Case 13 - AKI Flashcards
What are the risk factor for sepsis?
- Very young or old patients (under 1 or over 75 years)
- Chronic conditions such as COPD and diabetes
- Chemotherapy, immunosuppressants or steroids
- Surgery or recent trauma or burns
- Pregnancy or peripartum
- Indwelling medical devices such as catheters or central lines
- IVDU
What are the symptoms of sepsis?
- Fever, chills and diaphoresis
- Tachycardia
- Tachypnoea
- S: Slurred speech or confusion (often late sign)
- E: Extreme shivering or muscle pain
- P: Passing no urine (in a day)
- S: Severe breathlessness
- I: It feels like you’re going to die
- S: Skin mottle or discoloured
What investigations are carried out in sepsis?
- Blood gas: Lactate levels (raised in sepsis), BM, pH
- Blood culture
- FBC
- CRP: raised may be sign of bacterial infection
- U+E’s: kidneys are often affected early in sepsis
- Clotting screen: measure severity of sepsis
- LFT’s: source of infection
What is the treatment for sepsis? Sepsis 6:
- High flow oxygen
- IV antibiotics: broad spectrum at max dose within 1 hour of identifying high risk pts.
- IV fluid resuscitation: 500 ml bolus
- Blood culture and consider source control
- Check haemoglobin and serial lactate
- Hourly urine output measurement
What are the symptoms of hyperkalaemia?
- Fast irregular pulse
- Chest pain
- Weakness
- Palpitations
- Light-headed
What are the ECG changes in hyperkalaemia?
- Small/no P waves
- Prolonged PR
- Wide WRS
- Peaked T waves
- Slurring into ST (lead V1)
- VF
What are the causes of hyperkalaemia?
- Renal failure with oliguria/anuria
- Addison’s disease
- K-sparing diuretics
- Rhabdomyolysis
- Metabolic acidosis (DM)
What are the symptoms of hypernatraemia?
- Lethargy
- Thirst
- Weakness
- Irritability
- Confusion
- Signs of dehydration
- Coma
- Fits
What are the causes of hypernatraemia?
- Fluid loss > Na loss
- Diarrhoea
- Vomiting
- Burns
- Diabetes insipidus
- Primary hyperaldosteronism
- Excessive fluid resuscitation
What are the symptoms of hypercalcaemia?
- ‘Bones, stones, groans and psychic moans’ – bone pain, stones, abdominal groans (pain, nausea and vomiting) and psychiatric overtone (anxiety, depression, fatigue).
- Constipation
- Polyuria, polydipsia
- Anorexia
- Weight loss
- HTN
What are the ECG findings of hypercalcaemia?
Short QT interval
What are the causes of hypercalcaemia?
- Malignant - bone mets, PTHrP, myeloma
- Primary hyperparathyroidism
- Sarcoidosis
- Lithium
What are the symptoms of hypokalaemia?
- Muscle weakness
- Hypotonia
- Hyporeflexia
- Cramps
- Tetany
- Palpitations/arrhythmias
- Light-headed
- Constipation
What are the ECG changes in hypokalaemia?
- Small/inverted T waves
- Long PR
- ST depression
- Prominent U wave
What are the causes of hypokalaemia?
- Diuretics
- Cushings syndrome/Steroids/ACTH
- Diarrhoea, vomiting
- Pyloric stenosis
- Conn’s syndrome
What are the symptoms of hyponatraemia?
- Anorexia
- Nausea
- Malaise
- Headache
- Irritability, confusion
- Weakness
- Dropping GCS, seizures
- Oedema
- Falls
- HF
What are the symptoms of hypocalcaemia?
SPASMODIC’
- Spasms (Chvosteks sign)
- Perioral paraesthesia
- Anxious/irritable/irrational
- Seizures
- Increased smooth muscle tone and colic
- Wheeze
- Dysphagia
- Disorientation/confusion
- Dermatitis/impetigo
- Cardiomyopathy
What are the ECG findings in hypocalcaemia?
Long QT interval
What are the cause of hypocalcaemia?
- CKD
- Hypoparathyroidism
- Low Mg
- Low VitD
How to treat hypocalcaemia?
- Mild – give calcium
- Severe – calcium gluconate IV
How to treat hypokalaemia?
- If mild (>2.5mmol/L, no symptoms), give oral K supplement. Consider changing thiazide diuretics to K-sparing diuretics.
- If severe (<2.5mmol/L, dangerous symptoms), give IV potassium cautiously.
How to treat hyperkalaemia?
- Treat underlying cause
- Calcium gluconate or calcium chloride
- IV Insulin/dextrose infusion
- Salbutamol
- Bicarbonate
- IV NaCl and diuretic
- Haemodialysis
How to treat hyponatremia?
Correct underlying cause, never base treatment on NA concentration alone
How to treat hypernatremia?
- Give water orally
- IV Glucose 5%
What is AKI?
- Defined as decrease in kidney function.
- Rise in creatinine and blood urea nitrogen
What are the risk factors of AKI?
- Chronic kidney disease
- HF + HTN
- Diabetes
- Liver disease
- Older age (above 65 years)
- Cognitive impairment
- Nephrotoxic medications
- Contrast use
- Sepsis
What are the pre-renal causes of AKI?
- Renal artery stenosis
- Dehydration
- Hypotensions (hypovolaemia)
- Sepsis
- Shock
- Hepatorenal syndrome
- Severe HF
- Intra-abdominal hypertension/compartment syndrome
What are the renal causes of AKI?
- Glomerulonephritis
- Acute tubular nephrosis
- Interstitial nephritis
- Vasculitis
- NSAIDs
- ACEi
- ARBs
- Gentamicin
- Vancomycin
- Contrast media
- Rhabdomyolysis
- Myeloma
- Tumour lysis syndrome
What are the post-renal causes of AKI?
- Renal stones
- Pelvic cancer
- Prostate enlargement: BPH
Which medications are considered nephrotoxic?
- NSAIDs
- ACEi
- ARBs
- Gentamicin
- Vancomycin
- Contrast media
What is stage 1 AKI?
- Serum creatinine >26 μmol/L in 48 hours or 1.5-1.9 x baseline
- Urine output <0.5ml/kg/hr for >6 consecutive hours
What is stage 2 AKI?
- Serum creatinine 2.2-2.9 x baseline
- Urine output <0.5 ml/kg/hr for >12 hours
What is stage 3 AKI?
- Serum creatinine >354 μmol/L or >3x baseline or on RRT
- Urine output <0.3 ml/kg/hr for >24 hours or anuric for 12 hours
What are the symptoms of AKI?
- Fever
- Rash
- Joint pains
What are the signs of AKI?
- Rash
- Uveitis
- Hydration status
- Audible abdo bruits
- Palpable bladder
What are the investigations in AKI?
- ABG/VBG: for K+
- ECG: K+
- Urine dipstick
What do the results of urine dipstick in AKI suggest?
- 3+ proteinuria indicates intrinsic renal disease.
- If blood+ and protein+ then consider glomerulonephritis
How to treat AKI?
- IV fluid rehydration 500ml in 15 min in pre-renal AKI
- Stop nephrotoxic medications
- Relieve obstruction in a post-renal AKI
What does high BP do to the afferent and efferent arterioles?
Constricts the afferent, dilates the efferent
Why are ACE inhibitors and NSAIDs nephrotoxic?
- ACEi dilate the efferent arteriole
- NSAIDs block prostaglandins that normally dilate the afferent arteriole (effectively constricting the afferent arteriole)
What is the treatment for ATN?
- Supportive management
- IV fluids
- Stop nephrotoxic medications
- Treat complications
What does urinalysis of ATN show?
Muddy brown casts found on urinalysis is a pathognomonic finding
How long does it take for ATN to recover?
2-3 weeks
What is ATN?
- Damage and death (necrosis) of the epithelial cells of the renal tubules
- Damage to the kidney cells occurs due to ischaemia or toxins.
What are the 3 stages of ATN?
1- Oliguric phase: <500ml urine/day
2- Maintenance phase: No longer oliguric, creatinine stable
3- Polyuric recovery phase: large amounts of dilute urine, likely to be hypokalaemia
What are the complications of AKI?
- High K+: Hyperkalaemia
- Pulmonary oedema/fluid overload if low urine output – dark + concentrated urine
- Metabolic acidosis (kidneys usually excrete H+)
- High urea: Uraemic encephalopathy and uraemic pericarditis
- Low Ca, high PO4: lead to parathyroid hormone release which leads to bone breakdown.
