Atypical presentations and the nonspecific symptomatology can delay the diagnosis and
account for the fact that this diagnosis is frequently missed, even in the current era of
improved diagnostics. In a recent review, approximately 20% of reported cases of miliary TB in
the United States were diagnosed postmortem (30).
Organ Manifestations
At autopsy, organs with high blood flow, including lungs, spleen, liver, bone marrow, kidneys,
and adrenals, are frequently affected. Most organ system afflictions remain subclinical.
Concurrent, clinically apparent pulmonary disease is present in more than 50% of
patients with miliary TB. Respiratory symptoms (cough, dyspnea, pleuritic chest pain) are
present in 30% to 70% of patients. Hypoxemia, when looked for, is common and may progress
to acute respiratory failure and ARDS.
Gastrointestinal tract involvement is seen in 10% to 30% of patients with miliary TB.
Commonly reported symptoms include abdominal pain (diffuse or localizing to the right upper
quadrant), nausea, vomiting, and diarrhea. Liver function tests are frequently abnormal and
typically suggest a cholestatic pattern. Frank jaundice, ascites, cholecystitis (31), and pancreatitis
(32) are rare, but elevations of alkaline phosphatase and transaminases were reported in 83%
and 42% of patients in one series (33). Fulminant hepatic failure has been reported (34).
Cutaneous disease is rare except for in patients with underlying HIV infection (28,35–37).
The skin manifestations are as protean as the clinical manifestations of miliary TB. The most
typical skin lesions, termed “tuberculosis cutis miliaris disseminata” or “tuberculosis cutis
acuta generalisata”, are described as small papules or vesiculopapules (37). Rarely lichenoid,
macular, purpuric lesions, indurated ulcerating plaques, and subcutaneous abscesses have
been reported (35,37).
Adrenal gland involvement has been found in as many as 42% of autopsy-based case
series (38). A recent study using computed tomography (CT) found adrenal gland enlargement
in 91% of patients with miliary TB (39). Interestingly, overt adrenal insufficiency remains rare,
occurring in less than 1% of reported cases of miliary TB (33).
Central nervous system (CNS) disease, typically presenting as meningitis or brain
tuberculomas, is clinically evident in 15% to 30% of patients. Conversely, about one-third of
patients presenting with TB meningitis have underlying miliary TB (40). In a small series from
India, magnetic resonance imaging (MRI) with gadolinium enhancement revealed asympto-
matic brain lesions in all patients (41).
At autopsy, seeding of every organ in the body has been reported. Osteomyelitis, discitis,
and arthritis may be clinically evident. Eye disease is usually asymptomatic but can be
diagnostically important. Laryngitis may increase risk of transmission. Even in autopsy series,
cardiovascular involvement, with the exception of pericarditis, is distinctly rare. Mycotic aortic
aneurysms are unusual but can be the cause of fatal ruptures.
DIAGNOSIS
The issue with diagnosing miliary TB is generally not how and where to find the pathogens as
they tend to be everywhere in this disease. The problem is to consider the diagnosis in time
and to initiate diagnostic work up and therapeutic interventions without delay, as the host is
generally not able to controlM. tuberculosiswithout help. As miliary TB can be rapidly fatal,
useful diagnostic tests will have to have a short turnaround.
Previously, cryptic miliary TB was often diagnosed only at autopsy. However, with the
availability of high-resolution computed tomography (HRCT) scans, these patients can now be
diagnosed during life. Although miliary TB involves almost all organs, most often the
involvement is asymptomatic.
Laboratory
Laboratory abnormalities are common in patients with miliary TB, however, no specific
patterns of abnormal hematological and biochemical markers have been identified
(24,25,33,38).
A typically normocytic, normochromic anemia is seen in approximately 50% of the
patients. Most patients have a normal white blood cell count, but leukopenia and leukocytosis
Miliary Tuberculosis in Critical Care 423