Материал: 100_Cases_in_Clinical_Medicine

ANSWER 9

This patient presents with the typical symptoms of end-stage renal failure, namely anorexia, nausea, weight loss, fatigue, pruritus and cramps.

The elevated urea and creatinine levels confirm renal failure but do not distinguish between acute and chronic renal failure. Usually, in the former, there is either evidence of a systemic illness or some other obvious precipitating cause, e.g. use of nephrotoxic drugs/prolonged episode of hypotension, whereas in the latter there is a prolonged history of general malaise. If the patient has had previous blood tests measuring serum creatinine, these will be informative about the progression of deterioration of renal function. In this patient, the anaemia and hyperparathyroidism (raised alkaline phosphatase) are features indicating chronicity of the renal failure. The normochromic, normocytic anaemia is predominantly due to erythropoietin deficiency (the kidney is the major source of erythropoietin production). Hyperparathyroidism is a result of elevated serum phosphate levels due to decreased renal clearance of phosphate and reduced vitamin D levels (the kidney is the site of hydroxylation of 25-hydroxycholecalciferol to the active form 1,25-dihydroxycholecalciferol). A hand X-ray showing the typical appearances of hyperparathyroidism (erosion of the terminal phalanges and subperiosteal erosions of the radial aspects of the middle phalanges), implying long-standing renal failure can be helpful in distinguishing chronic and acute renal failure.

Renal ultrasound is the essential investigation. Ultrasound will accurately size the kidneys, and identify obvious causes for renal failure such as polycystic kidney disease or obstruction causing bilateral hydronephrosis. Asymmetrically sized kidneys suggest reflux nephropathy or renovascular disease. In this case, ultrasound showed two small (8 cm) echogenic kidneys consistent with long-standing renal failure. A renal biopsy in this case is not appropriate as biopsies of small kidneys have a high incidence of bleeding complications, and the sample obtained would show extensive glomerular and tubulo-interstitial fibrosis and may not identify the original disease. The patient’s renal failure may have been due to hypertension, or a primary glomerulonephritis such as IgA nephropathy. AfricanCaribbeans are more prone to develop hypertensive renal failure than other racial groups.

Antihypertensive medications are needed to treat her blood pressure adequately, oral phosphate binders and vitamin D preparations to control her secondary hyperparathyroidism, and erythropoietin injections to treat her anaemia. The case raises the dilemma of whether dialysis is appropriate in this patient. Hospital-based haemodialysis or home-based peritoneal dialysis are the options available. Her age and comorbid illnesses preclude renal transplantation. Conservative management without dialysis may be appropriate in this case.

KEY POINTS

•Patients often become symptomatic due to renal failure only when their glomerular filtration rate (GFR) is !15 mL/min, and thus may present with end-stage renal failure.

•Previous measurements of serum creatinine enable the rate of deterioration of renal function to be known.

•Renal ultrasound is the key imaging investigation.

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CASE 10: BACK PAIN

History

A 27-year-old woman is admitted to the emergency department complaining of pain across her back. She became unwell 2 days previously when she started to develop a fever and an ache in her back. The pain has become progressively more severe. She has vomited twice in the past 6 h. She has had no previous significant medical history, apart from an uncomplicated episode of cystitis 3 months ago.

Examination

She looks unwell and is flushed. Her temperature is 39.5°C. Her pulse is 120 beats/min and blood pressure 104/68 mmHg. Examination of the cardiovascular and respiratory systems is unremarkable. Her abdomen is generally tender, but most markedly in both loins. Bowel sounds are normal.

INVESTIGATIONS

Urinalysis: '' protein; ''' blood; '' nitrites

Urine microscopy: #50 red cells; #50 white cells

Abdominal X-ray: normal

Questions

•What is the likely diagnosis?

•How would you investigate and manage this patient?

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ANSWER 10

This woman has the symptoms and signs of acute pyelonephritis. Acute pyelonephritis is much more common in women than men, and occurs due to ascent of bacteria up the urinary tract. Pregnancy, diabetes mellitus, immunosuppression and structurally abnormal urinary tracts increase the likelihood of ascending infection.

!Differential diagnosis

Pyelonephritis causes loin pain which can be unilateral or bilateral. The differential diagnoses of loin pain include obstructive uropathy, renal infarction, renal cell carcinoma, renal papillary necrosis, renal calculi, glomerulonephritis, polycystic kidney disease, medullary sponge kidney and loin-pain haematuria syndrome.

Fever may be as high as 40°C with associated systemic symptoms of anorexia, nausea and vomiting. Some patients may have preceding symptoms of cystitis (dysuria, urinary frequency, urgency and haematuria), but these lower urinary tract symptoms do not always occur in patients with acute pyelonephritis. Many patients will give a history of cystitis within the previous 6 months. Elderly patients with pyelonephritis may present with nonspecific symptoms and confusion. Pyelonephritis may also mimic other conditions such as acute appendicitis, acute cholecystitis, acute pancreatitis and lower lobe pneumonia. There is usually marked tenderness over the kidneys both posteriorly and anteriorly. Severe untreated infection may lead on to septic shock.

The raised white cell count and CRP are consistent with an acute bacterial infection. Microscopic haematuria, proteinuria and leucocytes in the urine occur because of inflammation in the urinary tract. The presence of bacteria in the urine is confirmed by the reduction of nitrates to nitrites.

This woman should be admitted. Blood and urine cultures should be taken, and she should be commenced on intravenous fluids and antibiotics, until the organism is identified, and then an oral antibiotic to which the organism is sensitive can be used. Initial therapy could be with gentamicin and ampicillin, or ciprofloxacin. She should have a renal ultrasound scan to exclude any evidence of obstruction. In patients with obstructive uropathy, infection may lead to a pyonephrosis with severe loin pain, fever, septic shock and renal failure. If there is evidence of a hydronephrosis in the context of urinary sepsis, a nephrostomy should be inserted urgently to prevent these complications.

Patients with an uncomplicated renal infection should be treated with a 2-week course of antibiotics, and then have a repeat culture 10–14 days after treatment has finished to confirm eradication of infection. In patients with infection complicated by stones, or renal scarring, a 6-week course of treatment should be given.

KEY POINTS

•Acute pyelonephritis may present with or without preceding lower urinary tract symptoms.

•Renal ultrasound should be performed within 24 h of admission to exclude urinary tract obstruction.

•Antibiotics should be continued for at least 2 weeks in cases of acute pyelonephritis to minimize the risk of relapse.

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ENDOCRINOLOGY

CASE 11: WEIGHT GAIN

History

A 64-year-old man goes to his general practitioner (GP) because he has become increasingly overweight. He has gained 8 kg in weight over the past 6 months. He has noticed that he is constantly hungry. He has found that he is bruising easily. He finds it difficult to get up from his armchair or to climb stairs. He feels depressed and finds himself waking early in the mornings. He has had no previous physical or psychiatric illnesses. He is a retired miner and lives with his wife in a terraced house. He smokes 30 cigarettes per day and drinks 15 units of alcohol per week.

Examination

He is overweight particularly in the abdominal region. There are purple stretch marks on his abdomen and thighs. His skin is thin, and there are spontaneous bruises. His pulse is 76/min, regular, and blood pressure 168/104 mmHg. There is peripheral oedema. Otherwise, examination of his heart, respiratory and abdominal systems is normal. His neurological examination is otherwise normal, apart from some weakness in shoulder abduction and hip flexion.

INVESTIGATIONS

Questions

•What is the likely diagnosis?

•How would you investigate and manage this patient?

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ANSWER 11

The symptoms and signs of proximal myopathy, striae and truncal obesity are features of Cushing’s syndrome. The hyperglycaemia and hypokalaemia would fit this diagnosis. In addition psychiatric disturbances, typically depression, may occur in Cushing’s syndrome. Cushing’s disease is due to a pituitary adenoma secreting adrenocorticotrophic hormone (ACTH). The term ‘Cushing’s syndrome’ is a wider one, and encompasses a group of disorders due to overproduction of cortisol.

!Causes of Cushing’s syndrome

•ACTH secretion by a basophil adenoma of the anterior pituitary gland (Cushing’s disease).

•Ectopic ACTH secretion, e.g. from a bronchial carcinoma, often causing a massive release of cortisol and a severe and rapid onset of symptoms.

•Primary adenoma/carcinoma of the adrenal cortex (suppressed ACTH).

•Iatrogenic: corticosteroid treatment. This is the commonest cause in day-to-day clinical practice.

This patient’s primary presenting complaint is rapid-onset obesity. The principal causes of obesity are:

•genetic

•environmental: excessive food intake, lack of exercise

•hormonal: hypothyroidism, Cushing’s syndrome, polycystic ovaries and hyperprolactinaemia

•alcohol-induced pseudo-Cushing’s syndrome.

This patient should be investigated by an endocrinologist. The first point is to establish is that this man has abnormal cortisol secretion. There should be loss of the normal diurnal rhythm with an elevated midnight cortisol level or increased urinary conjugated cortisol excretion. A dexamethasone suppression test would normally suppress cortisol excretion. It is then important to exclude common causes of abnormal cortisol excretion such as stress/depression or alcohol abuse. Measurement of ACTH levels distinguishes between adrenal (low ACTH) and pituitary/ectopic causes (high ACTH). This patient drinks alcohol moderately and has a normal gamma-glutamyl transpeptidase. His depression seems to be a consequence of his cortisol excess rather than a cause, as he has no psychiatric history. He is having problems with stairs and his social circumstances need to be considered, but his mobility should improve with appropriate treatment.

His ACTH level is elevated. Bronchial carcinoma is a possibility as he is a heavy smoker and the onset of his Cushing’s syndrome has been rapid. However his chest X-ray is normal. In this man a magnetic resonance imaging (MRI) scan (T1-weighted coronal image) through the pituitary shows a hypointense microadenoma (Fig. 11.1, arrow). This can be treated with surgery or radiotherapy.

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