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Chapter 6: Disorders of the kidney 251

In primary FSGS, approximately 50% may respond Acute tubulointerstitial nephritis – drug-induced

to steroids, although relapse is common and longer The most common mechanism is a hypersensitivity re-
courses are generally required. Steroid resistant cases action to the drug, with lymphocytes and eosinophils
may respond to ciclosporin, and steroid-dependent infiltrating the interstitium causing tissue oedema. The
cases may benefit from the addition of ciclosporin or tubular epithelium undergoes acute necrosis.
cyclophosphamide. Patients present usually within 3 weeks of exposure
Secondary FSGS has no specific treatment. The FSGS with acute renal failure and variable fever, joint pains

may respond to withdrawal of any causative agent or and rashes. They often have haematuria and mild pro-
treatment of any underlying cause. teinuria. Urine volumes may be reduced or normal.
Classically there is eosinophilia and eosinophils in the
urine.
Prognosis
Withdrawal of the drug often leads to resolution. High
Patients with marked proteinuria, tubular atrophy, in-
dose steroids may be given.
terstitial fibrosis have a worse prognosis.
Chronic tubulointerstitial nephritis
Tubular and interstitial diseases Drugsandtoxinssuchascisplatinandheavymetalscause
chronicinflammation,characterisedbyfibrosisofthein-
Tubulointerstitial disease terstitium and atrophy of the tubules leading to chronic
renal failure (CRF). This picture is also common in id-
Definition
iopathic interstitial nephritis.
Tubulointerstitial disease, also called tubulointerstitial
Analgesic nephropathy is a particular form of tubu-
nephritis or interstitial nephropathy, is the term used for
lointerstitial disease caused by long-term use of NSAIDs.
inflammation of the renal parenchyma, i.e. the intersti-
There is chronic inflammation and there may also be is-
tium and tubules, with relative sparing of the glomeruli.
chaemic necrosis of the renal papillae, which can slough
off and cause obstruction. Analgesic nephropathy leads
Aetiology to CRF and there is also an increased risk of carcinoma
There are many causes, the most common being expo- of the urothelium.
sure to drugs, especially certain antibiotics and anal- Sickle cell disease and diabetic nephropathy can also
gesics, and infections. Often the diagnosis is idiopathic, cause ischaemic papillary necrosis.
if no agent is discovered (see Table 6.11).
Prognosis
This depends on the underlying cause. Acute tubuloin-
Table 6.11 Important causes of acute and chronic
tubulointerstitial disease terstitial nephritis has a good prognosis. Chronic renal
failure may progress to end-stage renal disease and re-
Acute Chronic
quire renal replacement therapy.
Drugs Penicillins, Lithium, Cisplatin
cephalosporins
Diuretics Heavy metals e.g. Renal tubular syndromes
lead
NSAIDs NSAIDs Definition
Infection Pyelonephritis Pyelonephritis, e.g. These are syndromes in which a metabolic disorder of
TB, reflux tubular function is the main feature. They may be inher-
Metabolic/ Hyperuricaemic Juvenile gouty
Endocrine nephropathy (with nephropathy ited or acquired.
haematological
malignancies) Aetiology
Ischaemic Sickle cell disease They may be classified as single or multiple defects,
Diabetes mellitus
or they can be grouped according to the part of the