Urinary and thirst Flashcards
Diabetes complications - acute: (3)
- Diabetes ketoacidosis: DKA (usually T1D)
- Hyperglycaemic hyperosmolar state: HHS (usually T2D)
- Hypoglycaemia
DKA characteristics (usually T1D)
- Glucose
- osmolality
- Ketones
- pH
- Hydration
- glucose > 11mmol/L
- Variable osmolality
- Ketonaemia >3mmol/L
- Acidosis pH < 7.3
- Less severe hypovolaemia
HHS characteristics (usually T2D):
- Glucose
- osmolality
- Ketones
- pH
- Hydration
- Marked hyperglycaemia (>30mmol/L)
- Marked serum hyper osmolality (320>Osm/kg)
- <3 mmol/L
- no ketone driven acidosis
- Hypovolaemia (severe dehydration)
Diabetes complications - chronic: microvascular (3)
- Retinopathy
- Nephropathy
- Neuropathy
Diabetes complications - Macrovascular: (3)
- C A
- C
- P
- Coronary artery disease
- Cerebrovascular disease
- Peripheral vascular disease
Poloyol pathway: (damage)
- Produces reactive….
- which cause damage to ….
- Produces reactive oxygen species which cause damage to blood vessels and endothelium, may cause neuropathy
Protein kinase C pathway:
- Causes a variety of issues
- Activation increases VEGF causing new vessel formation in the back of the eye. These new vessels are ineffective, causing retinopathy and retinal bleeds
Mechanisms of action for oral agents of DM
- Metformin
- Sulfonylurea
- Metformin: suppression of hepatic glucose
- Sulfonylurea: Increase in insulin secretion from beta cells
Mechanisms of action for oral agents of DM:
- GLP-1 Agonist
- DDP-4 inhibitors
They’re linked
- DPP-4 inhibitors – inhibit GLP-1 degradation,
- GLP-1 agonist – promotes glucose dependent insulin secretion
Sites of haematuria:
1. Glomerular
2. Non-glomerular (4)
- Glomerular
- Glomerulus - Non-glomerulus
- Kidney
- Ureter
- Bladder
- Urethra
Flexible cytoscopy:
- A flexible cystoscopy is a test that allows the doctor to look directly at the lining of the bladder, from the opening of the urethra. During the procedure a thin flexible ‘fibre-optic’ tube called a cystoscope is passed through the urethra
CT urogram:
- used to examine the kidneys, ureters and bladder
Sensitivity of visible haematuria for detecting cancer:
- Positive predictive value of haematuria for detecting cancer, especially in men
Risk factors for kidney or urinary tract cancer: (4)
- Age
- Smoking
- Exposures to benzene, aromatic amines (dyes, road fumes), carcinogens, chemotherapy, high doses of analgesics
- History of: Irritative voiding symptoms, Chronic urinary infections indwelling urinary catheter, pelvic irradiation
Glomerular causes of haematuria: (3)
- Antibody caused
- AN…
- Thin ….
- IgA nephropathy (+/- HSP)
- ANCA vasculitis
- Thin nephropathy
Non-glomerular causes of haematuria: kidney (3)
- Cancer
- Stones
- Trauma
Non-glomerular causes of haematuria: Ureters (2)
- Cancer
- Stones
Non-glomerular causes of haematuria: bladder (4)
- Cancer
- Infection
- Non-infective cystitis
- Stones
Non-glomerular causes of haematuria: Urethra (3)
- Cancer (prostate)
- Infection (prostatitis)
- Trauma
Clinical approach to haematuria:
- Confirm
- Check
- When
- Check
- Confirm haematuria by using a dip stick
- Check history for specific cause
- When appropriate, screening of whole urinary tract for cancers
- Check glomerular causes, rarer but still a possibility
Raised hydrostatic capillary pressure origin example : rise in venous pressure (3)
- Left heart failure: pressures rise in the dependent (pulmonary) circulation
- Insert pulmonary catheter to find pulmonary capillary pressure
- If PCP rises above 25mmHg then frank pulmonary oedema occurs
Systemic oedema:
- How
- Where
- Results from raised pressures in the systemic venous circulation leading to fluid accumulation in the interstitial spaces
- Often affects the lower body; legs, feet and ankles
Pitting oedema:
- Causes (2)
- A result of either a systemic problem, (heart, kidneys, liver function)
- Or localised problems with veins in the affected area (pregnancy and deep vein thrombosis)
Increased extravascular colloid osmotic pressure due to an increase in π i
- What causes it
- How
- When
- Capillary leak syndrome
- The release of cytokines causes proteins to accumulate in the extravascular space
- Occurs in sepsis and burns
Interstitial fluid: transudate
- Filtrate of…..
- Protein content
- Caused by (2)
- A plasma filtrate
- low protein content (<30 g/l
- increase capillary hydrostatic pressure i.e. cardiac/nephrotic/renal failure
- Reduce colloid osmotic pressure i.e. malnutrition
Interstitial fluid: exudate
- Filtrate of…..
- Protein content
- Caused by, example
- plasma
- High protein content: >30 g/l
- Factors that increase extravascular colloid osmotic pressure, i.e. increased capillary permeability to protein (burns, sepsis)
Capillary hydrostatic pressures (P):
- Generated by ….
- What does it cause?
- Propulsive forces
- When Pc > Pi , net filtration
Colloidal osmotic pressures (π):
- Generated by ….
- What does it cause
- Impermeable protein concentrations
- when πc > πi , Net absorption
Reduced plasma colloid osmotic pressure (πc): Nephrotic syndrome - explanation
- Presentation
- Nephrotic syndrome: damage to basement membrane of the glomerulus results in proteinuria and hypoalbuminaemia
- Oedema around the eyes, puffy face, pitting oedema of feet and ankles
Reduced plasma colloid osmotic pressure (πc): impaired protein synthesis
- Causes (3)
M
M S
I H S
- Malnutrition: reduced protein intake causes oedema around the belly (Kwashiorkor)
- Malabsorption syndromes: Pancreatic insufficiency, Cystic fibrosis, Intestine surface damage
- Impaired hepatic synthesis
Common causes of transudate effusion (increase in Pc or decreased π): (5)
- C/H/R
- N S
- P D
- P
- P E
- Cardiac/hepatic/renal failure
- Nephrotic syndrome
- Peritoneal dialysis
- Pericarditis
- Pulmonary embolism
Common causes of exudate effusions:
- P/TB
- I C
- C
- P
- P E
- Pneumonia/TB
- Inflammatory conditions
- Cancer
- Pancreatitis
- Pulmonary embolism
Non-cardiogenic pulmonary oedema:
- What is it?
- What causes it?
- Pulmonary oedema with no increase in pulmonary wedge pressures >18 mmHg
- Results from increased permeability of pulmonary capillaries from a direct or indirect pathological insult
Acute Respiratory Distress Syndrome (ARDS): causes
- F O
- P
- I I / D
- Re-E
- N C
- H A E
- Fluid overload
- Pancreatitis
- Inhalation injury / drowning
- Re-expansion of lungs after draining
- Neurogenic causes - head trauma / haemorrhage
- High altitude exposure
Acute Respiratory Distress Syndrome (ARDS):
- Definiton (specific to…)
- Diagnosis requires (3)
- A non-cardiogenic pulmonary oedema and diffuse lung inflammation syndrome (SPECIFIC)
- Acute onset (1 week)
- Bilateral opacities on chest X-ray
- PaO2/FiO2 ratio of <300 on PEEP
Ascites:
- What is it?
- What causes it?
- Fluid accumulation in the abdomen
- Portal hypertension, due to cirrhosis
Ascites: portal venous pressure increase causes (4):
- H D & F
- R P-H V P
- R H V D
- I V F
- Hepatic damage and fibrosis
- Raised post-hepatic venous pressures
- Reduced hepatic venous drainage
- Increased venous inflow
Non-pitting oedema caused by myxoedema:
- Association
- How does it cause oedema? (Mucop….)
- Myxoedema is commonly associated with severe hypothyroidism
- excessive deposition of mucopolysaccharides in the skin/dermis which attract water, leading to swelling
Lymph has three major functions:
- Protein
- Fat
- Immune
- Return protein and fluid from the extravascular fluid to maintain low protein conc.
- Aid absorption and transport of fat from the small intestine
- Immunological role - lymph glands, circulation of immune cells, removal of bacteria
Lymphoedema:
- Definition
- The lymphatic system fails to drain lymph, which accumulates in the tissues, usually arms and legs
Primary lymphoedema:
- A rare genetic condition whereby the lymphatic system fails to develop properly
Secondary lymphoedema:
- Many causes (6)
- s
- R
- C
- I/P I
- I C
- V D
- Basically anything that blocks/damages the lymph nodes
- Surgery
- Radiation treatment
- Cancer
- Infection/parasitic invasion
- Inflammatory conditions
- Venous diseases
Osmole:
- A unit of osmotic pressure equivalent to the amount of solute that dissociates in solution to form one mole of particles
OsmolaLity:
- Measure of the osmoles of solute per Kg of solvent
OsmolaRity:
- Measure of the osmoles of solute per L of solution
Polyuria:
Polydipsia:
Polyuria: excessive urine output
Polydipsia: excessive drinking
SIADH effects:
- Sodium/serum osmolality
- Urine output
- Urine osmolality
- Decrease
- Decrease
- Increase
Dehydration effects:
- Sodium/serum osmolality
- Urine output
- Urine osmolality
- Increase
- Decrease
- Increase
Diabetes insipidus:
- Sodium/serum osmolality
- Urine output
- Urine osmolality
- Increase
- Increase
- Decrease
ADH (anti-diuretic hormone): function
- ADH induces expression of water transport proteins in the late distal tubule and collecting duct to increase water reabsorption
ADH: method of action (3 steps)
- acts on …
- Increases water…
- by phosphorylation of….
- Acts on renal collecting ducts via V2 receptors to
- increase water permeability (cAMP-dependant mechanism)
*by phosphorylation of aquaporin, which leads to decreased urine formation
Causes of polydipsia: (6)
- D I
- D M
- P P
- Hc/E
- D
- U
- Diabetes insipidus
- Diabetes mellitus
- Primary Polydipsia
- Hypercalcaemia/Electrolyte disturbances
- Diuretics
- UTI
Diabetes insipidus: what is it?
- Disorder of AVP release or action
Diabetes insipidus - signs and symptoms: infants
- Forceful sucking
- Soaked nappies
Diabetes insipidus - signs and symptoms: Young children
- Primary enuresis
- Toilet training differences
Diabetes insipidus - signs and symptoms: older children
- High urinary output
- Nocturia
- Tiredness
Water deprivation test: Diabetes insipidus is confirmed if: (3)
- Plasma osmolality is rising
- Plasma Na is elevated
- Urine osmolality remains dilute
What is the cause of DI?: central
- Caused by
- Check for ….
- Other testing (2)
- Isolated ?????
- AVP deficiency
- Check for other pituitary hormones - ACTH, TSH, LH, FSH, Prolactin
- GH testing may be required
- MRI brain
- Cranial or Central DI is rarely isolated
What is the cause of DI?: nephrogenic
- Caused by
- How to test for it
- AVP resistance
- Genetic testing for mutation in AVP receptor
How to clinical test for nephrogenic vs central DI?
- Administer test dose of DDAVP (desmopresin) at the end of deprivation test
- If urine becomes concentrated = Central DI
- If no change occurs = Nephrogenic DI
SIADH: Signs and Symptoms (2)
- Reduced urine output
- Reduced sodium (dilutional) = nausea, vomiting, cramps, irritability, rarely seizures
SIADH meaning:
- Syndrome of Inappropriate ADH Secretion
Causes of SIADH:
- T
- C D
- CN
- D
- R O
- Tumours
- Chest disease
- CNS disorders
- Drugs
- Reset osmostat
Diabetes Mellitus: symptoms
- P
- P
- W
- F
- A
- N
· Polydipsia
· Polyuria
· Weight loss
· Fatigue
· Abdominal pain
- Nocturnal enuresis
How does diabetes cause these symptoms?
- Polyuria and Polydipsia
- Increase in glucose
- Renal excretion of glucose
- Osmotic diuresis with excessive water loss (polyuria)
- Dehydration
- Polydipsia to compensate
Diabetic Ketoacidosis (DKA): How does an insulin deficiency cause acidosis
- Increased lipolysis
- Increased FFA to the liver
- Ketogenesis
- Acidosis
DKA: treatment
· Mainstay of treatment:
- Rehydrate with IV fluids gradually over 48 hours
- Treat insulin deficiency with IV insulin
- Close monitoring of clinical condition, electrolyte and glucose levels
Diabetes mellitus: treatment
- Insulin
· Chronic disease management
· Screening for complications of diabetes
Primary Polydipsia:
· Excessive fluid intake caused by a behavioural
component
· Often from drinking non-water substances
· Don’t restrict water until DI or DM excluded
Psychogenic polydipsia:
- Psychogenic polydipsia: used to describe the association between polydipsia and psychiatric disorders e.g. schizophrenia/anxiety disorders (6-20% prevalence)
Diuretics: what do they do? (2)
- They reduce Na+ reabsorption in the tubular nephron, increasing Na+ excretion.
- An increase in Na+ in the urine increases water excretion by osmosis
Diuretics: why are they used? (2)
- Removal of …..
- Combinations of …..
- For the removal of fluid accumulations from interstitial space or the circulation when these have clinical consequences
- Combos of diuretics can be used to offset potential side effects
Osmotic diuresis: two possible principles of action
1. Osmotic diuresis
2. Ion transport modulators
- Add an impermeable solute to tubular fluid, to reduce H2O reabsorption
- Reduce Na+ reabsorption across the tubular membrane
Osmotic diuresis - Mannitol
- Method of action
- Filtered at glomerulus and is poorly reabsorbed, raises plasma and tubule osmolarity, reducing loss of Na+ in diuresis
Mannitol - Clinically useful characteristics (2)
- Does not enter eye or brain. This makes it useful in the treatment of raised intracranial/intraocular pressure
- Useful to drain relatively inaccessible oedema accumulations
Proximal tubule mechanics:
- Transport
- Flux
- Na+ in the tubule fluid is exchanged for H+, pumping Na+ into the epithelial cell where it is pumped out via an ATP-consuming Na-pump
- Na+ transport is accompanied by an osmotic flux (H2O) from tubular fluid
Carbonic Anhydrase (CA): role in proximal tubule
- Role
- How it does this in simple terms
- Inhibition
- CA catalyses the production of H2O and CO2 from HCO3- and H+
- It takes the H+ being exchanged for water and makes new water
- CA inhibition would reduce Na+ reabsorption and hence water re-uptake
Carbonic anhydrase inhibitors: Acetazolamide
- Action
- Effects
- Reduces Na+ reabsorption hence H2O reabsorption by suppressing H+ uptake
- Increases excretion of HCO3- (Na+, K+, H2O), causing metabolic acidosis and mildly alkaline urine
What does Acetazolamide treat?:
G
MA
P for AS
- Glaucoma: reduces the formation of aqueous humour
- Adjunct therapy in metabolic alkalosis
- Prophylaxis for altitude sickness
Mechanics of the ascending loop of Henle:
The concentration of … is generated by (2)
- The concentration gradient of the medullary interstitium is generated by:
1. An apical Na+/K+/2Cl- co-transporter
2. A basolateral Na-pump - The ascending limb is impermeable to water
Loop diuretics: Furosemide
- Action (ascending)
- Aims of action (2)
- End result
- Inhibits the Na+/K+/2Cl- co transporter to:
1. Reduce the medullary interstitial conc. gradient
2. Maintain a greater tubule osmolality - 20% of water load is usually reabsorbed by action of the co-transporter. Inhibition causes an equivalent water retention, causing a huge urine production increase
Loop diuretics: side effects (2)
- Hypovolaemia can occur leading to hypotension (lowered systemic arterial pressure)
- Loss of tubular fluid can result in hypokalaemia causing muscle weakness and possible ECG changes
Loop diuretic side effects: how to avoid hypokalaemia?
- Loss of excess K+ can be ameliorated by using loop diuretics in combination with K+-sparing diuretics
K+ sparing diuretics: Spironolactone
- Action
- Clinical use
- Blocks the aldosterone receptor, preventing the loss of K+ into the tubular fluid in the distal tubule
- This prevents hypokalaemia that can be caused by more powerful loop diuretics
K+ sparing diuretics: Amiloride and Triamterene
- Both block epithelial Na+ channels (ENaC), preventing loss K+ from Na+/K+ trade
- Limited efficacy in generating diuresis, so used in conjuction with stronger loop diuretics as a K+ preserver
K+-sparing diuretics: side effects
- Can cause Hyperkalaemia in patients with raised K+ from renal failure or diabetes
Renal tubule handling of ions and water:
- Transporter present
- What blocks this?
- Distal tubule cells express a Na+ - Cl- co-transporter that reabsorbs Na+ from the tubular lumen
- Thiazides
Thiazide-like diueretics:
- What are they?
- Action
- Example
- Several compounds that share the same effect but vary in structure.
- Block the Na+-Cl- co-transporter in the distal tubule , preventing reabsorption of Na+ from the tubular lumen
- Hydrochlorothiazide is a widely used example
Thiazide-like diuretics: side effects
- Hypokalaemia: Same as loop diuretics, thiazide-like diuretics increase urinary K+ losses
- Hypotension, dizziness and syncope due to hypovolaemia
Chronic kidney disease definition:
- Abnormal kidney function for more than 3 months, with implications for health
Three common causes of CKD:
- Diabetes
- Hypertension
- Obesity
eGfR meaning:
- Measures how much blood your glomeruli filters clean every minute based on your body size
Clinical utility of eGFR:
- Used to watch for the onset of kidney disease and monitor severity of existing cases
- > 90 is normal
Non-specific advanced CKD symptoms: (5)
- Fatigue
- Loss of appetite
- Nausea/vomiting
- Itchy skin
- Cramp
CKD symptom presentation:
- usually minimally symptomatic
Acute Kidney Disease (AKD):
- Abnormal kidney function present for less than 3 months, with implications for health
Acute Kidney Injury (AKI):
- Abnormal kidney function present for less than one week, with implications for health
acute renal failure: prerenal
- Definition
- Causes (3)
- Sudden and severe drop in blood pressure or interruption of blood flow to the kidneys
- Diarrhoea, Bleeding, Burns
acute renal failure: Intrarenal
- definition
- Causes (3)
- Direct damage to the kidneys
- Acute tubular necrosis, Drugs, autoimmune
acute renal failure: Postrenal
- Defintion
- Causes
- Sudden obstruction of urine flow
- enlarged prostate, kidney stones, bladder tumour or injury
Causes of acute renal failure: prevalence
1. Prerenal
2. Intrarenal
3. Postrenal
- 70%
- 10%
- 30%
Why can eGFRs not be used for AKD
- It takes a very large change in GFR to result in even a small measurable change in serum creatine (higher regions)
Symptoms of advanced AKD:
- Fatigue
- Loss of appetite
- Nausea/vomiting
- Cramp
End-Stage Kidney Disease (ESKD): Clinical definition (2)
- GFR < 15ml/min per 1.73m^2
OR - If they are on dialysis/transplant
The different names of Kidney failure:
- AK13 if dialysed for AKI
- CKD5D if dialysed for CKD
Kidney functions: (6)
- Remove (1)
- Regulate (4)
- Control (1)
-Remove soluble waste products from the blood
-Regulate amount of water in the blood
- Regulate amount of sodium in the blood
- Regulate acidity in blood
- Control calcium and phosphate metabolism
- Regulate blood cell production (produces erythropoietin)
Treatment for kidney failure effectiveness: Dialysis
- Only restores removal of waste solutes and Salt/water balance
Treatment for kidney failure effectiveness: kidney transplantation
- Restores all kidney functions
Typical features of a patient with a surgical atriovenous fistula: (3)
- Purplish bulging veins
- Swelling in arms/legs
- Decreased BP/HF
Lower UTI: Distinguishing signs
- Nocturia
- Suprapubic pain
- NO FEVER
Lower UTI: definiton
- Simple cystitis of the bladder/urethra
Upper UTI: definition
- Pyelonephritis (complicated infection) of the Aorta/Inferior VC/Ureters/Kidneys
upper UTI: distinguishing signs
- Fever
- Flank pain (renal angle tenderness)
- Raised heart rate
Micro-organisms that commonly cause UTI:
- E. coli (most common)
- Staphylococcus: colonises the UT and perineum
Common risk factors for urinary tract infections: Structural (4)
- Female
- Pregnancy
- Abnormal UT (congenital)
- Malignancy
Common risk factors for urinary tract infections: co-morbidities (5)
- Diabetes
- Immunocompromised
- Urinary catheter
- Ureteric stent
- Previous UT
Common risk factors for urinary tract infections: Other risk factors (2)
- Sexual activity
- Dehydration
Signs of UTI on dipstick: (3)
- Raised leukocyte levels
- Raised Nitrite levels
- RBC: Haematuria
Suspected UTI: when to use a dipstick test?
- Women (under 65) with suspected UTI
- Infants/children under 16 with suspected UTI
When to use Urine cultures: (5)
- Over 65 is symptomatic and antibiotic given
- Suspected polynephritis or sepsis
- Suspected UTI in men
- Urinary catheter in place
- Failed antibiotics/recurring UTI
Nervous control of the lower urinary tract -
bladder: M3 receptors
- Stimulated by
- Innervation type
- Effect
- Stimulated by ACh via the pelvic nerve
- Parasympathetic (pelvic) nerve
- Excitatory -> cause muscle contraction
Nervous control of the lower urinary tract -
bladder: B3 receptors
- Stimulated by …..
- Innervation type
- Effect
- Stimulated by NA via the hypogastric nerve
- Sympathetic nerve
- Inhibitory -> causes muscle relaxation
Nervous control of the lower urinary tract -
Urethra: a1 receptors
- Stimulated by…
- Innervation type
- Effect
- Stimulated by NA via the hypogastric nerve
-Sympathetic nerve - Excitatory -> urethra contraction
Nervous control of the lower urinary tract -
External urethral sphincter: nicotinic receptors
- Stimulated by
- Innervation type
- Effect
- Stimulated by ACh via Pudenal nerve
- Somatic innervation
- Excitatory -> EUS opens
The micturition cycles: peripheral nervous system: filling
- General state
- Parasympathetic
- Sympathetic
- Pudenal
- Bladder is relaxed; outflow tract contracted
- Parasympathetic nerve (S2-S4) inactive
- Sympathetic nerve (T11-L2) active, maintains bladder relaxation
- Pudenal nerve (S2 to S4) active, retain EUS closure
The micturition cycles: peripheral nervous system: voiding
- General state
- Parasympathetic
- Sympathetic
- Pudenal
- Bladder contracts, outflow tract relaxed
- Parasympathetic nerve: active, releases ACh, bladder contracts and urethra relaxes
- Sympathetic nerve inactive
- Pudenal nerve less active, EUS opens
The micturition cycles: Sacral coordination (CNS):
- PMC
- PMC, upon stimulation, leads to detrusor muscle contraction and urethral sphincter relaxation -> urination
Measurement of urinary tract function: Frequency-volume chart
- When is it used?
- What does it look at?
- Used in initial assessment for LUT
- Looks at nocturia, leakage, frequency
Measurement of urinary tract function: Ultrasound-bladder scan
- What does it look at
- When is it used
- Looks at residual volume and problems (UTI, CKD), can measure bladder volume
- Specialist assessment, bladder should void completely
Measurement of urinary tract function: Volume-flow measurements
- Filling urodynamics and video-urodynamics
- If a patient fails to respond to a conservative treatment of drugs
Types of urinary tract stones: Calcium stones
- Formation
- Risk factors
- Formed from calcium oxalate / phosphate
- Risk factors: hypercalciuria, hyperoxaluria and hyperparathyroidism
Types of urinary tract stones: Uric acid stones
- Risk factors
- Risk factors: High purine intake or malignancies
Types of urinary tract stones: Cystine stones
- Risk factors
- Risk factors: Reduced renal tubular reabsorption of cysteine, ornithine, lysine and arginine
Types of urinary tract stones: Struvite stones
- Made of
- Risk factor (bacterial)
- Made of magnesium ammonium phosphate
- Risk factors: chronic UTI of gram-ve, urease positive organisms
