Distinguishing between Acute Kidney Injury and Chronic Kidney Disease

One of the most effective ways to differentiate between acute kidney injury (AKI) and chronic kidney disease (CKD) is through the use of renal ultrasound. In most cases, patients with CKD will have small kidneys that are bilateral. However, there are some exceptions to this rule, including individuals with autosomal dominant polycystic kidney disease, diabetic nephropathy in its early stages, amyloidosis, and HIV-associated nephropathy.

In addition to renal ultrasound, there are other features that can suggest CKD rather than AKI. For example, individuals with CKD may experience hypocalcaemia due to a lack of vitamin D. By identifying these distinguishing factors, healthcare professionals can more accurately diagnose and treat patients with kidney disease. Proper diagnosis is crucial, as the treatment and management of AKI and CKD differ significantly.

Types of Kidney Tumours and Their Characteristics

Kidney tumours can present with symptoms such as haematuria, loin pain, fatigue, and weight loss. These symptoms should be considered as red flags for urgent referral for potential renal cancer. Renal cell carcinomas are the most common type of kidney tumours in adults, accounting for 80% of renal cancers. They are divided into clear cell (most common), papillary, chromophobe, and collecting duct carcinomas. Sarcomatoid renal cancers are rare and have a poorer prognosis compared to other types of renal cancer. Angiomyolipomas are benign kidney tumours commonly seen in patients with tuberous sclerosis. Transitional cell carcinomas account for 5-10% of adult kidney tumours and start in the renal pelvis. They are the most common type of cancer in the ureters, bladder, and urethra. Wilms’ tumour is the most common kidney cancer in children and is not likely to be found in adults.

Understanding the Different Types of Kidney Tumours

Treatment Options for Stage 4 Renal Cancer with Metastases

Loin pain, haematuria, and a palpable abdominal mass are the classic symptoms of renal cancer, which is not very common. When the cancer has metastasized to the adrenal gland, it becomes a stage 4 tumor. Targeted molecular therapy is the first-line treatment for stage 4 renal cancer with metastases. Immunomodulatory drugs such as sunitinib, temsirolimus, and nivolumab are commonly used for this purpose.

Other treatment options for renal cancer include cryotherapy, partial nephrectomy, radiofrequency ablation, and radical nephrectomy. Cryotherapy uses liquid nitrogen to freeze cancerous cells, but it is usually only used for early-stage disease and is not first-line here. Partial nephrectomy is reserved for patients with small renal masses, usually stage 1. Radiofrequency ablation can be used for non-surgical candidates with small renal masses without metastasis, usually stage 1 or 2. Radical nephrectomy involves removal of the entire kidney, which is primarily done for stage 2 and 3 renal cell cancers.

The most appropriate treatment for minimal change glomerulonephritis, which is likely the cause of this patient’s facial edema, hypoalbuminemia, and proteinuria, is prednisolone. This medication is a corticosteroid and is considered the mainstay of therapy for this condition. Adrenaline, albumin infusion, and furosemide are not appropriate treatments for this patient’s condition. While albumin infusion may be used as adjunctive therapy, its effects will only be temporary. Adrenaline is used to treat anaphylaxis and would not be effective in treating minimal change disease. Furosemide may be used as adjunctive therapy, but its effects will also be temporary.

Minimal change disease is a condition that typically presents as nephrotic syndrome, with children accounting for 75% of cases and adults accounting for 25%. While most cases are idiopathic, around 10-20% have a known cause, such as certain drugs, Hodgkin’s lymphoma, thymoma, or infectious mononucleosis. The pathophysiology of the disease involves T-cell and cytokine-mediated damage to the glomerular basement membrane, resulting in polyanion loss and reduced electrostatic charge, which increases glomerular permeability to serum albumin. The disease is characterized by nephrotic syndrome, normotension (hypertension is rare), and highly selective proteinuria, with only intermediate-sized proteins such as albumin and transferrin leaking through the glomerulus. Renal biopsy shows normal glomeruli on light microscopy, but electron microscopy reveals fusion of podocytes and effacement of foot processes.

Management of minimal change disease typically involves oral corticosteroids, which are effective in 80% of cases. For steroid-resistant cases, cyclophosphamide is the next step. The prognosis for the disease is generally good, although relapse is common. Approximately one-third of patients have just one episode, one-third have infrequent relapses, and one-third have frequent relapses that stop before adulthood.

The BASH guidelines for Sexually Transmitted Infections in Primary Care state that in young men, urethritis is typically caused by an STI. Men under the age of 35 rarely experience urine infections, so any sexually active man experiencing dysuria should be screened for STIs. The presence of leukocytes in the urine indicates the presence of pus cells, which are a result of an STI. Chlamydia is the most prevalent STI in the UK.

Chlamydia is a common sexually transmitted infection caused by Chlamydia trachomatis. It is prevalent in the UK, with approximately 1 in 10 young women affected. The incubation period is around 7-21 days, but many cases are asymptomatic. Symptoms in women include cervicitis, discharge, and bleeding, while men may experience urethral discharge and dysuria. Complications can include epididymitis, pelvic inflammatory disease, and infertility.

Traditional cell culture is no longer widely used for diagnosis, with nuclear acid amplification tests (NAATs) being the preferred method. Testing can be done using urine, vulvovaginal swab, or cervical swab. Screening is recommended for sexually active individuals aged 15-24 years, and opportunistic testing is common.

Doxycycline is the first-line treatment for Chlamydia, with azithromycin as an alternative if doxycycline is contraindicated or not tolerated. Pregnant women may be treated with azithromycin, erythromycin, or amoxicillin. Patients diagnosed with Chlamydia should be offered partner notification services, with all contacts since the onset of symptoms or within the last six months being notified and offered treatment.

The most appropriate investigation to arrange for a patient presenting with symptoms suggestive of a urinary tract infection or pyelonephritis is urinary microscopy and culture. It is important to obtain a sample before starting empirical antibiotics to guide subsequent antibiotic choice if the initial course is ineffective. While genital swabs may be useful if there is a history of sexually transmitted infection, they are not as important as urine culture in this situation. Cystoscopy and ultrasound scans of the abdomen may be useful in other situations, but are not urgently indicated in this case. Similarly, a CTKUB would not be useful in investigating the cause of the infection, which can be determined through urine culture.

Haemolytic uraemic syndrome (HUS) is a condition that causes progressive kidney failure and is associated with microangiopathic haemolytic anaemia and thrombocytopenia. There are two main types of HUS, one of which is associated with Shiga-like toxin (Stx) and is commonly seen in children who have had diarrhoea. The classic form of Stx-HUS is often caused by E. coli O157:H7 and is characterized by a history of gastroenteritis, fever, bloody diarrhoea, oedema, and hypertension. Henoch-Schönlein purpura is an acute disorder that affects small blood vessels in various parts of the body, including the skin, gastrointestinal tract, kidneys, and joints. It is characterized by a rash with bullae and ulcers, which typically appears in crops. Post-infectious glomerulonephritis is a condition that occurs after a streptococcal infection and is characterized by haematuria, proteinuria, red blood cell casts in the urine, oedema, and hypertension. Membranoproliferative glomerulonephritis is a rare cause of chronic nephritis that occurs primarily in children and young adults and may be idiopathic or secondary in aetiology. Acute interstitial nephritis is a condition that causes sudden kidney dysfunction, fever, and occasionally a rash, and is often associated with drug use.

Appropriate Investigations for Suspected Urinary Tract Infection

When a patient presents with symptoms suggestive of a urinary tract infection or pyelonephritis, the most appropriate investigation to arrange is urinary microscopy and culture. It is important to obtain a sample before starting empirical antibiotics, as this can guide subsequent antibiotic choice if the patient does not respond to the initial course. Recurrent episodes may require further investigation or referral to secondary care. Blood tests may be useful if the patient is unwell or has evidence of sepsis. However, a computed tomography of the kidneys, ureters, and bladder (CTKUB) would not be useful in this situation. Cystoscopy may be indicated for recurrent infections or unexplained bleeding, but not for a first episode. An urgent ultrasound of the renal tract may be useful to look for obstruction or anatomical abnormalities, but is not necessary for treatment. Inflammatory markers can be helpful, but urinary microscopy and culture are more appropriate in this situation.

The initial treatment for urinary incontinence differs depending on the type. For urge incontinence, bladder retraining is the recommended first-line approach. On the other hand, for stress incontinence, pelvic floor muscle training is the preferred initial treatment.

Understanding Urinary Incontinence: Causes, Classification, and Management

Urinary incontinence (UI) is a common condition that affects around 4-5% of the population, with elderly females being more susceptible. Several risk factors contribute to UI, including advancing age, previous pregnancy and childbirth, high body mass index, hysterectomy, and family history. UI can be classified into different types, such as overactive bladder (OAB)/urge incontinence, stress incontinence, mixed incontinence, overflow incontinence, and functional incontinence.

Initial investigation of UI involves completing bladder diaries for at least three days, vaginal examination, urine dipstick and culture, and urodynamic studies. Management of UI depends on the predominant type of incontinence. For urge incontinence, bladder retraining and bladder stabilizing drugs such as antimuscarinics are recommended. For stress incontinence, pelvic floor muscle training and surgical procedures such as retropubic mid-urethral tape procedures may be offered. Duloxetine, a combined noradrenaline and serotonin reuptake inhibitor, may also be used as an alternative to surgery.

In summary, understanding the causes, classification, and management of UI is crucial in providing appropriate care for patients. Early diagnosis and intervention can significantly improve the quality of life for those affected by this condition.

Stress incontinence is characterized by the involuntary release of urine during physical activity, coughing, or sneezing. Diagnosis is based on symptoms, and keeping a bladder diary can aid in evaluating the severity of the condition. Lifestyle changes, such as reducing caffeine intake, losing weight, and limiting fluid consumption, are recommended. Pelvic floor exercises should also be suggested. If symptoms persist despite these measures, surgery may be an option. If surgery is not feasible or desired, duloxetine, a serotonin-norepinephrine reuptake inhibitor (SNRI), may be prescribed. A ring pessary is not an effective treatment for stress incontinence, as it is used to address vaginal prolapse.

Understanding Urinary Incontinence: Causes, Classification, and Management

Urinary incontinence (UI) is a common condition that affects around 4-5% of the population, with elderly females being more susceptible. Several risk factors contribute to UI, including advancing age, previous pregnancy and childbirth, high body mass index, hysterectomy, and family history. UI can be classified into different types, such as overactive bladder (OAB)/urge incontinence, stress incontinence, mixed incontinence, overflow incontinence, and functional incontinence.

Initial investigation of UI involves completing bladder diaries for at least three days, vaginal examination, urine dipstick and culture, and urodynamic studies. Management of UI depends on the predominant type of incontinence. For urge incontinence, bladder retraining and bladder stabilizing drugs such as antimuscarinics are recommended. For stress incontinence, pelvic floor muscle training and surgical procedures such as retropubic mid-urethral tape procedures may be offered. Duloxetine, a combined noradrenaline and serotonin reuptake inhibitor, may also be used as an alternative to surgery.

In summary, understanding the causes, classification, and management of UI is crucial in providing appropriate care for patients. Early diagnosis and intervention can significantly improve the quality of life for those affected by this condition.

Managing Haematuria: Causes, Testing, and Referral Guidelines

The management of haematuria can be challenging due to the lack of widely followed guidelines. Haematuria is classified as either visible or non-visible, with the latter being found in approximately 2.5% of the population. Transient or spurious non-visible haematuria can be caused by factors such as urinary tract infections, menstruation, vigorous exercise, or sexual intercourse. Persistent non-visible haematuria, on the other hand, may be indicative of underlying conditions such as cancer, stones, benign prostatic hyperplasia, prostatitis, urethritis, or renal causes like IgA nephropathy or thin basement membrane disease.

Current evidence does not support routine screening for haematuria, but patients taking aspirin or warfarin should still be investigated. Urine dipstick is the preferred test for detecting haematuria, and persistent non-visible haematuria is defined as blood being present in 2 out of 3 samples tested 2-3 weeks apart. Renal function, albumin:creatinine (ACR) or protein:creatinine ratio (PCR), and blood pressure should also be checked. NICE urgent cancer referral guidelines recommend urgent referral for patients aged 45 years or older with unexplained visible haematuria or aged 60 years or older with unexplained non-visible haematuria and either dysuria or a raised white cell count on a blood test. Patients under 40 years of age with normal renal function, no proteinuria, and normotension may be managed in primary care.

In conclusion, managing haematuria requires careful consideration of the underlying causes and appropriate testing. Referral guidelines can help guide healthcare professionals in determining which patients require urgent or non-urgent referral for further investigation.

Management of a Patient with Suspected Bladder Tumour and Bleeding

When managing a patient with suspected bladder tumour and bleeding, it is important to consider the appropriate steps to take. Here are some options and their potential outcomes:

1. Arrange a full blood count: This test can help assess the degree of blood loss and guide the urgency of treatment.

2. Transfuse two units of O-negative blood: While patients with bladder tumours can bleed extensively, it is important to first assess the need for transfusion through a full blood count.

3. Flush the urinary catheter using normal saline: This step is appropriate for a blocked catheter, but not for a patient with active bleeding.

4. Remove the urinary catheter: This step can cause blood clots and urinary retention, and is not indicated for this patient.

5. Transfer to theatre for resection of tumour: While this may be necessary in cases of catastrophic bleeding, it is important to first assess the patient’s stability and obtain blood tests before planning definitive management.

In summary, careful consideration of the appropriate steps is crucial in managing a patient with suspected bladder tumour and bleeding.

Understanding Membranous Nephropathy: Causes, Symptoms, and Prognosis

Membranous nephropathy is a kidney disease that affects the glomeruli, the tiny blood vessels in the kidneys that filter waste from the blood. The disease is characterized by the thickening of the glomerular basement membrane, which can lead to proteinuria, or the presence of excess protein in the urine. Here are some key points to understand about membranous nephropathy:

Causes: The majority of cases of membranous nephropathy are idiopathic, meaning that the cause is unknown. However, secondary forms of the disease can be caused by underlying conditions such as solid organ malignancy, autoimmune diseases, infectious diseases, and certain medications.

Symptoms: Membranous nephropathy can present with symptoms such as edema (swelling), hypertension (high blood pressure), and proteinuria. Elevated levels of anti-nuclear antibody (ANA) may also be present.

Proteinuria: Glomerular proteinuria can be classified as selective or non-selective. Selective proteinuria is characteristic of childhood minimal change disease, while membranous nephropathy typically presents with non-selective proteinuria.

Prognosis: The course of membranous nephropathy can vary, with some patients experiencing spontaneous remission and others progressing to end-stage renal disease (ESRD). Successful treatment of the underlying cause may be curative in secondary forms of the disease, while immunosuppressive therapy may be appropriate for selected patients with idiopathic membranous nephropathy.

In conclusion, membranous nephropathy is a complex kidney disease that requires careful diagnosis and management. By understanding the causes, symptoms, and prognosis of the disease, patients and healthcare providers can work together to develop an effective treatment plan.

Diagnostic Methods for Renal Amyloidosis

Renal amyloidosis is a condition that can be challenging to diagnose. It is caused by the accumulation of proteinaceous material in tissues, which can be identified through a biopsy. Congo-red staining extracellular fibrillar material is a characteristic feature of amyloid protein in the kidney. While a urine dip may show proteinuria, a renal biopsy is necessary for a definitive diagnosis as proteinuria can be caused by other conditions. A bone marrow biopsy can confirm amyloidosis if there is suspicion of bone marrow infiltration. CT scans of the abdomen may reveal abnormalities in the kidneys or lymph nodes, but a renal biopsy is still required for a definitive diagnosis. As amyloidosis can affect other organs, a lung biopsy may not be the most targeted approach for diagnosing renal amyloidosis. Overall, a renal biopsy is the most reliable method for diagnosing renal amyloidosis.

This woman is experiencing an acute kidney injury, most likely caused by dehydration leading to pre-renal failure. The function of the kidneys is determined by the glomerulus’ ability to filter blood, which is dependent on the perfusion pressure of the glomerulus. This pressure is influenced by two factors: the overall blood flow to the kidney (which is reduced in cases of dehydration and hypovolemia) and the auto-regulation of the afferent and efferent arterioles, which fine-tunes the pressure.

Prostaglandin E2 mediates the dilation of the afferent arteriole to increase blood flow, while angiotensin II mediates the constriction of the efferent arteriole to increase pressure. Non-steroidal anti-inflammatory drugs can disrupt this auto-regulation by blocking prostaglandin E2, contributing to acute kidney injury. However, oral aspirin is an exception and does not harm the kidneys. Drugs that block angiotensin II, such as ACE inhibitors like Ramipril and angiotensin receptor blockers, should be avoided during an AKI as they also disrupt auto-regulation.

In contrast, ACE inhibitors and ARBs are beneficial in chronic kidney disease due to their antihypertensive and anti-inflammatory effects. In CKD, glomerular perfusion pressures are elevated, and reducing this pressure can help prevent glomerular damage and a decline in GFR.

Angiotensin-converting enzyme (ACE) inhibitors are commonly used as the first-line treatment for hypertension and heart failure in younger patients. However, they may not be as effective in treating hypertensive Afro-Caribbean patients. These inhibitors are also used to treat diabetic nephropathy and for secondary prevention of ischaemic heart disease. The mechanism of action of ACE inhibitors is to inhibit the conversion of angiotensin I to angiotensin II. They are metabolized in the liver through phase 1 metabolism.

ACE inhibitors may cause side effects such as cough, which occurs in around 15% of patients and may occur up to a year after starting treatment. This is thought to be due to increased bradykinin levels. Angioedema may also occur up to a year after starting treatment. Hyperkalaemia and first-dose hypotension are other potential side effects, especially in patients taking diuretics. ACE inhibitors should be avoided during pregnancy and breastfeeding, and caution should be exercised in patients with renovascular disease, aortic stenosis, or hereditary or idiopathic angioedema.

Patients receiving high-dose diuretic therapy (more than 80 mg of furosemide a day) are at an increased risk of hypotension when taking ACE inhibitors. Before initiating treatment, urea and electrolytes should be checked, and after increasing the dose, a rise in creatinine and potassium may be expected. Acceptable changes include an increase in serum creatinine up to 30% from baseline and an increase in potassium up to 5.5 mmol/l. Patients with undiagnosed bilateral renal artery stenosis may experience significant renal impairment. The current NICE guidelines provide a flow chart for the management of hypertension.

Treatment Options for Nephrogenic Diabetes Insipidus

Nephrogenic diabetes insipidus is a condition where the kidneys are unable to respond to ADH, resulting in excessive urination and thirst. Thiazide diuretics are paradoxically used to treat this condition by blocking the NaCl transporter in the distal tubule, leading to increased uptake of sodium and water in the proximal collecting duct. This results in less water loss through urination and improved symptoms. Desmopressin is not effective in treating nephrogenic diabetes insipidus as it works by increasing ADH levels. Loop diuretics like bumetanide are not used to treat this condition. Insulin has no use in diabetes insipidus. Terlipressin is only effective in cranial diabetes insipidus.

Although UTI in pregnancy may not show any symptoms, it still needs to be treated promptly to prevent the development of pyelonephritis. The common medications used to treat UTIs are nitrofurantoin and trimethoprim. Nitrofurantoin can be used during pregnancy, but it should be avoided at term as it can cause neonatal haemolysis. Trimethoprim should be avoided in the first trimester of pregnancy. Penicillins and cephalosporins are safe to use during pregnancy, but sulfonamides (such as sulfasalazine) and quinolones (such as ciprofloxacin) should be avoided.

Urinary tract infections (UTIs) are common in adults and can affect different parts of the urinary tract. The management of UTIs depends on various factors such as the patient’s age, gender, and pregnancy status. For non-pregnant women, local antibiotic guidelines should be followed if available. Trimethoprim or nitrofurantoin for three days are recommended by NICE Clinical Knowledge Summaries. However, if the patient is aged over 65 years or has visible or non-visible haematuria, a urine culture should be sent. Pregnant women with UTIs should be treated with nitrofurantoin, amoxicillin, or cefalexin for seven days. Trimethoprim should be avoided during pregnancy as it is teratogenic in the first trimester. Asymptomatic bacteriuria in pregnant women should also be treated to prevent progression to acute pyelonephritis. Men with UTIs should be offered a seven-day course of trimethoprim or nitrofurantoin unless prostatitis is suspected. A urine culture should be sent before antibiotics are started. Catheterised patients should not be treated for asymptomatic bacteria, but if symptomatic, a seven-day course of antibiotics should be given. Acute pyelonephritis requires hospital admission and treatment with a broad-spectrum cephalosporin or quinolone for 10-14 days. Referral to urology is not routinely required for men who have had one uncomplicated lower UTI.

Common Causes of Mortality in Dialysis Patients

Cardiovascular disease is the leading cause of death in the dialysis population, with mortality rates 10-20 times higher than the general population. Hyperkalaemia, often resulting from missed dialysis or dietary indiscretion, is the most common cause of sudden death in end-stage renal disease patients. Hypocalcaemia is a common manifestation of CKD and should be treated with calcium supplements. While there is no known association between reduced renal function and overall cancer risk, some studies suggest an increased risk of urinary, endocrine, and digestive tract cancers among dialysis patients. Sepsis related to dialysis is rare with modern techniques, but minimizing the use of temporary catheters can further reduce the risk.

The Renal Tubules: Functions and Regulation

The kidneys play a crucial role in maintaining the body’s fluid and electrolyte balance. This is achieved through the intricate workings of the renal tubules, which are responsible for filtering and reabsorbing various substances from the blood.

Vasopressin, also known as antidiuretic hormone, regulates water excretion in the distal convoluted tubule and collecting ducts. Its receptor, vasopressin 2, triggers the insertion of aquaporin-2 channels, allowing water to be reabsorbed down an osmotic gradient.

The distal convoluted tubule regulates pH by absorbing bicarbonate and secreting protons, as well as controlling sodium and potassium levels through aldosterone-mediated ion transport. It also participates in calcium regulation by reabsorbing it in response to parathyroid hormone.

The proximal convoluted tubule reabsorbs the majority of ions and water in the urinary space back into the body.

The ascending limb of the loop of Henle is impermeable to water, but actively reabsorbs sodium, potassium, and chloride ions. This generates a positive electrochemical potential difference in the lumen, driving more paracellular reabsorption of sodium and other cations.

The collecting ducts continue the work of water reabsorption and electrolyte balance initiated in the collecting tubules. Progenitor cells within the collecting duct epithelium respond to tubular injury by proliferating and expanding the principal cell population to maintain epithelial integrity, or by committing to a myofibroblastic phenotype and forming peritubular collars in response to increased intraluminal pressure.

Asymptomatic bacteriuria in pregnant women should be treated promptly with antibiotics. The recommended treatment is a 7-day course of nitrofurantoin. This is important to prevent the development of symptomatic urinary tract infection or pyelonephritis. Nitrofurantoin is safe to use in the first and second trimester, but should be avoided in the third trimester due to the risk of neonatal haemolysis. The patient’s blood pressure is within normal range and does not require treatment. The trace of protein in her urine is likely related to her asymptomatic bacteriuria and should be monitored with subsequent urine dips. Antihypertensive treatment is not necessary based on the trace of protein alone. Prescribing a 7-day course of trimethoprim is not recommended as it is contraindicated in the first trimester of pregnancy due to the increased risk of neural-tube defects. Prescribing aspirin, labetalol, and a 7-day course of nitrofurantoin is not necessary as the patient does not meet the diagnostic criteria for pre-eclampsia or pregnancy-induced hypertension. Similarly, prescribing aspirin, labetalol, and a 7-day course of trimethoprim is not recommended for the same reasons.

Urinary tract infections (UTIs) are common in adults and can affect different parts of the urinary tract. The management of UTIs depends on various factors such as the patient’s age, gender, and pregnancy status. For non-pregnant women, local antibiotic guidelines should be followed if available. Trimethoprim or nitrofurantoin for three days are recommended by NICE Clinical Knowledge Summaries. However, if the patient is aged over 65 years or has visible or non-visible haematuria, a urine culture should be sent. Pregnant women with UTIs should be treated with nitrofurantoin, amoxicillin, or cefalexin for seven days. Trimethoprim should be avoided during pregnancy as it is teratogenic in the first trimester. Asymptomatic bacteriuria in pregnant women should also be treated to prevent progression to acute pyelonephritis. Men with UTIs should be offered a seven-day course of trimethoprim or nitrofurantoin unless prostatitis is suspected. A urine culture should be sent before antibiotics are started. Catheterised patients should not be treated for asymptomatic bacteria, but if symptomatic, a seven-day course of antibiotics should be given. Acute pyelonephritis requires hospital admission and treatment with a broad-spectrum cephalosporin or quinolone for 10-14 days. Referral to urology is not routinely required for men who have had one uncomplicated lower UTI.