Approach to infectious disease ER Flashcards
Fever in the ER
- Very common ED complaint
- Normally 36.5- 37.5℃
- Various causes, but obviously infection is considered
most common - Broad DDx, and cause is not always clear
- Body temperature controlled by the hypothalamus
specific cytokines trigger elevation of the set point - Much like a thermostat in a house, during a fever, the
hypothalamic set point is raised to 37 -39℃ - A process of vasoconstriction, shivering raises the body’s
core temperature - Rectal temperature is more accurate than oral, which
tends to be lower
Fever vs hyperthermia
- Fever differs from hyperthermia, in which the
hypothalamus set point is unchanged - The elevated core temperature in hyperthermia can be
from various factors, hot environment etc. and can reach
higher temperatures than seen in fever - Hyperthermia typically not affected by antipyretics
- Hyperthermia is an uncontrolled increase and will exceed
the bodies capacity for heat regulation
Fever causes
- Infections
- Malignancy
- Inflammation
- Autoimmune diseases
- Medications- “Drug Fever”
Fever may not be produced in _____
newborns, elderly,
immunocompromised patients, etc
______ is considered
the Gold Standard for
meningitis, encephalitis, SAH
and other neurologic conditions
Lumbar puncture
Lumbar Puncture contraindications
- Typically a CT head is completed prior to the LP to rule out a space occupying lesion and/or increased intracranial pressure
Lumbar Puncture indications
– Suspected meningitis, encephalitis
– Suspected SAH
– CNS disease eg. Guillain-Barre syndrome or MS, CNS cancers
– Therapeutic relief of idiopathic intracranial hypertension
Lumbar Puncture collection
- Aseptic technique is critical
- Use the manometer in the
spinal tray to measure
opening pressure - Collect at least 1 mL in each
of 4 tubes - Fluid is used for analysis,
culture and PCR
Spinal Hematoma
– Ominous complication of LP- severe or persistent back pain, radicular pain,
new neuro symptoms, cauda equina Sx
– Most present in 6 hrs, Risks recall contraindications eg. anticoagulants
– STAT MRI and neurosurgical consultation
Post-lumbar puncture headache
– CSF leak, 24-48 hrs, most common. Tx- Spontaneous resolve or blood
patch if persistent
The key to rabies management is having an understanding of ______
pre- and post- exposure prophylaxis
In North America major vectors of rabies are:
include foxes, coyotes, bats,
skunks, raccoon.
Rabies and Dogs
- In the case of domesticated dogs in the US, the
large majority are vaccinated, although a dog
bite is a reportable event. Check dog Hx. - Rabies cases do occur in the US (38 cases from
2003-2016) - Worldwide, 99% of rabies is acquired by dog
bites - In the US, the majority of rabies cases are from
bats. Cases with unknown source do occur
Pathophysiology of Rabies
- Virus transmission is due to direct contact with salivary contact
- Source is salivary glands of the biting animal, and virus is deposited in tissues
- The rabies virus is a Lyssavirus. Replicates in the mammalian central nervous system, and is not associated with insect transmission.
- Long incubation period 20-90 days
- Ascends and replicates along peripheral neuronal axons,
progressing towards the spinal cord, and CNS - Replication in gray matter leads to spread to all tissues and organ systems
- Rabies encephalitis is a CNS infection with leukocyte infiltration, focal hemorrhage and demyelination in the gray matter
Rabies Pre-Exposure Prophylaxis
- Rabies vaccine is available, and can be offered
pre-exposure based on risk to individual
– Recreational or occupational exposure - lab workers, cavers, animal-control, wildlife worker, etc.
– Can be received from health department, PCP, veterinarian
– Vaccine given for pre-exposure does not negate need for
post-exposure treatment, but recommendations are
different. Patients need to be made aware of this
Rabies Vaccine Schedule (pre-exposure prophylaxis)
– Primary IM HDCV or PCECV; 1.0 mL (deltoid) one dose on
days 0,7 and 21 or 28 (Total of 3 doses)
– Booster HDCV or PCECV; 1.0 mL (deltoid) one dose
* Booster is given based on risk and serologic testing for
the rabies neutralizing antibodies; done q 6 months in
those of high risk. Booster given if titers low
Rabies Exposure
– Risk of rabies after a bite depends on severity of the wound,
depth, multiple bites, location, etc.
* Multiple bites near face 80- 100%
* Single bite 15-40%
* Superficial bite to the extremity 5%
* Contamination of a recent wound by saliva 0.1%
* Contact with rabid saliva on a older wound > 24 hrs 0%
* Transmission indirectly (eg. saliva on a tree branch or animal) is
theoretical
Any direct contact with a ____can be considered an exposure
bat
Is human to human exposure possible with rabies?
- Human to human exposure
possible
– Healthcare workers
treating rabies patients - Proper PPE, contact
precautions - Post exposure prophylaxis?
Rabies Post-Exposure Prophylaxis
No prior vaccine prophylaxis, pt. has not been immunized
* Human Rabies Immunoglobulin (HRIG)
* Co-administered with vaccine (Not the same syringe)
* One dose 20 IU/kg around the wound if possible, and the
rest is given IM, distant to vaccine injection site
* HRIG must be started within 7 days of vaccine start
* Vaccine is given; first dose given at same time as HRIG
* Rabies vaccine- HDCV or PCECV 1.0 mL (deltoid) one dose on
days 0, 3, 7, 14
Post-exposure prophylaxis if patient has received prior rabies vaccine
– Cleanse the wound as described above
– HRIG should not be given
– Simply give rabies vaccine booster HDCV or PCECV 1.0 mL
(deltoid) on days 0 and 3
Rabies Encephalitis
Acute encephalitis
* Prodrome
– Pain at bite site, malaise, HA, fever, N/V, anxiety, agitation,
depression
* Acute neurologic phase with CNS involvement
– Anxiety, depression, hyperventilation, aphasia, paralysis,
hydrophobia, aerophobia, confusion, delirium, hallucinations
* Coma about 10 days from symptom onset
* Death
Only 14 patients are known to survive, yet severe neurologic sequelae
Rabies Encephalitis treatment of clinical rabies
- Diagnosis can be difficult without an exposure history
– Maybe found postmortem - Serologic testing and CSF antibodies
- No specific therapy available
- Supportive measures
- Nearly 100% fatal
- Although proper prophylaxis is nearly 100% successful
Tetanus
- Associated with acute wound,
puncture, or contaminated wound - Acute onset of hypertonia, painful
muscle contractions and generalized
muscle spasm - Improved childhood vaccine programs,
boosters for adults, and decreased use
of animal fertilizers have resulted in a
decline in the incidence of tetanus.
Tetanus etiology
- Clostridium tetani is a motile non-encapsulated
anaerobic gram-positive rod - Commonly found in soil and animal feces
- Can survive in the environment for years
C. tetani produces two exotoxins
● tetanolysin
● tetanospasmin- neurotoxin
Tetanus pathophysiology
- Tetanospasmin is a neurotoxin responsible for the symptoms of tetanus. This toxin is taken up by peripheral nerves in a retrograde intraneuronal transport
● By this means, the toxin enters the
CNS
● Loss of normal inhibitory control
leading to tetany
Tetanus presentation
- Incubation period of < 24 hrs to >1 month
- Leads to muscle rigidity and painful muscle contraction
- Pain and stiffness in the masseter muscle (Lockjaw)
- Later descends to the neck, trunk, extremities
● Risus sardonicus (sardonic smile)
● Mental status is normal
● Spasm can last 3-4 wks
● Respiratory compromise
Tetanus Prophylaxis
- Vaccine programs have improved
- Tetanus toxoid has various
combinations - DTap is given to younger children
- Td or Tdap for adults
- Interesting to note, patients who get
disease and recover still need the
vaccine for immunity to occur
Tetanus Immunoglobulin
If patient has never had a tetanus vaccine and/or status is
unknown, or have less than 3 vaccines
* Patient should then receive immunoglobulin for higher
risk wounds, along with the toxoid vaccine
* Give at opposite sides to the toxoid vaccine
* May give in HIV patients regardless of vaccine status
Vaccine recommendations for tetanus
- Childhood vaccines- DTap <7 yrs old
- Adult boosters
– Normally every 7-10 years
– Give if 5 years has passed since last Td
and the wound is dirty, or puncture, etc.
– Give if 10 years has passed since last Td
for all wounds
– Give at least one Tdap booster
– Give if vaccine status is unknown
Tetanus Treatment
- Wound care and debridement
- Tetanus immunization
– Disease does not promote immunity - ICU admission
- Respiratory compromise → immediate neuromuscular
blockade and intubation - Minimize environmental stimuli
- Human tetanus immunoglobulin- neutralizes the toxin
- Metronidazole IV
- Benzodiazepine- muscle relaxant restores inhibition
Tuberculosis
- Cover precautions for a suspected case of TB
● Consider in patients with a
pneumonia like presentation,
especially if prior treatments have
failed.
● Patients with immunosuppressed
High Prevalence of TB (Risk factors)
- Recent arrivals from high-prevalence countries
- Patients with HIV
- Residents and staff of prisons and shelters
- Alcohol abuse or illicit drug users
- Elderly and nursing home patients
T/F Tuberculosis is a reportable
illness
T
Tuberculosis course and hospital management
- Culture lengths make it challenging
- Respiratory precautions in those at risk while awaiting results
– Clues include eg. Hemoptysis, night sweats, weight loss - Separate waiting area, or isolation room eg. negative pressure room
- Airborne Precautions
- Mask for the patient
- Chest X-ray
- Proper PPE for all caregivers
– Gown, N95, Gloves, Hand washing, etc - Minimize exposure
