Prescribing in Medical Emergencies Flashcards
COVID-19 pathophysiology
Can cause lung injury > direct pathological inflammatory insult to cells in the lung resulting in diffuse damage of the small airsacks > ARDS and hypoxaemic resp failure
Second effect on body is cytokine storm which is massively overexaggerated inflammation reaction in the body. Cardinal features include persistent fever, cytopenias and hyperferritinaemia.
ARDS and shock are the 2 main causes of death from COVID.
COVID-19 risk factors
- Older people with comorbidities more likely to present with symptomatic covid
- Patients with cardiovascular disease are more liekly to suffer with severe disease
- NHS identified these patient groups as high risk and require “shielding”: organ transplant, certain types of cancer treatment, have blood or bone marrow cancer, severe lung condition such as CF/asthma/copd, taking immunosuppressants, are pregnant or have serious heart condition.
COVID-19 presentation
- Incubation period: symptoms tend to occur around 5-11 days after first exposure to the virus
- Median time to recovery from symptom onset: 14 days
- Median onset between symptoms and critical care admission is 9-10 days
- Median time of death 18 days after symproms or recovery to discharge 22 days
Case definition of covid-19
Requiring admission to hospital (AND)
Have clinical or radiological evidence of: Pneumonia/ARDS/Influenza-like illness + one acute resp symptom/persistent cough/hoarseness/nasal discharge or congestion/SOB/sore throat/change in taste or smell
Patients who have symptoms that meet above criteria should be tested regardless of contact or travel history
It is a notifiable disease - should be reported to Public Health England.
Signs/symptoms of covid
Symptoms:
- Pyrexia ≥ 37.8oC (most but not all cases present with a fever)
- Constitutional symptoms (e.g. fatigue, myalgia, anorexia)
- Lower respiratory symptoms (e.g. cough with or without sputum, dyspnoea)
- “Silent hypoxia”—a respiratory compromise without shortness of breath. This is particularly true in older adults
- Gastrointestinal symptoms (e.g. nausea, diarrhoea)
- Atypical presentations, particularly in patients who are immunocompromised
Signs:
- Pharyngitis or tonsil enlargement
- Lower respiratory signs: e.g. crackles, pleural rub
Inpatient investigations for covid
- U+Es: calculate CURB score (high creatinine)
- Other biochemistry (high CRP, high ferritin, high trop, high LDH)
- FBC (lymphocytopenia, low platelets)
- Clotting: PT time and INR, D-dimers, Fibrinogen (high PT/INR)
- LFTs (high billirubin, ALT/AST)
- ABGs (hypoxia, high lactate)
- Blood cultures and microbiology
- Imaging: CXR +/- CT thorax (local consolidation, ground glass opacity, bilateral pulmonary infiltrate)
- Coronavirus swabs
Virological testing for covid
Diagnostic samples for suspected cases include:
- Nasopharyngeal swabs +/-
- Sputum (if obtainable)
Upper resp tract samples are as follows:
- Individual nose and throat swabs in separate collection tubes; OR
- Combined nose and throat swab in one collection tube containing universal transport medium; OR
- Single swab used for throat then nose
*do not send the sample through a pneumatic tube system
~75% sensitive, however highly specific
Principles of care provision: general issues (covid)
- Isolation/cohort wards/transmission based precaution
- Communication - restricted access to relatives
- PPE - plastic apron, surgical mask, eye protection, disposable gloves. AGPs require surgical gown and FFP3 respirator
- Ceiling of care decisions: ensure DNACPR in place, advanced directive, use of clinical frailty score (CFS) in those >65
- Death: medical certificate of cause of death (MCCD) must be provided by a practitioner that has seen deceased alive in last 14 days
Principles of care provision: medical issues (covid)
- Oxygenation: hypoxia associated with poor outcomes
- Fluid management: patients rarely shocked on admission (advice oral rehydration), if shocked AVOID vigorous fluid resus use conservative fluid strategy to avoid ARDS, crystalloids should be used.
- Thromboprophylaxis: LMWH unless contraindicated
- Antibiotics (SMART/FOCUS/Sepsis)
- Monitoring: regular documentation of RR, SaO2, temp, HR, BP, mental state, pain scale
- Allied health issues: physiotherapy, dietician
- Underlying disease management: ensure ongoing monitoring and management of any chronic disease issues
- Critical care: required for up to 5% of patients, consider early invasive ventilation
- Other complications: coagulopathy, DIC, acute myocarditis, heart failure
- Delirium: provide regular orientation for patient, avoid constipation, treat pain, maintain oxygenation, identify and treat infections early, avoid urinary retention, review meds
- Cardiopulmonary resuscitation
- Palliation: restlessness and agitation - MIDAZOLAM 2.5-5mg SC
- Treatment: corticosteroids (DEXAMETHASONE PO 6mg OD
for 7-10 days or IV 5.94 mg OD for 7-10days / HYDROCORTISONE IV 50mg TDS for 7-10days
Features of deterioration/concern (covid) - mild/moderate/severe
Mild: sats >92% OA, RR<20, normotensive, usual cognition
Moderate: oxygen requirement of >4L per min, inspired oxygen >25%
Severe: unable to maintain target sats (92-96% or 88-92% in type 2 resp failure.), inspired oxygen of >50% to maintain target sats., RR > 30 despite oxygen, pH < 7.2, systolic BP <90, other organ failure, decreased conscious state
Classic signs of type 1 (IgE) allergic drug reaction
Urticaria, itching, angiooedema, bronchospasm, wheeze, hypotension
Symptoms typically occur within 30 mins of drug administration but not necessarily with first dose. Patient should continue to be observed for 6-12 hours following recovery.
ACE inhibitors can cause a pure angiooedema reaction - potentially many years after taking the medication
What to do in case of e.g. sepsis and unknown drug history?
- Phonecall to GP or review of summary care record
- Main concern whether patient has penicillin allergy which would mean they cannot be offered Tazocin
- Essential however that antibiotics are initiated asap given sepsis
- Severe allergies to gentamicin is rare (though not impossible). In this case still give and have emergency meds prepared in case.
- If details cannot be confirmed, you may need to select second line alternative to Tazocin
Who can an allergy history be reliably obtained from?
- Patient
- Carer
- GP
- Community pharmacist
- Care home
- Medical notes
- Summary care record
Taking an allergy history
- All current and any recent drugs, including any over-the-counter medicines, herbal preparations and injections (including vaccines or contrast media).
- The generic (non-proprietary or approved) name for the drug suspected of causing a reaction(s).
- The exact signs, symptoms and severity of the allergic reaction.
- When the reaction occurred.
- How long the drug was taken before the reaction occurred.
- Whether the allergy is a first-hand recollection
- Document allergy status on drug chart, patient notes,, electronic systems and give wrist band
Non-allergic drug reactions
Common non-allergic drug-induced rashes:
- MORBILLIFORM RASH > resemble urticaria but the lesions expand and become confluent unlike urticaria
- ERYTHEMA MULTIFORME > may arise secondary to infection, or drugs such as penicillins, phenytoin and statins. Can rarely progress to SJS and potentially fatal Toxic Epidermal Necrolysis (TEN)
- FIXED DRUG ERUPTIONS > erythematous plaques that recur in the same place when the same drug is taken e.g. paracetamol, tetracyclines and NSAIDs
- PHOTOSENSITIVITY
Cross-reacting drugs
PENICILLINS and CEPHALOSPORINS
- Individuals with allergic history to penicillin are at risk of reacting to cephalosporins and other beta-lactam antimicrobials (both contain beta-lactam ring) so these should be avoided.
- 3rd generation cephalosporins (e.g. ceftriaxone), however, can be used in these patients but with caution
CARBAPENAMS and MONOBACTAMS
- Carbapenems include Doripenam, Meropenam, Ertapenam etc.. also contain beta-lactam ring. Patients allergic to peniccilin should also have high degree of sensitivity to Carbapenems however in practice only 1% show this.
- Aztreonam (monobactam) can be safely prescribed to penicillin-allergic patients
**Hypersensitivity testing and specialist advice should be sought for patients where the use of penicillin and cephalosporin are clinically required
