Tetanus And Rabies Flashcards
Mimics of Tetanus?
Strychnine poisoning
Rabies
Hypocalcaemic tetany
What kind of bacteria is tetanus?
Clostridium Tetani
Anaerobic gram positive bacilli
What is tetanospasmin?
A neurotropic toxin
Travels to spinal cord and disrupts inhibitory neurotransmitters
What is risus sardonicus? Opisthotonus?
Lock jaw smile
Extensive back spasm
How does WHO define tetanus?
It is a clinical diagnosis
How do you Dx tetanus?
Spatula test, they bite down
Clinical diagnosis!!
What is the clinical course?
Injury
7 days later get trismus, dysphagia and back pain
Period of onset is time until spasms which occur around day 10
Typically occur in face, nack, back and rigidity
After day 10, CVS, GI/renal and pyrexia
What are the types of tetanus?
Cephalic tetanus– most rare, lower cranial nerve muscles
Localised tetanus– spasms around muscle of wound, weakness in that leg
Neonatal tetanus
Both progress to generalised tetanus
Treatment?
Minimise light and any stimulus
1st Benzodiazepines , titrate IV benzos such as diazepam and lorazepam
2nd Chlorpromazine
3rd Vecuronium (neuromuscular blockade)
Then use human antitoxin can also use equine
Surgical debridement and metronidazole
Use really short acting beta blockers such as esmolol and morphine, clonidine and magnesium sulphate
Complications of tetanus?
Bone fractures
Rhabdomyolysis
PE
Pressure sores
Muscle rigidity
What is the vaccine?
Need full course of vaccination
You can Never get natural immunity to tetanus!
3 doses followed by 3 boosters
How do you prevent neonatal tetanus?
Clean delivery practice
Vaccinate women of reproductive age
In Jun-immunised pregnant women give them 2 doses of tetanus toxoid one month apart
What is elimination of tetanus defined as?
Elimination defined as <1 NNT case per 1000 live births in every district per year
Is there any reduction in GCS during tetanus, if a patient is confused with muscular spasms is it tetanus?
No!
There is never a reduction in GCS
What causes nocturnal onset of chest discomfort, breathlessness, abdo pain or early morning paralysis?
Caused by Burngarus bites
What are the two main families of snakes?
Viperidae: Relatively short, thich body, short tail and strike like lightening
Elapidae: Relatively long thin body, long tail uniformly coloured
What is the vector of African Tryp?
Glossina Spp.
What are the two species of African Tryp?
T.B. Gambiense is central and West Africa
T.B. Rhodesiense in East Africa
What is the main cause of African sleeping sickness?
Gambiense
What is the most endemic Country of T B Gambiense?
DRC
Gabon
Congo
Which country has both TB Gambiense and TB Rhodiense?
Uganda
Compare clinical features of Rhodesiense with Gambiense
Rhodesiense has trypanosomal chancre ++, can be absent in Gambiense
Haemo-lymphatic stage in Gambiense is low grade fever, no neurological symptoms, typically Posterior Cervical lymphadenopathy
The Haemo-lymphatic stage in Rhodesiense is high fever, lymphadenopathy, rash on legs, multi-organ failure
Meningo-encephalitis stage is seen more in Gambiense compared to rhodesiense as rhodesiense is severe and therefore is diagnosed beforehand
What is time between bite and onset of symptoms in rhodesiense?
10 days
What is winterbottom sign?
Painless poster or Cervical lymphadenopathy in TB Gambiense
What is criteria for diagnosis of Meningo-encephalitis stage?
Presence of tryps in CSF
>5 Leukocytes
(presence of Mott cells)
How do you diagnose gambiense?
CATT (card agglutination test)
LFT
Then go on to do a blood film, lymph node aspiration and use centrifugation methods
Hat in the non endemic setting, who gets rhodesiense vs Gambiense?
Rhodesiense seen almost excludively in tourists from Tanzania, Malawi, Zambia
Mostly diagnosed by blood smear and most are in stage 1, diagnosed within 3 weeks of exposure
Gambiense mostly in migrants
DRC, Gabon and Angola
39% diagnosed by blood smear, 77% diagnosed in stage 2 and diagnostic delay 3-12 months
How do you treat Gambiense?
Fexinidazole for stage 1 and
2nd Stage: Fexinidazole
Except if advanced disease/presence of >100 WBC in CSF where NECT is preferred
Need f/u for 2 years and LP every 6 months if had 2nd Stage Gambiense
How do you treat TB Rhodesiense?
First Stage: Suramin (risk of proteninuria, exfoliative dermatitis, Mazotti test if onchocerciasis)
Second Stage: Suramin and Melarsoprol (Very toxic causes polyneuropathy, hepatitis, haemolysis and encephalitis)
What spreads Ebola?
Pteropodidae fruit bad
How does Ebola spread? incubation time?
Contact with bodily fluids, not aersolised
Incubate 2-21 days
How does Ebola present?
Fever
Bleeding
Bloody diarrhoea
Dx of Ebola?
PCR
Clinica stages of Ebola?
Dry followed by wet (diarrhoea, vomiting) and then stage 3 which is coma, hiccups, haemorrage and seizures
Type of virus Marburg and main reservoir?
Filo virus
Reservoir of lasa virus? Type of virus?
Mastomys natalensis
Arena virus
Signs of lasa?
High fever, sore throat, vomiting, chest pain sensorineural hearing loss
What does hanta virus cause in old world?
Causes haemorrhagic renal failure
What does new world hanta virus cause?
Influenza like illness which causes rapidly progressing pulmonary disease
How is CCHF transmitted?
Ticks are the main vectors
Associated with cattle slaughtering
Clinical signs of scorpion sting? How does envenoming work?
Localised agonising pain
Ion channels block Na, K and Ca channels
Initial parasympathetic signs; vomiting, secretions, sweating, priaprism
Neurotoxic signs; fasiculations, tonic-colonic spasms
Tx initially of scorpion sting?
Digital block of lidocaine or tetracaine
Need ICU tx
Brown recluse spiders also known as? Clinical presentation?
Loxoceles spp
Initial discomfort, erythema
Develops blue/red/white sign
Becomes necrotic eschar
What is a severe complication of loxoceles?
Fever, hemolytic Anaemia, jaundice and AKI
Only 4-19% will develop visceral complications
What spiders cause Neurotoxic araneism?
Lactrodectus spiders (brown and black widow)
Latin American banana spiders (Phoneutria), and
Sydney/Australian funnel-web spiders (Atrax, Hadronyche)
What symptoms do Neurotoxic spiders cause?
Local: immediate pain, sweating, gooseflesh/goose bumps
• Systemic: rapidly-evolving headache, nausea, vomiting, profuse
generalized sweating, fever, priapism, painful muscle spasms,
tremors, rigidity that may cause respiratory distress or simulate an
acute abdomen
Types of fish poisoning?
Ciguatera
Scombroid
Tetrodotoxic
Where is ciguatera fish poisoning and what is it?
Ciguatoxins caused by
Typically round tropical countries
Caused by psuedomonas bacteria
What fish are ciguatoxic?
Grouper
Barracuda
Parrotfish
Moray eel
Trigger fish
red bass
What are the clinical features of ciguatera toxin?
GI symptoms which become parastehsiae, paradoxical dysasthesia, pruritus, numbness and weakness
What type of fish have scombroid poisoning?
Mackerel
Albacore
Yellow fin tuna
Bonito
What are the immediate symptoms of scombroid?
Immediate peri-oral tingling
Histaminic anapylactic reaction
Case fatality is low
Urticaria like rash with throbbing headache, dizziness and syncope
What does Pufferfish poisoning lead to?
Tetrodotoxic poisonings derviced from psuedomonas bacteria
What does shellfish poisoning do?
Diarrheal is due to okadaic acid
Neurotoxic is due to brevetoxin
Paralytic is caused by tetrahydropurine
Domoic acid causes amnesia
Rapid onset parastehsiae, but no paralysis
How do you treat marine poisoning?
Elimante gut contents
-ciguatera poisoning need IV mannitol and restore fluids
-Scombroid poisoning give adrenaline and histamine H1 and H2 receptor blockers
What is important to note seafood toxins?
They are heat and acid resistant!
Prevent eating large tropical sea fish and eat only fresh fish to prevent scombroid poisoning
Tx of amatoxin mushroom poisoning?
Silibinin
N-acetyl cysteine
High dose benzyl penicillin
What are species of rabies and what predominates? What kind of virus is rabies?
Mainly type 1 rabies
Lyssa virus
Where is most rabies worldwide?
India
Two types of presentations in dogs?
Dumb (60%) and furious (40%)
How long does rabies incubate for?
20-90 days
Can be years
What is the clinica picture of rabies?
Earliest symptom is itching
Encephalomyelitis can be furious such as hydrophobic spasms, rapid deterioration into coma, die from cardiac and respiratory arrest
Paralytic ‘dumb’ rabies which is ascending flaccid paralysis. This has a longer survival
How does Paralytic rabies present?
Prodromal fever, headache, parastehsiae at bite site
Pain, flaccid paralysis, Sensory abnormalities in limb.
No hydrophobia, excitation or convulsions.
Death from bulbar and resp paralysis or cardiac arrhythmias
How do you diagnose rabies?
PCR of bodily fluids such as CSF, tears, skin biopsy.
Can immunofluorescence antigen seen in skin biopsy of hairy area
Autopsy/post-mortem needle autopsy
What is post exposure prophylaxsis?
Throughourly clean the wound
Vaccine (x5) and RIG
0, 3, 7, 14 and 28 days is the vaccine regimen
Void suturing the wound
Abx and tetanus if required
What are the categories of rabies post exposure
Cat 1: touching or being licked/intact skin
Cat 2: nibbles without breaking skin
Cat 3: Bites or scratches with breaking skin causing bleeding, contact of saliva with broken skin/mucous membranes and ANY contact with bats
How do you manage CAT 1-3 when not vaccinated?
Cat 1- clean wound and no PEP
Cat 2- clean wound, Vaccinate immediately only give RIG if immunocompromised
Cat 3- clean wound, Vaccinate immediately and RIG
What do you do with immunosuppressed patients for PEP?
Need 5 doses of vaccine irrespective of PREP
Need RIG for category 2 and 3 cases
How else can you give PEP?
4 doses IM over 21-28 days OR give 3 or 2 dose mutli-site ID over 7 days
For those with PrEP either give 2 doses IM over 3 days or give mutli-site ID on 1 day
When is it too late to give PEP?
Too late to give RIG?
When is it too late to give RIG after starting vaccine?
There is no time limit for giving PEP due to long incubation exposure
Too late to give RIG if exposure was more than 1 year ago
Do not give RIG >7 days after starting vaccination process and do not give RIG to immunocompetent people with PrEP
