Infectious diseases Flashcards
What stain is used to highlight gram-positive bacteria?
Crystal violet
What classification system is used for cellulitis?
Eron classification
What are some treatment options for Influenza?
Oseltamivir
Zanamivir
Common viral causes of gastroenteritis?
Rotavirus
Noravirus
What are some causes of Haemolytic Uraemic Syndrome?
Shigella
E.Coli 0157
What are the most common bacterial causes of Meningitis?
Neisseria Meningitides
Streptococcus Pneumoniae
What are the special tests for Meningitis on clinical examination?
Kernig’s Sign
Brudzinki’s test
What is the stain used for Mycobacterium Tuberculosis ?
Zeihl-Neelsen stain
What us disseminated TB called?
Miliary TB
When and why is Co-Trimoxazole used in HIV
When CD4<200mm3
As prophylaxis against pneumocystis jirovecii pneumonia
What is the most severe form of malaria?
Falciparum Malariae
What is the disease vector for Malaria?
Female Anopheles Mosquito
What is the treatment for severe malaria?
Artesunate
How do you diagnose cryptosporidium?
Modified Ziehl-Neelsen stain (acid-fast stain) of the stool may reveal the characteristic red cysts of cryptosporidium
What are some lab findings of Legionella pneumoniae?
Lymphopaenia
Hyponatraemia
Deranged LFTs
How do you diagnose Glandular fever?
Heterophil antibody test (Monospot test) - suggested by NICE in 2nd week of illness
What bacteria are gram positive rods?
Actinomyces
Bacillus Anrthracis (Anthrax)
Clostridium
Diptheria
Listeria moncytogenes
What bacteria are gram-negative rods?
Escherichia coli
Haemophilus Influenzae
Pseudomonas Aeruginosa
Salmonella Sp.
Shigella Sp.
Campylobacter jejuni
How would CSF of bacterial menigitis appear?
Cloudy
Low Glucose
High Protein
White cells most polymorphs
How would CSF of viral meningitis appear?
Clear/Cloudy
60-80% of plasma glucose
Normal protein
Mainly Lymphocytes
What is the most common organism found in central line infections?
Staphylococcus epidermis
What antibiotic is used as prophylaxis for contacts of patients with meningococcal meningitis?
Oral ciprofloxacin or rifampicin
What is used to assess drug sensitivities in TB?
Sputum culture
What CXR findings would you expect in TB?
- Upper lobe cavitation is the classical finding of reactivated TB
- Bilateral hilar lymphadenopathy
What is a classical history of Yellow fever?
Classic description involves sudden onset of high fever, rigors, nausea & vomiting. Bradycardia may develop. A brief remission is followed by jaundice, haematemesis, oliguria
What are the features of Cardiovascular Lyme disease?
After 30 days expect heart block
Peri/myocarditis
What are the features of Neurological Lyme disease?
- Facial nerve palsy
- Radicular pain
- Meningitis
What is the management of early Lyme disease?
Doxycycline
What is the management of disseminated Lyme disease?
Ceftriaxone
What is the investigation of choice for Legionella?
Urinary antigen
What is the most common cause of Travellers’ diarrhoea?
E.Coli
What is Brucellosis?
Caused by small non-motile facultative aerobic intracellular Gram-negative coccobacilli. It is the most common zoonotic infection worldwide.
How is Brucellosis transmitted?
- Commonly contracted via consumption of untreated milk/dairy as well as raw meat or liver
What are the clinical features of Brucellosis?
- Often non-specific, with persistent and undulant fever, weight loss, night sweats, lymphadenopathy and joint pain/myalgia or spinal tenderness
What is the gold standard investigation for Brucellosis?
- Bone marrow culture
What is Erysipelas?
Infection of the dermis and upper subcutaneous tissue
What are some risk factors for developing Cellulitis?
- Previous Cellulitis
- Venous insufficiency
- Immune deficiency
- Breaks in the skin barrier
- Obesity
- Fissured toes or heels due to athletes foot or tinea pedis
What is the common organism in Erysipelas?
Group A Beta-Haemolytic Streptococci
What is Cholera?
Cholera is an acute, secretory diarrhoea caused by infection with Vibrio cholerae of the O1 and O139 serogroups. It is a severe, life-threatening disease if not treated promptly.
What are the investigations in Cholera?
- Stool culture: GOLD STANDARD
- Rapid diagnostic tests: these can provide a diagnosis within hours but are less sensitive and specific than culture
What is the management of Cholera?
- Aggressive fluid replacement
- Antibiotics: Doxycycline or co-trimoxazole
What is a mild infection of C.Diff?
Mild infection: not associated with an increased white cell count (WCC). Typically associated with fewer than 3 episodes of loose stools per day.
What is a moderate infection of C.Diff?
Moderate infection: associated with an increased WCC (but less than 15 × 109 per litre). Typically associated with 3 to 5 loose stools per day.
What is a severe infection of C.Diff?
Severe infection: associated with a WCC greater than 15 × 109 per litre, or an acutely increased serum creatinine concentration (greater than 50% increase above baseline), or a temperature higher than 38.5 degrees Celsius, or evidence of severe colitis (abdominal or radiological signs).
What is a life-threatening infection of C.Diff?
Life-threatening infection: symptoms and signs include hypotension, partial or complete ileus, toxic megacolon or CT evidence of severe disease.
What is the first line investigation for C.Diff?
Stool culture, which must also be toxin positive
What is the first-line treatment for C.Diff
ORAL vancomycin
What is Tetanus caused by?
Clostridium Tetani
What are risk factors for Tetanus?
- High risk associated with wounds contaminated with garden soil, manure or caused by rusty metals
What is the treatment of Tetanus?
- Metronidazole
- Tetanus immunoglobulin must be given
- Supportive care, may require I+V
What investigations might you do for COVID-19?
- RT-PCR testing of an upper respiratory swab to detect SARS-CoV2 RNA
- Chest X-ray or CT scan to identify bilateral lower lung ground glass infiltrates or other abnormalities
- Laboratory tests to identify lymphopenia, increased D-dimer levels, elevated ferritin, and elevated LDH
What is the treatment for Hospitalized patients with COVID-19 with a supplemental oxygen requirement?
Administration of Dexamethasone and Remdesivir in hospitalized patients with hypoxia requiring supplemental oxygenation
What infectious causes might cause a cavitating lung lesion?
- Bacterial such as S.Aureus, TB, Klebsiella, S.Pneumoniae
- Fungal: Histoplasmosis, coccidioidomycosis, candida
What investigations should you do to confirm EBV?
FBC: Elevated lymphocytes
Monospot test: Should be conducted in the second week of illness
How do you get Bacillus Cereus?
Mainly in reheated rice
How do you get Clostridium Perfringens?
Usually found in reheated meat dishes or cooked meats
When are antibiotics indicated in Gastroenteritis?
- Systemically unwell
- Immunosuppressed
- Elderly
What is the most common bacterial cause of Gastroenteritis in the UK?
Campylobacter Jejuni
What is the appearance of Campylobacter Jejuni on microscopy?
Gram-negative rods with characteristic ‘seagull’ shape
What medication can you give in Influenza?
Antiviral treatment with neuraminidase inhibitors (Oseltamivir Tamiflu) if within 48 hours of symptom onset and at risk of complications
What is Leprosy?
Mycobacterial disease that is endemic in a large number of developing countries which is carried by certain animals
What are the features of disseminated lepromatous/multibacillary leprosy?
Where there is poor Th1 cell mediated responses so the bateria become widely disseminated
- Causes diffuse symmetrical peripheral nerve damage through demyelination of peripheral nerves as well as skin changes
- Facial changes include nose destruction and ear swellings
How do you treat Leprosy?
- Dapsone
- Rifampicin
- Clofazimine
What is measles caused by and how does it spread?
-Measles Morbillivirus
- Transmitted via droplets from the nose, mouth, or throat of infected persons
What investigations can you do for Measles?
1st: Measles-specific IgM and IgG serology (ELISA), most sensitive 3-14 days after onset of the rash.
2nd: Measles RNA detection by PCR, best for swabs taken 1-3 days after rash onset.
What is the most common cause of Meningitis?
Viral meningitis, predominantly caused by enteroviruses
What are the CSF features of Bacterial meningitis?
- May be clear or turbid
- 100-200 PMNs
- Culture results positive (may be negative depending on how heavily infected the meninges are)
- Protein raised due to bacterial protein contamination
- Low glucose as bacteria use as an energy source
What are the CSF features of Viral meningitis?
- Clearly or slightly turbid
-15-500x10 9 lymphocytes - Negative culture results
- 0.5-1g/L protein,glucose normal
What are the CSF features of Tubercular Meningitis?
- Clear or slightly turbin
- Fibrin web may develop
- 30-500x10 9 lymphocytes plus PMNs, negative gram staining
- Protein 1-6g/L
- Glucose 0-2.2
What is empirical antibiotic therapy for suspected bacterial meningitis?
2g of IV Ceftriaxone twice daily with IV amoxicillin.
What are some complication of Meningitis?
- Septic shock
- Disseminated Intravascular Coagulation
- Coma
- Subdural effusions
- Syndrome of inappropriate antidiuretic hormone secretion
- Seizures
- Delayed complications: Hearing loss, cranial nerve dysfunction, hydrocephalus, intellectual deficits, ataxia, blindness
- Death
What is the treatment of Cryptococcal meningitis?
Initiation therapy with IV Amphotericin B and oral flucytosine for 2 weeks, followed by maintenance therapy with oral fluconazole for 8 weeks, followed by long-term low dose oral fluconazole as maintenance therapy
What investigations can you do for Mumps?
Usually clinical - need to notify the local Health Protection Unit whenever it is considered.
Need laboratory confirmation using oral fluid sample (salivary IgM)
Can use serum serology (IgM or IgG)
High-resolution ultrasound can differentiate orchitis from torsion.
What antibiotics should be given for an animal bite?
Co-Amoxiclav
What pathogen is associated with pneumonia in alcoholics?
Klebisella
What is Staph Aureus?
A Gram POSITIVE, Catalase POSITIVE and Coagulase POSITIVE organism
How do you differentiate between staphylococci and streptococci?
Whether they may catalase or not
Staph makes catalase whereas streptococcus does not
What are genital warts caused by?
90% are caused by HPV 6 and 11
What is the incubation period of Ebola?
2-21 days
How do you diagnose Leptospirosis?
Serology
How do you treat leptospirosis?
High-dose benzylpenicillin or doxycycline
Give examples of Live Attenuated vaccines?
BCG
MMR
Oral polio
Yellow fever
Oral Typhoid
What is the percentage probability that a unmedicated HIV positive woman gives birth to a HIV seropositive child?
20-40%
What investigations would you do to confirm C. Diff?
Stool/faeces sample sent for Cdiff PCR/microscopy and culture
Testing for C.diff toxin
How is C.Diff spread?
Direct contact person to person from environmental contamination
What is the mode of transmission for EBV?
Salivary exchange
What are some of the complications of infectious mononucleosis?
- Post viral chronic fatigue syndrome
- Splenic rupture
- Guillain barre syndrome
- Encephalitis
- Meningitis
- Hepatitis