<![CDATA[Mock36 Actinomycosis]]>25-year-old female patient with Crohn's disease on steroids. Presents with a 4 cm facial ulcer.

Cause for ulcer in this patient?

Immunocompromised
Steroid therapy

What will you do for this ulcer?

Wound swab

What investigations will you do?

Urgent gram stain & microscopy cultures & sensitivities

Greenish with pus, what is your differential diagnosis? Abscess when opened it showed grey greenish tissue with yellow granules, differential diagnosis?

Actinomycosis

What are the granules?

Sulphur granules

Six weeks of follow up, patient developed sinus, and the wound not heal, what could be the cause?
Local causes

Presence of debris or necrotic tissue
Active infection / osteomyelitis
Poor vascular supply

Systemic diseases

Immunodeficiency / diabetes
Malnutrition

Medications

Corticosteroids

Type of Actinomycosis bacteria?

Gram positive anaerobic filamentous bacteria

Common sites?

Neck, thorax, appendix

Where exactly in the neck?

Jaw/angle of the mandible (Cervicofacial actinomycosis)

Patient developed mandible osteomyelitis, what are the causes? How can you get osteomyelitis in mandible?

Direct trauma
Local sepsis
After dental operations from sinuses
TB

Cells in acute inflammation? Chronic inflammation?

Acute inflammation: predominantly neutrophilic infiltration
Chronic inflammation: mononuclear cells, which include macrophages, lymphocytes, and plasma cells

Cause of Enlarge local lymph node in this case?

Infection

Could inflamed lymph node turn to tumour? What could be the tumour?

Lymphoma

Pathology of osteomyelitis? Definition of involucrum? Why bone necrosis?
See Osteomyelitis station

What the cell responsible for bone formation?

Osteoblasts

Function of osteoclast?

Bone resorption, remodelling

Different bone cells

Osteoblasts
Function: produce bone matrix ("osteoid"). Make type I collagen and other matrix proteins
Line new bone surfaces and follow osteoclasts in cutting cones
Receptors: PTH (parathyroid hormone), vitamin D, glucocorticoids, oestrogen, PGS, ILS

Osteocytes

Osteoblast surrounded by bone matrix. Represent 90% of all bone cells - Function: maintain & preserve bone. Long cell processes communicate via canaliculi
Receptors: PTH (release calcium), calcitonin (do not release calcium)

Osteoclasts

Large, multinucleated cells derived from the same line of cells as monocytes & macrophages
Function: when active, use a "ruffled border" to resorb bone; found in Howship's lacunae
Receptors: calcitonin, oestrogen, IL-1, RANK L. Inhibited by bisphosphonates

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