Keywords

FormalPara Clinical Scenario

A 40 year old female international traveller presents with a history of fever, dysuria and a serum creatinine of 208 μmol/L (2.35 mg/dL). She is assessed as confused in the emergency department, but has been found to be haemodynamically stable, with a temperature of 37 °C (98.6 °F), a blood pressure of 130/75 mmHg, and pulse of 70 beats per minute. She has indicated that she is due to fly back home in 2 days’ time.

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Introduction

Kidney disease is increasing in incidence worldwide, with increasing numbers of patients on kidney replacement therapy; more kidney patients are looked after by internists, general practitioners and other specialties than by nephrologists. Furthermore, kidney disease is now the 12th leading cause of death worldwide, and a staggering 14.5 million people are estimated to require kidney replacement therapy by 2030 [1, 2]. The initial approach to diagnosis of kidney disease, and management of patients on kidney replacement therapy requires a careful history, physical exam and initial laboratory tests, which are emphasised in this chapter.

Common Kidney Patient Presentations

Kidney patients present may with symptoms, signs and abnormal investigations, with a hitherto unknown kidney disease. Careful history taking and a full physical examination can help the clinician to arrive at a provisional diagnosis for the kidney condition - these include common kidney syndromes, such as nephrotic syndrome, nephritic syndrome, chronic kidney disease and acute kidney injury (Fig. 1.1). A tailored investigation with urinalysis, blood tests and imaging can help to identify the cause of kidney disease, and formulate a management plan.

Fig. 1.1
The diagram has 14 symptoms associated with kidney disease. It has symptoms in different body parts, including the heart, skin, face, mouth, limbs, lungs, and veins.

Physical signs that can be associated with kidney disease

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Patients with known kidney disease, on kidney replacement therapy may also present with complications of chronic kidney disease, or complications of their modality of kidney replacement therapy. For example, haemodialysis patients may present to the emergency department with shortness of breath—particularly following a prolonged interdialytic period, such as after the weekend; peritoneal dialysis patients and kidney transplant patients may present with fever and abdominal pain, both requiring careful history and physical examination to arrive at a likely differential diagnosis, and start immediate treatment if necessary. Kidney replacement therapy is available in all countries; and patients are frequently managed by clinicians other than nephrologists, hence a good working knowledge about how to make a prompt diagnosis, and manage complications is important amongst nephrologists and non-nephrologists alike, in all regions of the world (Table 1.1).

Table 1.1 The approach to the kidney patient depends on the presence of a past history of kidney replacement therapy
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Common Kidney Syndromes and Definitions

Haematuria: Abnormal number of red blood cells (RBCs) in the urine, either visible or detected on urine examination, >3 RBCs/high power field under the microscope.

Nephrotic syndrome: Significant proteinuria (>3 g/day), with oedema, hypoalbuminaemia, hypercholesterolaemia, and a hypercoagulable state.

Nephritic syndrome: Glomerular haematuria with proteinuria, dysmorphic RBCs, red cell casts, often a raised serum creatinine, and hypertension.

Acute kidney injury: A sudden rise in serum creatinine over hours or days (>50% from baseline).

Chronic kidney disease: Gradual, progressive and irreversible rise in serum creatinine over at least 3 months.

Kidney stones: Colicky loin pain, haematuria with graveluria.

Urinary tract obstruction: Inability to pass urine, with structural and functional abnormalities with urinary retention.

Kidney tubule defects: Abnormalities of electrolytes, acid-base in blood and urine.

Urinary tract infections: Infections of kidney, ureter, urinary bladder, prostate or urethra.

Anatomical Localisation of Kidney Diseases

The presenting signs, and symptoms, and presence of blood and urinary abnormalities are dependent on the anatomical structure of the urinary tract involved, as shown in the Table 1.2.

Table 1.2 Clinical features of kidney diseases, as determined by anatomical involvement of the urinary organs
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Aetiology of Kidney Syndromes

Understanding the common causes of kidney syndromes can help to inform the approach to diagnosis and management. Some of the aetiologies may present with acute or chronic kidney diseases, the understanding of which helps with determining the reversibility of the pathological process and urgency of treatment (Table 1.3).

Table 1.3 Common causes of kidney syndromes
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Approach to a Patient with Kidney Disease

A careful history and physical exam is necessary to identify the kidney syndrome and identify the cause. The duration of illness is important to determine the syndrome: for example, acute kidney injury (AKI) develops in hours to days, and chronic kidney disease (CKD) over months. The presence of fever, skin rash and joint pains indicates systemic disease. Visible haematuria indicates glomerular or renal tract bleeding. The presence of oedema may be associated with nephrotic syndrome, fluid retention or end stage kidney disease (ESKD). The physical is followed by tests of blood and urine (Tables 1.4 and 1.5).

Table 1.4 Approach to common kidney syndromes
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Table 1.5 Conditions causing abnormalities in complement levels
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Radiological Abnormalities

Radiological abnormalities of the urinary tract may be picked up incidentally, and should prompt further history taking, physical examination and tests to establish a diagnosis.

Haematuria

Haematuria is defined as an abnormal number of red cells in the urine i.e. more than 3 red blood cells seen under one high power field under the laboratory microscope. Haematuria may originate from the kidneys, or from the urinary tract. Table 1.6 can help with differentiating between the two:

Table 1.6 Clinical features of haematuria from kidney compared to that from urinary outflow tract
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Investigations for haematuria will be guided by the presentation, but may include urine microscopy, urinary protein quantification, ultrasound of the kidneys and urinary tract, and CT and cystoscopy if necessary (Tables 1.7 and 1.8).

Table 1.7 Common causes of haematuria
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Table 1.8 Causes of red or brown urine
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Presentation of Kidney Failure Patients on Kidney Replacement Therapy

Common presenting features for kidney failure patients on kidney replacement therapy include, fever, breathlessness, chest pain, confusion, fatigue, falls and abnormal blood tests such as hyperkalaemia and rising serum creatinine in a kidney transplant patient. Infection and malfunction of dialysis vascular access are very common causes of acute admissions for patients on haemodialysis and peritoneal dialysis, followed by breathlessness due to fluid volume overload. Rapid ultrafiltration on haemodialysis and obligatory ultrafiltration with peritoneal dialysis can alternatively lead to volume depletion, hypotension and falls, particularly in elderly dialysis patients. Fatigue and tiredness due to anaemia and malnutrition are also common complaints in patients on renal replacement therapy.

A rising serum creatinine on routine blood test results is a common reason for hospital attendance in kidney transplant recipients, which could be due to acute transplant rejection, urinary infection, transplant urinary tract obstruction, transplant renal artery stenosis, or most commonly volume depletion (Table 1.9).

Table 1.9 Common causes to consider based on symptoms and blood results in patients on kidney replacement therapy
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Conclusions

Returning to the clinical scenario from the beginning of the chapter, the differential diagnosis with the available information is extremely broad, and includes an acute kidney injury, chronic kidney disease, a new presentation with glomerulonephritis, urinary tract infection, or an infective complication of known end stage kidney disease. Further clarification is only really possible through eliciting a careful medical history, and performing a thorough physical examination, which will in turn determine the most appropriate next investigations, and an appropriate, safe plan for management, including whether she is likely to be fit to fly home:

The patient had been assessed as confused because she was having difficulty communicating with staff in the emergency department: thankfully, one of the hospital nursing team was able to speak with her coherently in her native language. She shows the assessing clinician a letter from her nephrology team at home, which on translation, indicates that she has end stage kidney disease due to IgA nephropathy, and was transplanted with a deceased donor (donation after circulatory death (DCD)) kidney 5 years ago, and is chronically immune suppressed with tacrolimus and mycophenolate mofetil. Her most recent serum creatinine level was 200 μmol/L (2.26 mg/dL) 2 months ago, and she has a history of recurrent transplant urinary tract infections, most recently an Escherichia Coli, fully sensitive to standard antimicrobial agents.

A full physical examination reveals—in addition to the findings reported previously—a non-functioning right radiocephalic arteriovenous fistula from previous haemodialysis, a right-sided Rutherford-Morrison scar, overlying a non-tender mass. There is mild suprapubic tenderness. There was no peripheral oedema, but she had a mild resting tremor. Neither her white cell count nor CRP were raised; her tacrolimus trough level was 6 ng/mL, and her blood sugar was 5.6 mmol/L; Her urinalysis was positive for leukocytes and nitrites, but was otherwise clear. A transplant renal tract ultrasound revealed no evidence of obstruction, a small post-micturition bladder residual volume of 60 mL, and normal resistive indices (RIs) of 0.68.

A clinical diagnosis of kidney transplant urinary tract infection is made: given the absence of haemodynamic compromise, and a clear history of similar presentations, with a serum creatinine at her baseline, and on agreement with both the local nephrology, and her home nephrology teams, it was deemed appropriate to manage her in an ambulatory manner—avoiding admission—and encouraging oral fluid intake of 2–3 litres of fluid per day, and commencement of a course of oral antibiotics (amoxycillin + clavulanic acid 6750 mg orally tds for a 5 day course), with a view to being re-assessed by her local nephrology team in a week’s time, on return to her native country.