Infectious disease Flashcards
Which live attenuated viral vaccines are there?
- MMR vaccine (Measles, mumps, rubella)
- Varicella Zoster vaccine
- Polio vaccine (oral)
- Yellow fever vaccine
Which live attenuated bacterial vaccines are there?
- BCG vaccine
2. Tularemia vaccine (not safe or in use yet)
Which inactivated viral vaccines are there?
- Hepatitis B vaccine
- Influenza vaccine
- Polio vaccine (subcutaneous)
- Rabies vaccine
Which inactivated bacterial vaccines are there?
- DTP vaccine (Diphtheria, tetanus, pertussis)
- Anthrax vaccine
- H. influenza vaccine
- N. meningitidis vaccine
What neurological disorder can measles cause after several years of latency?
Subacute sclerosing panencephalitis
What oral rash is often seen in a patient with measles?
Koplik spots. They are seen 2-3 days before the rash appears.
Where does the measles rash usually first appear?
Rash first appears in the head area and then descends.
Characteristic symptom of mumps?
Enlargement of parotid salivary glands (unilateral in 25% of cases)
Can mumps lead to meningitis?
Yes. Before the vaccine was introduced it was the most common cause of viral meningitis.
For what patients is rubella dangerous?
Pregnant patients as it can cause congenital rubella sydrome or miscarriage
In what cases should immunisation (vaccination) be postponed?
If patient is suffering from acute febrile illness, especially respiratory
(Exception is made if there is a suspicion of rabies)
Are vaccines that contain egg contraindicated to persons allergic to egg?
No. Only if it causes a severe allergic reaction.
What patients should not receive live attenuated vaccines?
- Patients on steroid treatment
- Pregnant patients
- Immunocompromised patients (children with HIV should be vaccinated though)
What does the disease progression of HIV look like?
- HIV transmission
- Primary HIV infections
- Clinical latent period with or without persistent generalized lymphadenopathy
- Early symptomatic HIV infection
- AIDS (=CD4 count below 200)
- Advanced HIV infection (CD4 count below 50)
What does the primary HIV infection look like?
Mimics mononuleosis symptoms and occurs withing the first two to four weeks after someone is infected (but can take longer)
- Fever
- Lymphadenopathy
- Pharyngitis
How do you diagnose HIV?
ELISA and Western blott after that to confirm the diagnosis. After that, you can start testing the CD4 count and the viral load.
What is the normal CD4 cell count?
1000 cells/ul of blood
What AIDS defining illnesses are there?
- Candidiasis in the esophagus, bronchi, trachea
- Cryptococcosis (extrapulmonary)
- CMV infection of any other organ than liver, spleen or lymph nodes. (CD4 <50 if disseminated)
- Kaposi sarcoma (More common at CD4 <200, but can occur at any CD4 level)
- Lymphoma (especially non-hodgkin) (CD4 200-500)
- Mycobacterium avium complex (CD4 <50)
- Pneumocystis jirovecii (CD4 <200)
- Toxoplasmosis
- Tuberculosis (CD4 200-500 for pulmonary, <200 for miliary, but can occur at any CD4 level)
- Cervical cancer
- Recurrent pneumonia
- Sepsis due to non-typhoid salmonella
What complications of HIV can occur at any CD4 counts?
- Lymphoma
- Tuberculosis
- Kaposi sarcoma
- Herpes zoster
What is the most common AIDS-defining illness?
Pneumocystis jirovecii pneumonia
What is the treatment for Pneumocystis jirovecii pneumonia?
TMP-SMX. The treatment is the same as the prophylaxis.
What are the signs and symptoms of Pneumocystis jirovecii pneumonia?
Non-productive cough, dyspnea, normal sounds on auscultation
Interstitial infiltrates with ground glass appearance on X-ray
What are the most common causes for neurological complaint in AIDS?
- Toxoplasma gondii
- Primary lymphoma of the CNS
- Progressive multifocal leukoencephalopathy
What is the most common cerebral cerebral mass in AIDS patients?
CNS toxoplasmosis
What are the signs and symptoms of toxoplasmosis?
Headache, confusion, fever, lethargy, seizures, coma
What is progressive multifocal leukoencephalopathy caused by?
JC virus
How is progressive multifocal leukoencephalopathy diagnosed?
By MRI as it is demyelinising and not a mass-lesion
What is the most common manifestation of a systemic fungal infection in HIV positive patients?
Cryptococcosis
What is characteristic for cryptococcal meningitis?
Very high ICP
What is the treatment for cryptococcal meningitis?
- Fluconazole
- Amphotericin B (2nd line)
What is the goal of antiretroviral therapy?
Achieving a viral load under 50
What are the different classes of drugs in management of HIV?
- Entry inhibitors
- Nucleoside/nucleotide reverse transcriptase inhibitors (NRTI)
- Non-nucleoside reverse transcriptase inhibitors (NNRTI)
- Integrase inhibitors
- Protease inhibitors
Entry inhibitors
Interfere with binding, fusion and entry of HIV to the host cell by blocking one of several targets e.g. the CCR5 receptor.
Nucleoside/nucleotide reverse transcriptase inhibitors (NRTI)
Nucleoside/nucleotide analogues that inhibit reverse transcriptase
Side effect:
- Lipoatrophy (not as much of a problem w/ newer drugs)
- Mitochondrial toxicity (can lead to lactic acidosis!)
Non-nucleoside reverse transcriptase inhibitors (NNRTI)
Non-competitive inhibitors of reverse transcriptase
Integrase inhibitors
Inhibit the viral enzyme integrase, which is responsible for integration of viral DNA into the DNA of the infected cell.
Protease inhibitors
Block the viral protease enzyme necessary to produce mature virions.
Side effect:
- Metabolic alterations (increased visceral fat being the most common)
What classes of drugs does the most common HIV therapy consist of?
2 NRTIs + integrase inhibitor
When should antiretroviral therapy be initiated?
As soon as possible
Cerebrospinal fluid in normal lumbar puncture
- Clear fluid
- Opening pressure 10-20 cm H2O
- WBC 0-5 cells/microliter
- Glucose >60% of serum glucose
- Protein 15-45 mg/dl
Cerebrospinal fluid in bacterial meningitis
- Clear, cloudy or purulent fluid
- > 25 cm H2O opening pressure (=elevated)
- WBC >1000 cells/microliter (doesn’t have to be this high though)
- Glucose <40% of serum glucose
- Protein >50 mg/dl
Numbers that are “normal” do not rule out bacterial meningitis
Cerebrospinal fluid in viral meningitis
- Clear fluid
- Normal or elevated opening pressure
- WBC 10-1000 cells (lymphocytes)
- Glucose is normal, but can be low in HSV infection
- Protein is normal or a little elevated
Cerebrospinal fluid in tuberculosis meningitis
- Clear or opague (yellow-ish) fluid (due to high fibrinogen level)
- Elevated opening pressure
- 50-500 WBCs (lymphocytes)
- Glucose is lower than viral meningitis but higher than bacterial
- Protein is elevated. Not as much as in bacterial meningitis, but higher than viral.
- LOW CHLORINE!
Cerebrospinal fluid in fungal meningitis
- Clear or cloudy
- Elevated opening pressure
- WBC 10-500 cells
- Low glucose
- Elevated protein
What is the common cause of viral encephalitis?
Herpetic encephalitis (HSV-1)
When is lumbar puncture contraindicated?
- If patients displays signs of increased intracranial pressure
- Low platelet level
- Skin infection near the site of lumbar puncture
- Acute spinal cord trauma
- Severe scoliosis
What are the most common causes of aseptic meningitis?
- Arboviruses
- Enteroviruses
- Poliovirus
- Coxsackie virus
- Echovirus
- HSV-2
Signs and symptoms of aseptic meningitis
- Fever (usually low-grade in the initial stage and higher temperature at the onset of neurological signs)
- Headache (almost always present, often reported as severe)
- Nausea and vomiting
- Signs of meningeal irritation (positive Brudzinski or Kernig sign)
- Altered mental status
- Muscle ache
The absence of meningeal signs does not rule out meningitis
Signs and symptoms of encephalitis
- Alterations of consciousness
- Focal neurological signs
- Seizures
- Headache
- Fever
Common causes of encephalitis
- HSV-1
2. Arboviruses (TBE virus, yellow fever virus, dengue virus, japanese encephalitis virus, west nile virus)
What is the best diagnostic test in HSV encephalitis and what is the treatment?
MRI as you might see changes in the frontal and temporal lobe.
IV acyclovir is the treatment. Foscarnet in case of resistance.
Signs and symptoms of flavivirus encephalitis (e.g. west nile virus, japanese encephalitis)
- Parkinsonian movement disorder (masklike facies, tremors, cogwheel rigidity etc.)
- Upper motor neuron involvement (flaccid paralysis that resembles polio)
- Seizures (more common among children)
What empiric drug therapy is given if you suspect meningitis?
Steroids (dexamethasone) + antibiotics (3rd generation cephalosporine + ampicillin or meropenem as the only antibiotic) + acyclovir (if there is the slightest suspicion of HSV being the causative agent)
Steroids are given either before or with the antibiotics, not after.
These are the Swedish guidelines. In our exam, they probably want Vancomycin to be added to the therapy as well.
Signs and symptoms of bacterial meningitis
- Fever
- Chills
- Headache
- Signs of meningeal irritation
- Vomiting
- Confusion
- Petechiae (present in 50% of patients w/ meningococcal meningitis)
How do you diagnose bacterial meningitis?
Lumbar puncture is the only way to get a definitive diagnosis. CT is only done to exclude ICP or another lesion.
When should the dexamethasone therapy in case of meningitis be discontinued?
If it is not caused by S. pneumonia, it should be discontinued.
Signs and symptoms of tuberculosis meningitis
- Usually subacute or chronic presentation
- Persistent fever and increasing headache over a pariod of weeks or months
- Decreased chlorine in CSF examination
- Cranial nerve palsies
What are the common causes of bacterial meningitis?
- Pneumococci
- Meningococci
- Haemophilus influenzae
- Listeria monocytogenes
- Beta-hemolytic streptococci
- Mycobacterium tuberculosis
Who should be contacted if a patient has a spinal and/or brain abscess?
Neurosurgeon
What is a brain abscess?
Focal intracerebral infection that begins as a localized area of cerebritis and develops into a collection of pus surrounded by a well-vascularized capsule
Develops step by step Early cerebritis (Day 1-3) > Late cerebritis (Day 4-9) > Early encapsulated stage (Day 9-14) > Late encapsulated stage (Day >14)
Early cerebritis
- Patient usually doesn’t contact a doctor by this point
- Focal area of inflammation
- Can suddenly develop seizures or septic emboli
Late cerebritis
- Usually complains about headache that doesn’t respond to painkillers
- MRI can be used for diagnosis
- Expansion of cerebritis
Early capsulate stage
- Establishment of a ring-enhancing lesion
Where do brain abscesses most commonly originate from?
- Sinus infection
- Middle ear infection
- Tooth infection
Signs and symptoms of brain abscesses
A lot of abscesses are in the “silent” part of the brain and the signs and symptoms can be quite non-specific
- Headache (65%)
- Vomiting (52%)
- Fever (50%)
- Lethargy (45%)
- Seizures (33%) - sudden onset
- Papilledema (55%)
- Focal deficits (40%)
- Nuchal rigidity (18%)
How are brain abscesses treated?
Either with antibiotics or surgically. Antibiotic treatment usually lasts quite a long time.
<2 cm, antibiotics (surgery rarely required)
2-4 cm, variable
>4 cm, surgical drainage
3rd generation cephalosporin + metronidazole (empirical treatment)
Steroids are not given!
What is the best way to diagnose spinal abscesses?
MRI
Lumbar puncture is STRONGLY contraindicated!
What are the most common sources of infection for spinal abscesses?
- No source identified (30%)
- IV drug abusers (26%)
- Skin and soft tissue infection (22%)
- Spinal surgery (12%)
- Bone or joint infection (7%)
Bacteria usually access the epidural space by contiguous spread or hematogenous dissemination
Signs and symptoms of spinal abscesses
- Back pain and tenderness (the most common symptom)
- Fever
- Neurologic deficits
This is the classic triad, but only 8% of patients experience all of these symptoms
What is the most common localization of a spinal abscess?
Thoracic (44%)
Lumbosacral (35%)
Cervical (21%) < Most dangerous localization
What families of ticks can transmit pathogens to humans?
- Ixodidae (hard ticks)
- Argaside (soft ticks)
What bacteria is Lyme disease caused by?
The spirochete Borrelia burgdorferi
What are the three clinical stages or Lyme disease?
- Early localized
- Early disseminated
- Chronic disseminated
What is the clinical manifestation of early localized Lyme disease?
Erythema migrans
- 3 days - 1 month incubation time
- Macule or papule at the site of the bite which extends centrifugally and increasing to several dozen cm in diameter within 2 weeks
- Should atleast be 5 cm in diameter
- Occurs in 60-80% of cases
- Treat at once, no need for Ig test
How long time does it take for antibodies to appear in Lyme disease?
Several weeks (slides say 4-6, but can appear within 2-3)
What ocular manifestations can Lyme disease present with?
Uncommon, but:
Early -> Conjunctivitis, periorbital edema
Late -> Optic neuritis
What is the clinical manifestation of early disseminated Lyme disease?
Lymphocytoma
- Solitary, deep red, slightly tender nodule
- Appears at the site of the tick bite or remote from it (often earlobe in children and nipple in adults)
Atrioventricular block
- May progress to asystole
Cranial neuropathies
- Especially facial nerve palsy
What is the clinical manifestation of late disseminated Lyme disease?
Acrodermatitis chronica atrophicans
- More common in Europe
Joint involvement
- Usually the large joints
How is Lyme disease diagnosed?
Serology: ELISA + western blotting confirmation
What is the treatment for Lyme disease?
Doxycycline
How does Tularemia typically present and how is it transmitted?
Transmitted by
- Mosquito
- Tick bite
- Deer flies
- Direct contact with infected animal
- Contaminated water or meat
Ulceroglandular
- Tender lymphadenopathy
- Skin lesion appears either before, simultaneously or after the lymphadenopathy and starts as a red painful papule in the region draining into the involved lymph nodes
- The papule then undergoes necrosis, leaving a tender ulcer with a raised border
Glandular
- Enlargement of the lymph nodes, but without evident cutaneous lesions
- Fever
- Chills
- Headache
- Malaise
- Anorexia
- Fatigue
What is the 1st line drug when treating Tularemia?
Streptomycin
Ciprofloxacin in Sweden
What is tick paralysis?
Prolonged attachment of tick that causes paralysis. It beings in the lower extremities and ascends symmetrically. Rapid resolution of symptoms when tick is removed
What bacteria causes Rocky mountain spotted fever?
Rickettsia Ricketsii
What are the risk factors for Rocky mountain spotted fever?
- Male sex
- Exposure to dogs
- Residence in a grassy or wooden area
(Patient is usually a 5-9 year old child)
How does Rocky mountain spotted fever manifest clinically?
It usually begins with fever, headache and myalgia. After 3-5 days the patient develops a pathognomic rash. The rash is usually on the palms and soles.
How is Rocky mountain spotted fever treated?
Doxycycline
How does Babesiosis usually present clinically?
It is quite similar in presentation to malaria
- Malaise
- Fever
- Headache
- Hemolytic anemia
- Anorexia
- Drenching sweat
- Kidney failure
How is Babesiosis diagnosed?
Blood smear
How does Ehrlichiosis (Anaplasmosis) manifest clinically?
Difficult to recognize clinically
- Acute onset
- Fever
- Myalgia
- Chills
- Night sweats
- Headache
How does tick-borne encephalitis typically present?
Bi-phasic
Illness -> Resolves -> Illness
What are the most important pathogens when it comes to solid organ transplantation?
Viruses: CMV, Herpesvirus, HIV, Hepatitis (A, B, C, D), HTLV-1, LCMV
Fungi: Histoplasma, Coccoidoides, Cryptococcus
Protozoa: Toxoplasma, Malaria, T. Cruzii
Bacteria: TB
Prions: Creutzfeldt-Jakob disease
What are the SIRS criteria?
2 or more of the following: Temperature: >38 or <36 Tachycardia: >90 RR: >20/min or CO2 <32 mmHG / 4 kPa WBC: > 12000 or <4000
What sepsis patients need to be isolated?
Those infected with Neisseria meningitidis
What pathogen causes Waterhouse-Friderichsen syndrome?
N. meningitidis
How does Waterhouse-Friderichsen syndrome present?
Massive hemorrhage into one or both adrenal glands. Characterized by overwhelming bacterial infection leading to massive blood invasion, organ failure, coma, low BP and shock, DIC with widespread purpura, rapidly developning adrenocortical insufficiency and death.
How is Waterhouse-Friderichsen syndrome treated?
Ceftriaxone + hydrocortisone to reverse hypoadrenal shock
How is disseminated intravascular coagulation (DIC) treated?
- Sepsis is the most common cause, so antimicrobial treatment is essential.
- Platelets and plasma
- Concentrates of coagulation inhibitors
How is neutropenic fever defined?
- Neutrophil count <500
- Fever >38,3 in a single oral measure or >38 for over 1 hour
What are typical clinical manifestations of Typhoid fever (Salmonella typhi)?
- Rose-colored spots
- Sustained fever
- Bradycardia
- Splenomegaly
- Drowsiness
- Confusion
- Diarrhea
- Travel history to India
What can the level of hypoglycemia in malaria predict?
The severity of the outcome
In which diseases does the patient often display a double quotidian fever? (two fever spikes in a day)
- Miliary TB
- Endocarditis
In which diseases does the patient often display sustained fever?
- Brucellosis
- Typhoid fever
- Tularemia
- Rickettsiosis
In which diseases does the patient often display remittent fever? (Patient always has fever, but with fluctuating temperatures)
- Mycoplasma pneumonia
- Plasmodium falciparum malaria
In which diseases does the patient often display relapsing fever? (Fever comes, goes away and then comes again)
- Lymphomas
- Lyme disease (Borreliosis)
- Dengue fever
In which diseases does the patient often display Faget sign? (Bradycardia and fever, which is quite contradictory as a febrile person mostly presents with tachycardia)
- Typhoid fever
- Brucellosis
- Brain abscess
- Tularemia
- Yellow fever
Clinical manifestation of liver cirrhosis
- Jaundice
- Ascites
- Spider angiomas
- Palmar erythema
- Easily bruised
- White nails
- Gynecomastia
What is ALT indicative for?
Liver damage (more specific than AST)
What is AST indicative for?
Also liver damage, but less specific than ALT
What do you test when you test PT?
Prothrombin time -> the time it takes for your plasma to clot
What is the definition of fulminant hepatic failure?
Massive necrosis of liver cells eventually accompanied by hepatic encephalopathy without pre-existing chronic lives disease
What are the most common causes for fulminant hepatic failure?
Toxic induced or viral causes are the most common
What lab results are usually seen when it comes to cirrhosis in chronic hepatitis?
- High AST:ALT ratio (Hepatocytes are massively destroyed, hence the low ALT production)
- Low albumin
- Prolonged PT
- Elevated bilirubin
- Low platelets
What is the Child-Pugh score used for?
Assessing the prognosis of liver cirrhosis
Why can liver cirrhosis cause kidney failure?
The kidney failure is due to changes in blood flow. Decreased liver function leads to changes in intestinal blood flow which in turn leads to altered blood flow and vessel tone in the kidney
What is the criteria used to assess the severity of hepatic encephalopathy?
West Haven criteria
What is standard drug therapy in hepatic encephalopathy?
Lactulose
What is the viral genome of Hepatitis A and how is transmitted? Is it chronic?
- ssRNA
- Feco-oral transmission
- Not chronic
What is the viral genome of Hepatitis B and how is it transmitted?
- dsDNA
- It’s present in all bodily fluids of infected persons (higly unlikely that it is spread by e.g. kissing)
When can passive HBV passive immunization be used?
Passive immunization = Hep B immunoglobulin
- Can be given at birth to decrease perinatal transmission
- Short term protection
What other virus does the HBV active vaccine protect against?
Hepatitis D virus
What markers are used when it comes to HBV?
HBV DNA
- The viral load
- Measures current virus activity
HBeAG
- Indicator of active viral replication
HBsAg
- Indicates current HBV infection
What is Gianotti-Crosti syndrome?
A reaction of the skin to a viral infection. Hepatitis B virus and Epstein–Barr virus are the most frequently reported pathogens.
A symmetrical papular or papulovesicular skin rash occurring mainly on the face and distal aspects of the four limbs. Lasts for atleast 10 days.
What is the treatment for chronic hepatitis B?
- IFN alpha
- Lamivudine
- Entecavir
- Tenofovir
What is the viral genome of Hepatitis C and how is it transmitted?
- ssRNA
Transmitted by
- IV users
- Blood transfusion
- Tattooing
- Sexually
Can HCV be cured?
Yes, with direct acting antivirals such as NS5B polymerase inhibitors
Who are at risk for Hepatitis E virus?
Pregnant women
How does malaria develop in the body?
Parasites are injected by mosquitos into blood as sporozoites > sporozoites invade hepatocytes > transform into hypnozoites in liver > exit liver into blood as merozoites > multiply in erythrocytes and are now called trofozoites > erythrocytes eventually get so big that they burst > parasites burst out and infect other erythrocytes
What species of plasmodium malaria can remain dormant in the liver for years?
P. Ovale and P. Vivax
The only regimen to eradicate them is Primaquine
What species of malaria is the most common and most dangerous?
Plasmodium falciparum
Cyclical fever is the hallmark of malaria and occurs shortly before or at the time of red cell lysis, but how often does it occur in the different species of malaria?
P. vivax and P. ovale
- Every 48 hours
P. malariae
- Every 72 hours
P. falciparum
- Does not follow the characteristic pattern
- Continous fever with intermittent irregular spikes is more characteristic
What are the signs and symptoms of malaria?
- Hepatomegaly
- Anemia
- Jaundice
- Splenomegaly due to the destruction of erythrocytes
- Decrease in platelets -> Bruised more easily
- Fever and chills
The symptoms are quite unspecific in the beginning. If the patient has a history of travelling to malaria endemic areas and presents with symptoms of flu -> test for malaria
Best time to test for malaria is when the patient has high fever
The malaria attack has three stages, which ones?
- Cold stage (lasts between 15 min - hours)
- Hot stage (lasts for hours)
- Can cause brain damage in young children
- Tachycardia
- Altered consciousness
- May have abdominal symptoms such as nausea and vomiting, abdominal pain, diarrhea - Sweating stage
- Generalized diaphoresis
- Patient can have a feeling of impending doom
What species of malaria can cause microvascular dysfunction?
P. falciparum
How is malaria diagnosed?
Blood smear
If the clinical picture is characteristic, repeat blood smear if results are negative the first time
How is malaria treated?
Quinine is the main drug that should be offered in severe malaria (slides)
Artesunate I.V for severe falciparum cases (Sweden)
Artemeter for mild falciparum cases (Sweden)
Quinine for easy cases of ovale, vivax and malariae (Sweden)
What are the prophylactic drugs for malaria?
- Doxycycline (Contraindicated in pregnancy)
- Atovaquone-Proguanil (malarone) (contraindicated in pregnancy)
- Mefloquine (avoid alcohol)
- Chloroquine
- Primaquine
What amoeba can cause symptomatic Amoebiasis?
Entamoeba Histolytica
What are the signs and symptoms of symptomatic amoebiasis?
- Dysentery (Diarrhea w/ blood)
- Abscesses in liver and other organs (most common in liver)
- Rectal pain
It can live in the body for a long time without any symptoms
What is the route of transmission for E. histolytica?
Ingestion of cyst from fecally contaminated water or food
How is amoebiasis diagnosed?
- Stool sample
- Serology
- Non-invasive imaging of the liver
Signs and symptoms of amoebic liver abscess?
- Usually located in the right lobe
- Single lesion
- Encapsulated with a necrotic center
What is leishmaniasis caused by?
Parasites of the leishmania type, spread by certain sandflies
Typically affect HIV positive patients
What types of leishmanias are there?
- Mucocutaneous leishmaniasis
- Cutaneous leishmaniasis (most common)
- Visceral leishmaniasis
How does cutaneous leishmaniasis present?
Presents as a papule that gradually increases in size, becomes crusted. Nontender. Eventually ulcerates.
How does mucocutaneous leishmaniasis present?
Both skin and mucosal ulcers with damage primarily of the nose and mouth
How does visceral leishmaniasis present?
Also called “Black fever” or “Kala-azar”
Signs:
- Fever (100%)
- Weightloss (100%)
- Cough (75%)
- Low WBC
- Hypergammaglobulinemia
- Diarrhea
- Epistaxis
- Hepatosplenomegaly
- Lymphadenopathy
- Hyperpigmented skin
How is leishmaniasis diagnosed?
By demonstration of amastigotes in infected tissue
How is leishmaniasis treated?
Amphotericin B
How is schistosomiasis transmitted?
People become infected when larval forms of the parasite – released by freshwater snails – penetrate the skin during contact with infested water.
What is another name for acute schistosomiasis and what are the signs and symptoms?
Katayama fever
- Fever
- Urticaria
- Fatigue
- Hepatosplenomegaly
- Abdominal pain
- Dry cough with changes on X-ray
How is schistosomiasis diagnosed?
- Microscopic examination of stools or urine (eggs can be found)
- Examine water that is suspected for causing the transmission
- Serological testing (ELISA)
What is the treatment for schistosomiasis?
Praziquantel (in a single dose)
What is Onchocerciasis (river blindness) caused by and how is it transmitted?
It is caused by the parasite O. volvolus, a roundworm. Transmitted by a type of black fly.
What are the signs and symptoms of onchocerciasis?
- It is the second-most common cause of blindness due to infection, after trachoma
- Causes changes in skin and bones
- Extensive disfiguring skin changes
- Eventually form nodules commonly located over bony prominences
How is onchocerciasis diagnosed?
Biopsy of the skin into saline and wait for larva to come out
How is onchocerciasis treated?
Ivermectin is the drug of choice
What is lymphatic filariasis caused by?
Mostly by Wuchereria bancrofti (90%), parasites trasmitted by mosquitos
What are the signs and symptoms of acute lymphatic filariasis?
- Inflammation of limbs or scrotum
- Tropical pulmonary eosinophilia
What are the signs and symptoms of chronic lymphatic filariasis?
- Elephantiasis
- Hydrocele
What causes Hydatid disease (Echinococcosis)?
Caused by parasitic tapeworm. Mostly transmitted to humans from dogs. Dogs are infected by sheep.
What are the signs and symptoms of echinococcosis?
- Formation of “cyst in a cyst”
- Symptoms based on localization of the cyst (75% are localized in liver, 5-15% in lungs, other 10-20%)
- Many cysts are asymptomatic and only found incidentally
How is echinococcosis diagnosed and treated?
- USG
- Surgical intervention combined with albendazole treatment before and after the surgery
What are the signs and symptoms of Echinococcus multilocularis?
- It takes 5-15 years to develop symptoms after infection
- Most cysts are present in the liver
- Resembles an aggressive neoplastic disease and can be metastatic
- Jaundice is usually the first initial symptom
- Budd-Chiari syndrome (triad of abdominal pain, ascites and hepatosplenomegaly due to thrombosis in hepatic veins and/or inferior vena cava)
What is the most common cause of nosocomial diarrhea?
Clostridium difficile infection (gram positive, spore-forming anaerobic bacillus)
What is usually the cause behind clostridium difficile infection?
It is usually antibiotic-related. All antibiotics can predispose for a clostridium difficile infection due to them causing changes in the gut flora
What are the signs and symptoms of clostridium difficile infection?
- Mild to moderate diarrhea
- Pseudomembranous colitis
- Fulminant colitis
How is clostridium difficile diagnosed?
- PCR
- Enzyme immunoassay
- Tissue culture cytotoxinity assay (test for toxin A and B that is released by the bacteria)
- Stool test
How is clostridium difficile treated?
Asymptomatic
- No need for treatment
Mild to moderate disease
- Oral metronidazole
Severe disease
- Oral vancomycin
Relapse
- Vancomycin
How is salmonella typhi or paratyphi diagnosed?
By culturing pathogen from stool
Signs and symptoms of pneumonia caused by Streptococcus pneumoniae?
- Older patient
- It is common that the patient suffers from a chronic disease
- Abrupt onset
- Fever
- Chills
- Productive cough
Signs and symptoms of pneumonia caused by Staphylococcus aureus?
- Older patient
- Can be acquired nosocomially
- Rapid progression of illness
- Can lead to abscess formation
Signs and symptoms of pneumonia caused by Mycoplasma pneumoniae?
- Common among young patient (5-40 years old)
- Can exhibit atypical symptoms
- Subacute presentation
Signs and symptoms of pneumonia caused by Legionella?
- Usually acquired abroad (often due to air-condition contaminated water)
- Cough
- Fever
- Myalgia
- Abdominal symptoms such as nausea, vomiting and diarrhea may also be present!
What are some complications of pneumococcal pneumonia?
- Purulent pericarditis
- Pericarditis
- Endocarditis
What bacteria causes tetanus?
The gram positive, anaerobic, spore-forming bacillus Clostridium tetani. It is the toxin produced by the bacteria that actually causes the disorder.
Will a person with tetanus develop changes in consciousness?
No
What are the signs and symptoms of tetanus?
- Symmetrical increase of muscle tone that starts in the head and travels down the body
- Increased muscle tone in masseter muscle (lockjaw)
- Risus sardonicus
- Opisthotonus
How is tetanus diagnosed?
Clinical picture is the only diagnostic test
What can mimic tetanus?
Strychnine poisoning since it also inhibits GABA and glycine
What is the treatment of tetanus?
Depends on the severity
- HTIG (Human tetanus immunoglobulin)
- Vaccine
- Metronidazole
- Asess the airways and ventilation
- Benzodiazepine IV
- Intubation
- Neuromuscular blockade
Also remember to give rabies prophylaxis if it was acquired through a bite wound
What bacteria causes botulism and how is it transmitted?
- Clostridium botulinum (bacteria, but the disorder is caused by the toxin it produces)
- Food-borne transmission
What are the signs and symptoms of botulism?
- Paralytic disorder that begins with cranial nerve impairment
- Symptoms start from the head and progresses down
- Symmetrical descending paralysis
- No changes in consciousness
- Diplopia
- Ptosis
- Dilated pupils
- Respiratory failure
- Dry mouth
- Urinary retention
How does the botulinum toxin act?
It prevents the release of the neurotransmitter acetylcholine from axon endings at the neuromuscular junction
How is botulism diagnosed?
- Primarily a clinical diagnosis
- A definite diagnosis can be made if botulinum toxin is identified in the food, stomach or intestinal contents, vomit or feces
What is the treatment for botulism?
- Antitoxins
- Intubation with respiratory support
What bacteria causes diphtheria and how is transmitted?
- Corynobacterium diptheria
- It is transmitted by respiratory droplets
- The bacteria can produce toxins that affect the heart, kidneys, nervous system and respiratory tract
What is the clinical picture of diphtheria?
- The patient comes in with something that looks ike bacterial pharyngitis or mononucleosis (grey/white plaque on pharynx and tonsils)
- Lymphadenopathy on neck and submandibular lymphadenopathy (severe cases -> bull neck)
- Fever
- Sore throat
What can the toxin that difteria affect?
Cardiac toxicity
- Myocarditis
- AV block
- Congestive heart failure
Neurological toxicity
- Local paralysis of the soft palate
- Inhibits synthesis of myelin
Renal toxicity
- Kidney failure
What is ebola caused by and which species is the most dangerous?
- Ebola virus (single stranded RNA)
- Zaire species
How is ebola spread?
Bodily fluids (mostly from other humans, but can also be transmitted from certain animals such as bats)
- Blood
- Feces
- Vomit
What is the clinical picture of ebola?
4-10 days incubation period
First symptoms
- Fever
- Fatigue
- Myalgia
- Headache
Day 10
- Sudden high fever
- Hematemesis (Vomiting blood)
Day 11
- Bruising
- Brain damage
- Bleeding from mouth, nose, eyes, anus, ears
Day 12
- Loss of consciousness
- Seizure
- Massive internal bleeding
- Death
What is the treatment of ebola?
Symptomatic treatment
- Fluids
- Electrolytes
- O2
What is leptospirosis caused by and how is it spread?
- The bacteria Leptospira interrogans
- Humans are infected either directly through exposure to the urine of an infectious animal or indirectly, generally through fresh water contaminated by infectious urine.
What are the signs and symptoms of leptospirosis?
Generally asymptomatic
If not, it usually presents with influensa-like symptoms
In severe cases
- Extreme myalgia
- Weil syndrome (kidney failure, liver damage and hemorrhage, conjunctival suffusion (red eyes))
- Vasculitis
How is leptospirosis treated?
Penicillin (slides
Sweden
- Doxycycline in mild cases
- Benzylpenicillin in severe cases
What is the treatment for tuberculosis?
First
- Isoniazid for 8 weeks
- Rifampicin for 8 weeks
- Pyrazinamide for 8 weeks
- Ethambutol (or streptomycin) for 8 weeks
Second (given directly after the first treatment)
- Isonizaid + rifampicin for 7-10 months
What herpes viruses are there and what genome do they have?
- They are all DNA viruses
There are nine that are known to infect humans
- HSV-1
- HSV-2
- VZV
- CMV
- EBV
- HHV 6A / 6B
- HHV 7
- HHV 8
What is Mollaret syndrome (benign recurrent lymphocytic meningitis)?
- It is characterized by repeated episodes of meningitis, typically lasting two to five days, occurring weeks to years apart
- It is caused by HSV-2 mostly (but also HSV-1)
- Unusual
Where does Varicella zoster virus stay dormant after the primary infection (chickenpox)?
- Nerves, including the cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia
- It can reactivate later on and cause neurologic conditions
How does chickenpox manifest clinically?
- Fluid filled vesicles that eventually crust within a few days. Heal within a few weeks.
- The vesicles are in different stages
- Fever is usually low
How does herpes zoster manifest clinically?
- Unilateral rash in a single dermatome (area of skin innervated by a nerve)
Ramsay hunt syndrome type 2 (Herpes zoster oticus)
- Facial palsy
- Ear pain
- Vesicular rash in the ear canal
What is the primary infection caused by Epstein-Barr virus?
- Classic infectious mononucleosis
- Common among adolescents and young adults
What are the signs and symptoms of mononucleosis?
- Pharyngitis
- Enlarges tonsils
- Exudate on tonsils
- Generalized lymphadenopathy
- Fever
- Splenomegaly
- Hepatomegaly
- Patient develops characteristic maculopapular rash if it is misdiagnosed and patient is given beta-lactam antibiotics.
How is mononucleosis diagnosed?
- Heterophile antibody test
- CBC
- Monospot
How is mononucleosis treated?
Not treated in uncomplicated cases
In severe cases
- Steroids may be useful if there is a risk of airway obstruction, a very low platelet count, or hemolytic anemia.
What causes erysipelas?
Usually caused by group A streptococcus
Staphylococci less commonly
What conditions can predispose to erysipelas?
- A cut in the skin
- Venous insufficiency
- Lymphatic stasis
What are the signs and symptoms of erysipelas?
Can be the first presentation of diabetes, so check glucose!
- Fever
- Chills
- Sharply demarcated superficial infection with intense redness that spreads gradually
What are differential diagnoses for erysipelas?
- DVT (but no fever present here!)
- Septic arthritis
- Necrotizing fasciitis
How is erysipelas treated?
Treated with Penicillin G in severe cases
Give three examples of viruses that can cause viral hemorrhagic fever
- Ebola virus
- Dengue virus
- Yellow fever virus
What causes dengue fever and how is it transmitted?
- Dengue virus
- Aedes mosquitos (no human-human transmission)
What are the signs and symptoms of dengue fever?
- 80% are asymptomatic or have only mild symptoms such as an uncomplicated fever
- Sudden onset fever
- Headache
- Pain in muscle and joints
- Rash in 50-80% of symptomatic patients a few days later in the course of the illness (rash resembles measles rash)
How is dengue fever diagnosed?
- Mainly clinically
- Tourniquet test
- PCR
How is dengue fever treated?
- There is no specific antiviral treatment
- Maintain proper fluid balance
Should you perform a colonoscopy on a patient with fulminant colitis?
No, it is contraindicated
How is typhoid fever treated?
- Ciprofloxacin
- Ceftriaxone
Name three bacteria or viruses that can cause vasculitis
- Streptococcus pneumoniae
- Staphylococcus aureus
- Salmonella typhi
- Treponema pallidum
- Rickettsia ricketsii
- Cytomegalovirus
- HSV-1 and HSV-2
- Mycobacterium tuberculosis
- Hepatitis B virus
- HIV
What is cat-scratch disease and how is it transmitted?
A disease caused by the bacteria Bartonella henselae. It is transmitted by either a scratch or a bite from a cat
What are the signs and symptoms of cat-scratch disease?
- Mild to moderate fever in about 1/3 of cases
- A primary skin change (papula or vesicle that may resemble an insect bite) is often formed at the site of scratch or bite approximately 7-14 days after contact and may persist for several months with moderate production of pus.
- Local lymphedema that can be tender and sometimes suppurative. Most common in the axilla.
How is cat-scratch disease diagnosed?
PCR
How is cat-scratch disease treated?
- It is usually self-limiting
- Doxycycline
- Azithromycin
Name some tick-borne diseases
- Lyme disease
- Rocky mountain spotted fever
- Anaplasmosis
- Tularemia
- TBE
- Babesiosis