti malarial antibodies. Treatment involves antimalarials followed by long term Prophylaxis to remove the add on antigenic stimulus of repeated infection to allow the reticuloendothelial system to return to normal.
Describe Hantavirus and its features
Haemorrhagic RNA virus that causes Haemorrhage is fever with renal syndrome, endemic in Korea and other Asian countries. Humans become infected with contact with rodent urine, saliva or faeces.
Features: Symptoms usually develop 1-2 weeks after exposure. Initial symptoms include intense headaches, back and abdominal pain, fever, chills, nausea and blurred vision. Later symptoms include shock, vascular leakage, acute renal failure.
What is the treatment of tapeworm?
Niclosamide
Describe Cysticercosis and its features
A tissue infection caused by the young form of the pork tapeworm. Usually acquired by eating food or drinking water contaminated by tapeworm eggs. Taenia solium
Features: Cutaenous lumps which may become painful and swollen then resolve. A specific form called neurocysticercosis can cause neurological eosinophilia, fever may occurs
Diagnosis is made by serum anticystercal antibodies, CSF ELISA for cysterical antigens in neurcysticosis our resolution of lesionsnwith treatment with albendaxole
Describe Histoplasmosis and its features.
A disease caused by the fungus Histoplasma capsulatum. It primarily affects the lungs. It is common among AIDs patients. Histoplasma capsulatum is found in soil, often associated with decaying bat guano or bird droppings.
Features: Symptoms occur 3-17 days after exposure average around 12-14 days. Acute phase is non-specific respiratory symptoms, often cough or flu-like. CXR findings are normal in 40-70% of cases. Chronic histoplasmosis can resemble TB. Hepatosplenomegaly.
What are the antibiotics used in the treatment of Clostriudium Perfringens?
Benzylpenicllin or Clindamycin
Describe Babesiosis and its features
This is tick-borne malaria-like illness caused by species of the intra-erythrocytic protozoan Babesia. The intra-erythrocytic Babesia destroy the red blood cells, causing haemolytic anaemia and haemoglobinuria. Babesiosis is frequent in endemic areas of the USA, particularly Long Island, New York, Nantucket, Massachusetts.
Features: Similar to malaria i.e. fever, chills rigors, headache. A b-lymphocyte response is elicited with a. Secondary reactive polyclonal hypergammaglobulinaemia. Patient without a spleen ave a more fulminant and prolonged clinical course and may have overwhelming infection and a fatal outcome.
Describe Cat Scratch Disease its features and management.
An infectious disease that results from the scratch of bite of a cat. Caused by Bartonella Henselae in the cats saliva.
Features: Typically include a non-painful bump or blister at the site of injury and painful and swollen lymphadenopathy typically within 3-14 days following infection. Headaches, malaise, chills, arthritis.
Management:
-supportive +/- Azithromycin or Doxycycline if optic neuritis present.
Describe Melioidosis and its features
Caused by Burkholderia Pseudomallei. Endemic in Thailand and northern Australia. Incubation 1-21 days mean 9 days.
Causes pneumonia, pulmonary abscesses and pleural effusions resulting in septic shock.
Describe Brucellosis, and its features.
Caused by a frame negative bacterium that is transmitted by contact with infected livestock.
The typical incubation period is 1-3 weeks with an insidious onset.
Features: Mailaise, Fever, back pain, and night sweats. Back pain is common, occuring in around 50%. The findings of an leucoerythroblastic blood film and raised transamininases fit with the diagnoses. Diagnosis is made via bone marrow culture or serum agglutination testing.
Describe the vaccination protocol for Rabies infection
If previously immunised a vaccination on the day and on day 3.
If not previously immunised will need vaccination on day wit IV Immunoglobulin, and vaccinations on days 3, 7 , 14 and 30
