Acute Care and Trauma (1) Flashcards
What is acute kidney injury (AKI)?
An acute decline in kidney function, leading to a rise in serum creatinine and/or a fall in urine output
What is the aetiology of acute kidney injury (AKI)?
Pre-renal, renal and post renal
AKI may be due to various insults such as:
- impaired kidney perfusion
- exposure to nephrotoxins
- outflow obstruction
- intrinsic kidney disease
What are the risk factors of acute kidney injury (AKI)?
Advanced age
Underlying kidney disease
DM
Sepsis: may result in ATN, pre-kidney AKI from hypotension
Nephrotoxins e.g. aminoglycosides, NSAIDs, vancomycin
What are the pre-renal causes of an AKI?
Reduced renal perfusion:
1. Shock (hypovolaemic, septic, cardiogenic)
2. Hepatorenal syndrome (liver failure)
What are the renal causes of an AKI?
- Acute tubular necrosis: ischaemia, drugs and toxins
- Acute glomerulonephritis
- Acute interstitial nephritis: NSAIDs, penicillins, sulphonamides
- Vessel obstruction:
- Renal artery/vein thrombosis
- Cholesterol emboli
- Vasculitis
Other causes: myeloma, haemolysis, nephropathy
What are the post renal causes of an AKI?
Stone
Tumour (pelvic, prostate, bladder)
Blood clots
Retroperitoneal fibrosis
What are the presenting symptoms of AKI?
Usually asymptomatic
Lower urinary tract symptoms:
- Urgency
- Frequency
- Hesitancy
Low urine output (oliguria)
Malaise
Anorexia
Nausea and vomiting
Pruritus (itching)
Drowsiness
Convulsions, coma (caused by uraemia)
What are the signs of acute kidney injury (AKI) on physical examination?
- Reduced urine output
- Pulmonary and peripheral oedema
- Arrhythmias (secondary to changes in potassium and acid-base balance)
- Features of uraemia (e.g. pericarditis or encephalopathy)
What are the appropriate investigations for AKI?
- U&Es: serum creatinine (rise of 26 micro mol/L in 48 hours or >50% in 7 days), potassium, sodium and urea
- Urinalysis: all suspected AKI patients, cellular casts (glomerulonephritis)
- Renal ultrasound: if no identifiable cause of deterioration or risk of obstruction
- ECG: changes associated with hyperkalaemia (tented T waves) and CXR
What is the management plan for AKI?
1.Assess hydration and fluid balance:
Pulse rate, lying and standing BP, JVP, skin turgor, chest auscultation, peripheral oedema, central venous pressure, fluid and weight charts. ECG monitoring (hyperkalaemia)
- If hypovolaemic (+ hyperkalaemia)
- fluid resuscitation
- review medications and stop nephrotoxins
- identify and treat underlying cause
others:
- vasoactive drug
- blood transfusion - If hypervolaemic (+ pulmonary oedema and hyperkalaemia)
- loop diuretic (under specialist supervision) and sodium restriction
- identify and treat underlying cause
consider: renal replacement therapy
Metabolic acidosis (if pH < 7.2): 50–100 mL of 8.4% bicarbonate via central line over 15–30 min
What medications can cause an AKI?
Acute tubular necrosis (ATN):
- Paracetamol
- Aminoglycosides
- Amphotericin B (anti-fungal)
- NSAIDs
- ACE-inhibtors
- Lithium
Acute interstitial nephritis:
- NSAIDs
- Penicillins
- Sulphonamides
Others: opioids, other antibiotics e.g. trimethoprim, vancomycin
What is the treatment for acute pulmonary oedema?
P- positioning (sit up)
O- oxygen
D- diuretic (furosemide) and fluid restriction
M- (dia)morphine
A- anti-emetics
N- nitrates (GTN infusion if SBP >110, or 2 puffs GTN spray if SBP >90)
What are the possible complications of acute kidney injury (AKI)?
Common and life-threatening:
- Hyperkalaemia
- Sepsis
- Metabolic acidosis
- Pulmonary oedema
- Hypertension
Less common:
Gastric ulceration, bleeding (platelet dysfunction), muscle wasting (hypercatabolic state), uraemic pericarditis, uraemic encephalopathy, acute cortical necrosis
What is acute respiratory distress syndrome?
A syndrome of acute and persistent lung inflammation with increased vascular permeability
What are the causes of acute respiratory distress syndrome?
(TOAST)
Transfusion
Overdose of drugs
Aspiration
Sepsis
Transplantation
(PIP)
Pneumonia
Injury/burns
Pancreatitis
What is ARDS characterised by?
A - Absence of raised capillary wedge pressure
R - Reduced blood oxygen (hypoxaemia)
D - Double-sided infiltrates (bilateral infiltrates)
S - sudden onset (acute- within 1 week)
What are the causes of ARDS?
Infection: sepsis, pneumonia
Massive blood transfusion
Trauma
Smoke inhalation
Acute pancreatitis
Covid-19
Cardio-pulmonary bypass
What is the aetiology of acute respiratory distress syndrome?
Severe insult to lungs
Inflammatory mediators released
Capillary permeability increases
Results in pulmonary oedema, reduced gas exchange and reduced lung compliance
(Injury, inflammation, increased permeability)
What are the pathological stages of ARDS?
Exudative
Proliferative
Fibrotic
What are the presenting symptoms of ARDS?
Rapid deterioration of respiratory function
Dyspnoea
Cough
Symptoms of cause
What are the signs of ARDS on physical examination?
Think SMURF: fast, blue, noisy:
Cyanosis
Tachypnoea
Tachycardia
Widespread crepitations
Hypoxia refractory to oxygen treatment
(Usually bilateral but may be asymmetrical in early stages)
What are the clinical features of ARDS?
Dyspnoea
Elevated respiratory rate
Bilateral lung crackles
Low oxygen saturations
What are the appropriate investigations for ARDS?
1st line:
CXR- bilateral infiltrates
ABG- low partial oxygen pressure
Sputum/ blood/ urine cultures- positive if underlying infection
Amylase- elevated in cases of acute pancreatitis
Others:
BNP- <100 nanograms/L make HF less likely, so ARDS more likely
Pulmonary artery catheterisation- Pulmonary artery occlusion pressure (PAOP) ≤18 mmHg suggests ARDS
What are the two key investigations for ARDS?
Chest x-ray and ABG
What is the criteria for ARDS (American-European Consensus Conference)?
- Acute onset (within 1 week of a known risk factor)
- Pulmonary oedema: bilateral infiltrates on chest x-ray (‘not fully explained by effusions, lobar/lung collapse or nodules)
- Non-cardiogenic (pulmonary artery wedge pressure needed if doubt)
- pO2/FiO2 < 40kPa (300 mmHg)
What is the management for ARDS?
Due to the severity of the condition patients are generally managed in ITU
Oxygenation/ventilation to treat the hypoxaemia
General organ support e.g. vasopressors as needed
Treatment of the underlying cause e.g. antibiotics for sepsis
Certain strategies such as prone positioning and muscle relaxation have been shown to improve outcome in ARDS
What is adrenal insufficiency?
Deficiency of adrenal cortical hormones (mineralocorticoids, glucocorticoids and androgens)
What is the aetiology of adrenal insufficiency?
Primary (Addisons disease): Autoimmune (>70%)
Secondary: Pituitary or hypothalamic disease.
Surgical: After bilateral adrenalectomy.
Medical: (iatrogenic) sudden cessation of long-term steroid therapy
What are the risk factors for adrenal insufficiency?
4Is:
1. Infections: Tuberculosis, meningococcal septicaemia (Waterhouse–Friderichsen syndrome), Cytomegalovirus (HIV patients)
2. Infiltration: Metastasis (lung, breast, melanoma), lymphomas, amyloidosis
3. Infarction: Secondary to thrombophilia
4. Inherited: Adrenoleukodystrophy 1, ACTH receptor mutation
What is the most common cause of adrenal insufficiency?
Most common cause is iatrogenic- sudden cessation in long term steroid therapy
Primary causes are rare
What are the presenting symptoms of acute adrenal insufficiency?
(Addisonian crisis)
Acute adrenal insufficiency with major haemody-
namic collapse often precipitated by stress (e.g. infection or surgery)
What are the presenting symptoms of chronic adrenal insufficiency?
Non-specific vague symptoms such as dizziness, anorexia, weight loss, diarrhoea, vomiting, abdominal pain, lethargy, weakness, depression
What are the clinical features of adrenal insufficiency?
Postural hypotension
Increased pigmentation: more noticeable on buccal mucosa, scars, skin creases, nails, pressure points (resulting from melanocytes being stimulated by increased ACTH levels)
Loss of body hair in women (androgen deficiency)
Associated autoimmune conditions: e.g. vitiligo
What are the clinical features of an Addisonian crisis?
Hypotensive shock
Tachycardia
Pale
Cold and clammy
Oliguria
What are the appropriate investigations for adrenal insufficiency?
Definite investigation is ACTH stimulation (synACTHen) test
9am serum cortisol may also be helpful
What results would be seen in Addison’s disease on a synACTHen test/ 9am serum cortisol test?
> 500 nmol/l makes Addison’s very unlikely
< 100 nmol/l is definitely abnormal
100-500 nmol/l should prompt a ACTH stimulation test to be performed
ACTH stimulation test should show an increase in plasma cortisol levels 30 minutes after giving Synacthen 250ug IM
What are the appropriate investigations for an Addisonian crisis?
Bloods- Haematology (FBC for neutrophilic, CRP and ESR for infection)
Biochemistry (U&Es for hyperkalaemia, hyponatraemia, hypoglycaemia and metabolic acidosis)
Microbiology (blood cultures)
Urine- MCS
What are the causes of an Addisonian crisis?
Sepsis or surgery causing an acute exacerbation of chronic insufficiency (Addison’s, Hypopituitarism)
Adrenal haemorrhage eg Waterhouse-Friderichsen syndrome (fulminant meningococcemia)
Steroid withdrawal
What is the management for Addisonian crisis?
Hydrocortisone 100 mg im or iv
1 litre normal saline infused over 30-60 mins or with dextrose if hypoglycaemic
Continue hydrocortisone 6 hourly until the patient is stable (no fludrocortisone is required because high cortisol exerts weak mineralocorticoid action)
Oral replacement may begin after 24 hours and be reduced to maintenance over 3-4 days
Treat the underlying cause e.g. Abx for sepsis
What is the management plan for adrenal insufficiency?
Replacement therapy of glucocorticoid and mineralocorticoid
Combination of: Hydrocortisone (usually given in 2 or 3 divided doses, 20-30 mg per day, with the majority given in the first half of the day) and fludrocortisone
Patient education: importance of not missing doses, MedicAlert bracelets, hydrocortisone injection for crisis
Management of intercurrent illness: glucocorticoid dose should be doubled with fludrocortisone staying the same
What precaution must be taken in a patient with adrenal insufficiency and hypothyroidism?
Give hydrocortisone before thyroxine to avoid precipitating an Addisonian crisis
What are the possible complications of adrenal insufficiency?
Hyperkalaemia
Death during an Addisonian crisis
What is the prognosis for patients with adrenal insufficiency?
Adrenal function rarely recovers, but normal life expectancy can be expected if treated
What is alcohol withdrawal?
A patient who is alcohol dependent and has stopped or reduced their alcohol intake within hours or days of presentation
What is the mechanism of alcohol withdrawal?
- Chronic alcohol consumption enhances GABA mediated inhibition in the CNS (similar to benzodiazepines) and inhibits NMDA-type glutamate receptors
- Alcohol withdrawal is thought to be lead to the opposite (decreased inhibitory GABA and increased NMDA glutamate transmission)
What is alcohol dependence?
Characterized by three or more of:
. Withdrawal on cessation of alcohol
. Tolerance
. Compulsion to drink, difficulty controlling termination or the levels of use
. Persistent desire to cut down or control use
. Time is spent obtaining, using, or recovering from alcohol
. Neglect of other interests (social, occupational, or recreational)
. Continued use despite physical and psychological problems
What are the features of alcohol withdrawal?
Symptoms start at 6-12 hours: tremor, sweating, tachycardia, anxiety
Peak incidence of seizures at 36 hours
Peak incidence of delirium tremens is at 48-72 hours: coarse tremor, confusion, delusions, auditory and visual hallucinations, fever, tachycardia
What are the presenting symptoms of alcohol withdrawal?
HAD A PINT
Headache
Anxiety/ agitation
Depression
Anorexia
Palpitations
Insomnia
Nausea
Tremor
What are the signs of chronic alcohol misuse?
Dupuytrens contracture
Palmar erythema
Bruising
Spider naevi
Telangiectasia- widened venules cause threadlike red lines or patterns on the skin
Bilateral parotid enlargement
Gynaecomastia
Smell of alcohol
What are the appropriate investigations for alcohol withdrawal?
A to E approach
VBG: respiratory alkalosis with delirium tremens
Bloods: Increased MCV, thrombocytopenia, hypomagnesaemia, hypokalaemia, hypophosphataemia, elevated AST, ALT, and GGT
Coagulation studies: prolonged INR and prothrombin time
Drug screen: barbiturates, paracetamol
What is the management plan for a patient with alcohol withdrawal?
First-line: long-acting benzodiazepines e.g. chlordiazepoxide or diazepam (lorazepam may be preferable in patients with hepatic failure) with a reducing dose protocol
B1 thiamine, pabrinex
Carbamazepine also effective in treatment of alcohol withdrawal
Patients with a history of complex withdrawals from alcohol (i.e. delirium tremens, seizures, blackouts) should be admitted to hospital for monitoring until withdrawals stabilised
What are the possible complications of alcohol withdrawal?
Seizures (generalised tonic-clonic) - cause of fatality
Delirium tremens
What are the complications of chronic alcohol use?
Cerebral atrophy and dementia
Cerebellar degeneration
Optic atrophy
Peripheral neuropathy
Myopathy
Indirect effects include hepatic encephalopathy, thiamine deficiency, causing Wernickes encephalopathy or Korsakoffs psychosis
What is the prognosis for patients with alcohol withdrawal?
Depends on complications.
Alcoholic fatty liver is reversible on abstinence from alcohol
In general, 5-year survival rates in those with alcoholic cirrhosis who stop drinking are 60–75%, but < 40% in those who continue
What is anaphylaxis?
A severe, life-threatening, generalised or systemic hypersensitivity reaction
What cells are the drivers behind anaphylaxis?
There is sudden release of mast cell- and basophil-derived mediators into the circulation
What is anaphylaxis characterised by?
Rapidly developing life-threatening airway and/or breathing and/or circulation problems
Usually associated with skin and mucosal changes
What is the aetiology of anaphylaxis?
Immunologic: IgE-mediated or immune complex/complement-mediated
Non-immunologic: mast cell or basophil degranulation without the involvement of antibodies (e.g. reactions caused by vancomycin, codeine, ACE inhibitors)
What are the common identified causes of anaphylaxis?
Food (e.g. nuts) - the most common cause in children
Drugs
Venom (e.g. wasp sting)
What is the Resus Council UK’s definition of anaphylaxis?
The sudden onset and rapid progression of symptoms
Airway and/or Breathing and/or Circulation problems
What are the Airway and/or Breathing and/or Circulation problems seen in anaphylaxis?
Airway: swelling of the throat and tongue →hoarse voice and stridor
Breathing: respiratory wheeze and dyspnoea
Circulation: hypotension and tachycardia
What does it mean if a patient is not having an ABC symptoms in anaphylaxis?
That they are not in true anaphylaxis
What are the skin and mucosal changes seen in anaphylaxis?
Generalised pruritus
Widespread erythematous or urticarial rash
What are the appropriate investigations for anaphylaxis?
Clinical diagnosis
Later:
Serum mast cell tryptase (measured within 15 min–3 h after onset of symptoms)= elevated up to 12 hours post event
Histamine levels (measured preferably within 30 min after symptom onset) and urinary metabolites of histamine (which may remain elevated for several hours after symptom onset)
ABG: elevated lactate
ECG: Non-specific ST ECG changes are common post-adrenaline
What is the management plan for a patient with anaphylaxis?
Intramuscular adrenaline 500 micrograms (0.5ml 1 in 1,000)
Can be repeated every 5 minutes if necessary
Best site for IM injection is the anterolateral aspect of the middle third of the thigh
Other medications (not as important):
Oxygen
Chlorphenamine - only when patient is stabilised
What is refractory anaphylaxis?
Defined as respiratory and/or cardiovascular problems persist despite 2 doses of IM adrenaline
IV fluids should be given for shock
Expert help should be sought for consideration of an IV adrenaline infusion
What is the management plan for a patient with anaphylaxis following stabilisation?
Non-sedating oral antihistamines, in preference to chlorphenamine, may be given following initial stabilisation especially in patients with persisting skin symptoms (urticaria and/or angioedema)
Establish if it is true anaphylaxis: Serum tryptase levels
All patients with a new diagnosis of anaphylaxis should be referred to a specialist allergy clinic
An adrenaline injector should be givens an interim measure before the appointment
What should be given to patients with anaphylaxis post specialist allergy assessment?
Patients should be prescribed 2 adrenaline auto-injectors
Training should be provided on how to use it
How do you discharge patients following an anaphylactic reaction?
Risk-stratified approach to avoid biphasic reactions (can occur 1–72 h after the first reaction in up to 20% of patients)
What is the risk-stratified approach to discharge following anaphylaxis?
- Fast-track discharge (after 2 hours of symptom resolution):
- good response to a single dose of adrenaline
- complete resolution of symptoms
- has been given an adrenaline auto-injector and trained how to use it
- adequate supervision following discharge - Minimum 6 hours after symptom resolution:
- 2 doses of IM adrenaline needed, or previous biphasic reaction - Minimum 12 hours after symptom resolution:
- severe reaction requiring > 2 doses of IM adrenaline
- patient has severe asthma
- possibility of an ongoing reaction (e.g. slow-release medication)
- patient presents late at night
- patient in areas where access to emergency access care may be difficult
- observation for at 12 hours following symptom resolution
What are the possible complications of anaphylaxis?
Respiratory failure
Shock
Death
What is the prognosis for patients with anaphylaxis?
Good if prompt treatment given
What is an arterial blood gas (ABG)?
A procedure to measure the acidity (pH) and the levels of oxygen and carbon dioxide in the blood from an artery
What are the indications for an arterial blood gas?
Respiratory failure - in acute and chronic states.
Any severe illness which may lead to a metabolic acidosis:
- Cardiac/ Liver/ Renal failure
- Hyperglycaemic states associated with diabetes mellitus
- Multiorgan failure
- Sepsis
- Burns
Poisons/toxins
Ventilated patients
What are the possible complications of an arterial blood gas?
Local hematoma
Arterial vasospasm
Arterial occlusion
Air or thrombus embolism
LA anaphylactic reaction
Infection at the puncture site
What are the articulating surfaces of the ankle?
Tibia + fibula + talus
What are the two ligaments involved in the ankle joint?
Medial and lateral ligament (originating from the corresponding malleolus)
What are the muscle groups and movements of the ankle joint?
Plantarflexion: muscles in posterior compartment of leg (gastrocnemius, soleus, plantaris and posterior tibialis)
Dorsiflexion: muscles in anterior compartment of leg (tibialis anterior, extensor hallucis longus and extensor digitorum longus)
What is the neurovascular supply of the ankle?
Aterial supply = Malleolar branches of anterior tibial, posterior tibial and fibular arteries
Innervation is provided by tibial, superficial fibular and deep fibular nerves
What are the most common causes of posterior heel pain?
Achilles tendon disorders
What are the common achilles tendon disorders?
Tendinopathy (tendinitis)
Partial tear
Complete rupture of the Achilles tendon
What are some risk factors for Achilles tendon disorders?
Quinolone use (e.g. ciprofloxacin) is associated
Hypercholesterolaemia → predisposes to tendon xanthomata
What are the features of achilles tendinopathy (tendinitis)?
- Gradual onset of posterior heel pain that is worse following activity
- Morning pain and stiffness are common
What is the management of achilles tendinopathy (tendinitis)?
Typically supportive
1. Simple analgesia
2. Reduction in precipitating activities
3. Calf muscle eccentric exercises (self-directed or through physiotherapy)
What are the features of Achilles tendon rupture?
Suspected if the patient reports the following whilst playing a sport or running:
1. An audible ‘pop’ in the ankle
2. Sudden onset significant pain in the calf
2. Inability to walk or continue the sport
What is the examination for Achilles tendon rupture?
Simmond’s triad
1. Ask the patient to lie prone with their feet over the bed
2. Look for an abnormal angle of declination - there will be a greater dorsiflexion of the injured foot compared to the other
3. Feel for a gap in the tendon and gently squeeze the calf muscles: if there is a rupture the achilles tendon injured foot will stay in a neutral position
What is the imaging modality of choice for Achilles tendon rupture?
Ultrasound
What is the Thompson test?
Lack of plantar flexion when calf is squeezed
What is the management for Achilles tendon rupture?
Acute referral to orthopaedic specialist
1. Non-operative : functional bracing/ casting in resting equinus
2. Operative: open end-to-end achilles tendon repair (for acute ruptures < 6 weeks) or percutaneous repair
What are some complications of Achilles tendon rupture?
Re-rupture: higher with non-operative management
Wound healing complications
Sural nerve injury (percutaneous repair)
What are ankle fractures?
Very common injuries which generally occur due to a twisting mechanism
What are the locations of ankle fractures?
Breakdown by fracture type:
1. Isolated malleolus fracture = 70%
2. Bimalleolar = 20%
3. Trimalleolar = 7%
What are the risk factors for ankle fractures?
Male
Younger age (mainly 15-24 years)
Obesity
Smoking
Alcohol consumption
What is the main mechanism of injury for ankle fractures?
Twisting injuries
What are the three ligament complexes that stabilise the ankle?
- Deltoid
- Lateral ligament complex
- Syndesmosis
What are the two tendons which stabilise the ankle?
- Peroneal tendons: peroneus longus and brevis
- Posterior tibial tendon
What are the neurovascular structures surrounding the ankle?
- Anterior tibial artery and depot peroneal nerve
- Posterior tibial artery and tibial nerve
- Superficial peroneal nerve
- Sural nerve
What are the features of an ankle fracture?
Severe ankle pain
Difficulty or inability to walk
What are the findings of an ankle fracture of a physical exam?
Ecchymosis and swelling
Deformity
Limited ankle motion
What are the Ottawa ankle rules for an ankle fracture?
State that x-rays are only necessary if there is pain in the malleolar zone and:
1. Inability to weight bear for 4 steps
2. Tenderness over the distal tibia
3. Bone tenderness over the distal fibula
What is the Weber system in ankle fractures?
Describe ankle fractures related to the level of the fibular fracture:
Type A = below the syndesmosis
Type B = fractures start at the level of the tibial plafond and may extend proximally to the syndesmosis
Type C = above the syndesmosis which may itself be damaged
How is the Weber system for ankle fractures classified?
Type A: infrasyndesmotic
Type B: transsyndesmotic
Type C: Suprasyndesmotic
What are some differentials for an ankle fracture?
Ankle sprain
Syndesmotic injury
Achilles tendon rupture
What are some features of an ankle sprain?
May be able to weight bear
Positive anterior drawer or talar tilt test
Radiographs without fracture
What are the principles of management for ankle fractures?
Depends on the stability of the ankle joint and patient’s comorbidities
All fractures should be promptly reduced to remove pressure on the overlying skin and subsequent necrosis
Young patients = usually require surgical repair often using a compression plate
Elderly patients = usually fare better with conservative management as their thin bones do not hold metalwork well
What are some of the non-operative management options for ankle fractures?
Short-leg AO splint
Short-leg cast
CAM boot
(for stable ankle fractures and those unfit for surgery)
What are some of the operative management options for ankle fractures?
Open reduction internal fixation
External fixation
What are the Ottawa rules (ankle fractures)?
An x-ray is only required if there is any pain in the malleolar zone and one of the following:
1. Bony tenderness at the lateral malleolar zone
2. Bony tenderness at the medial malleolar zone
3. Inability to walk 4 weight bearing steps immediately after the injury
What is the management of ankle fractures according the Weber classification?
Type A: Usually stable → reduction and cast →ORIF occasionally needed
Type B: Stability variable → may require ORIF
Type C: Unstable fracture → ORIF
What is a lisfranc injury?
When bones in the midfoot are broken or ligaments that support the midfoot are torn
What is a metatarsal stress fracture?
Stress fracture = tiny cracks in the bone caused by repetitive force often from overuse
A hairline fracture in one of the long metatarsal bones in the foot from overly stressing the foot when using it in the same way repeatedly
What is aspirin (salicylate) overdose?
Excess ingestion of salicylates e.g. aspirin causing toxicity
What are the risk factors of aspirin overdose?
Deliberate self-harm
Suicidal intent
By accident e.g. in children
What are the features of aspirin overdose?
Hyperventilation (centrally stimulates respiration)
Tinnitus
Lethargy
Sweating, pyrexia
Nausea/vomiting
Hyperglycaemia and hypoglycaemia
Seizures
Coma
What is a key finding in aspirin overdose?
Mixed respiratory alkalosis and metabolic acidosis
How does aspirin overdose cause a mixed respiratory alkalosis and metabolic acidosis?
- Early stimulation of the respiratory centre leads to a respiratory alkalosis via hyperventilation
- Later the direct acid effects of salicylates (combined with acute renal failure) may lead to an acidosis
What is the aetiology of aspirin overdose?
- Aspirin increases respiratory rate and depth by stimulating the CNS respiratory centre
- This hyperventilation produces respiratory alkalosis in the early phase
- The body then compensates by increasing urinary bicarbonate and K+ excretion, causing dehydration and hypokalaemia
- Loss of bicarbonate together with the uncoupling of mitochondrial oxidative phosphorylation by salicylic acid and build up of lactic acid can lead to metabolic acidosis
What are the investigations for aspirin overdose?
ABC management
ABG: initially respiratory alkalosis; later concomitant metabolic acidosis
Salicylate levels - determines management
Bloods e.g. U&Es for hypokalaemia (and hypocalcaemia), FBC, LFTs
ECG: signs of hypokalaemia = flattening and inversion of T waves, visible U wave and some ST depression in severe
What are the salicylate levels in moderate and severe aspirin overdoses?
Moderate = 500- 750mg/L
Severe = >750mg/L
* >700mg/L is an indication for haemodialysis
What is the management of aspirin overdose?
ABC approach
Charcoal if early enough
Urinary alkalisation with IV sodium bicarbonate → enhances elimination of aspirin in the urine
Haemodialysis
What are the indications for haemodialysis in aspirin overdose?
Serum concentration > 700mg/L
Metabolic acidosis resistant to treatment
Acute renal failure
Pulmonary oedema
Seizures
Coma
What is asthma?
Chronic inflammatory airway disease characterised by:
1. Variable reversible airway obstruction
2. Airway hyper-responsiveness
3. Bronchial inflammation
What is the epidemiology of asthma?
Affects around 8% in the UK
More common in boys until teenage years
More common in women
What is the pathology of asthma?
Chronic airway inflammation (often eosinophilic inflammation)
Bronchial hyperreactivity to a variety of stimuli causing reversible airway obstruction
What are some of the stimuli in asthma?
Allergens e.g. pets, house dust mites
Emotion
Exercise
Change in air temperature
Pollution (indoors and outdoors)
Viruses
Occupational exposure e.g. flour dust, latex, chemicals (hairdresser)
What are some of the features in the history for asthma?
Wheeze
Chest tightness
Cough
Breathlessness
Symptoms can be diurnal e.g. nocturnal cough
Ask about triggers
Ask about smoking history which exacerbates asthma
What are the examination findings for asthma?
Mouth: oral candida (inhaled steroids without rinsing mouth out), nasal polyps
Hands: fine tremor (excess bronchodilator use)
HR: high (exacerbation or excess bronchodilator use)
Skin: eczema
Chest: audible expiratory wheeze, cough (poor control or acute exacerbation), high RR (acute), polyphonic expiratory wheeze (poor control or acute exacerbation)
What are the two types of wheeze heard in asthma patients?
Audible expiratory wheeze
Polyphonic expiratory wheeze = poor control or acute exacerbation
How is the diagnosis of asthma made in adults?
- Ask if their symptoms are better on days away from work/ during holidays - could be occupational asthma
- Spirometry with a bronchodilator reversibility (BDR) test
- All patients should have a FeNO test
What is a FeNO test for suspected asthma?
Fractional exhaled nitric oxide
Levels of NO correlate with levels of eosinophils inflammation which is found in asthma
Considered positive is equal to or above 40 parts per billion (35 ppb for children)