Assessment of the Renal Patient

Abstract

Nephrologists encounter patients with a spectrum of renal disease, from asymptomatic incidental findings to severe renal impairment or electrolyte disturbance in a critically ill patient. Many of these patients will have significant comorbidity, often alongside previously diagnosed chronic renal disease. These factors mean the assessment of the ‘renal patient’ can be a challenging proposition to the less. There are numerous approaches to the assessment of patients with kidney disease, and practitioners will develop their own style with time. The ‘practical’ strategy we outline here is only one of many but one that we find successful in day-to-day practice.

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Nephrologists encounter a spectrum of renal disease, from asymptomatic incidental findings to newly diagnosed renal impairment to life-threatening metabolic disturbance in a critically ill patient. Many of these patients will have significant comorbidity, often alongside previously diagnosed chronic renal disease. These factors mean the assessment of the ‘renal patient’ can be a challenging proposition. There are numerous approaches to the assessment of patients with kidney disease, and practitioners will develop their own style with time. The ‘practical’ strategy we outline here is only one of many but one that we find successful in day-to-day practice.

In this chapter we approach the assessment of the renal patient with a series of such questions. This strategy is outlined in Fig. 1.1. Unsurprisingly, as with any area of acute medicine, the first priority will be to ask if the patient is safe. This question provides the starting point of this chapter.

Fig. 1.1

An approach to the assessment of the ‘renal patient’. Our approach is initially based on asking three questions. The first priority is always to ensure any life-threatening clinical situation is addressed. Establishing whether a patient is known to renal services is always important. The assessment of a patient with a known renal problem will be focused on progression and complications of their condition. Conversely the work-up will be will be concentrated on making a diagnosis if the patient has no known renal history. Classification of a new presentation into one of the many ‘renal syndromes’ e.g. acute pre-renal impairment or nephrotic syndrome, will mean further assessment can be appropriately targeted. In parallel, the patient’s intravascular volume status will likely be relevant to almost every ‘renal patient’ whether in the evaluation of potential pre-renal acute kidney injury, management of oedema and hypertension in a patient with nephrotic syndrome or to establish the cause of intradialytic hypotension in a patient receiving outpatient haemodialysis

After addressing any life-threatening emergency, the usual next question in any renal patient will be to ask: What is this patient’s intravascular volume status? An accurate assessment of this is absolutely central to both the diagnosis and management of patients with kidney disease. Assessment of fluid balance is usually based on multiple sources of clinical information, and we discuss the utility of these in the second section of this chapter. However assessing fluid balance is primarily a practical skill, so although tips and guidance can be provided in a textbook, this can be no substitute for repeated practice.

Alongside the assessment of intravascular volume status, the other critical step will be to clarify is this patient already being managed for an underlying kidney condition. The approach to the patient with established kidney disease, for example, a patient receiving dialysis or being treated for an inflammatory glomerulonephritis, will be completely different from the approach to the patient who presents with a renal disorder for the first time. In these cases where the patient is known to a renal service, the assessment will be focused on optimising the management of the underlying condition and addressing associated complications. This aspect of the assessment of the kidney patient is addressed in the last section of the chapter.

If the current presentation is the patient’s first consultation with a renal specialist, the primary purpose of the assessment will be to establish the underlying cause of the renal disorder. This is a clinical scenario in which there is often diagnostic uncertainty, representing some of the most interesting and sometimes challenging areas of the nephrology practice. This aspect of the clinical assessment comprises the majority of this chapter. In this section the approach to different renal syndromes is outlined.

Urgent Assessment for Renal Emergencies

As with any acutely unwell patient, the first priority must be to assess and correct potentially life-threatening physiological dysfunction. Alongside the maintenance of an adequate airway, ventilation and circulation, urgent renal-specific issues are likely to relate to assessment and treatment of either metabolic disturbance, most often hyperkalaemia, acidaemia, or fluid overload. Any of these scenarios may be and indication for urgent renal replacement therapy (RRT) if not responsive to medical manoeuvres. Furthermore uraemic encepholapathy, pericarditis are likely to be absolute indications for instituting dialysis (see Chaps. 7, 9 and 10 on acute renal replacement, acid-base and electrolyte disturbances, respectively).

When there is an indication for urgent renal replacement therapy (RRT) attention must be given to the most appropriate form of dialysis or haemofiltration. Requirements will depend on the need for other organ support, but the use of an extracorporeal circuit, even with the low blood flows used in continuous therapies such as haemofiltration, risks haemodynamic instability. Therefore adequate, usually invasive, monitoring and access to vasopressors or inotropes are mandatory in cardiovascularly unstable patients receiving RRT. Critically, immediate management often depends on whether the acidaemic or hyperkalaemic patient has a remediable medical condition; a patient with urinary retention and potassium of 7.2 mmol/L may respond rapidly to medical therapy following relief of obstruction, whereas a septic oliguric hypotensive patient with a potassium of 5.8 mmol/L is much more likely to need renal replacement in the coming hours.

Assessment of Intravascular Volume Status

The evaluation of fluid status is critical in the assessment and management of all renal patients.

Table 1.1 shows some of the clinical parameters that have merit in assessing fluid balance. Some such as serial measurement of weight and orthostatic blood pressure should be incorporated into routine ward observations even on non-renal wards. Where appropriate patients such as those discharged home with recovering AKI or nephrotic syndrome may also benefit from monitoring their own weight and postural blood pressure to help inform changes in fluid status. Other signs such as peripheral temperature and observation of central veins are often useful, whereas skin turgor and dryness of mucous membranes are on the whole poor, insensitive and non-specific clinical tools.

Table 1.1 Clinical assessment of fluid status

Investigations may also be helpful in assessment of intravascular volume status. The chest radiograph can confirm fluid overload, but is not particularly sensitive for mild/moderate overload, and acute lung injury can occur without an increase of right sided filling pressure (see Fig. 1.2a, b). In one study using pulmonary artery measurements, where fluid overload was defined as a pulmonary artery occlusion pressure ≥18 mmHg, radiologists achieved a diagnostic sensitivity of 55–65 %. This improved to 70 % by including cardiothoracic ratio (CTR) >0.55 and a vascular pedicle width (VPW) (the horizontal distance between the point where the superior vena cava crosses the right main bronchus and the origin of the left subclavian artery) measurement of >70 mm [1]. Therefore in practical terms a single chest-x-ray is unlikely to be useful, it may be a valuable tool when serial measurements are used.

Fig. 1.2

(a) CXR of a patient with raised left ventricular end-diastolic pressure (LVEDP) showing upper lobe blood diversion, fluid in the fissure and Kerley B lines. This approximately equates to an LVEDP of 18 mmHg or above. (b) Frank pulmonary oedema in the same patient within 24 h in the absence of any filling or cardiac event but in the presence of sepsis. This demonstrates that pulmonary oedema on a CXR is not necessarily indicative of excessive filling pressures per se

In addition, there are also near-patient tests that may become more commonly utilised. Bioimpedance is one such technique and is an inexpensive and non-invasive technique to estimate body water. Given the difficulties with the clinical assessment of fluid status, the possibility of an easily usable objective measure is attractive. Unfortunately as with many of the clinical parameters guiding assessment of fluid balance, a single measurement in an individual patient does appear to add significant value to clinical assessment. Serial measures may again be more useful, so this technique may be most appropriate in patients regularly attending dialysis or the outpatient department rather than in the acute situation [2].

Biochemical measures that have been advocated as indices of fluid status such as a disproportionately high urea:creatinine ratio, raised serum urate or elevated serum lactate also lack sensitivity and specificity but may be helpful as part of a constellation of features associated with intravascular volume depletion.

A number of methods using continuous monitoring and aimed at detecting changes in cardiac output in response to altered venous return (e.g. using respiratory cycle variation, passive leg raising or a fluid challenge) are useful in experienced hands. Importantly however, measures of fluid-responsiveness are likely to reflect a number of variables rather than just intravascular volume, so should always be considered as part of a more comprehensive assessment. Finally a variety of invasive cardiovascular measurements can be used to more accurately assess fluid status where sophisticated monitoring is available and are reviewed comprehensively elsewhere [3]. There remains significant debate as to the advantages and disadvantages of the various methods of invasive monitoring, and the knowledge base in this area of critical care is continuously evolving.

Assessment of the Patient When the Renal Disorder Has Yet to Be Identified and/or Characterised

This next section of this chapter discusses the approach to the patient when they present for the first time with a renal disorder to the reviewing nephrologist. In these cases a diagnosis needs to be established. Although renal physicians are faced with an enviable variety of clinical scenarios, these can usually be grouped into a number of renal ‘syndromes’. These renal syndromes although not diagnoses in themselves are useful descriptions to help direct further investigation and to facilitate communication between physicians. An initial approach to these renal syndromes is outlined below. Following this the more general aspects of the history and the clinical examination, which might be helpful in establishing the cause of a renal disorder in patients presenting with any one of these renal syndromes is presented.

Presentation with Renal Impairment

An impaired kidney function, as identified by an increase in the serum creatinine, is the commonest reason for referral to a nephrologist. Patients may first present with symptoms directly related to renal dysfunction (Table 1.2). Often however, the presence of renal impairment will be identified by blood tests performed following a clinical presentation unrelated to the kidney.

Table 1.2 Symptoms attributable to renal dysfunction

Does the Patient Have Acute or Chronic Renal Injury?

The urgency of further investigation in a patient with renal impairment is critically dependent on whether the identified kidney dysfunction is acute (occurring over days to weeks) or chronic (occurring over months to years). Differentiation of these clinical scenarios is straightforward if the patient has been historically diagnosed with CKD, if previous blood tests are available or if the patient is aware of previous episodes of AKI or CKD. The distinction can be all the more difficult in cases of acute on chronic renal dysfunction where only knowledge of baseline creatinine figures will uncover whether there is an element of acute deterioration in GFR. Suggestive evidence may come from a likely acute precipitating event, the long-standing presence of a risk factor or a childhood history raising the possibility of previously undiagnosed renal dysplasia. Often, however, these clues are not immediately to hand, so other evidence may needed to judge the likely time course of the presenting renal dysfunction.

The duration of symptoms can be a useful indicator of chronicity; however, the high prevalence of subclinical advanced renal impairment means that in many cases the underlying disorder may have been present for some time before the patient reports the onset of illness. Furthermore the presence of risk factors or a systemic disorder known to put the patient at risk of chronic kidney disease (see below) does not provide definite evidence for pre-existing renal dysfunction. The single best markers of long-standing (and consequently irreversible) renal impairment are radiological measurements. Bipolar kidney length <10 cm in combination with an increase in cortical echogenicity (defined as a higher pixel density in the renal cortex than the liver) are the best predictors of advanced chronic kidney disease [4]. Exceptions to this rule occur where the size of chronically diseased kidneys is preserved, most typically in diabetes but also cystic diseases such as APCKD, protein deposition diseases such as amyloid, chronic obstruction, xanthomatous pyelonephritis and HIV nephropathy.

Biochemical markers such as potassium, calcium, phosphate, parathyroid hormone and haemoglobin have been described in textbooks as indicators of chronicity of renal dysfunction. However, these parameters have limited utility in practice since all can also change rapidly in the context of AKI.

Diagnostic Breakdown of Acute or Chronic Renal Dysfunction

Assessment of a patient with AKI is described in detail in Chap. 5; however, the classical subdivision into prerenal, intrinsic and postrenal causes of impairment is a useful approach in any patient presenting with either acute or chronic renal impairment, so it will also be outlined here.

Prerenal

A ‘prerenal’ aetiology suggests hypoperfusion of the kidney. This is a critical component of the assessment of patients with AKI as this form of insult is usually associated with an acute presentation. However, renal artery stenosis and chronic hypovolaemia in patients with high output gastrointestinal stomas may develop more insidiously and present as CKD. Therefore, potential precipitants of prerenal injury should be sought in all patients with renal dysfunction.

Circulatory shock, whether vasodilatory, cardiogenic or hypovolaemic, will invariably lead to an acute prerenal injury (even if it is subclinical) and should be straightforward to identify. Other more subtle forms of prerenal kidney injury (such as those due to a less clinically apparent degree of intravascular volume depletion) may be less obvious initially but remain important considerations. The potential precipitants of prerenal injury are outlined in Table 1.3.

Table 1.3 Assessment of potential precipitants of prerenal kidney injury

Postrenal Causes

Postrenal causes of renal impairment are particularly important to detect since the associated renal injury often reversible with relief of the obstruction. Furthermore, obstruction is a common cause for unexpected deterioration in patients with established kidney disease.

Although the clinical history or examination (Table 1.4) may suggest an obstructive cause of kidney injury, the exclusion of a postrenal cause of renal impairment cannot be made without radiological investigation. A renal ultrasound is often the first-line investigation. There are important limitations which should be considered when interpreting evidence of obstruction on renal ultrasound:

Table 1.4 Symptoms, findings and clinical history suggestive of urinary tract obstruction or conditions associated with obstruction

• ‘False positives’ can occur in cases of chronic dilation of the pelvi-calyceal system. Functional imaging should be pursued in attempting to establish the significance of morphological abnormality where kidney function is adequate for these tests to be useful. Renograms with the addition of diuretics using nuclear medicine tracers can be helpful in this context (discussed in Chap. 38).

• ‘False negatives’ can occur in anuric patients who may not have pelvi-calyceal dilatation. If the history is suggestive, more detailed anatomical imaging such as MRI or CT may be helpful. Occasionally in these cases a diagnostic trial of relief of obstruction should be considered.

Symptomatic changes in urine volume are not usually diagnostically helpful. Patients with significant obstruction usually notice no change in their urine volume. Clinical presentations and past history that might suggest a postrenal cause of kidney dysfunction are shown in Table 1.4.

Intrinsic Renal

Intrinsic renal causes of AKI and CKD are numerous but can be grouped into broad categories for the purpose of initial assessment (Table 1.5). Other chapters in the rest of this textbook are devoted to the assessment and management of each of these conditions.

Table 1.5 Simple classification and diagnostic clues to intrinsic renal causes of renal dysfunction

Examination of the urine is absolutely critical in establishing the diagnosis of intrinsic renal injury, and the role of urinalysis and urine microscopy is discussed in detail in Chap. 2.

Presentations Other than with Biochemical Evidence of Change in Renal Function

Although the majority of patients referred for the first time to nephrologists will have a degree of kidney dysfunction, not all patients will present with renal failure. Patients with isolated urinary abnormalities are often sent for expert review, and the assessment of isolated haematuria and proteinuria is discussed in detail in the following chapter. In addition to urinary abnormalities, nephrologists will find themselves faced with a diverse range of clinical syndromes secondary to disorders of the kidney. Similarly these syndromes and the logical diagnostic approaches are discussed in detail in the chapters devoted to the presenting syndrome or the underlying diagnoses. However an introduction to these presentations alongside important diagnostic clues is discussed briefly below.

Haematuria

Haematuria can originate from anywhere along the urinary tract, so it is important to identify coexistent lower urinary tract symptoms in any patient with visible blood in the urine. Intermittent visible haematuria can be temporarily associated with an upper respiratory tract infection (suggestive of IgA nephropathy) or related to exercise. Periodic haematuria can be seen in patients with endometriosis. Finally myoglobinuria will often lead to a false-positive dipstick urinalysis for haematuria.

Proteinuria

Proteinuria is identified either on dipstick testing, during routine medical, as part of a surveillance programme (e.g. for diabetes), or for the investigation of associated oedema, but patients with nephrotic range proteinuria can on occasion present having noticed frothy urine. History of past episodes of dipstick-positive proteinuria is helpful but is rarely recalled by patients.

Nephrotic Syndrome

The presentation of nephrotic syndrome is usually unambiguous. Diagnostic difficulties can occur in the presence of anuria, advanced renal failure or in the context of other causes for hypoalbuminaemia. For patients with nephrotic syndrome, swelling of the face or ‘puffy eyes’ in the morning can be an early symptom, pedal oedema and frothy urine may be noted, and fatigue or tiredness are also common complaints. For some individuals nephrotic syndrome may be precipitated by vaccinations, insect bites or non-specific infections. The definition, investigation and initial management of nephrotic syndrome are covered in Chap. 12.

Hypertension

Uncontrolled or unexpected hypertension is a fairly common referral to the nephrologist. Beyond emergency care, and determining duration, severity and compliance, the main consideration is the degree to which an underlying cause should be sought (Table 1.6). A secondary cause is more likely if hypertension occurs before the age of 40 years (the younger the patient, the greater the likelihood of a secondary cause), there is a history of severe end-organ damage, it presents as accelerated hypertension or there is a family history of early hypertension/stroke. It is important to recognise that the commonest cause of secondary hypertension relates to underlying CKD.

Table 1.6 Evaluation of the patient with hypertension

Loin Pain

Although kidney stones are a common and potentially serious cause of loin pain, pain arising from the kidneys can occur in numerous conditions (Table 1.7).

Table 1.7 Pain associated with renal disease

Nephrolithiasis is usually accompanied by severe symptoms although it may only be on direct questioning that patients mention passing ‘gravel’, i.e. small sand-like material. Working or living in hot, dehydrating environments, multiple long flights and salt intake as well as any dietary precipitants such as betel nut are all associated with stones in epidemiological studies. Any history of obstruction, lithotripsy or stone removal is also clearly important. Identifying if and where any stones have been analysed is very helpful and can expedite appropriate preventative therapy if reports can be obtained.

Electrolyte Disorders

The renal physician is often asked to provide assistance in the diagnosis and management of patients with electrolyte abnormalities. Renal tubular syndromes are discussed in detail later in this book, although differentiation of renal tubular abnormalities from endocrine, metabolic or gastroenterological aetiologies can be difficult.

Where an abnormal finding is unexpected or sudden, the possibility of an aberrant value should be considered. For example, the recognition of the abnormal lab finding as being the result of blood sampling from a drip arm or patient misidentification can save significant anxiety. Symptomatology can be non-specific, such as muscle weakness with hyperkalaemia, or classic such as perioral paraesthesia and latent tetany in hypocalcaemia. The urgency of investigation and treatment will typically depend on both the severity and the chronicity of any abnormality.

Changes in Urinary Volume

Urinary volumes in the absence of disease can vary at least tenfold, so aside from anuria patients may find it difficult to recognise clinically important changes in urinary volume. Oliguria is a manifestation of advanced renal impairment of any cause; however, acute absolute anuria is rare and the causes are listed in Table 1.8.

Table 1.8 Causes of acute anuria

Conversely, patients may find polyuria difficult to distinguish from urinary frequency, but this is important to differentiate. One approach to assessment is shown in Table 1.9.

Table 1.9 Assessment of polyuria

Renal Manifestation of Multisystem Disorders

Abnormalities of the kidney occur in a large number and diverse range of systemic disorders with vascular, inflammatory, malignant or infective aetiologies (Table 1.10). Indeed, where the kidney represents the first clinical manifestation of these disorders, the renal physician may be best placed to establish diagnosis with predominantly extrarenal involvement. In these cases it is often attention to a comprehensive clinical history and examination that will reveal an underlying disorder.

Table 1.10 Common multisystem disorders with renal involvement

General Aspects of the Clinical History Relevant to Establishing a Renal Diagnosis

In patients first presenting to a nephrologist once the presenting renal syndrome (e.g. new renal impairment nephrotic syndrome or an electrolyte disorder) has been determined, a further clinical history and examination can be pursued. A clear understanding of what brought the patient to seek medical attention at this time alongside a past medical and surgical history is likely to provide further valuable information.

Age

The age at presentation can be a clue to diagnosis in a patient with renal impairment. A patient presenting with ESRD in his or her 20s may well have an inherited or congenital cause, and it is important to determine if symptoms started in childhood or adolescence. Age may make some diagnoses much less likely. For example, it is very unusual for lupus nephritis to present late in life, whereas primary vasculitides may well present in a patient’s eighth or ninth decade. In addition, the significant age-associated decline in GFR and increase in the prevalence of CKD mean that the elderly are more vulnerable to acute kidney injury (AKI).

Gender

Some renal diseases show a significant gender bias and patterns of inheritance may give a significant clue to the diagnosis when a clear family history is available. For example, X-linked conditions like Alport’s syndrome and Anderson-Fabry’s disease have a male bias, whereas conditions such as Takayasu’s arteritis, fibromuscular dysplasia and systemic lupus erythematosus have a very strong female preponderance.

Ethnicity and Country of Origin

Ethnicity and country of origin may be pointers to increased exposure to risk factors for some renal diseases and comorbid conditions that may affect the kidneys. There are many examples of this and some examples are given in Table 1.11.

Table 1.11 Ethnicities and countries of origin associated with increased risk of kidney disease

Family History

In a new patient it is important to ask about a family history of any kidney problems such as dialysis, renal transplantation or familial renal disease (Table 1.12). If there is evidence of a family history and the diagnosis is not obvious, then age of onset, severity and phenotypic characteristics are helpful. Efforts should be made to obtain (with consent) medical diagnoses of the relatives; information from another renal unit may expedite a diagnosis and prevent an unnecessary further investigation. The pattern of inheritance is crucial: affected siblings with unaffected parents suggest recessive disease, especially if there is endogamy or consanguinity. Affected individuals in consecutive generations are consistent with autosomal dominant, mitochondrial and X-linked inheritance; male-to-male transmission of a trait excludes X-linked disease or mitochondrially encoded disorder.

Table 1.12 Family history in renal disease

Obstetric History

An abnormal obstetric history can be a pointer to chronic underlying renal disease. Moreover, dipstick urinalysis and blood pressure measurement are recorded regularly from booking until delivery as part of routine maternity care. These findings may unveil both pregnancy-associated and pre-existing renal disease. If the patient is not clear about the details, it is often worthwhile pursuing via her family practitioner or obstetric unit.

The number of pregnancies, including miscarriages, stage of pregnancy reached and any reason for early delivery can be highly relevant as outlined in Table 1.13.

Table 1.13 Obstetric history and renal disease

Occupation

Occupation may be a factor in the risk of developing some renal conditions (Table 1.14). Sometimes the exposure is not immediately apparent, and a detailed history of both occupation and hobbies is important to avoid continued risk of deterioration.

Table 1.14 Occupations predisposing or exacerbating renal disease

Travel and Hobbies

In addition to considering the patient’s geographical origins, a travel history should be sought. This is particularly important in the context of AKI. Relevant questions are shown in Table 1.15. Relevant hobbies include water sports (leptospirosis), pets (hantavirus) and endurance sports (haematuria, rhabdomyolysis).

Table 1.15 Key travel questions

Psychosocial History

There are several aspects of the psychosocial history that are germane to the care of the renal patient. There remains a significant bias to CKD in lower socio-economic groups. Lower educational attainment, mental health problems, substance misuse and unstable home circumstances can pose barriers to engagement with medical professionals, delay recognition of ill health and diagnosis, limit adherence and influence suitability for home therapies. Getting a clear understanding of a patient’s psychosocial history is therefore fundamental to the delivery of full and effective care. In addition, there are certain abused substances that have associations with renal disease shown in Table 1.16.

Table 1.16 Substance misuse

Medication and Allergy

The kidneys are susceptible to a wide range of adverse effects from medications and their active metabolites. Different medications may cause toxicity in a variety of sites within the kidney. It is essential to obtain a history of (1) prescribed and (2) non-prescription drugs and (3) recreational or illicit drugs. Ward prescription charts and inpatient procedural records such as anaesthetic charts, as well as redundant completed drug charts, should be reviewed to identify potential toxins in use at the onset of renal dysfunction. Accurately identifying a complete drug history may be time-consuming, but confirming prior use of aminoglycosides, exposure to a common cause of tubulointerstitial nephritis or that a patient is taking a product containing aristolochic acid may be critically important to establishing the cause of renal dysfunction. Key elements of the drug history are shown in Table 1.17.

Table 1.17 Key elements of medication history

Clues on Clinical Examination to Help Establish the Cause of a Renal Disorder

A thorough clinical examination is an essential part of the approach to any patient presenting either acutely or to the outpatient department. Accurate fluid assessment will be critical to most presentations to the renal physician and is discussed in detail above. Alongside intravascular volume assessment, other findings on clinical examination can provide important clues to the aetiology of a renal presentation. These examination findings are summarised in Table 1.18.

Table 1.18 Examination tips and renal disease

Assessment of the Patient with Known Renal Disease

Many renal conditions are chronic, and it is common to encounter patients who have previously been investigated or treated either locally or in another centre. When a patient is known to suffer from a renal disorder, the aim of the assessment will usually be focused on the management of the underlying condition or associated complications rather than the underlying cause of the renal disease (which may or may not have already been diagnosed). Those in contact with renal services frequently have complex and chronic histories, and the importance of handling the transfer of care cannot be overstated (see Chap. 49). Fortunately patients are increasingly involved in their own care, have a good understanding of their disease and have access to their clinical records. When they do not, it is important to make the effort to trace historical imaging, blood and urine results. In all patients known to have renal disease, the nature and duration of the condition, as well as histological details if available, are an essential starting point of any assessment. Patients with known renal disease will broadly fall into the following groups allowing the clinician to focus their clinical assessment on relevant issues.

Patients with ESRD Treated with Dialysis

Patients with ESRD may have been receiving renal replacement therapy for many years and have been treated with several treatment modalities. Renal physicians will often be integral to the holistic care of patients on dialysis programmes. Therefore, alongside dialysis-related issues the renal specialist increasingly needs at least a basic understanding of a broad range of medical, surgical and psychiatric problems so that appropriate further expertise can be sought when necessary. When thinking about dialysis-related problems, presentations will commonly be related to dialysis access (including infection) and intradialytic issues (instability, adequacy or complications). Important considerations for the assessment of the patient on dialysis are outlined in Table 1.19.

Table 1.19 Clinical assessment specific to the dialysis patient

Patients with ESRD with Functioning Kidney Transplants

The management of graft dysfunction will represent a substantial workload for any transplant unit, so the nephrologist needs to be fluent in the further management of a transplant patient with a rise in the serum creatinine. Once again assessment of intravascular volume status is a critical element. In addition, the management of immunosuppression-related complications such as infection and malignancy will need specific attention in transplant patients. Finally, patients with kidney transplants will often present to their ‘home’ transplant unit with transplant-related issues and problems not immediately associated with the allograft or associated complications. Table 1.20 outlines aspects of clinical assessment important in the patient with a functioning renal allograft.

Table 1.20 Clinical assessment specific to the transplant patient

Patients with ESRD on Conservative Care Programmes

Increasingly renal units have large and successful conservative care programmes. One of the reasons patients may have decided that they do not wish to receive active care for ESRF is to reduce time spent in a medical environment. Although these patients may have decided not to undergo dialysis or transplantation, the assessment and prompt management of fluid status, anaemia, bone-mineral disorders, nausea and pain can have a significant impact on quality of life and should be pursued as a priority.

When patients are clearly close to death the renal physician may need to play an active part in ensuring that the appropriate end-of-life care can be effectively delivered and in the most appropriate environment.

Patients with CKD and a Reduced GFR

Some form of chronic kidney disease is thought to affect between 5 and 10 % of the population in Western countries. Nephrologists will often be asked to help manage this group of patients who may often suffer with multiple comorbidities. The increasing recognition of the increased risk of AKI in those with CKD as well as the contribution of AKI to the future progression of CKD means that a key focus of the assessment of this group of patients surrounds the management, and prevention, of a further decline in kidney function. The approach to this clinical situation should be similar to that set out in the section on establishing the cause of previously undiagnosed renal impairment set-out in detail above.

Patients with CKD also commonly present with fluid overload, and the nephrologist will often be asked for advice, again underlying the importance of thorough assessment of intravascular volume status.

In this group of patients particular attention should also be focused on the prescription of medication at the dose appropriate for the patients GFR. Failure to dose-reduce medications can lead to acute-on-chronic kidney injury or alternatively significant adverse effects due to drug or metabolite accumulation (see Chap. 56).

The management of patients with stable CKD also needs to address the complications of decreased renal function, specifically anaemia, bone-mineral disorder and cardiovascular risk. These are addressed in the chapters on chronic kidney disease management.

Patients with Inflammatory Renal Diseases and/or Requiring Immunosuppression

Patients suffering from systemic vasculitis, SLE, nephrotic syndrome or other inflammatory renal conditions will often be taking immunosuppressive drugs. In addition to the issues related to CKD or dialysis, the possibility of disease relapse and the consequences of immunosuppression needs to be considered when these patients present to renal services. An approach to this group of patients is outlined in Table 1.21.

Table 1.21 Clinical assessment specific to the patient with inflammatory renal disease

Summary

Patients attending renal specialists present with an enormous diversity of clinical problems. An approach to the review of patients using a system similar to the one outlined in this chapter allows for comprehensive and organised recognition of both the background and current problems. In this group of often extremely complex patients, it is by focusing the assessment on answering the relevant questions at hand that clinical problems will be appropriately prioritised and timely and safe treatment instigated. The critical importance of accurate assessment of intravascular volume status in almost all areas of renal medicine cannot be overemphasised, and this is a skill that can only be learned with repeated practice. Although as experience is gained each clinician will develop their own unique approach to clinical assessment, it is only with a systematic approach that nephrologists can be confident of providing safe, efficient and high-quality care to their patients.