Mycoplasma pneumoniae is an atypical bacterium, widely recognised as the aetiological agent of respiratory tract infections. These infections may cause a number of complications affecting various organs. Nephrological complications of Mycoplasma pneumoniae infection include interstitial nephritis and glomerulonephritis with the deterioration of renal function and acute renal injury. In some cases, renal impairment due to Mycoplasma pneumoniae infection requires renal replacement therapy or steroid therapy, but these are usually transient disturbances which disappear after treatment. In such cases, the prognosis is good. The paper presents a case of acute interstitial nephritis in the course of Mycoplasma pneumoniae infection in a 17-year-old girl. The patient complained about pain in the lumbar region, loss of appetite, polydipsia, polyuria, fever and vomiting. She also had a cough lasting for 3 months. The girl admitted that she had consumed 5 tablets of ketoprofen 100 mg and 2 tablets of seahorse extract imported from Ukraine. During the hospitalisation an increase in inflammatory parameters, increase levels of creatinine to 3.2 mg/dl and urea to 73 mg/dl as well as hypokalaemia to 2.9 mmol/l. Urinalysis revealed a trace of protein, and the urine collection showed albuminuria and increased albumin-to-creatinine ratio. Chest X-ray demonstrated inflammatory changes, and a serological examination confirmed the infection with Mycoplasma pneumoniae. After the causal (clarithromycin) and symptomatic treatment, the symptoms resolved and renal inflammatory parameters normalised. It is being suspected that the aetiology of pneumonia was mycoplasmatic, and the development of acute renal injury was caused by two factors: Mycoplasma pneumoniaeassociated tubulointerstitial nephritis and the ingestion of considerable doses of non-steroidal anti-inflammatory drugs.

Mycoplasma pneumoniae, clinical manifestation, acute interstitial nephritis, tubulointerstitial nephritis, acute renal injury