Nephrology Flashcards
AKI
Cause, stages sx, ix, mx
Improving Global Outcomes (KDIGO) criteria as below:
- Increase in serum creatinine by >26.5 mmol/l within 48 h, or
- Increase in serum creatinine > 1.5x the baseline within the last 7 days, or
- Urine output < 0.5 ml/kg/h for 6 hours
Causes:
Pre-renal:
- hypovolaemia
- renal artery stenosis
- NSAIDs, ACE inhibitors, ARBs, diuretics
- heart failure, sepsis
Renal:
- acute glomerulonephritis, nephrotic syndrome
- acute tubular necrosis due to ischaemia or toxins, rhabdomyolysis
- acute interstitial nephritis secondary to drugs
- renal vein thrombosis, vasculitis
Post-renal:
- stone or blocked catheter
- urethral or ureteric strictures
- abdominal or pelvic tumour
- bph
Stages:
Stage 1 - any of:
- Creatinine rise of 26 micromol/L or more within 48 hours
- Creatinine rise to 1.5-1.99x baseline within 7 days
- Urine output < 0.5 mL/kg/hour for more than 6 hours
Stage 2 - any of:
- Creatinine rise to 2-2.99x baseline within 7 days
- Urine output < than 0.5 mL/kg/hour for more than 12 hours
Stage 3 - any of:
- Creatinine rise to 3x baseline or higher within 7 days
- Creatinine rise to 354 micromol/L or more with either
- Acute rise of 26 micromol/L or more within 48 hours or
- 50% or more rise within 7 days
- Urine output < than 0.3 mL/kg/hour for 24 hours
- Anuria for 12 hours
Sx:
- may be asymptomatic
- nausea and vomiting
- confusion
- HTN
- bladder distension
- hypotension in pre-renal causes
- raised JVP
- oedema
Ix:
- urinalysis
- ECG for hyperkalaemia
- blood gas for acidosis
- U+E
- LFT
- clotting
- bone profile
- CK
- CRP
- US KUB, next line is CT
- renal biopsy
Mx:
- IV fluid resus
- catheter may be definite mx in post-renal causes due to obstruction
- suspend NSAIDs, aminoglycosides, ACE inhibitors, ARBs
-renal replacement therapy with dialysis or haemofiltration (remembered by the AEIOU mnemonic):
- Acidosis (severe metabolic acidosis with pH of <7.20)
- Electrolyte imbalance (resistant hyperkalaemia)
- Intoxication (AKI secondary to certain drugs or poisons)
- Oedema (refractory pulmonary oedema)
- Uraemia (uraemic encephalopathy or pericarditis)
BPH
Def, sx, ix, mx
non-cancerous enlargement of the prostate gland, particularly the transition zone, leading to the compression of the urethra and subsequent lower urinary tract symptoms (LUTS)
Sx:
- hesitancy
- weak stream
- frequency
- urgency
- nocturnal
- incomplete sensation
Ix:
- IPSS: Score 20–35: severely symptomatic.
Score 8–19: moderately symptomatic.
Score 0–7: mildly symptomatic.
- digital rectal exam
- PSA to rule out cancer
Mx:
- alpha blocker (tamsulosin)
- 5-alpha reductase inhibitors (finasteride)
- TURP
Bladder cancer
CKD
Dehydration
Diabetic nephropathy
Epididymitis and orchitis
Multiple myeloma
Nephrotic syndrome
Prostate cancer
Testicular cancer
Urinary tract calculi
Urinary incontinence
Causes, types, sx, ix, mx
Causes:
- urge: idiopathic, neuro conditions, inflammation and bladder irritants
- stress: urethral hypermobility and intrinsic sphincter deficiency
- overflow: enlarged prostate (bph, cancer and inflammation), diabetes, obstructing masses, fistulas, spinal cord injuries and anticholinergic meds
Transcient causes:
• D – elirium
• I – nfection
• A – thropy
• P – harmaceuticals
• E – xcess excretion
• R – estricted mobility
• S – tool impaction
Ix:
- bladder diary
- urinary stress test
- urinanalysis
- renal function tests
- PSA
- post void residual bladder scan
- renal Uss
- MRI
Mx:
• Self-monitoring
• Bladder training - Kegles
• Lifestyle changes
- Absorbent materials, urine bottles, vaginal pessaries
- Caffeine reduction
- Weight loss
• Medical equipment
• Surgery
• Drug review
• Medication -Antimuscarinics, topical oestrogen, alpha-adrenergic antagonists (selective vs non-selective), 5-alpha reductase inhibitors
Urinary tract infection (UTI)
Stages, types, sx, dx, ix, mx
Types:
- Cystitis: lower UTI- urethra or bladder infection, prostitis, often uncomplicated but can progress to upper or complicated UTI.
- Pyelonephritis: upper –or complicated UTI, or ureters, kidney infection usually due to bacterial ascent.
- Typical: Uncomplicated, self-resolving. Common pathogens include uropathogenic E. coli, Klebsiella pneumoniae, and Enterococcus faecalis.
- Atypical: Seriously ill, Poor urine flow, Abdominal/bladder mass, Raised creatinine,Septicaemia, Failure to respond to Abx in 48 hours, Non-E.coli organisms.
- Recurrent: Two or more UTIs in six months or three or more in 12 months.
- Catheter associated UTI
Sx:
- Lower: urinary frequency, urinary urgency, suprapubic pain, dysuria, heamaturia
- Upper: fever, chills, flank pain, nausea, vomiting, costovertebral or renal angle tenderness, recurrent lower UTI symptoms
Dx:
- Nitrites: strongly suggestive of bacteriuria, as nitrates are broken down into nitrites only in the presence of bacteria.
- Leukocyte esterases: an enzyme leukocytes produce in response to bacteria in the urine.
- On MC&S, the following findings would be consistent with a UTI:
- Bacteriuria: the presence of bacteria in urine. Historically, ≥ 105 bacterial colonies/mL of urine were needed to diagnose a UTI. However, a UTI can be diagnosed if the symptoms are present with as low as 102 bacterial colonies/mL. If there is bacteriuria without symptoms, this is termed asymptomatic bacteriuria. It is more common in older patients, and asymptomatic bacteriuria is only treated in pregnant women, before urological operations or if there are associated symptoms.
- Pyuria: the presence of WBCs in the urine. Sterile pyuria (WBCs in the urine, without infection) can indicate a range of diagnoses, including renal malignancy, pelvic malignancy and genitourinary tuberculosis
Ix:
- renal US
- USS
- CT (acute)
Mx:
- personal hygiene
- vit c supplement
- D-mannose, cranberry products
- analgesia
- first line is nitrofurantoin or trimethoprim
- for men and older people the course is 7 days
- for women it is 3
- avoid trimethoprim in the first trimester and nitrofuratoin in the final and course is 7 days
Diabetes insipidus
Def, types, cause, sx, ix, mx
characterised by either an inadequate production (AVP-D) or an insufficient renal response (AVP-R) to arginine vasopressin (AVP), also called antidiuretic hormone (ADH).
Cause:
AVP deficiency:
- head trauma
- sarcoidosis
- meningitis
- sickle cell disease
AVP resistance:
- lithium
- metabolic disturbance
- chronic renal disease
Sx:
- Large volumes of dilute urine (>3 litres in 24 hours and a urine osmolality of <300 mOsm/kg)
- Nocturia
- Excessive thirst
Ix:
- U+E showing raised Na
- blood glucose to rule out mellitus
- urine dip
- urine osmolality (raised (>295 mOsm/kg) with inappropriately dilute urine (urine osmolality < 300 mOsm/kg))
- water deprivation test (In AVP-D, urine osmolality increases with ADH administration. In AVP-R, urine osmolality remains low/unchanged despite ADH administration)
Mx:
- AVP-D= desmopressin and Na monitoring
- AVP-R= correct metabolic abnormalities, high dose desmopressin, thiazide diuretic
