A 36 year old male patient has reported to you with swelling in the submandibular region. His tongue is elevated and he complains of dysphagia. He has high fever. Intra orally examination reveals grossly destructed lower first molar. High fever associated with the above patient may be due to

**Core Concept**
Dental infections, particularly those involving the mandibular molars, can lead to the spread of infection to deeper tissues and structures due to their proximity to the mandibular canal and the submandibular space. This can result in the formation of a submandibular space infection, also known as Ludwig's angina.

**Why the Correct Answer is Right**
The high fever associated with this patient is likely due to the spread of infection to the submandibular space, causing Ludwig's angina. This condition is characterized by the collection of pus in the submandibular space, leading to swelling, pain, and difficulty swallowing. The infection can spread to the lymph nodes, bone, and other tissues, causing a systemic inflammatory response and fever.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not directly related to the symptoms described. While it's possible for the patient to have a fever due to a viral infection, the clinical presentation does not support this as the primary cause.
* **Option B:** While dental infections can cause fever, the clinical presentation of Ludwig's angina is more specific and severe, involving swelling, pain, and difficulty swallowing.
* **Option C:** This option is not relevant to the clinical presentation described. While it's possible for the patient to have a fever due to a systemic infection, the localized nature of the symptoms suggests a more specific cause.

**Clinical Pearl / High-Yield Fact**
Ludwig's angina is a dental emergency that requires prompt attention to prevent airway compromise and systemic complications.

**Correct Answer: B. Ludwig's angina.**

✓ Correct Answer: D. All of the above