Infectious Diseases Flashcards
Outline the criteria for SIRS
2 or more of Temperature above 38 or below 36 Heart rate above 90 Resp rate above 20 or PaCO2 below 32 WCC over 12k or below 4k Hyperglycaemia in absence of diabetes
Define “sepsis”
Confirmed SIRS and suspected/present infection
Define “severe sepsis”
Sepsis with organ dysfunction
Give examples of evidence of organ dysfunction in severe sepsis
Arterial hypoxaemia Oliguria Thrombocytopenia Hypotension Raised Cr Raised lactate
Define “septic shock”
Arterial hypotension (systolic below 90, mean below 65) for 1 hour despite fluid resuscitation Lactate above 4
What is the definition of pyrexia of unknown origin?
Temperature above 38.3 for more than 3 weeks with no obvious cause
Suggest some causes of pyrexia of unknown origin
CTD's (Marfan's, EDS) Rheumatoid arthritis PMR Tumours Drugs PE IBD
List some investigations you would do in pyrexia of unknown origin
FBC, U+E, albumin
Renal function
CXR
Immunology (antibodies)
What is nosocomial fever?
Temperature above 38 occurring 48h after hospital admission, usually as a result of environmental exposure or medical intervention
List causes of nosocomial fever
Risk factors (alcoholism, CVD, faecal incontinence, ulcers, indwelling catheters, malignancy, procedures) Infection (UTI, pneumonia, skin, prosthesis, AIDS) Inflammation (vasculitis, aspiration, autoimmunity, drugs) Ischaemia (MI, stroke, PE, bowel obstruction)
Which organisms cause malaria?
P vivax
P ovale
P malare
P falciparum
List some symptoms and signs of malaria
Fever Rigors Headache Dizziness Jaundice Flushed Sweating for hours Anaemia
How is malaria investigated?
Serial thin + thick blood film
FBC
Outline treatment for malaria
Chloroquine
Primaquine
Prophylaxis for travellers
Which organism causes typhoid? How is it spread?
Salmonella typhi
Faeco-oral
List some symptoms and signs of typhoid
Malaise High fever Bradycardia Cough Constipation Abdo pain
How is typhoid investigated?
Blood/bone marrow culture
LFT’s
Outline treatment for typhoid
Fluid replacement and nutrition
Ciprofloxacin, ceftriaxone
Which organism causes dysentry? How is it spread?
Shigella
Faeco-oral
List some symptoms and signs of dysentry
Abdo pain Bloody diarrhoea Sudden fever Headache Neck stiffness
How is dysentry investigated?
Stool culture
Which organism causes cholera? How is it spread?
Vibrio cholerae
Faeco-oral
List symptoms and signs of cholera
Profuse “ricewater” stools
Fever
Vomiting
Rapid dehydration
How is cholera investigated?
Stool culture and microscopy
Outline treatment of cholera
Sachet rehydration
Erythromycin, ciprofloxacin
Barrier nursing
List some common signs of tropical infections and suggest diseases behind them
Jaundice (hepatitis, liver abscess, yellow fever) Diarrhoea, vomiting Erythema nodosum (sarcoid, TB, Strep) Itch (scabies) Ulcers/nodules (leishmaniasis)
Suggest sources of infection of the following organisms that cause gastroenteritis: Staph aureus Bacillus cereus Salmonella Clostridium perfringens Campylobacter Listeria E. coli 0157 Cryptosporidium
Staph aureus (meat) Bacillus cereus (rice) Salmonella (poultry, dairy) Clostridium perfringens (meat) Campylobacter (poultry) Listeria (cheese) E. coli 0157 (raw meet) Cryptosporidium (cows)
Which of the hepatitis viruses are DNA and which are RNA?
A, C, D and E are RNA viruses
B is DNA virus
How is hepatitis A spread?
Faeco-oral
Travellers
Institutions (workplaces)
List some symptoms and signs of hepatitis A
Fever Jaundice Malaise Arthralgia Anorexia Nausea
What are the notable investigation results for hepatitis A?
Raised AST and ALT
IgM/IgG antibody
Outline treatment for hepatitis A
Supportive
Avoid alcohol
Interferon-alpha
How is hepatitis B spread?
Blood products
IV drug use
Sex
Haemophiliacs
List some symptoms and signs of hepatitis B
Fever Jaundice Malaise Arthralgia Anorexia Nausea Extrahepatic features
What are the notable investigation results for hepatitis B?
Hep B S Ag
Hep B e Ag
Outline treatment for hepatitis B
Vaccination
Avoid alcohol
Peg-interferon
Antivirals
How is hepatitis C spread?
Blood transfusions
IV drug use
Sex
List symptoms and signs of hepatitis C
Mild/asymptomatic compared to hep A and B
May develop cirrhosis
What are the notable investigation results for hepatitis C?
Deranged LFT’s
Anti Hep C virus antibody
PCR
Positive liver biopsy
Outline treatment of hepatitis C
Ribavirin
Peg-interferon
How is Giardia spread?
Faeco-oral Travel Anal sex Playgroups Swimming Pets, animals Contaminated water
List symptoms and signs of Giardia infection
Bloating Flatulence Abdo pain Loose stools Explosive diarrhoea Malabsorption Loss of weight
How is Giardia investigated?
Direct fluorescent antibody assay
Repeated stool microscopy
Duodenal fluid analysis
Outline treatment of Giardia
Good hygiene
Tinidazole
Avoid alcohol and milk
Which organism causes tetanus?
Clostridium tetanii
How is tetanus spread?
Spores in faeces, soil, dust, instruments
Diabetics have increased risk
Recent wounds/skin breaks
List symptoms and signs of tetanus
May appear 1 day to several months after injury Fever Malaise Headache Trismus Grin-like posture Spasms Autonomic upset Arched body
How is tetanus treated?
ABCDE approach, may need intubation/tracheostomy Human tetanus Ig IV Diazepam for spasms Metronidazole, benzylpenicillin Active vaccination, wound cleansing
List common infections caused by Staphylococci
Pneumonia
Endocarditis
Septic arthritis
Osteomyelitis
List common infections caused by Streptococci
Wound and skin infections Necrotising fasciitis Pneumonia Glomerulonephritis Tonsillitis Meningitis
List common infections caused by Clostridia
Tetanus
Gas gangrene
Colitis
Paralysis
Which strain of herpes virus is usually associated with genital herpes?
HSV-2
List symptoms and signs of genital herpes
Flu-like ilness
Grouped vesicles/papules around groin and throat
Shallow ulcers
How is genital herpes investigated?
Viral swab of penetrated ulcer for PCR
Which strain of herpes virus is usually associated with encephalitis?
HSV-1
Which part of the brain does herpes virus typically affect?
Frontal and temporal lobes
List symptoms and signs of herpes encephalitis
Fever Fits Headache Odd behaviour Dysphasia Hemiparesis
How is herpes encephalitis investigated?
CSF PCR (may be positive up to 5 days after treatment)
CT/MRI/EEG
Antibody titre
Which strain of herpes causes chickenpox and shingles?
Varicella zoster
List symptom and signs of chickenpox and shingles
Contagious febrile illness Crops of blisters that scab after days Pain in dermatomal distribution Fever Malaise
What is the general treatment for herpes virus infections?
Aciclovir
Paracetamol
What is infectious mononucleosis and which organism causes it?
Glandular fever caused by EBV
Attacks B-cells and causes proliferation of cytotoxic T-cells
How is infectious mononucleosis transmitted?
Kissing
Saliva, droplet spread
List symptoms and signs of infectious mononucleosis
Sore throat Fever Malaise Lymphadenopathy Palatal petechiae Splenomegaly
What are some complications of infectious mononucleosis?
Meningitis, encephalitis CN lesions (esp. VII) Neuropathy Thrombocytopenia Splenic rupture
What investigations are done for infectious mononucleosis?
Blood film (lymphocytosis, atypical lymphocytes) Monospot antibody test shoes heterophilic antibodies
What diseases/conditions can give a false +ve Monospot antibody test?
Hepatitis Parovirus Lymphoma Leukaemia Pancreatic cancer
How is infectious mononucleosis treated?
Avoid alcohol
Steroid if very swollen
NEVER AMOXICILLIN
When does CMV typically infect? How is it spread?
After acute infections
Spread by direct contact esp in health workplaces, blood transfusions, organ transplants
List signs and symptoms of CMV infection
Fever Pneumonitis Hepatitis Retinitis Jaundice Hepatosplenomegaly
How is CMV investigated?
Serology (IgM if acute)
PCR of blood/CSF/broncho lavage
Outline treatment for CMV
Rest and fluids
Ganciclovir IV if serious
Weekly PCR post-transplantation
List symptoms and signs of tuberculosis infection
Malaise Weight loss Night sweats Haemoptysis Pleurisy Genitourinary disturbance (loin pain, dysuria) Vertebral collapse Meningitis
How is TB investigated?
Latent TB: Mantoux test, IFN-gamma test
Active TB: CXR, sputum microscopy for acid-fast bacilli on ZN staining
Bronchoscopy + lavage if no sputum production
List TB investigations in order of fastest to slowest
PCR
ZN stain
Culture
Outline treatment regime for pulmonary TB
RIPE: Rifampicin, Isoniazide, Pyrazinamide, Ethambutol
2 months RIPE, 4 months RI
Monitor renal and liver function
Outline treatment regime for CNS TB
RIPE: Rifampicin, Isoniazide, Pyrazinamide, Ethambutol
2 months RIPE, 10 months RI
Monitor renal and liver function
What are the notable side effects of rifampicin?
Hepatitis
Orange secretions
Inactivates OCP
What are the notable side effects of isoniazide?
Hepatitis
Neuropathy
Agranulocytosis
What are the notable side effects of pyrazinamide?
Hepatitis
Arthralgia
Gout
Porphyrias
What are the notable side effects of ethambutol?
Hepatitis
Colour blindness
How is influenza investigated?
Nasopharyngeal swab for culture/PCR
Serology
How is toxoplasma gondii spread?
Poorly cooked meat
Animals (esp cats)
Soil, faecal contact (cat litter)
List symptoms and signs of toxoplasmosis
Sore throat/glandular fever
Eye pain
Focal neurology if serious
How is toxoplasmosis investigated?
Antibody titre (IgM specific)
PCR
Lymph node and CNS biopsy
CT scan shows ringed lesions
Outline toxoplasmosis treatment
Self-limiting
Pyrimethanine + sulfadiazine
Cook food properly, good hygiene
What type of virus is HIV? How is it spread?
RNA retrovirus that attacks and depletes CD4 cells
Spread via sexual contact, infected blood products and IV drug abuse
Also perinatal spread risk
List symptoms and signs of HIV infection
Acutely may be asymptomatic with transient illness (fever, malaise, rash, myalgia) Persistent generalised lymphadenopathy Night sweats Fever Diarrhoea Weight loss Opportunistic infections
List some opportunistic infections that may occur due to HIV
Oral candidiasis Herpes Seborrhoeic dermatitis Leukoencephalopathy PCP Toxoplasmosis Meningitis Tuberculosis
Outline investigations done for HIV
Serum/salivary HIV antibody (ELISA) PCR or core p24 antigen in plasma CD4 count Home kit testing Monitor U+E, Cr, Br Pregnancy test
How can HIV be prevented?
Safe sex (condoms)
Screen high risk groups
Educate drug users
Control STI’s
Outline post-exposure prophylaxis for HIV
Wash well
Report to occupational health
Hep B immunosation
Follow up testing at 12 and 24 weeks
What therapy is used for HIV?
HAART (NNRTi + 2x NRTi)
e.g. efavirenz + zidovudine/emtricatibine/tenofivir/lamivudine