Common Kidney Disorders and their Clinical Presentations

Autosomal Dominant Polycystic Kidney Disease (ADPKD)
ADPKD is a progressive disorder characterized by cyst formation and enlargement in the kidney and other organs. Patients may experience pain in the abdomen, flank or back, and hypertension is a common early manifestation. Palpable, bilateral flank masses are present in advanced ADPKD.

Renal Cell Carcinoma (RCC)
RCC is the most common type of kidney cancer in adults. It may remain clinically occult for most of its course, with only 10% of patients presenting with the classic triad of flank pain, haematuria, and unilateral palpable flank mass. RCC presents with hypercalcaemia manifestations in 5% of cases and with varicocele in 2% of men.

Renal Calculi
Renal calculi, or nephrolithiasis, classically present with sudden onset of severe pain originating in the flank and radiating inferiorly and anteriorly. On examination, there is dramatic costovertebral angle tenderness.

Prostatic Carcinoma
Most cases of prostate cancer are identified by screening in asymptomatic men. Symptoms include urinary complaints or retention, back pain, and haematuria. Findings in patients with advanced disease include bony tenderness, lower-extremity oedema or deep venous thrombosis, and an overdistended bladder due to outlet obstruction.

Renal Amyloidosis
Patients with renal amyloidosis typically present with proteinuria and/or hypertension, followed by progressive renal failure. Haematuria is not a feature.

Clinical Presentations of Common Kidney Disorders

Appropriate Referrals and Investigations for Patients with Haematuria

Haematuria, or blood in the urine, can be a sign of underlying bladder cancer. According to The National Institute for Health and Care Excellence guidelines, patients aged over 45 years with unexplained visible haematuria should be urgently referred for potential bladder cancer. Additionally, patients over 60 years with unexplained non-visible haematuria and either dysuria or a raised white cell count on a blood test should also be referred urgently.

An ultrasound scan might be arranged by the secondary care team for investigation of the bleeding from the renal tract. However, arranging this as an initial investigation through primary care could delay diagnosis. A 2-week wait ‘cancer exclusion’ referral would be more appropriate.

A cystoscopy might be arranged as part of the investigation, but this should be arranged via the hospital team after the patient has been referred via the 2-week-wait pathway. Arranging an outpatient cystoscopy as a first-line investigation would be inappropriate since it could lead to a delay in diagnosis.

Starting oral antibiotics would not help the patient, as her urine dip is negative for infection. Antibiotics could be considered if she had presented with symptoms or signs of infection such as dysuria, frequency or burning on urination. Frank haematuria which presents without symptoms of infection may be suggestive of bladder cancer, therefore she needs to be referred for further investigation.

Haemolytic uraemic syndrome (HUS) is a condition characterized by the simultaneous occurrence of microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury. This set of blood tests shows all three of these symptoms, indicating a possible diagnosis of HUS. HUS is most commonly found in children, with 90% of cases caused by Shiga toxin-producing E. coli. However, a patient with normal renal function and high platelet count is unlikely to have HUS, as low platelet count is a typical symptom. If a patient has ongoing diarrhoea or vomiting due to E. coli infection, they may require intravenous fluids to support their renal function. A raised haemoglobin level is not expected in HUS, as patients usually have reduced haemoglobin due to microangiopathic haemolytic anaemia. Additionally, HUS typically causes thrombocytopenia, not high platelet count. In some cases, children with HUS may require platelet transfusion.

Understanding Chronic Kidney Disease Stages and GFR Categories

Chronic kidney disease (CKD) is a condition characterized by a gradual loss of kidney function over time. To assess the severity of CKD, healthcare professionals use a staging system based on the glomerular filtration rate (GFR), which measures how well the kidneys are filtering waste from the blood.

A GFR of >90 without other evidence of kidney disease indicates normal renal function. However, if the GFR falls below this level, the patient may be classified into one of the following stages:

– CKD stage 2: GFR 60-89 ml/min/1.73 m2 (mildly decreased)
– CKD stage 3a: GFR 45-59 ml/min/1.73 m2 (mildly to moderately decreased)
– CKD stage 3b: GFR 30-44 ml/min/1.73 m2 (moderately to severely decreased)
– CKD stage 4: GFR 15-29 ml/min/1.73 m2 (severely decreased)
– CKD stage 5: GFR <15 ml/min/1.73 m2 (kidney failure) To further assess the risk of adverse outcomes, the 2008 NICE guideline on CKD recommends subdividing stage 3 into 3a and 3b and adding the suffix P to denote significant proteinuria at any stage. Significant proteinuria is defined as a urinary albumin:creatinine ratio (ACR) of 30 mg/mmol or higher. Understanding the GFR categories and CKD stages can help healthcare professionals diagnose and manage CKD, as well as educate patients on their kidney function and potential risks.

Diagnosing stages 1 and 2 of CKD should only be done if there is accompanying evidence to support the eGFR.

Understanding Chronic Kidney Disease: eGFR and Classification

Chronic kidney disease (CKD) is a condition that affects the kidneys’ ability to filter waste products from the blood. Serum creatinine, a commonly used measure of kidney function, may not provide an accurate estimate due to differences in muscle mass. To address this, formulas such as the Modification of Diet in Renal Disease (MDRD) equation were developed to estimate the glomerular filtration rate (eGFR). The MDRD equation takes into account variables such as serum creatinine, age, gender, and ethnicity.

It is important to note that certain factors may affect the accuracy of eGFR results, such as pregnancy, muscle mass, and recent consumption of red meat. CKD can be classified based on eGFR, with stage 1 indicating a GFR greater than 90 ml/min with some sign of kidney damage on other tests. Stage 2 indicates a GFR of 60-90 ml/min with some sign of kidney damage, while stage 3a and 3b indicate a moderate reduction in kidney function with GFR ranges of 45-59 ml/min and 30-44 ml/min, respectively. Stage 4 indicates a severe reduction in kidney function with a GFR range of 15-29 ml/min, while stage 5 indicates established kidney failure with a GFR less than 15 ml/min, which may require dialysis or a kidney transplant. It is important to note that if all kidney tests are normal, there is no CKD.

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.

Medical Conditions Explained: Nephrogenic Diabetes Insipidus, Cranial Diabetes Insipidus, Chronic Reflux Nephropathy, Syndrome of Inappropriate Antidiuretic Hormone Secretion, and Psychogenic Polydipsia

Nephrogenic Diabetes Insipidus (DI)
Nephrogenic DI is a condition where the kidneys are unable to concentrate urine due to resistance to the action of antidiuretic hormone (ADH). This can be caused by lithium toxicity, which is commonly used to treat bipolar affective disorder. Symptoms include passing large volumes of dilute urine and a urinary specific gravity of 1.005 or less. Treatment involves replacing fluid losses with dextrose and water or hypo-osmolar intravenous fluids, as well as a low-protein, low-sodium diet. Alternative medication to lithium may be considered after consultation with a psychiatrist.

Cranial Diabetes Insipidus
Cranial DI, also known as central or neurogenic DI, is caused by decreased secretion of ADH, resulting in polyuria and polydipsia. Urine osmolality will be less than 300 mOsm/kg after a water deprivation test, and will rise to over 750 mOsm/kg after ADH administration.

Chronic Reflux Nephropathy
Reflux nephropathy is a condition where urine flows back from the bladder to the kidneys, causing renal damage. It is typically seen in children with urinary tract abnormalities, but can also occur with conditions that obstruct urine flow. Symptoms include those of nephrotic syndrome and urinary tract infections, but this diagnosis is not consistent with the clinical presentation in this scenario.

Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)
SIADH is characterized by hyponatremia and hypo-osmolality due to excessive secretion or action of ADH, resulting in impaired water excretion. However, the patient in this scenario is presenting with hypernatremia, which is not consistent with SIADH.

Psychogenic Polydipsia
Psychogenic polydipsia is excessive fluid intake without physiological stimuli, often caused by psychiatric disorders such as schizophrenia or bipolar affective disorder. It is accompanied by the sensation of dry mouth.

The first-line investigation for suspected prostate cancer has been replaced by multiparametric MRI, replacing TRUS biopsy. This change was made in the 2019 NICE guidelines for investigating suspected prostate cancer in secondary care.

Investigation for Prostate Cancer

Prostate cancer is a common type of cancer that affects men. The traditional investigation for suspected prostate cancer was a transrectal ultrasound-guided (TRUS) biopsy. However, recent guidelines from NICE have now recommended the increasing use of multiparametric MRI as a first-line investigation. This is because TRUS biopsy can lead to complications such as sepsis, pain, fever, haematuria, and rectal bleeding.

Multiparametric MRI is now the first-line investigation for people with suspected clinically localised prostate cancer. The results of the MRI are reported using a 5-point Likert scale. If the Likert scale is 3 or higher, a multiparametric MRI-influenced prostate biopsy is offered. If the Likert scale is 1-2, then NICE recommends discussing with the patient the pros and cons of having a biopsy. This approach helps to reduce the risk of complications associated with TRUS biopsy and ensures that patients receive the most appropriate investigation for their condition.

Overview of Medications Used in the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis is a chronic autoimmune disease that affects the joints and can lead to disability. There are several medications used in the management of this condition, each with their own benefits and potential side effects.

Penicillamine is a drug commonly used in the treatment of rheumatoid arthritis, but it can also cause secondary membranous nephropathy, a condition characterized by proteinuria. Hydroxychloroquine is another medication that can be used for active rheumatoid arthritis, but its main complication is ocular toxicity. Sulfasalazine is primarily used for ulcerative colitis, but can also be used for rheumatoid arthritis under expert advice. Cyclophosphamide is rarely used for rheumatoid arthritis and is associated with the rare but serious complication of haemorrhagic cystitis. Methotrexate is a commonly used medication for severe Crohn’s disease and moderate to severe rheumatoid arthritis, but its main complication is bone marrow suppression.

It is important for patients to work closely with their healthcare providers to determine the most appropriate medication for their individual needs and to monitor for potential side effects.

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.