From the Guidelines
Tuberculosis (TB) does not have hepatic metastasis, as it is an infectious disease caused by Mycobacterium tuberculosis bacteria, not a cancer. However, TB can affect the liver directly through hematogenous spread from a primary infection site, typically the lungs, resulting in hepatic tuberculosis, which is considered disseminated or extrapulmonary TB rather than metastasis 1. Hepatic involvement in TB may present as tuberculous granulomas, tuberculous hepatitis, or rarely as a tuberculoma (a mass-like lesion).
Key Considerations
- The term "metastasis" specifically refers to the spread of cancer cells from a primary tumor to distant organs, which is fundamentally different from how infectious diseases like TB spread throughout the body.
- Treatment for hepatic TB follows standard TB treatment protocols with a multi-drug regimen including isoniazid, rifampin, ethambutol, and pyrazinamide for 2 months, followed by isoniazid and rifampin for an additional 4 months (total 6 months therapy) 1.
- In cases of drug resistance or extensive disease, treatment duration may be extended, and expert consultation is advisable, especially for patients with preexisting advanced liver disease or those at risk of drug-induced hepatitis 1.
Clinical Implications
- Patients with severe tuberculosis often require the initiation of an alternate regimen during the time the offending drug(s) are held, and consultation with local and state health departments is advised 1.
- Gastrointestinal reactions are common, especially early in therapy, and can be managed with antacids or by taking medications at bedtime 1.
- Drug-induced hepatitis is the most frequent serious adverse reaction to the first-line drugs, and hepatotoxic drugs should be stopped immediately if suspected, with careful evaluation and exclusion of other causes of abnormal liver function tests 1.
From the Research
Hepatic Metastasis in Tuberculosis
- Tuberculosis (TB) can affect various parts of the body, including the liver, but the concept of "hepatic metastasis" typically refers to the spread of cancer from one part of the body to another.
- In the context of TB, the term "metastasis" is not commonly used; instead, the spread of TB to other parts of the body, including the liver, is referred to as "extrapulmonary tuberculosis" or "disseminated tuberculosis" 2.
- The liver can be involved in TB, either as a result of hematogenous spread from a primary site, usually the lungs, or by direct spread from adjacent organs 2.
- Hepatic TB can manifest in various forms, including tuberculous granulomas, abscesses, or diffuse hepatic involvement, and can be difficult to diagnose, especially in the absence of a known history of TB or concurrent pulmonary involvement 2.
Diagnosis and Treatment
- The diagnosis of hepatic TB often requires a combination of clinical suspicion, imaging studies, and histopathological confirmation 2.
- Treatment of hepatic TB typically involves the use of antituberculous medications, which can be associated with hepatotoxicity, as reported in several studies 3, 4, 5, 6.
- Monitoring of liver function tests is essential during treatment with antituberculous medications to detect any signs of hepatotoxicity early on 4, 5.
Hepatotoxicity of Antituberculous Medications
- Certain antituberculous medications, such as isoniazid, rifampicin, pyrazinamide, and ethambutol, have been associated with hepatotoxicity, ranging from mild elevations in liver enzymes to severe hepatic failure 3, 4, 5, 6.
- The risk of hepatotoxicity can be increased when these medications are used in combination, and close monitoring of liver function tests is necessary to minimize this risk 5.