Neutropenic Fever

Neutropenic Fever

Neutropenia is defined as an absolute neutrophil count (ANC) < 500 cells/mm3 (or 1000 cells/mm3 with expected decrease to 500)

o   ANC=WBC x (neutrophil%+bands%)

• Mild: 1000 – 1500

• Mod: 500 – 1000

• Severe: 100 – 500

• Profound: <100

Causes of neutropenia

o   Chemotherapy - Kills not only cancer cells but also infection fighting neutrophils

o   Drugs (clozapine, methimazole, sulfa drugs), Sepsis, Autoimmune diseases (SLE, RA), Transplants, Alcoholism, Myelodysplastic syndrome, Viral illnesses

Neutropenic Fever is defined as a fever of 38C (100.4F) plus ANC <500 cells/mm3

o   Most severe in those suffering from hematological malignancies

o   Mortality reduced from 90% to 2-21% with early antibiotics

ED Management

o   Full set of labs (Lactate level, CBC, BMP, blood culture x 2, UA, urine culture)

o   CXR

o   CT head with LP if indicated (high suspicion for meningitis) or unknown source

o   *skin exam (decubs, cellulitis); *ORAL exam (mucositits)

o   IVF

o   **Antibiotics

o   Isolation if possible

Common infectious agents

o   Gram negative organisms (E. Coli, Klebsiella, Pseudomonas)

o   MRSA, MSSA, Strep viridans

First line antibiotics

o   Zosyn OR Cefepime OR Ceftazadime OR Carbapenem — Though pseudomonal infection is actually uncommon, bacteremia from it is quite concerning; therefore, your AB regimen (even if single) should always include coverage against it

o   Add Vancomycin if concerned for gram positive bug—  Ie: prior MRSA infections, cellulitis, mucositis, already on gram negative prophylaxis

o   Adjustments based on past history/colonization

• MRSA: vanc, linezolid, daptomycin

• Pseudomonas/ESBL: carbapenems

• Klebsiella: polymyxin-colistin, tigecycline

o   Add antiviral and antifungal medications if clinical suspicion high

*interestingly, low risk patients based on MASCC or CISNE scoring systems and good oncology follow up can be considered for outpatient management with augmentin+ciprofloxacin. Obviously, this is at the discretion of the ED team.

Neutropenic Enterocolitis aka Typhlitis

o   Triad: triad of neutropenia + fever + RLQ pain

o   Bacterial invasion of intestinal mucosa causing necrotizing abdominal infection

o   Conservative management with AB unless peritoneal/bowel perforated

o   Up to 50% mortality

Resources:

rebelEM

LITFL

Cocaine overdose

Cocaine Overdose

Pathophysiology - Sympathomimetic toxidrome associated with following signs and symptoms:  

CNS: Cerebral ischemia/infarct, intraparenchymal or subarachnoid hemorrhage, cerebral artery vasospasm, cerebral vasculitis, cerebral atrophy, and cerebral vascular thrombosis.

Cardiac: Myocardial ischemia/infarct, cardiac arrhythmias, dilated cardiomyopathy, infective endocarditis (IVDA), aortic rupture/dissection, acceleration of coronary atherosclerosis.

Pulmonary: Nasal septal perforation, oropharyngeal ulceration, inhalational injuries (smoking crack cocaine), pneumomediastinum, pneumothorax, pulmonary infarct, hypersensitivity pneumonitis.

GI: Gastroduodenal ulceration/perforation, intestinal infarct/perforation, colitis.

Renal: ARF secondary to rhabdomyolysis, renal infarct.

OB: Placental abruption, low birth weight, microcephaly.

Psych: Paranoia, delirium, suicidal ideation

Initial approach and management:

Start with ABCs:

Airway and breathing — O2 as needed. 

If RSI intubation is needed  avoid succinylcholine - plasma cholinesterase (PChE) metabolizes both succinylcholine and cocaine, and coadministration of succinylcholine can prolong the effects of cocaine and the paralysis from succinylcholine 

In the setting of rhabdomyolysis and hyperthermia, succinylcholine may worsen hyperkalemia and cause life-threatening arrhythmias

Use rocuronium as paralytic and  benzodiazepines, etomidate, or propofol for induction

Cardiovascular complications result in 

Central cardiovascular stimulation responds well to benzodiazepines

Refractory or symptomatic cocaine-induced hypertension can use phentolamine (bolus of 5 to 10 mg intravenously (IV) every 5 to 15 min PRN) 

Alternatives nitroglycerin or nitroprusside

Avoid beta-blockers (unopposed α-adrenergic activity) 

Avoid calcium channel blockers (may potentiate seizures and death)

Massive cocaine toxicity may result in hypotension due to sodium-channel blockade, cardiac dysrhythmias, or cardiac ischemia

treat with 2 to 3 L of rapidly infused isotonic saline

if no improvement use direct-acting vasopressors such as norepinephrine or phenylephrine 

Obtain EKG to evaluate QRS for widening, if present use hypertonic sodium bicarbonate at a dose of 1 to 2 mEq/kg 

Psychomotor agitation can be treated with benzodiazepines like diazepam be given in an initial dose of 10 mg IV, then 5 to 10 mg IV every 3 to 5 minutes 

Hyperthermia -  cool rapidly, optimally in 30 minutes or less, to a goal core body temperature of <102°F. 

Gastrointestinal decontamination should be considered especially in cases of body packing but remember that the popular methods of cocaine use are nonenteral 

Activated charcoal reduces the lethality of oral cocaine - adminitter at 1 g per kg body weight (up to 50 g) Q4h. 

Cocaine abuse + abdominal pain => concern for aortic pathology or intestinal ischemia/infarct or colitis

Specific syndromes:

Chest pain — it causes vasoconstriction and enhances thrombus formation, increasing the risk of myocardial ischemia even in a very young patients. 

EKG changes and positive trops consider ASA +/- nitroglycerin, phentolamine (( IV bolus of 1 to 2.5 mg every 5 to 15 minutes PRN) to reverse cocaine-induced vasospasm, cardiology consult for cath

Crack lung — Crack lung is a syndrome of hemorrhagic alveolitis from inhalational cocaine use 

Ensure oxygenation, ventilation, and symptomatic care

Early intubation

Disposition:

Severe complications of cocaine abuse - admission

If acute findings from cocaine toxicity resolve - obs 6 to 8 hours and d/c if pt back to baseline. 

Pts with cocaine-associated chest pain (CACP) are observed for 8 to 12 hours while two sets of cardiac biomarkers and repeat electrocardiograms (ECGs) are obtained. 

Pts with psychomotor agitation, hyperthermia, or other neurological complications consider admission unless pt is back to baseline and symptom free after  6 to 8 hours of observation.

Pearls:

The differential diagnosis of cocaine toxicity should include: methamphetamine abuse, ecstasy abuse, cathinone abuse, and LSD abuse

Smoking and IV injection offer rapid cocaine absorption (< 30 sec), as opposed to snorting (2.5 min) and ingestion (PO 2-5 mins).

Cocaine-induced MIs have been reported as late as 15 hours following substance abuse

References: Uptodate, EMDocs

Ankle fractures

Ankle fractures:

Start with good H&P:

History:

Mechanism, height of the fall, direction of the foot inversion

Consider age, steroid use, hx of neoplasm, prior surgeries, hardware

Physical:

Start from the knee down, neurovascular intact, ROM, strength, severe tenderness, instability, rash/ulcers

Ottawa Ankle rules 

Classification of the injury: stable/unstable?

Many classifications are available but for ED we can use Closed Ring System: 

Think of an ankle as a ring of bone and ligaments surrounding the talus consisting of the tibia, the medial malleolus and medial deltoid ligaments, the fibula and lateral ligaments and calcaneus.

A single disruption in the ring - stability most likely preserved

Two disruptions - think instability and will likely cause the joint to shift.

Exceptions: Lateral malleolus fracture even with no medial injury may become unstable.

Isolated syndesmosis injury

Approach to ankle injuries x-ray interpretation

Here is an EM focused summary

Look at the cortical disruption of each bone

Look at the soft tissue swelling

Look at the spaces between the bones

Look within the bones

Ask for a mortise view (no, it’s not a GOT character) in addition to the standard AP and lateral views

Look at the tib/fib, knee and base of the 5th metatarsal

Key areas:

Talar shift: look to make sure there is congruence between the clear space on either side of the talus; go further - measure the medial clear space and the lateral clear space. If they are incongruent or the medial clear space is >4mm the ankle is likely unstable.

Talar tilt: The lines in red below should be parallel. Talar tilt indicates an unstable ankle 

Just a few commonly missed fractures at the ED:

High ankle sprain: The isolated syndesmosis injury - isolated distal tibiofibular syndesmosis injury, with ligamentous disruption can result in unstable ankle injury.

Look at the tibio-fibular clear-space: Measure the gap between the tibia and fibula 1cm proximal to the tibial plafond on both the AP view and mortise view. They should be <6mm. If  >6mm, suspect a syndesmosis injury.

Tillaux fracture - fracture is an intra-articular Salter-Harris class III fracture of the distal tibia with avulsion of the anterolateral tibial epiphysis.

Remember that in children, the ligaments tend to be stronger than the growth plate. Tillaux fractures can be considered “the syndesmosis injury of children”

Snowboarder’s fracture - A snowboarder’s fracture is a lateral process of the talus fracture that is commonly misdiagnosed as a simple ankle sprain. 

Lateral process of the talus fracture also known as a snowboarder’s fracture

Bottom line: 

Reassess including the if the pt is still neurovascular intact

If pt can’t ambulate get further workup

If in doubt call radiology

Persistent pain but pt wants to go hoe, splint with ortho follow up

References: CoreEM, EMDoc, Uptodate, Radiopedia