1. health and fitness
2. disease

SCHOOL of MEDICINE
DEPARTMENT of INTERNAL MEDICINE
Extrapulmonary Tuberculosis
Prevalence
• Globally prevalence of tuberculosis (TB) infection is estimated at 32%
• The percentage of US cases that occur among foreign-born persons is
increasing (53% in 2003)
• Extrapulmonary TB seen in over 50% of patients with concurrent AIDS
• Risk of extrapulmonary TB increases with immunosuppression
Case Presentation
A 64 year-old Hispanic male without a significant past medical history presented with a complaint of “rectal pain.” The pain was
worse with bowel movements and as a result the patient reported a fear of eating. The patient denied any associated nausea,
vomiting, fevers, chills, melena or bright red blood per rectum. He did report a two week history of a dry nonproductive cough.
Additionally he had a 50 pack-year smoking history and multiple sexual partners without consistent use of protection.
On examination the patient was hypotensive with a blood pressure of 80/60 mmHg, tachycardic and had a decrease in weight
from 60kg to 45kg in less than 6 months. Breath sounds were clear bilaterally and rectal examination revealed a 4 cm by 4 cm
rectal ulceration. Stool exam was brown and guiac positive. Laboratory examination revealed a mild leukocytosis with normal
differential and chest radiology showed diffuse patchy opacifications.
Given the patient’s social history, weight loss and chest radiology findings there was concern for human immunodeficiency virus
(HIV) infection and Pneumocystis jiroveci pneumonia. He was started on trimethoprim-sulfamethoxazole and admitted for further
evaluation. The patient’s hypotension responded to fluids. He was evaluated by gastroenterology and infectious disease
services. HIV testing was negative. A new working diagnosis of rectal malignancy with lymphangitic spread to the lungs was
made. The patient underwent colonoscopy with biopsies. Sigmoid ulcerations were also noted. Rectal biopsies revealed
caseating granulomas and 2+ acid fast bacilli (AFB). Induced sputum later showed 4+ AFB. The patient was placed in isolation
and started on a four drug regimen for treatment of miliary tuberculosis (TB).
Discussion
National TB surveillance data reveals that almost one-fifth of TB cases in the United States are extrapulmonary. Gastrointestinal
TB is a diagnostic challenge in the absence of a pulmonary infection. Only 2% of gastrointestinal TB cases present after 60
years of age. Most commonly the intestinal lesions are ulcerative. Symptoms include abdominal pain, diarrhea, weight loss,
fever, melena and rectal bleeding. Rectal lesions usually present as anal fissures, fistulas or perirectal abscesses. It is essential
to distinguish TB enteritis from inflammatory bowel disease such as Crohn’s disease as the initiation of immunosuppressive
therapy in a patient with tuberculosis can lead to dissemination. Our patient presented with rectal involvement and likely had
disseminated TB. Classic miliary TB is defined as millet like seeding of TB bacilli in the lung and is seen in 1-3% of all TB cases.
It can mimic many diseases and in some cases up to 50% are diagnosed ante mortem. A high index of clinical suspicion is
important as early diagnosis and treatment correlate with improved outcomes.
Conclusions
Rectal tuberculosis is rare. A case of undiagnosed rectal TB presenting as an acute perianal abscess is reported. Lack of
suspicion for rectal TB in such a case can lead to delays in diagnosis and significant risks of exposure to healthcare personnel.
Anorectal Tuberculosis
Incidence:
• One-third world population is infected with TB
• Extrapulmonary forms of TB are present in 10-15% of all cases of TB, but can be
found in 40 to 60% of patients with concomitant HIV infection
• Gastrointestinal (GI) tract is the 6th most frequent site of extrapulmonary TB
(From most to least common: lymphatic, genitourinary, bone/joint, miliary,
meningeal, gastrointestinal)
• Anorectal TB compromises less than 2% of cases of abdominal TB
• Only 3 cases of anorectal TB reported in the last 22 years in the United Kingdom
Presentation:
• Fourth decade of life with a 4:1 male predominance
• Symptoms: weight loss (40-90%), abdominal pain (80-95%), fever (40-70%),
change in bowel habits (50%), anorexia and malaise
• Hematochezia (due to mucosal trauma by stool) is common (88%)
• Massive hemorrhage is rare due to obliterative endarteritis caused by TB
Pathogenesis:
TB bacilli can reach the GI tract by four different mechanisms: 1) hematogenous
spread, 2) ingestion of bacilli from sputum or unpasteurized milk from infected bovine,
3) direct spread from adjacent organs and 4) lymphatic spread from infected lymph
nodes
Pathology:
• GI TB can involve any part of the GI tract from mouth to anus
• Most common site of GI involvement is the ileocecal region due to abundance of
lymphoid tissue (M cells and Peyer’s patches)
• Ulcers are superficial and do not penetrate the muscularis
They tend to be transversely oriented versus the longitudinal and serpiginous
appearance of Crohn’s ulcers
• There are 4 morphological types of anorectal TB lesions: ulcerative (most common),
verrucous, lupoid and miliary
• The ulcerative form typically presents as a superficial ulceration with a hemorrhagic
necrotic base that is covered with thick purulent secretions of mucous
Diagnosis:
• Chest radiology shows pulmonary lesions <25% of cases
• Colonoscopy requires multiple biopsies from the ulcer edge
• Cultures are positive in 40% of biopsies
• Acid-fast bacilli (AFB) staining is variable and polymerase chain reaction (PCR)
testing for TB DNA is helpful in difficult to diagnose cases
Figure 1 – Prevalence of all forms of tuberculosis per 100,000 inhabitants, 2005
(Source: World Health Organization)
Clinical Clues Suggesting Extrapulmonary TB
Treatment:
• Conventional anti-TB therapy for 6 months (99% cure rate) although some expand
to 12-18 months (94% cure rate)
• Surgery is indicated only if there is a complication. Most commonly it is intestinal
obstruction (15-60%), fistula (25%), perforation (15%) and rarely hemorrhage
• Ascites with lymphocyte predominance and negative bacterial cultures
• Chronic lymphadenopathy (especially cervical)
• Cerebral spinal fluid lymphocytic pleocytosis with elevated protein and
low glucose
SUMMARY POINTS
• Exudative pleural effusion with lymphocyte predominance, negative
bacterial cultures, and pleural thickening
• Joint inflammation (monoarticular) with negative bacterial cultures
Figure 3 - Chest CT scan later in the admission
• Persistent sterile pyuria
• TB-endemic country of origin
• Unexplained pericardial effusion, constrictive pericarditis or pericardial
Gastrointestinal tuberculosis is a diagnostic challenge in the absence of
pulmonary infection. It can involve any part of the alimentary tract from the
mouth to anus.
Include evaluation for anorectal tuberculosis in the management of recurrent
anorectal fistulas, ulcers and abscesses.
Figure 2 - Chest X-ray on initial presentation
Histological demonstration of chronic granulomatous inflammation with
caseation is pathognomonic of tuberculosis.
calcification
• Vertebral osteomyelitis involving the thoracic spine
In most instances superficial biopsies may not reveal the bacilli and only 36%
of cultures yield a positive result. Consider PCR testing.
Anorectal tuberculosis usually responds well to anti-tubercular drugs and
these patients seldom require any further surgical intervention.
Extrapulmonary Manifestations
Tuberculous Lymphadenitis
Skeletal Tuberculosis
Abdominal Tuberculosis
Gastrointestinal Tuberculosis
Tuberculous Peritonitis
A high suspicion leads to prompt diagnosis and treatment and avoids
unnecessary exposure to health care staff.
Pleural Tuberculosis
Central Nervous System TB
Genitourinary Tuberculosis
Milliary Tuberculosis
Tuberculous Pericarditis
Acknowledgements
Michael Gilles, MD – Department of Gastroenterology, University of New Mexico
Mark Hubbell, MD – Department of Pathology, University of New Mexico
Figure 4 – Colon, sigmoid ulcer
Figure 5 – Sigmoid ulcer biopsy, submucosal caseating
granuloma
References:
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