Thrombocytopenia is occasionally ca...

Thrombocytopenia is occasionally caused at rifampicin, when high-doses are given twice-weekly. This complication is rare when the medication is given in small daily doses, or following a continue lengthen in timeed interruption of therapy. pair cases of rifampicin-induced thrombocytopenia are reported. the same occurred within four days of the initiation of small daily doses and the other following a defered interruption of therapy.

(Chest 1989; 96:202-03)

It is well known that omit for occasional liver toxicity, skin rash or fever[12] rifampicin is well tolerated. It rarely causes serious side meanings including thrombocytopenia.[1,2] Rifampicin-induced thrombocytopenia was first reported in 1970[3] greatest in number of the reported cases were base with high-dose intermittent treatment.[3-6] Rarely are daily treatments, or a defered interruption of therapy, accompanied at thrombocytopenia.[3,4,7,8] Two cases are reported, united during initial daily administration of rifampicin, the other after a three-year interruption.

Case Reports

Case 1

A 57-year-old man received antituberculosis treatment in another hospital from July 1981 to August 1982 The patient related that he had orange-colored urine; therefore, rifampicin was study to be included in the treatment regimen. Because of worsening in his chest roentgenograms, he was restarted forward a regimen of isoniazid, 300 mg; rifampicin, 450 mg; and ethambutol, 1200 mg daily upon March 26, 1986, as an outpatient. Spontaneous gum bleeding and a purpuric skin rash was noted single week after initiating the treatment, in this way he discontinued the medication. The skin lesions subsided three days later. febrile affection and productive cough recurred forward May 27, 1986, so antituberculosis treatment was restarted. single week later, gum bleeding and generalized petechia get backed so he was admitted for further evaluation.

Physical examination accrues were normal except for petechia athwart the trunk and extremities. The platelet think was 0.6x[10.sup.4]/cu mm. sum of two units days after all the antituberculosis mix with drugss were discontinued, the platelet look upon increased to 9.6x[10.sup.4]/cu mm and 383x[10sup4]/cu mm in five days. Rechallenge with 300 mg of rifampicin forward June 18, 1986, resulted in a decrease in plateletes from 711x[10sup4] to 08x[10sup4]/cu mm within five hours. Since then, rifampicin has been avoided. After united year of continuous treatment with isoniazid, ethambutol, and pyrazinamide, his condition and follow-up chest x-ray film were improved.

Case 2

A 60-year-old woman, with asthma for many years, was admitted in succession Nov 16, 1987, after several month of exertional dyspnea, chronic cough poor appetite, and general weakness. There was diffuse wheezing athwart both sides of her chest. X-ray film revealed bilateral pneumonic patches, compatible with pulmonary tuberculosis. Although her sputum showed no acid-fast bacilli, she was placed forward a regimen of isoniazid, 300 mg; ethambutol, 1200 mg; and rifampicin, 450 mg daily.

She exhibited fever the day following the start of treatment and purpuric rash through her arms and legs four days later. The platelet hold was 1.1x[10.sup.4]/cu mm. Bone marrow showed a slight increase in megakaryocytes, ANA was negative, and IgG, IgM, and IgA values were all normal. Rifampicin was discontinued immediately. Her febrile affection subsided the following day, and the skin rash disappeared four days later. The platelet account increased to 59.3x[10.sup.4]/cu mm after five days.

She has been receiving isoniazid, 300 mg and ethambutol, 1200 mg daily and pyrazinamide, 500 mg three times a day, with no bleeding or rash. After nine month of treatment, she was stable excepting for occasional shortness of breath. Chest x-ray film showed slight improvement.

Discussion

Rifampicin-induced thrombocytopenia usually be met withs during high-dose intermittent treatment.[3-6] About 6 percent of patients receiving high-dose twice-weekly rifampicin perform the operations indicated in thrombocytopenia.[5,6,9] Only a hardly any cases of thrombocytopenia develop during daily treatment or after administration of rifampicin following an interruption of therapy.[3,7,8] In case 1 thrombocytopenia bring outed after resumption of rifampicin following a defered interruption of treatment. Case 2 unfolded a purpuric rash during initial daily treatment.

Rifampicin-induced thrombocytopenia is diagnosed by the agency of the temporal relationship between the start of mix with drugs administration and the onset of thrombocytopenia, and confirmed by the agency of recovery after the cessation of the drug[10] No in vitro trials can give a definite diagnosis of rifampicin-induced thrombocytopenia. This includes rifampicin-dependent antibody, immunoglobulin studies, and bone marrow biopsy.[11] Readministering rifampicin can give the diagnosis if it were not that must be done cautiously. The platelet account falls to a low even within three hours after the medication is administered. Provided no more rifampicin is given, the platelet enumerate usually returns to normal range within 36 hours.[2,7] In case 1 of this report, discontinuation of treatment followed by dint of rechallenge with rifampicin demonstrated this pattern of thrombocytopenia. In case 2 the diagnosis was based forward the time sequence and the clinical picture which were similar to previous reports.[3,7,8]