Nephrology Basics Flashcards
How do patients with kidney disease typically present?
- Abnormal blood test- raised urea, creatinine, reduced eGFR, electrolyte abnormalities
- Abnormal urine test - microscopic haematuria, proteinuria, microalbuminuria
- Change in urinary frequency or problems urinating - polyuria, haematuria, nocturia, urgency
- New onset hypertension
- Oedema in dependent areas
- Non-specific symptoms - nausea, vomiting, malaise
- Ipsilateral flank pain (obstructive nephrolithiasis)
- Incidental discovery of abnormal kidney anatomy - horseshoe, absent or ptotic kidney, asymmetry, angiomyolipoma, kidney mass, polycystic kidneys
- Systemic disease - skin changes in scleroderma, vasculitis, SLE, arthritis
What are the important history in patients referred for kidney disease evaluation?
- Previous diagnosis (historical urea, creatinine)
- History of asymptomatic urine abnormalities (haematuria, proteinuria)
- Altered urinary frequency or urgency
- Change in urine character or appearance (smell, colour, frothy)
- History of diabetes (duration, severity, end organ damage)
- History of hypertension and cardiac history
- Previous exposure to nephrotoxic medications
Recent changes in medication doses, new medications, OTC
- NSAIDs, antibiotics
- RAAS inhibitors - Recent endoscopic procedure requiring bowel clearance (acute phosphate nephropathy due to enema)
- Recent scans (CIN)
- Recent systemic infections or intercurrent illnesses
- Family history of kidney diseases, RRT
- History of autoimmune diseases
- Smoking history - high risk of progression
What familial diseases are characterised by kidney involvement?
- ADPKD (chromosome 4 and 16); ARPKD (chromosome 6)
- AD tubulointerstitial kidney disease
- FSGS (chromosomes 1, 9, 19, 11, 19)
- Hypertension
- Fabry disease
- Alport syndrome
- Sickle cell nephropathy
- Familial hypercalcaemic hypocalciuria
- Cystinuria
- HDR (Barakat) syndrome (hypoparathyroidism, sensorineural hearing loss, kidney disease)
- Liddle syndrome - mineralocorticoid excess
- Barter and Gitelman syndrome
- Congenital nephrotic syndrome
What are the common symptoms of advanced CKD?
- Reduced appetite (protein aversion)
- Easy fatigability
- Generalised weakness
- Weight loss (cachexia) or gain (fluid retention)
- AMS (lethargy, coma, dificult concentrating)
- Nausea, vomiting, dyspepsia
- Metallic taste
- Itch or pruritus (uraemia)
- Seizures
- Difficulty breathing
- Body swelling - dependent areas, or generalised
- Intractable hiccups
- Frothy appearance of urine
- Reduced sexual libido, erectile dysfunction
- Restless legs
What are the signs that can be elicited in CKD?
- Hypertension
- Pallor (anaemia)
- Volume overload - elevated JVP, oedema, pulmonary oedema
- Friction rub (uraemic pericarditis)
- Asterixis and myoclonus (uraemic encephalopathy)
What is a bedside diagnostic test to suggest presence of diabetic nephropathy?
Fundoscopy - diabetic retinopathy
Vascularisation between retina and kidneys correlate with typical microvascular complications in DM
What are the extrarenal manifestations associated with kidney diseases?
- Dermatologic - pruritus, itch
- Arthritis, musculoskeletal symptoms
- Haemoptysis
- Hearing loss
- Abdominal discomfort
- Cervicocranial aneurysm
Itch in kidney diseases and how to manage the itch
Pruritus -> recurrent scratching -> excoriation and lichen simplex chronicus
Treatment:
1. Emollients, lotion, keratolytic agents
2. Ultraviolet B radiation
3. Topical capsaicin 0.025% - reduces substance P in type C nerve endings
4. Topical tacrolimus 0.03% for 3 weeks then 0.01% for 3 weeks
5. Gabapentin
6. Naltrexone
7. Others: activated charcoal, ondansetron, cromolyn, cholestyramine, thalidomide, erythropoietin, lidocaine
What is calciphylaxis (calcific uraemic arteriolopathy)?
Painful, subcutaneous purpuric plaques and nodules.
Necrose in advanced disease
Bilateral, symmetrical distribution over the extremities
Mottled or violaceous discolouration with reticular pattern (similar to livedo reticularis)
Worse prognosis for proximal lesions (trunk, buttocks, thighs) than distal (forarms, fingers, calves, toes)
Risk Factors
Poorly controlled 2’ hyperparathyroidism
Uncontrolled DM
Obesity
Female
Duration of RRT
History of skin trauma
Warfarin use
Increased expression of osteopontin and bone morphogenic protein 4 -> inducers of vascular calcification
What are the treatment options for calciphylaxis?
- Prevention and aggressive control of secondary hyperparathyroidism
- IV sodium thiosulfate 5-25g at end of dialysis - chelates calcium, anti-oxidant, improves local blood flow
- Biphosphonates
- Hyperbaric oxygen therapy
What is nephrogenic systemic fibrosis?
Progressive fibrosis and thickening of skin (painful), appears as plaques/papules/nodules asymmetrical distribution over distal extremities
Fibrosis of other organs (pleura, diaphragm)
Gadolinium contrast deposition into bones and slow mobilisation from bone over time
Interval to manifestation 2 days to 18 months
High fatality with no effective treatment
Prevention with haemodialysis - eliminates 92% of gadolinium after 2 sessions, 99% after 3 sessions
Intensified PD regime - eliminates 90% in 2 days with regimen of 10-15 exchanges per day
What are the causes of palpable kidneys?
- ADPKD
- Large kidney tumours
- Obstruction with severe hydronephrosis
- Very large kidney cyst
What are the causes and significance of abdominal bruit?
- Normal variant in 5-25%, especially in younger individuals
- Renovascular disease (systodiastolic bruit over epigastric)
- Portal hypertension (periumbilical venous hum)
- Pancreatic cancer (epigastric bruit)
- Splenic arteriovenous malformation (LUQ bruit)
- Liver cancer (RUQ bruit)
- Abdominal aortic aneurysm
Antibiotics that do not require renal dose adjustment (5)
Ceftriaxone
Metronidazole
Cloxacillin
Fusidic acid
Clindamycin
Cleveland Thakar Score for AKI after Cardiac Bypass
- Gender (female)
- Congestive heart failure
- LVEF < 35%
- IABP use (2 points)
- COPD
- Insulin requiring diabetes
- Previous cardiac surgery
- Emergency surgery (2 points)
- Surgery type
- CABG only (0)
- Valve only (1)
- CABG and valve (2)
- Others (2) - Preoperative creatinine
- < 106 umol/L (0)
- 106 - 185 umol/L (2)
- 186 above umol/L (5)
