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103: Spirochetes and TB – If these have you confused, let’s get it sorted it out

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Lyme Disease 

  • Borrelia burgdorferi
  • Transmitted by a deer tick bite – it takes between 36 and 48 hours to transfer the bacteria
  • The deer tick is found in high grass or wooded areas

Signs and Symptoms

  • Early localized stage (about 1 week after the bite)
  • Erythema Migrans – Bull’s eye rash (about 1 week after bite)
  • Fever
  • Malaise
  • Flu like symptoms
  • Early disseminated stage (weeks)
  • Muscle and joint pain
  • Facial or Bell’s palsy
  • Severe headaches and neck stiffness – due to inflammation of the spinal cord (meningitis)
  • Pain and swelling in the large joints (such as knees)
  • Pericarditis, arrhythmias
  • Shooting pains that may interfere with sleep
  • Late disseminated stage (months)
  • Arthritis most commonly in the large joints
  • Shooting pains
  • Polyneuropathy
    • Numbness and tingling in the hands or feet
  • Mood changes and memory loss
  • Fatigue
  • Untreated disease can have significant cognitive and psychological manifestations

Physical exam findings

  • Erythema Migrans
    • A small, red bump may appear at the site of the tick bite, which later the redness expands forming a rash in a bull’s eye pattern, with a red outer ring surrounding a clear area.

Diagnosis

  • Clinical exam and history is key
    •   A history including possible exposure to a tick.  Most patients will not have any memory of a tick bite. Remember they’re tiny.
  • Blood tests 
    • There are many cross-reactive issues with false positives. A diagnosis should consist of history and physical and multiple lab results.
    • Enzyme-linked immunosorbent assay (ELISA) test.
      • Detects antibodies to B. burgdorferi.
      • False negatives in the early stage of Lyme disease
    • Western blot test.
      • Done following a positive ELISA test
      • Detects antibodies to several proteins of B. burgdorferi.
    • Polymerase chain reaction (PCR)
      • This is most helpful in joint fluid

Treatment

  • Prevention
    • Protective clothing
      • Light colored
      • Long sleeve
      • Long pants tucked into socks
    • Use of insect repellent
  • Antibiotics
    • Doxycycline -Not for kids under 8 or pregnant woman use amoxicillin
    • Ceftriaxone – administered intravenously
  • NSAIDs for pain

Syphilis 

  • A highly contagious sexually-transmitted disease, including oral and anal sex
  • Caused by the spirochete bacterium Treponema pallidum subspecies pallidum
  • M > F
  • Classification
    • Primary –  typically acquired by direct sexual contact with the infectious lesions of another person. Development of lesions
    • Secondary – occurs approximately four to ten weeks after the primary infection
    • Latent – having serologic proof of infection without symptoms of disease
    • Tertiary – occur approximately 3 to 15 years after the initial infection.  Classified further into:
      • Gummatous syphilis
        • Slow growing inflammatory masses that destroy local tissue
      • Late neurosyphilis
      • Cardiovascular syphilis
      • Congenital syphilis – transmission from mother to fetus during pregnancy

Clinical Presentation

  • Primary (3 days – 3 months after contact)
    • Chancre sores – lesions where the bacteria appears at the point of contact
      • A single, firm, painless, non-itchy ulceration.  It has a clean base and clear borders
    • Enlarged Lymph nodes
  •   Secondary (4 – 10 weeks after primary)
    • Symmetrical, reddish-pink rash on the trunk and extremities, including the palms and soles of the feet.  It is a maculopapular rash that is usually painless and does not itch*.
    •   Fever
    •   Sore throat
    •   Malaise
    •   Weight loss
    •   Hair loss
    •   Headache
  • Latent may be caught on routine screening
  • Tertiary syphilis is beyond the scope of these notes

Diagnosis

  • Dark field microscopy is the most sensitive diagnostic test, but technically difficult and not usually available
  •   Can not be cultured
  •   Blood tests
    • Nontreponemal – positive at 4-6 weeks and during primary and secondary, but are negative during tertiary phase. Good for screening but are not very specific 
      • Venereal Disease Research Laboratory (VDRL)
      • Rapid Plasma Reagin Tests (RPR)
    • Treponemal – detect antibodies and are very specific 
    • Treponema Pallidum Particle Agglutination (TPHA) used after VDRL to confirm results of a positive test
  • Fluorescent Treponemal Antibody Absorption Test (FTA-Abs)
  • Testing for tertiary syphilis
  • Lumbar puncture
  • Joint aspiration
  • Tissue biopsy

Treatment

  •   Medications
    • Benzathine Penicillin G – administered intramuscularly, single dose, during the early stage of infection
    • Doxycycline
    • Tetracycline
  • Sexual abstinence and treatment of all sexual partners
  • Syphilis needs to reported to the CDC

Jarisch – Herxheimer reaction

  • An immune response to the materials released by the destruction of the spirochetes
  • Fever / chills
  • Muscle pain
  • Headache
  • No need to stop treatment
  • Resolves in 24 hours

Tuberculosis

  • Mycobacterium tuberculosis –  slow-growing bacteria
  • Mode of transmission: Droplet/Contact
  • About 10% of people exposed will develop primary TB – 50% of those will go on to progressive TB
  • Active vs latent
  • Most people will who move into a latent phase will never have had symptoms and they are not infectious
  • They may have reactivation especially in an immunocompromised state
  • Ghon & Ranke complexes 
    • Ghon focus is a granuloma formed around active TB 
    • These are caseating granulomas because inside the tissue dies and looks like rotten cheese
    • This Ghon focus + the same thing happening in a near by lymph node is a Ghon complex
    • A Ranke complex is a fibrotic calcified Ghon complex that can be seen on X-ray
  •   Infection outside the lungs – Extrapulmonary tuberculosis
    • Pleura – tuberculous pleurisy
    • Central nervous system – tuberculous meningitis
    • Lymphatic system – in scrofula of the neck
    • Genitourinary system – urogenital tuberculosis
    • Bones and joints – Pott disease of the spine, osseous tuberculosis
    • Abscess through skin – tuberculous ulcer
    • Disseminated TB – miliary tuberculosis

Clinical Presentation

  • A cough with thick, cloudy, bloody sputum for more than 2 weeks
  • Shortness of breath
  • Chest pain
  • Drenching night sweats
  • Fatigue
  • Generalized weakness
  • Loss of appetite
  • Unexplained weight loss (consumption)
  • Nail Clubbing

Physical Exam Findings

  • Apical post tussive rales
  • Look of chronic illness and weight loss

Diagnosis

  • TB Skin test / PPD Test (purified protein derivative) / Mantoux Test does not differentiate between active infection and latent infection
    • Read at 48-72 hours
    • Positive test based on size of induration
      • No risk factors induration > than 15 mm
      • Medium risk factors induration > 10 mm
        • Travelers from high TB area
        • Injection drug user
        • Healthcare workers
        • DM, Renal failure etc
      • High risk induration of > 5 mm
        • Immunocompromised patient
        • Evidence of TB on chest X-ray

  • Interferon-Gamma Release Assay – IGRA 
    • Blood test is more specific to TB
    • Does not give a false positive with TB vaccine
    • More expensive
  • Sputum culture give a definitive diagnosis – 6 to 8 weeks to provide result
  • DNA / RNA amplification is also definitive and takes 1-2 days
  • Chest X-ray
    • Nodular infiltrates
    • Hilar/paratracheal lymph node enlargement
    • Ranke complexes 
  • Biopsy of Caseating granulomas
  • For Extrapulmonary Tuberculosis
    • Biopsy
    • Urine culture – renal TB
    • Lumbar puncture – TB meningitis
    • CT scan – miliary TB and to detect lung cavities caused by TB
    • MRI – TB in the brain or the spine

Treatment

  • Medications
  • Standard treatment begins with an intensive 2 months of four antibiotics
    • Isoniazid (INH)
    • Rifampin (RIF)
    • Ethambutol (EMB)
    • Pyrazinamide (PZA)
  • Followed by another 2-7 months of INH and RIF in most cases
  • Directly Observed Therapy (DOT)
    • Regular physician visits, who monitors medication intake
    • Ensures that people follow medicine instructions due to long treatment course for TB
  • TB Med side effects
    • INH – peripheral neuropathy, B6 helps reduce this
    • RIF – hepatitis, flu like symptoms, orange body fluid
    • EMB – optic neuritis – red green vision loss

Atypical Mycobacterial Disease

  • Also known a nontuberculous mycobacteria (NTM)
  • The most common organism is Mycobacterium avium
  •  Increase risk with cystic fibrosis with immune compromise
  •  May result to the following types of infections:
    • Pulmonary disease is the most common issue
    • Lymphadenitis
    • Skin and soft tissue disease

Clinical Presentation

  •   Cough
  •   Weight loss
  •   Coughing up blood or mucus
  •   Weakness or fatigue
  •   Fever and chills
  •   Night sweats
  •   Lack of appetite and weight loss

Physical exam findings

  •   Cervical and submandibular lymphadenopathy

Diagnosis

  •   Sputum Culture
  •   Tissue Culture
  •   Polymerase chain reaction (PCR)
  •   Radiographic Imaging studies – Chest X-ray

Treatment

  • Depends on the tissue affected 
  • Lung 
  • Clarithromycin
  • Azithromycin
  • Lymphadenitis 
  • Excisional biopsy 
  • Cuteness infection
  • Doxycycline 
  • Rifampin with streptomycin